fix format

This change extends the multi-step query support to percentiles and
cardinality aggregations by exposing their underlying sketches.

Changes:
- Add CardinalityMetricResult struct with value and HLL sketch
- Update PercentilesMetricResult to include DDSketch
- Update MetricResult::Cardinality to use CardinalityMetricResult
- Update finalization to include sketches in results
- Add tests verifying sketch data is present in results

JSON output changes:

Percentiles:
  Before: { "values": {...} }
  After:  { "values": {...}, "sketch": {...} }

Cardinality:
  Before: { "value": 10.0 }
  After:  { "value": 10.0, "sketch": {...} }

The sketch fields enable downstream systems to merge results across
multiple query steps using the raw sketch data.

.claude/skills/rationalize-deps/SKILL.md

@@ -0,0 +1,125 @@
+---
+name: rationalize-deps
+description: Analyze Cargo.toml dependencies and attempt to remove unused features to reduce compile times and binary size
+---
+
+# Rationalize Dependencies
+
+This skill analyzes Cargo.toml dependencies to identify and remove unused features.
+
+## Overview
+
+Many crates enable features by default that may not be needed. This skill:
+1. Identifies dependencies with default features enabled
+2. Tests if `default-features = false` works
+3. Identifies which specific features are actually needed
+4. Verifies compilation after changes
+
+## Step 1: Identify the target
+
+Ask the user which crate(s) to analyze:
+- A specific crate name (e.g., "tokio", "serde")
+- A specific workspace member (e.g., "quickwit-search")
+- "all" to scan the entire workspace
+
+## Step 2: Analyze current dependencies
+
+For the workspace Cargo.toml (`quickwit/Cargo.toml`), list dependencies that:
+- Do NOT have `default-features = false`
+- Have default features that might be unnecessary
+
+Run: `cargo tree -p <crate> -f "{p} {f}" --edges features` to see what features are actually used.
+
+## Step 3: For each candidate dependency
+
+### 3a: Check the crate's default features
+
+Look up the crate on crates.io or check its Cargo.toml to understand:
+- What features are enabled by default
+- What each feature provides
+
+Use: `cargo metadata --format-version=1 | jq '.packages[] | select(.name == "<crate>") | .features'`
+
+### 3b: Try disabling default features
+
+Modify the dependency in `quickwit/Cargo.toml`:
+
+From:
+```toml
+some-crate = { version = "1.0" }
+```
+
+To:
+```toml
+some-crate = { version = "1.0", default-features = false }
+```
+
+### 3c: Run cargo check
+
+Run: `cargo check --workspace` (or target specific packages for faster feedback)
+
+If compilation fails:
+1. Read the error messages to identify which features are needed
+2. Add only the required features explicitly:
+   ```toml
+   some-crate = { version = "1.0", default-features = false, features = ["needed-feature"] }
+   ```
+3. Re-run cargo check
+
+### 3d: Binary search for minimal features
+
+If there are many default features, use binary search:
+1. Start with no features
+2. If it fails, add half the default features
+3. Continue until you find the minimal set
+
+## Step 4: Document findings
+
+For each dependency analyzed, report:
+- Original configuration
+- New configuration (if changed)
+- Features that were removed
+- Any features that are required
+
+## Step 5: Verify full build
+
+After all changes, run:
+```bash
+cargo check --workspace --all-targets
+cargo test --workspace --no-run
+```
+
+## Common Patterns
+
+### Serde
+Often only needs `derive`:
+```toml
+serde = { version = "1.0", default-features = false, features = ["derive", "std"] }
+```
+
+### Tokio
+Identify which runtime features are actually used:
+```toml
+tokio = { version = "1.0", default-features = false, features = ["rt-multi-thread", "macros", "sync"] }
+```
+
+### Reqwest
+Often doesn't need all TLS backends:
+```toml
+reqwest = { version = "0.11", default-features = false, features = ["rustls-tls", "json"] }
+```
+
+## Rollback
+
+If changes cause issues:
+```bash
+git checkout quickwit/Cargo.toml
+cargo check --workspace
+```
+
+## Tips
+
+- Start with large crates that have many default features (tokio, reqwest, hyper)
+- Use `cargo bloat --crates` to identify large dependencies
+- Check `cargo tree -d` for duplicate dependencies that might indicate feature conflicts
+- Some features are needed only for tests - consider using `[dev-dependencies]` features

.claude/skills/simple-pr/SKILL.md

@@ -0,0 +1,60 @@
+---
+name: simple-pr
+description: Create a simple PR from staged changes with an auto-generated commit message
+disable-model-invocation: true
+---
+
+# Simple PR
+
+Follow these steps to create a simple PR from staged changes:
+
+## Step 1: Check workspace state
+
+Run: `git status`
+
+Verify that all changes have been staged (no unstaged changes). If there are unstaged changes, abort and ask the user to stage their changes first with `git add`.
+
+Also verify that we are on the `main` branch. If not, abort and ask the user to switch to main first.
+
+## Step 2: Ensure main is up to date
+
+Run: `git pull origin main`
+
+This ensures we're working from the latest code.
+
+## Step 3: Review staged changes
+
+Run: `git diff --cached`
+
+Review the staged changes to understand what the PR will contain.
+
+## Step 4: Generate commit message
+
+Based on the staged changes, generate a concise commit message (1-2 sentences) that describes the "why" rather than the "what".
+
+Display the proposed commit message to the user and ask for confirmation before proceeding.
+
+## Step 5: Create a new branch
+
+Get the git username: `git config user.name | tr ' ' '-' | tr '[:upper:]' '[:lower:]'`
+
+Create a short, descriptive branch name based on the changes (e.g., `fix-typo-in-readme`, `add-retry-logic`, `update-deps`).
+
+Create and checkout the branch: `git checkout -b {username}/{short-descriptive-name}`
+
+## Step 6: Commit changes
+
+Commit with the message from step 3:
+```
+git commit -m "{commit-message}"
+```
+
+## Step 7: Push and open a PR
+
+Push the branch and open a PR:
+```
+git push -u origin {branch-name}
+gh pr create --title "{commit-message-title}" --body "{longer-description-if-needed}"
+```
+
+Report the PR URL to the user when complete.

.github/workflows/coverage.yml

@@ -15,11 +15,11 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - name: Install Rust
-        run: rustup toolchain install nightly-2024-07-01 --profile minimal --component llvm-tools-preview
+        run: rustup toolchain install nightly-2025-12-01 --profile minimal --component llvm-tools-preview
       - uses: Swatinem/rust-cache@v2
       - uses: taiki-e/install-action@cargo-llvm-cov
       - name: Generate code coverage
-        run: cargo +nightly-2024-07-01 llvm-cov --all-features --workspace --doctests --lcov --output-path lcov.info
+        run: cargo +nightly-2025-12-01 llvm-cov --all-features --workspace --doctests --lcov --output-path lcov.info
       - name: Upload coverage to Codecov
         uses: codecov/codecov-action@v3
         continue-on-error: true

.github/workflows/test.yml

@@ -39,11 +39,11 @@ jobs:
 
     - name: Check Formatting
       run: cargo +nightly fmt --all -- --check
-    
+
     - name: Check Stable Compilation
       run: cargo build --all-features
 
-    
+
     - name: Check Bench Compilation
       run: cargo +nightly bench --no-run --profile=dev --all-features
 
@@ -59,10 +59,10 @@ jobs:
 
     strategy:
       matrix:
-        features: [
-            { label: "all", flags: "mmap,stopwords,lz4-compression,zstd-compression,failpoints" },
-            { label: "quickwit", flags: "mmap,quickwit,failpoints" }
-        ]
+        features:
+          - { label: "all", flags: "mmap,stopwords,lz4-compression,zstd-compression,failpoints,stemmer" }
+          - { label: "quickwit", flags: "mmap,quickwit,failpoints" }
+          - { label: "none", flags: "" }
 
     name: test-${{ matrix.features.label}}
 
@@ -80,7 +80,21 @@ jobs:
     - uses: Swatinem/rust-cache@v2
 
     - name: Run tests
-      run: cargo +stable nextest run --features ${{ matrix.features.flags }} --verbose --workspace
+      run: |
+        # if matrix.feature.flags is empty then run on --lib to avoid compiling examples
+        # (as most of them rely on mmap) otherwise run all
+        if [ -z "${{ matrix.features.flags }}" ]; then
+          cargo +stable nextest run --lib --no-default-features --verbose --workspace
+        else
+          cargo +stable nextest run --features ${{ matrix.features.flags }} --no-default-features --verbose --workspace
+        fi
 
     - name: Run doctests
-      run: cargo +stable test --doc --features ${{ matrix.features.flags }} --verbose --workspace
+      run: |
+        # if matrix.feature.flags is empty then run on --lib to avoid compiling examples
+        # (as most of them rely on mmap) otherwise run all
+        if [ -z "${{ matrix.features.flags }}" ]; then
+          echo "no doctest for no feature flag"
+        else
+          cargo +stable test --doc --features ${{ matrix.features.flags }} --verbose --workspace
+        fi

Cargo.toml

@@ -15,7 +15,7 @@ rust-version = "1.85"
 exclude = ["benches/*.json", "benches/*.txt"]
 
 [dependencies]
-oneshot = "0.1.7"
+oneshot = "0.1.13"
 base64 = "0.22.0"
 byteorder = "1.4.3"
 crc32fast = "1.3.2"
@@ -27,7 +27,7 @@ regex = { version = "1.5.5", default-features = false, features = [
 aho-corasick = "1.0"
 tantivy-fst = "0.5"
 memmap2 = { version = "0.9.0", optional = true }
-lz4_flex = { version = "0.11", default-features = false, optional = true }
+lz4_flex = { version = "0.12", default-features = false, optional = true }
 zstd = { version = "0.13", optional = true, default-features = false }
 tempfile = { version = "3.12.0", optional = true }
 log = "0.4.16"
@@ -37,9 +37,9 @@ fs4 = { version = "0.13.1", optional = true }
 levenshtein_automata = "0.2.1"
 uuid = { version = "1.0.0", features = ["v4", "serde"] }
 crossbeam-channel = "0.5.4"
-rust-stemmers = "1.2.0"
+rust-stemmers = { version = "1.2.0", optional = true }
 downcast-rs = "2.0.1"
-bitpacking = { version = "0.9.2", default-features = false, features = [
+bitpacking = { version = "0.9.3", default-features = false, features = [
     "bitpacker4x",
 ] }
 census = "0.4.2"
@@ -50,13 +50,12 @@ fail = { version = "0.5.0", optional = true }
 time = { version = "0.3.35", features = ["serde-well-known"] }
 smallvec = "1.8.0"
 rayon = "1.5.2"
-lru = "0.12.0"
+lru = "0.16.3"
 fastdivide = "0.4.0"
 itertools = "0.14.0"
 measure_time = "0.9.0"
 arc-swap = "1.5.0"
 bon = "3.3.1"
-i_triangle = "0.38.0"
 
 columnar = { version = "0.6", path = "./columnar", package = "tantivy-columnar" }
 sstable = { version = "0.6", path = "./sstable", package = "tantivy-sstable", optional = true }
@@ -71,23 +70,22 @@ futures-util = { version = "0.3.28", optional = true }
 futures-channel = { version = "0.3.28", optional = true }
 fnv = "1.0.7"
 typetag = "0.2.21"
-geo-types = "0.7.17"
 
 [target.'cfg(windows)'.dependencies]
 winapi = "0.3.9"
 
 [dev-dependencies]
-binggan = "0.14.0"
-rand = "0.8.5"
+binggan = "0.14.2"
+rand = "0.9"
 maplit = "1.0.2"
 matches = "0.1.9"
 pretty_assertions = "1.2.1"
-proptest = "1.0.0"
+proptest = "1.7.0"
 test-log = "0.2.10"
 futures = "0.3.21"
 paste = "1.0.11"
 more-asserts = "0.3.1"
-rand_distr = "0.4.3"
+rand_distr = "0.5"
 time = { version = "0.3.10", features = ["serde-well-known", "macros"] }
 postcard = { version = "1.0.4", features = [
     "use-std",
@@ -115,7 +113,8 @@ debug-assertions = true
 overflow-checks = true
 
 [features]
-default = ["mmap", "stopwords", "lz4-compression", "columnar-zstd-compression"]
+default = ["mmap", "stopwords", "lz4-compression", "columnar-zstd-compression", "stemmer"]
+stemmer = ["rust-stemmers"]
 mmap = ["fs4", "tempfile", "memmap2"]
 stopwords = []
 
@@ -175,6 +174,31 @@ harness = false
 name = "exists_json"
 harness = false
 
+[[bench]]
+name = "range_query"
+harness = false
+
 [[bench]]
 name = "and_or_queries"
 harness = false
+
+[[bench]]
+name = "range_queries"
+harness = false
+
+[[bench]]
+name = "bool_queries_with_range"
+harness = false
+
+[[bench]]
+name = "str_search_and_get"
+harness = false
+
+[[bench]]
+name = "merge_segments"
+harness = false
+
+[[bench]]
+name = "regex_all_terms"
+harness = false
+

README.md

@@ -123,6 +123,7 @@ You can also find other bindings on [GitHub](https://github.com/search?q=tantivy
 - [seshat](https://github.com/matrix-org/seshat/): A matrix message database/indexer
 - [tantiny](https://github.com/baygeldin/tantiny): Tiny full-text search for Ruby
 - [lnx](https://github.com/lnx-search/lnx): adaptable, typo tolerant search engine with a REST API
+- [Bichon](https://github.com/rustmailer/bichon): A lightweight, high-performance Rust email archiver with WebUI
 - and [more](https://github.com/search?q=tantivy)!
 
 ### On average, how much faster is Tantivy compared to Lucene?

benches/agg_bench.rs

@@ -1,7 +1,8 @@
 use binggan::plugins::PeakMemAllocPlugin;
 use binggan::{black_box, InputGroup, PeakMemAlloc, INSTRUMENTED_SYSTEM};
-use rand::prelude::SliceRandom;
+use rand::distr::weighted::WeightedIndex;
 use rand::rngs::StdRng;
+use rand::seq::IndexedRandom;
 use rand::{Rng, SeedableRng};
 use rand_distr::Distribution;
 use serde_json::json;
@@ -53,27 +54,33 @@ fn bench_agg(mut group: InputGroup<Index>) {
     register!(group, stats_f64);
     register!(group, extendedstats_f64);
     register!(group, percentiles_f64);
-    register!(group, terms_few);
-    register!(group, terms_many);
+    register!(group, terms_7);
+    register!(group, terms_all_unique);
+    register!(group, terms_150_000);
     register!(group, terms_many_top_1000);
     register!(group, terms_many_order_by_term);
     register!(group, terms_many_with_top_hits);
+    register!(group, terms_all_unique_with_avg_sub_agg);
     register!(group, terms_many_with_avg_sub_agg);
-    register!(group, terms_few_with_avg_sub_agg);
+    register!(group, terms_status_with_avg_sub_agg);
+    register!(group, terms_status_with_histogram);
+    register!(group, terms_zipf_1000);
+    register!(group, terms_zipf_1000_with_histogram);
+    register!(group, terms_zipf_1000_with_avg_sub_agg);
 
     register!(group, terms_many_json_mixed_type_with_avg_sub_agg);
 
     register!(group, cardinality_agg);
-    register!(group, terms_few_with_cardinality_agg);
+    register!(group, terms_status_with_cardinality_agg);
 
     register!(group, range_agg);
     register!(group, range_agg_with_avg_sub_agg);
-    register!(group, range_agg_with_term_agg_few);
+    register!(group, range_agg_with_term_agg_status);
     register!(group, range_agg_with_term_agg_many);
     register!(group, histogram);
     register!(group, histogram_hard_bounds);
     register!(group, histogram_with_avg_sub_agg);
-    register!(group, histogram_with_term_agg_few);
+    register!(group, histogram_with_term_agg_status);
     register!(group, avg_and_range_with_avg_sub_agg);
 
     // Filter aggregation benchmarks
@@ -132,12 +139,12 @@ fn extendedstats_f64(index: &Index) {
 }
 fn percentiles_f64(index: &Index) {
     let agg_req = json!({
-      "mypercentiles": {
-        "percentiles": {
-          "field": "score_f64",
-          "percents": [ 95, 99, 99.9 ]
+        "mypercentiles": {
+            "percentiles": {
+                "field": "score_f64",
+                "percents": [ 95, 99, 99.9 ]
+            }
         }
-      }
     });
     execute_agg(index, agg_req);
 }
@@ -152,10 +159,10 @@ fn cardinality_agg(index: &Index) {
     });
     execute_agg(index, agg_req);
 }
-fn terms_few_with_cardinality_agg(index: &Index) {
+fn terms_status_with_cardinality_agg(index: &Index) {
     let agg_req = json!({
         "my_texts": {
-            "terms": { "field": "text_few_terms" },
+            "terms": { "field": "text_few_terms_status" },
             "aggs": {
                 "cardinality": {
                     "cardinality": {
@@ -168,13 +175,20 @@ fn terms_few_with_cardinality_agg(index: &Index) {
     execute_agg(index, agg_req);
 }
 
-fn terms_few(index: &Index) {
+fn terms_7(index: &Index) {
     let agg_req = json!({
-        "my_texts": { "terms": { "field": "text_few_terms" } },
+        "my_texts": { "terms": { "field": "text_few_terms_status" } },
     });
     execute_agg(index, agg_req);
 }
-fn terms_many(index: &Index) {
+fn terms_all_unique(index: &Index) {
+    let agg_req = json!({
+        "my_texts": { "terms": { "field": "text_all_unique_terms" } },
+    });
+    execute_agg(index, agg_req);
+}
+
+fn terms_150_000(index: &Index) {
     let agg_req = json!({
         "my_texts": { "terms": { "field": "text_many_terms" } },
     });
@@ -222,11 +236,10 @@ fn terms_many_with_avg_sub_agg(index: &Index) {
     });
     execute_agg(index, agg_req);
 }
-
-fn terms_few_with_avg_sub_agg(index: &Index) {
+fn terms_all_unique_with_avg_sub_agg(index: &Index) {
     let agg_req = json!({
         "my_texts": {
-            "terms": { "field": "text_few_terms" },
+            "terms": { "field": "text_all_unique_terms" },
             "aggs": {
                 "average_f64": { "avg": { "field": "score_f64" } }
             }
@@ -234,6 +247,60 @@ fn terms_few_with_avg_sub_agg(index: &Index) {
     });
     execute_agg(index, agg_req);
 }
+fn terms_status_with_histogram(index: &Index) {
+    let agg_req = json!({
+        "my_texts": {
+            "terms": { "field": "text_few_terms_status" },
+            "aggs": {
+                "histo": {"histogram": { "field": "score_f64", "interval": 10 }}
+            }
+        }
+    });
+    execute_agg(index, agg_req);
+}
+
+fn terms_zipf_1000_with_histogram(index: &Index) {
+    let agg_req = json!({
+        "my_texts": {
+            "terms": { "field": "text_1000_terms_zipf" },
+            "aggs": {
+                "histo": {"histogram": { "field": "score_f64", "interval": 10 }}
+            }
+        }
+    });
+    execute_agg(index, agg_req);
+}
+
+fn terms_status_with_avg_sub_agg(index: &Index) {
+    let agg_req = json!({
+        "my_texts": {
+            "terms": { "field": "text_few_terms_status" },
+            "aggs": {
+                "average_f64": { "avg": { "field": "score_f64" } }
+            }
+        },
+    });
+    execute_agg(index, agg_req);
+}
+
+fn terms_zipf_1000_with_avg_sub_agg(index: &Index) {
+    let agg_req = json!({
+        "my_texts": {
+            "terms": { "field": "text_1000_terms_zipf" },
+            "aggs": {
+                "average_f64": { "avg": { "field": "score_f64" } }
+            }
+        },
+    });
+    execute_agg(index, agg_req);
+}
+
+fn terms_zipf_1000(index: &Index) {
+    let agg_req = json!({
+        "my_texts": { "terms": { "field": "text_1000_terms_zipf" } },
+    });
+    execute_agg(index, agg_req);
+}
 
 fn terms_many_json_mixed_type_with_avg_sub_agg(index: &Index) {
     let agg_req = json!({
@@ -290,7 +357,7 @@ fn range_agg_with_avg_sub_agg(index: &Index) {
     execute_agg(index, agg_req);
 }
 
-fn range_agg_with_term_agg_few(index: &Index) {
+fn range_agg_with_term_agg_status(index: &Index) {
     let agg_req = json!({
         "rangef64": {
             "range": {
@@ -305,7 +372,7 @@ fn range_agg_with_term_agg_few(index: &Index) {
                 ]
             },
             "aggs": {
-                "my_texts": { "terms": { "field": "text_few_terms" } },
+                "my_texts": { "terms": { "field": "text_few_terms_status" } },
             }
         },
     });
@@ -361,12 +428,12 @@ fn histogram_with_avg_sub_agg(index: &Index) {
     });
     execute_agg(index, agg_req);
 }
-fn histogram_with_term_agg_few(index: &Index) {
+fn histogram_with_term_agg_status(index: &Index) {
     let agg_req = json!({
         "rangef64": {
             "histogram": { "field": "score_f64", "interval": 10 },
             "aggs": {
-                "my_texts": { "terms": { "field": "text_few_terms" } }
+                "my_texts": { "terms": { "field": "text_few_terms_status" } }
             }
         }
     });
@@ -411,6 +478,13 @@ fn get_collector(agg_req: Aggregations) -> AggregationCollector {
 }
 
 fn get_test_index_bench(cardinality: Cardinality) -> tantivy::Result<Index> {
+    // Flag to use existing index
+    let reuse_index = std::env::var("REUSE_AGG_BENCH_INDEX").is_ok();
+    if reuse_index && std::path::Path::new("agg_bench").exists() {
+        return Index::open_in_dir("agg_bench");
+    }
+    // crreate dir
+    std::fs::create_dir_all("agg_bench")?;
     let mut schema_builder = Schema::builder();
     let text_fieldtype = tantivy::schema::TextOptions::default()
         .set_indexing_options(
@@ -419,20 +493,47 @@ fn get_test_index_bench(cardinality: Cardinality) -> tantivy::Result<Index> {
         .set_stored();
     let text_field = schema_builder.add_text_field("text", text_fieldtype);
     let json_field = schema_builder.add_json_field("json", FAST);
+    let text_field_all_unique_terms =
+        schema_builder.add_text_field("text_all_unique_terms", STRING | FAST);
     let text_field_many_terms = schema_builder.add_text_field("text_many_terms", STRING | FAST);
-    let text_field_few_terms = schema_builder.add_text_field("text_few_terms", STRING | FAST);
+    let text_field_few_terms_status =
+        schema_builder.add_text_field("text_few_terms_status", STRING | FAST);
+    let text_field_1000_terms_zipf =
+        schema_builder.add_text_field("text_1000_terms_zipf", STRING | FAST);
     let score_fieldtype = tantivy::schema::NumericOptions::default().set_fast();
     let score_field = schema_builder.add_u64_field("score", score_fieldtype.clone());
     let score_field_f64 = schema_builder.add_f64_field("score_f64", score_fieldtype.clone());
     let score_field_i64 = schema_builder.add_i64_field("score_i64", score_fieldtype);
-    let index = Index::create_from_tempdir(schema_builder.build())?;
-    let few_terms_data = ["INFO", "ERROR", "WARN", "DEBUG"];
+    // use tmp dir
+    let index = if reuse_index {
+        Index::create_in_dir("agg_bench", schema_builder.build())?
+    } else {
+        Index::create_from_tempdir(schema_builder.build())?
+    };
+    // Approximate log proportions
+    let status_field_data = [
+        ("INFO", 8000),
+        ("ERROR", 300),
+        ("WARN", 1200),
+        ("DEBUG", 500),
+        ("OK", 500),
+        ("CRITICAL", 20),
+        ("EMERGENCY", 1),
+    ];
+    let log_level_distribution =
+        WeightedIndex::new(status_field_data.iter().map(|item| item.1)).unwrap();
 
     let lg_norm = rand_distr::LogNormal::new(2.996f64, 0.979f64).unwrap();
 
     let many_terms_data = (0..150_000)
         .map(|num| format!("author{num}"))
         .collect::<Vec<_>>();
+
+    // Prepare 1000 unique terms sampled using a Zipf distribution.
+    // Exponent ~1.1 approximates top-20 terms covering around ~20%.
+    let terms_1000: Vec<String> = (1..=1000).map(|i| format!("term_{i}")).collect();
+    let zipf_1000 = rand_distr::Zipf::new(1000.0, 1.1f64).unwrap();
+
     {
         let mut rng = StdRng::from_seed([1u8; 32]);
         let mut index_writer = index.writer_with_num_threads(1, 200_000_000)?;
@@ -442,15 +543,25 @@ fn get_test_index_bench(cardinality: Cardinality) -> tantivy::Result<Index> {
             index_writer.add_document(doc!())?;
         }
         if cardinality == Cardinality::Multivalued {
+            let log_level_sample_a = status_field_data[log_level_distribution.sample(&mut rng)].0;
+            let log_level_sample_b = status_field_data[log_level_distribution.sample(&mut rng)].0;
+            let idx_a = zipf_1000.sample(&mut rng) as usize - 1;
+            let idx_b = zipf_1000.sample(&mut rng) as usize - 1;
+            let term_1000_a = &terms_1000[idx_a];
+            let term_1000_b = &terms_1000[idx_b];
             index_writer.add_document(doc!(
                 json_field => json!({"mixed_type": 10.0}),
                 json_field => json!({"mixed_type": 10.0}),
                 text_field => "cool",
                 text_field => "cool",
+                text_field_all_unique_terms => "cool",
+                text_field_all_unique_terms => "coolo",
                 text_field_many_terms => "cool",
                 text_field_many_terms => "cool",
-                text_field_few_terms => "cool",
-                text_field_few_terms => "cool",
+                text_field_few_terms_status => log_level_sample_a,
+                text_field_few_terms_status => log_level_sample_b,
+                text_field_1000_terms_zipf => term_1000_a.as_str(),
+                text_field_1000_terms_zipf => term_1000_b.as_str(),
                 score_field => 1u64,
                 score_field => 1u64,
                 score_field_f64 => lg_norm.sample(&mut rng),
@@ -465,8 +576,8 @@ fn get_test_index_bench(cardinality: Cardinality) -> tantivy::Result<Index> {
         }
         let _val_max = 1_000_000.0;
         for _ in 0..doc_with_value {
-            let val: f64 = rng.gen_range(0.0..1_000_000.0);
-            let json = if rng.gen_bool(0.1) {
+            let val: f64 = rng.random_range(0.0..1_000_000.0);
+            let json = if rng.random_bool(0.1) {
                 // 10% are numeric values
                 json!({ "mixed_type": val })
             } else {
@@ -475,8 +586,10 @@ fn get_test_index_bench(cardinality: Cardinality) -> tantivy::Result<Index> {
             index_writer.add_document(doc!(
                 text_field => "cool",
                 json_field => json,
+                text_field_all_unique_terms => format!("unique_term_{}", rng.random::<u64>()),
                 text_field_many_terms => many_terms_data.choose(&mut rng).unwrap().to_string(),
-                text_field_few_terms => few_terms_data.choose(&mut rng).unwrap().to_string(),
+                text_field_few_terms_status => status_field_data[log_level_distribution.sample(&mut rng)].0,
+                text_field_1000_terms_zipf => terms_1000[zipf_1000.sample(&mut rng) as usize - 1].as_str(),
                 score_field => val as u64,
                 score_field_f64 => lg_norm.sample(&mut rng),
                 score_field_i64 => val as i64,
@@ -528,7 +641,7 @@ fn filter_agg_all_query_with_sub_aggs(index: &Index) {
                 "avg_score": { "avg": { "field": "score" } },
                 "stats_score": { "stats": { "field": "score_f64" } },
                 "terms_text": {
-                    "terms": { "field": "text_few_terms" }
+                    "terms": { "field": "text_few_terms_status" }
                 }
             }
         }
@@ -544,7 +657,7 @@ fn filter_agg_term_query_with_sub_aggs(index: &Index) {
                 "avg_score": { "avg": { "field": "score" } },
                 "stats_score": { "stats": { "field": "score_f64" } },
                 "terms_text": {
-                    "terms": { "field": "text_few_terms" }
+                    "terms": { "field": "text_few_terms_status" }
                 }
             }
         }

benches/and_or_queries.rs

@@ -55,29 +55,29 @@ fn build_shared_indices(num_docs: usize, p_a: f32, p_b: f32, p_c: f32) -> (Bench
     {
         let mut writer = index.writer_with_num_threads(1, 500_000_000).unwrap();
         for _ in 0..num_docs {
-            let has_a = rng.gen_bool(p_a as f64);
-            let has_b = rng.gen_bool(p_b as f64);
-            let has_c = rng.gen_bool(p_c as f64);
-            let score = rng.gen_range(0u64..100u64);
-            let score2 = rng.gen_range(0u64..100_000u64);
+            let has_a = rng.random_bool(p_a as f64);
+            let has_b = rng.random_bool(p_b as f64);
+            let has_c = rng.random_bool(p_c as f64);
+            let score = rng.random_range(0u64..100u64);
+            let score2 = rng.random_range(0u64..100_000u64);
             let mut title_tokens: Vec<&str> = Vec::new();
             let mut body_tokens: Vec<&str> = Vec::new();
             if has_a {
-                if rng.gen_bool(0.1) {
+                if rng.random_bool(0.1) {
                     title_tokens.push("a");
                 } else {
                     body_tokens.push("a");
                 }
             }
             if has_b {
-                if rng.gen_bool(0.1) {
+                if rng.random_bool(0.1) {
                     title_tokens.push("b");
                 } else {
                     body_tokens.push("b");
                 }
             }
             if has_c {
-                if rng.gen_bool(0.1) {
+                if rng.random_bool(0.1) {
                     title_tokens.push("c");
                 } else {
                     body_tokens.push("c");

benches/bool_queries_with_range.rs

@@ -0,0 +1,288 @@
+use binggan::{black_box, BenchGroup, BenchRunner};
+use rand::prelude::*;
+use rand::rngs::StdRng;
+use rand::SeedableRng;
+use tantivy::collector::{Collector, Count, DocSetCollector, TopDocs};
+use tantivy::query::{Query, QueryParser};
+use tantivy::schema::{Schema, FAST, INDEXED, TEXT};
+use tantivy::{doc, Index, Order, ReloadPolicy, Searcher};
+
+#[derive(Clone)]
+struct BenchIndex {
+    #[allow(dead_code)]
+    index: Index,
+    searcher: Searcher,
+    query_parser: QueryParser,
+}
+
+fn build_shared_indices(num_docs: usize, p_title_a: f32, distribution: &str) -> BenchIndex {
+    // Unified schema
+    let mut schema_builder = Schema::builder();
+    let f_title = schema_builder.add_text_field("title", TEXT);
+    let f_num_rand = schema_builder.add_u64_field("num_rand", INDEXED);
+    let f_num_asc = schema_builder.add_u64_field("num_asc", INDEXED);
+    let f_num_rand_fast = schema_builder.add_u64_field("num_rand_fast", INDEXED | FAST);
+    let f_num_asc_fast = schema_builder.add_u64_field("num_asc_fast", INDEXED | FAST);
+    let schema = schema_builder.build();
+    let index = Index::create_in_ram(schema.clone());
+
+    // Populate index with stable RNG for reproducibility.
+    let mut rng = StdRng::from_seed([7u8; 32]);
+
+    {
+        let mut writer = index.writer_with_num_threads(1, 4_000_000_000).unwrap();
+
+        match distribution {
+            "dense" => {
+                for doc_id in 0..num_docs {
+                    // Always add title to avoid empty documents
+                    let title_token = if rng.random_bool(p_title_a as f64) {
+                        "a"
+                    } else {
+                        "b"
+                    };
+
+                    let num_rand = rng.random_range(0u64..1000u64);
+
+                    let num_asc = (doc_id / 10000) as u64;
+
+                    writer
+                        .add_document(doc!(
+                            f_title=>title_token,
+                            f_num_rand=>num_rand,
+                            f_num_asc=>num_asc,
+                            f_num_rand_fast=>num_rand,
+                            f_num_asc_fast=>num_asc,
+                        ))
+                        .unwrap();
+                }
+            }
+            "sparse" => {
+                for doc_id in 0..num_docs {
+                    // Always add title to avoid empty documents
+                    let title_token = if rng.random_bool(p_title_a as f64) {
+                        "a"
+                    } else {
+                        "b"
+                    };
+
+                    let num_rand = rng.random_range(0u64..10000000u64);
+
+                    let num_asc = doc_id as u64;
+
+                    writer
+                        .add_document(doc!(
+                            f_title=>title_token,
+                            f_num_rand=>num_rand,
+                            f_num_asc=>num_asc,
+                            f_num_rand_fast=>num_rand,
+                            f_num_asc_fast=>num_asc,
+                        ))
+                        .unwrap();
+                }
+            }
+            _ => {
+                panic!("Unsupported distribution type");
+            }
+        }
+        writer.commit().unwrap();
+    }
+
+    // Prepare reader/searcher once.
+    let reader = index
+        .reader_builder()
+        .reload_policy(ReloadPolicy::Manual)
+        .try_into()
+        .unwrap();
+    let searcher = reader.searcher();
+
+    // Build query parser for title field
+    let qp_title = QueryParser::for_index(&index, vec![f_title]);
+
+    BenchIndex {
+        index,
+        searcher,
+        query_parser: qp_title,
+    }
+}
+
+fn main() {
+    // Prepare corpora with varying scenarios
+    let scenarios = vec![
+        (
+            "dense and 99% a".to_string(),
+            10_000_000,
+            0.99,
+            "dense",
+            0,
+            9,
+        ),
+        (
+            "dense and 99% a".to_string(),
+            10_000_000,
+            0.99,
+            "dense",
+            990,
+            999,
+        ),
+        (
+            "sparse and 99% a".to_string(),
+            10_000_000,
+            0.99,
+            "sparse",
+            0,
+            9,
+        ),
+        (
+            "sparse and 99% a".to_string(),
+            10_000_000,
+            0.99,
+            "sparse",
+            9_999_990,
+            9_999_999,
+        ),
+    ];
+
+    let mut runner = BenchRunner::new();
+    for (scenario_id, n, p_title_a, num_rand_distribution, range_low, range_high) in scenarios {
+        // Build index for this scenario
+        let bench_index = build_shared_indices(n, p_title_a, num_rand_distribution);
+
+        // Create benchmark group
+        let mut group = runner.new_group();
+
+        // Now set the name (this moves scenario_id)
+        group.set_name(scenario_id);
+
+        // Define all four field types
+        let field_names = ["num_rand", "num_asc", "num_rand_fast", "num_asc_fast"];
+
+        // Define the three terms we want to test with
+        let terms = ["a", "b", "z"];
+
+        // Generate all combinations of terms and field names
+        let mut queries = Vec::new();
+        for &term in &terms {
+            for &field_name in &field_names {
+                let query_str = format!(
+                    "{} AND {}:[{} TO {}]",
+                    term, field_name, range_low, range_high
+                );
+                queries.push((query_str, field_name.to_string()));
+            }
+        }
+
+        let query_str = format!(
+            "{}:[{} TO {}] AND {}:[{} TO {}]",
+            "num_rand_fast", range_low, range_high, "num_asc_fast", range_low, range_high
+        );
+        queries.push((query_str, "num_asc_fast".to_string()));
+
+        // Run all benchmark tasks for each query and its corresponding field name
+        for (query_str, field_name) in queries {
+            run_benchmark_tasks(&mut group, &bench_index, &query_str, &field_name);
+        }
+
+        group.run();
+    }
+}
+
+/// Run all benchmark tasks for a given query string and field name
+fn run_benchmark_tasks(
+    bench_group: &mut BenchGroup,
+    bench_index: &BenchIndex,
+    query_str: &str,
+    field_name: &str,
+) {
+    // Test count
+    add_bench_task(bench_group, bench_index, query_str, Count, "count");
+
+    // Test all results
+    add_bench_task(
+        bench_group,
+        bench_index,
+        query_str,
+        DocSetCollector,
+        "all results",
+    );
+
+    // Test top 100 by the field (if it's a FAST field)
+    if field_name.ends_with("_fast") {
+        // Ascending order
+        {
+            let collector_name = format!("top100_by_{}_asc", field_name);
+            let field_name_owned = field_name.to_string();
+            add_bench_task(
+                bench_group,
+                bench_index,
+                query_str,
+                TopDocs::with_limit(100).order_by_fast_field::<u64>(field_name_owned, Order::Asc),
+                &collector_name,
+            );
+        }
+
+        // Descending order
+        {
+            let collector_name = format!("top100_by_{}_desc", field_name);
+            let field_name_owned = field_name.to_string();
+            add_bench_task(
+                bench_group,
+                bench_index,
+                query_str,
+                TopDocs::with_limit(100).order_by_fast_field::<u64>(field_name_owned, Order::Desc),
+                &collector_name,
+            );
+        }
+    }
+}
+
+fn add_bench_task<C: Collector + 'static>(
+    bench_group: &mut BenchGroup,
+    bench_index: &BenchIndex,
+    query_str: &str,
+    collector: C,
+    collector_name: &str,
+) {
+    let task_name = format!("{}_{}", query_str.replace(" ", "_"), collector_name);
+    let query = bench_index.query_parser.parse_query(query_str).unwrap();
+    let search_task = SearchTask {
+        searcher: bench_index.searcher.clone(),
+        collector,
+        query,
+    };
+    bench_group.register(task_name, move |_| black_box(search_task.run()));
+}
+
+struct SearchTask<C: Collector> {
+    searcher: Searcher,
+    collector: C,
+    query: Box<dyn Query>,
+}
+
+impl<C: Collector> SearchTask<C> {
+    #[inline(never)]
+    pub fn run(&self) -> usize {
+        let result = self.searcher.search(&self.query, &self.collector).unwrap();
+        if let Some(count) = (&result as &dyn std::any::Any).downcast_ref::<usize>() {
+            *count
+        } else if let Some(top_docs) = (&result as &dyn std::any::Any)
+            .downcast_ref::<Vec<(Option<u64>, tantivy::DocAddress)>>()
+        {
+            top_docs.len()
+        } else if let Some(top_docs) =
+            (&result as &dyn std::any::Any).downcast_ref::<Vec<(u64, tantivy::DocAddress)>>()
+        {
+            top_docs.len()
+        } else if let Some(doc_set) = (&result as &dyn std::any::Any)
+            .downcast_ref::<std::collections::HashSet<tantivy::DocAddress>>()
+        {
+            doc_set.len()
+        } else {
+            eprintln!(
+                "Unknown collector result type: {:?}",
+                std::any::type_name::<C::Fruit>()
+            );
+            0
+        }
+    }
+}

benches/merge_segments.rs

@@ -0,0 +1,224 @@
+// Benchmarks segment merging
+//
+// Notes:
+// - Input segments are kept intact (no deletes / no IndexWriter merge).
+// - Output is written to a `NullDirectory` that discards all files except
+//  fieldnorms (needed for merging).
+
+use std::collections::HashMap;
+use std::io::{self, Write};
+use std::path::{Path, PathBuf};
+use std::sync::{Arc, RwLock};
+
+use binggan::{black_box, BenchRunner};
+use rand::prelude::*;
+use rand::rngs::StdRng;
+use rand::SeedableRng;
+use tantivy::directory::error::{DeleteError, OpenReadError, OpenWriteError};
+use tantivy::directory::{
+    AntiCallToken, Directory, FileHandle, OwnedBytes, TerminatingWrite, WatchCallback, WatchHandle,
+    WritePtr,
+};
+use tantivy::indexer::{merge_filtered_segments, NoMergePolicy};
+use tantivy::schema::{Schema, TEXT};
+use tantivy::{doc, HasLen, Index, IndexSettings, Segment};
+
+#[derive(Clone, Default, Debug)]
+struct NullDirectory {
+    blobs: Arc<RwLock<HashMap<PathBuf, OwnedBytes>>>,
+}
+
+struct NullWriter;
+
+impl Write for NullWriter {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        Ok(buf.len())
+    }
+
+    fn flush(&mut self) -> io::Result<()> {
+        Ok(())
+    }
+}
+
+impl TerminatingWrite for NullWriter {
+    fn terminate_ref(&mut self, _token: AntiCallToken) -> io::Result<()> {
+        Ok(())
+    }
+}
+
+struct InMemoryWriter {
+    path: PathBuf,
+    buffer: Vec<u8>,
+    blobs: Arc<RwLock<HashMap<PathBuf, OwnedBytes>>>,
+}
+
+impl Write for InMemoryWriter {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        self.buffer.extend_from_slice(buf);
+        Ok(buf.len())
+    }
+
+    fn flush(&mut self) -> io::Result<()> {
+        Ok(())
+    }
+}
+
+impl TerminatingWrite for InMemoryWriter {
+    fn terminate_ref(&mut self, _token: AntiCallToken) -> io::Result<()> {
+        let bytes = OwnedBytes::new(std::mem::take(&mut self.buffer));
+        self.blobs.write().unwrap().insert(self.path.clone(), bytes);
+        Ok(())
+    }
+}
+
+#[derive(Debug, Default)]
+struct NullFileHandle;
+impl HasLen for NullFileHandle {
+    fn len(&self) -> usize {
+        0
+    }
+}
+impl FileHandle for NullFileHandle {
+    fn read_bytes(&self, _range: std::ops::Range<usize>) -> io::Result<OwnedBytes> {
+        unimplemented!()
+    }
+}
+
+impl Directory for NullDirectory {
+    fn get_file_handle(&self, path: &Path) -> Result<Arc<dyn FileHandle>, OpenReadError> {
+        if let Some(bytes) = self.blobs.read().unwrap().get(path) {
+            return Ok(Arc::new(bytes.clone()));
+        }
+        Ok(Arc::new(NullFileHandle))
+    }
+
+    fn delete(&self, _path: &Path) -> Result<(), DeleteError> {
+        Ok(())
+    }
+
+    fn exists(&self, _path: &Path) -> Result<bool, OpenReadError> {
+        Ok(true)
+    }
+
+    fn open_write(&self, path: &Path) -> Result<WritePtr, OpenWriteError> {
+        let path_buf = path.to_path_buf();
+        if path.to_string_lossy().ends_with(".fieldnorm") {
+            let writer = InMemoryWriter {
+                path: path_buf,
+                buffer: Vec::new(),
+                blobs: Arc::clone(&self.blobs),
+            };
+            Ok(io::BufWriter::new(Box::new(writer)))
+        } else {
+            Ok(io::BufWriter::new(Box::new(NullWriter)))
+        }
+    }
+
+    fn atomic_read(&self, path: &Path) -> Result<Vec<u8>, OpenReadError> {
+        if let Some(bytes) = self.blobs.read().unwrap().get(path) {
+            return Ok(bytes.as_slice().to_vec());
+        }
+        Err(OpenReadError::FileDoesNotExist(path.to_path_buf()))
+    }
+
+    fn atomic_write(&self, _path: &Path, _data: &[u8]) -> io::Result<()> {
+        Ok(())
+    }
+
+    fn sync_directory(&self) -> io::Result<()> {
+        Ok(())
+    }
+
+    fn watch(&self, _watch_callback: WatchCallback) -> tantivy::Result<WatchHandle> {
+        Ok(WatchHandle::empty())
+    }
+}
+
+struct MergeScenario {
+    #[allow(dead_code)]
+    index: Index,
+    segments: Vec<Segment>,
+    settings: IndexSettings,
+    label: String,
+}
+
+fn build_index(
+    num_segments: usize,
+    docs_per_segment: usize,
+    tokens_per_doc: usize,
+    vocab_size: usize,
+) -> MergeScenario {
+    let mut schema_builder = Schema::builder();
+    let body = schema_builder.add_text_field("body", TEXT);
+    let schema = schema_builder.build();
+    let index = Index::create_in_ram(schema.clone());
+
+    assert!(vocab_size > 0);
+    let total_tokens = num_segments * docs_per_segment * tokens_per_doc;
+    let use_unique_terms = vocab_size >= total_tokens;
+    let mut rng = StdRng::from_seed([7u8; 32]);
+    let mut next_token_id: u64 = 0;
+
+    {
+        let mut writer = index.writer_with_num_threads(1, 256_000_000).unwrap();
+        writer.set_merge_policy(Box::new(NoMergePolicy));
+        for _ in 0..num_segments {
+            for _ in 0..docs_per_segment {
+                let mut tokens = Vec::with_capacity(tokens_per_doc);
+                for _ in 0..tokens_per_doc {
+                    let token_id = if use_unique_terms {
+                        let id = next_token_id;
+                        next_token_id += 1;
+                        id
+                    } else {
+                        rng.random_range(0..vocab_size as u64)
+                    };
+                    tokens.push(format!("term_{token_id}"));
+                }
+                writer.add_document(doc!(body => tokens.join(" "))).unwrap();
+            }
+            writer.commit().unwrap();
+        }
+    }
+
+    let segments = index.searchable_segments().unwrap();
+    let settings = index.settings().clone();
+    let label = format!(
+        "segments={}, docs/seg={}, tokens/doc={}, vocab={}",
+        num_segments, docs_per_segment, tokens_per_doc, vocab_size
+    );
+
+    MergeScenario {
+        index,
+        segments,
+        settings,
+        label,
+    }
+}
+
+fn main() {
+    let scenarios = vec![
+        build_index(8, 50_000, 12, 8),
+        build_index(16, 50_000, 12, 8),
+        build_index(16, 100_000, 12, 8),
+        build_index(8, 50_000, 8, 8 * 50_000 * 8),
+    ];
+
+    let mut runner = BenchRunner::new();
+    for scenario in scenarios {
+        let mut group = runner.new_group();
+        group.set_name(format!("merge_segments inv_index — {}", scenario.label));
+        let segments = scenario.segments.clone();
+        let settings = scenario.settings.clone();
+        group.register("merge", move |_| {
+            let output_dir = NullDirectory::default();
+            let filter_doc_ids = vec![None; segments.len()];
+            let merged_index =
+                merge_filtered_segments(&segments, settings.clone(), filter_doc_ids, output_dir)
+                    .unwrap();
+            black_box(merged_index);
+        });
+
+        group.run();
+    }
+}

benches/range_queries.rs

@@ -0,0 +1,365 @@
+use std::ops::Bound;
+
+use binggan::{black_box, BenchGroup, BenchRunner};
+use rand::prelude::*;
+use rand::rngs::StdRng;
+use rand::SeedableRng;
+use tantivy::collector::{Count, DocSetCollector, TopDocs};
+use tantivy::query::RangeQuery;
+use tantivy::schema::{Schema, FAST, INDEXED};
+use tantivy::{doc, Index, Order, ReloadPolicy, Searcher, Term};
+
+#[derive(Clone)]
+struct BenchIndex {
+    #[allow(dead_code)]
+    index: Index,
+    searcher: Searcher,
+}
+
+fn build_shared_indices(num_docs: usize, distribution: &str) -> BenchIndex {
+    // Schema with fast fields only
+    let mut schema_builder = Schema::builder();
+    let f_num_rand_fast = schema_builder.add_u64_field("num_rand_fast", INDEXED | FAST);
+    let f_num_asc_fast = schema_builder.add_u64_field("num_asc_fast", INDEXED | FAST);
+    let schema = schema_builder.build();
+    let index = Index::create_in_ram(schema.clone());
+
+    // Populate index with stable RNG for reproducibility.
+    let mut rng = StdRng::from_seed([7u8; 32]);
+
+    {
+        let mut writer = index.writer_with_num_threads(1, 4_000_000_000).unwrap();
+
+        match distribution {
+            "dense" => {
+                for doc_id in 0..num_docs {
+                    let num_rand = rng.random_range(0u64..1000u64);
+                    let num_asc = (doc_id / 10000) as u64;
+
+                    writer
+                        .add_document(doc!(
+                            f_num_rand_fast=>num_rand,
+                            f_num_asc_fast=>num_asc,
+                        ))
+                        .unwrap();
+                }
+            }
+            "sparse" => {
+                for doc_id in 0..num_docs {
+                    let num_rand = rng.random_range(0u64..10000000u64);
+                    let num_asc = doc_id as u64;
+
+                    writer
+                        .add_document(doc!(
+                            f_num_rand_fast=>num_rand,
+                            f_num_asc_fast=>num_asc,
+                        ))
+                        .unwrap();
+                }
+            }
+            _ => {
+                panic!("Unsupported distribution type");
+            }
+        }
+        writer.commit().unwrap();
+    }
+
+    // Prepare reader/searcher once.
+    let reader = index
+        .reader_builder()
+        .reload_policy(ReloadPolicy::Manual)
+        .try_into()
+        .unwrap();
+    let searcher = reader.searcher();
+
+    BenchIndex { index, searcher }
+}
+
+fn main() {
+    // Prepare corpora with varying scenarios
+    let scenarios = vec![
+        // Dense distribution - random values in small range (0-999)
+        (
+            "dense_values_search_low_value_range".to_string(),
+            10_000_000,
+            "dense",
+            0,
+            9,
+        ),
+        (
+            "dense_values_search_high_value_range".to_string(),
+            10_000_000,
+            "dense",
+            990,
+            999,
+        ),
+        (
+            "dense_values_search_out_of_range".to_string(),
+            10_000_000,
+            "dense",
+            1000,
+            1002,
+        ),
+        (
+            "sparse_values_search_low_value_range".to_string(),
+            10_000_000,
+            "sparse",
+            0,
+            9,
+        ),
+        (
+            "sparse_values_search_high_value_range".to_string(),
+            10_000_000,
+            "sparse",
+            9_999_990,
+            9_999_999,
+        ),
+        (
+            "sparse_values_search_out_of_range".to_string(),
+            10_000_000,
+            "sparse",
+            10_000_000,
+            10_000_002,
+        ),
+    ];
+
+    let mut runner = BenchRunner::new();
+    for (scenario_id, n, num_rand_distribution, range_low, range_high) in scenarios {
+        // Build index for this scenario
+        let bench_index = build_shared_indices(n, num_rand_distribution);
+
+        // Create benchmark group
+        let mut group = runner.new_group();
+
+        // Now set the name (this moves scenario_id)
+        group.set_name(scenario_id);
+
+        // Define fast field types
+        let field_names = ["num_rand_fast", "num_asc_fast"];
+
+        // Generate range queries for fast fields
+        for &field_name in &field_names {
+            // Create the range query
+            let field = bench_index.searcher.schema().get_field(field_name).unwrap();
+            let lower_term = Term::from_field_u64(field, range_low);
+            let upper_term = Term::from_field_u64(field, range_high);
+
+            let query = RangeQuery::new(Bound::Included(lower_term), Bound::Included(upper_term));
+
+            run_benchmark_tasks(
+                &mut group,
+                &bench_index,
+                query,
+                field_name,
+                range_low,
+                range_high,
+            );
+        }
+
+        group.run();
+    }
+}
+
+/// Run all benchmark tasks for a given range query and field name
+fn run_benchmark_tasks(
+    bench_group: &mut BenchGroup,
+    bench_index: &BenchIndex,
+    query: RangeQuery,
+    field_name: &str,
+    range_low: u64,
+    range_high: u64,
+) {
+    // Test count
+    add_bench_task_count(
+        bench_group,
+        bench_index,
+        query.clone(),
+        "count",
+        field_name,
+        range_low,
+        range_high,
+    );
+
+    // Test top 100 by the field (ascending order)
+    {
+        let collector_name = format!("top100_by_{}_asc", field_name);
+        let field_name_owned = field_name.to_string();
+        add_bench_task_top100_asc(
+            bench_group,
+            bench_index,
+            query.clone(),
+            &collector_name,
+            field_name,
+            range_low,
+            range_high,
+            field_name_owned,
+        );
+    }
+
+    // Test top 100 by the field (descending order)
+    {
+        let collector_name = format!("top100_by_{}_desc", field_name);
+        let field_name_owned = field_name.to_string();
+        add_bench_task_top100_desc(
+            bench_group,
+            bench_index,
+            query,
+            &collector_name,
+            field_name,
+            range_low,
+            range_high,
+            field_name_owned,
+        );
+    }
+}
+
+fn add_bench_task_count(
+    bench_group: &mut BenchGroup,
+    bench_index: &BenchIndex,
+    query: RangeQuery,
+    collector_name: &str,
+    field_name: &str,
+    range_low: u64,
+    range_high: u64,
+) {
+    let task_name = format!(
+        "range_{}_[{} TO {}]_{}",
+        field_name, range_low, range_high, collector_name
+    );
+
+    let search_task = CountSearchTask {
+        searcher: bench_index.searcher.clone(),
+        query,
+    };
+    bench_group.register(task_name, move |_| black_box(search_task.run()));
+}
+
+fn add_bench_task_docset(
+    bench_group: &mut BenchGroup,
+    bench_index: &BenchIndex,
+    query: RangeQuery,
+    collector_name: &str,
+    field_name: &str,
+    range_low: u64,
+    range_high: u64,
+) {
+    let task_name = format!(
+        "range_{}_[{} TO {}]_{}",
+        field_name, range_low, range_high, collector_name
+    );
+
+    let search_task = DocSetSearchTask {
+        searcher: bench_index.searcher.clone(),
+        query,
+    };
+    bench_group.register(task_name, move |_| black_box(search_task.run()));
+}
+
+fn add_bench_task_top100_asc(
+    bench_group: &mut BenchGroup,
+    bench_index: &BenchIndex,
+    query: RangeQuery,
+    collector_name: &str,
+    field_name: &str,
+    range_low: u64,
+    range_high: u64,
+    field_name_owned: String,
+) {
+    let task_name = format!(
+        "range_{}_[{} TO {}]_{}",
+        field_name, range_low, range_high, collector_name
+    );
+
+    let search_task = Top100AscSearchTask {
+        searcher: bench_index.searcher.clone(),
+        query,
+        field_name: field_name_owned,
+    };
+    bench_group.register(task_name, move |_| black_box(search_task.run()));
+}
+
+fn add_bench_task_top100_desc(
+    bench_group: &mut BenchGroup,
+    bench_index: &BenchIndex,
+    query: RangeQuery,
+    collector_name: &str,
+    field_name: &str,
+    range_low: u64,
+    range_high: u64,
+    field_name_owned: String,
+) {
+    let task_name = format!(
+        "range_{}_[{} TO {}]_{}",
+        field_name, range_low, range_high, collector_name
+    );
+
+    let search_task = Top100DescSearchTask {
+        searcher: bench_index.searcher.clone(),
+        query,
+        field_name: field_name_owned,
+    };
+    bench_group.register(task_name, move |_| black_box(search_task.run()));
+}
+
+struct CountSearchTask {
+    searcher: Searcher,
+    query: RangeQuery,
+}
+
+impl CountSearchTask {
+    #[inline(never)]
+    pub fn run(&self) -> usize {
+        self.searcher.search(&self.query, &Count).unwrap()
+    }
+}
+
+struct DocSetSearchTask {
+    searcher: Searcher,
+    query: RangeQuery,
+}
+
+impl DocSetSearchTask {
+    #[inline(never)]
+    pub fn run(&self) -> usize {
+        let result = self.searcher.search(&self.query, &DocSetCollector).unwrap();
+        result.len()
+    }
+}
+
+struct Top100AscSearchTask {
+    searcher: Searcher,
+    query: RangeQuery,
+    field_name: String,
+}
+
+impl Top100AscSearchTask {
+    #[inline(never)]
+    pub fn run(&self) -> usize {
+        let collector =
+            TopDocs::with_limit(100).order_by_fast_field::<u64>(&self.field_name, Order::Asc);
+        let result = self.searcher.search(&self.query, &collector).unwrap();
+        for (_score, doc_address) in &result {
+            let _doc: tantivy::TantivyDocument = self.searcher.doc(*doc_address).unwrap();
+        }
+        result.len()
+    }
+}
+
+struct Top100DescSearchTask {
+    searcher: Searcher,
+    query: RangeQuery,
+    field_name: String,
+}
+
+impl Top100DescSearchTask {
+    #[inline(never)]
+    pub fn run(&self) -> usize {
+        let collector =
+            TopDocs::with_limit(100).order_by_fast_field::<u64>(&self.field_name, Order::Desc);
+        let result = self.searcher.search(&self.query, &collector).unwrap();
+        for (_score, doc_address) in &result {
+            let _doc: tantivy::TantivyDocument = self.searcher.doc(*doc_address).unwrap();
+        }
+        result.len()
+    }
+}

benches/range_query.rs

@@ -0,0 +1,260 @@
+use std::fmt::Display;
+use std::net::Ipv6Addr;
+use std::ops::RangeInclusive;
+
+use binggan::plugins::PeakMemAllocPlugin;
+use binggan::{black_box, BenchRunner, OutputValue, PeakMemAlloc, INSTRUMENTED_SYSTEM};
+use columnar::MonotonicallyMappableToU128;
+use rand::rngs::StdRng;
+use rand::{Rng, SeedableRng};
+use tantivy::collector::{Count, TopDocs};
+use tantivy::query::QueryParser;
+use tantivy::schema::*;
+use tantivy::{doc, Index};
+
+#[global_allocator]
+pub static GLOBAL: &PeakMemAlloc<std::alloc::System> = &INSTRUMENTED_SYSTEM;
+
+fn main() {
+    bench_range_query();
+}
+
+fn bench_range_query() {
+    let index = get_index_0_to_100();
+    let mut runner = BenchRunner::new();
+    runner.add_plugin(PeakMemAllocPlugin::new(GLOBAL));
+
+    runner.set_name("range_query on u64");
+    let field_name_and_descr: Vec<_> = vec![
+        ("id", "Single Valued Range Field"),
+        ("ids", "Multi Valued Range Field"),
+    ];
+    let range_num_hits = vec![
+        ("90_percent", get_90_percent()),
+        ("10_percent", get_10_percent()),
+        ("1_percent", get_1_percent()),
+    ];
+
+    test_range(&mut runner, &index, &field_name_and_descr, range_num_hits);
+
+    runner.set_name("range_query on ip");
+    let field_name_and_descr: Vec<_> = vec![
+        ("ip", "Single Valued Range Field"),
+        ("ips", "Multi Valued Range Field"),
+    ];
+    let range_num_hits = vec![
+        ("90_percent", get_90_percent_ip()),
+        ("10_percent", get_10_percent_ip()),
+        ("1_percent", get_1_percent_ip()),
+    ];
+
+    test_range(&mut runner, &index, &field_name_and_descr, range_num_hits);
+}
+
+fn test_range<T: Display>(
+    runner: &mut BenchRunner,
+    index: &Index,
+    field_name_and_descr: &[(&str, &str)],
+    range_num_hits: Vec<(&str, RangeInclusive<T>)>,
+) {
+    for (field, suffix) in field_name_and_descr {
+        let term_num_hits = vec![
+            ("", ""),
+            ("1_percent", "veryfew"),
+            ("10_percent", "few"),
+            ("90_percent", "most"),
+        ];
+        let mut group = runner.new_group();
+        group.set_name(suffix);
+        // all intersect combinations
+        for (range_name, range) in &range_num_hits {
+            for (term_name, term) in &term_num_hits {
+                let index = &index;
+                let test_name = if term_name.is_empty() {
+                    format!("id_range_hit_{}", range_name)
+                } else {
+                    format!(
+                        "id_range_hit_{}_intersect_with_term_{}",
+                        range_name, term_name
+                    )
+                };
+                group.register(test_name, move |_| {
+                    let query = if term_name.is_empty() {
+                        "".to_string()
+                    } else {
+                        format!("AND id_name:{}", term)
+                    };
+                    black_box(execute_query(field, range, &query, index));
+                });
+            }
+        }
+        group.run();
+    }
+}
+
+fn get_index_0_to_100() -> Index {
+    let mut rng = StdRng::from_seed([1u8; 32]);
+    let num_vals = 100_000;
+    let docs: Vec<_> = (0..num_vals)
+        .map(|_i| {
+            let id_name = if rng.random_bool(0.01) {
+                "veryfew".to_string() // 1%
+            } else if rng.random_bool(0.1) {
+                "few".to_string() // 9%
+            } else {
+                "most".to_string() // 90%
+            };
+            Doc {
+                id_name,
+                id: rng.random_range(0..100),
+                // Multiply by 1000, so that we create most buckets in the compact space
+                // The benches depend on this range to select n-percent of elements with the
+                // methods below.
+                ip: Ipv6Addr::from_u128(rng.random_range(0..100) * 1000),
+            }
+        })
+        .collect();
+
+    create_index_from_docs(&docs)
+}
+
+#[derive(Clone, Debug)]
+pub struct Doc {
+    pub id_name: String,
+    pub id: u64,
+    pub ip: Ipv6Addr,
+}
+
+pub fn create_index_from_docs(docs: &[Doc]) -> Index {
+    let mut schema_builder = Schema::builder();
+    let id_u64_field = schema_builder.add_u64_field("id", INDEXED | STORED | FAST);
+    let ids_u64_field =
+        schema_builder.add_u64_field("ids", NumericOptions::default().set_fast().set_indexed());
+
+    let id_f64_field = schema_builder.add_f64_field("id_f64", INDEXED | STORED | FAST);
+    let ids_f64_field = schema_builder.add_f64_field(
+        "ids_f64",
+        NumericOptions::default().set_fast().set_indexed(),
+    );
+
+    let id_i64_field = schema_builder.add_i64_field("id_i64", INDEXED | STORED | FAST);
+    let ids_i64_field = schema_builder.add_i64_field(
+        "ids_i64",
+        NumericOptions::default().set_fast().set_indexed(),
+    );
+
+    let text_field = schema_builder.add_text_field("id_name", STRING | STORED);
+    let text_field2 = schema_builder.add_text_field("id_name_fast", STRING | STORED | FAST);
+
+    let ip_field = schema_builder.add_ip_addr_field("ip", FAST);
+    let ips_field = schema_builder.add_ip_addr_field("ips", FAST);
+
+    let schema = schema_builder.build();
+
+    let index = Index::create_in_ram(schema);
+
+    {
+        let mut index_writer = index.writer_with_num_threads(1, 50_000_000).unwrap();
+        for doc in docs.iter() {
+            index_writer
+                .add_document(doc!(
+                    ids_i64_field => doc.id as i64,
+                    ids_i64_field => doc.id as i64,
+                    ids_f64_field => doc.id as f64,
+                    ids_f64_field => doc.id as f64,
+                    ids_u64_field => doc.id,
+                    ids_u64_field => doc.id,
+                    id_u64_field => doc.id,
+                    id_f64_field => doc.id as f64,
+                    id_i64_field => doc.id as i64,
+                    text_field => doc.id_name.to_string(),
+                    text_field2 => doc.id_name.to_string(),
+                    ips_field => doc.ip,
+                    ips_field => doc.ip,
+                    ip_field => doc.ip,
+                ))
+                .unwrap();
+        }
+
+        index_writer.commit().unwrap();
+    }
+    index
+}
+
+fn get_90_percent() -> RangeInclusive<u64> {
+    0..=90
+}
+
+fn get_10_percent() -> RangeInclusive<u64> {
+    0..=10
+}
+
+fn get_1_percent() -> RangeInclusive<u64> {
+    10..=10
+}
+
+fn get_90_percent_ip() -> RangeInclusive<Ipv6Addr> {
+    let start = Ipv6Addr::from_u128(0);
+    let end = Ipv6Addr::from_u128(90 * 1000);
+    start..=end
+}
+
+fn get_10_percent_ip() -> RangeInclusive<Ipv6Addr> {
+    let start = Ipv6Addr::from_u128(0);
+    let end = Ipv6Addr::from_u128(10 * 1000);
+    start..=end
+}
+
+fn get_1_percent_ip() -> RangeInclusive<Ipv6Addr> {
+    let start = Ipv6Addr::from_u128(10 * 1000);
+    let end = Ipv6Addr::from_u128(10 * 1000);
+    start..=end
+}
+
+struct NumHits {
+    count: usize,
+}
+impl OutputValue for NumHits {
+    fn column_title() -> &'static str {
+        "NumHits"
+    }
+    fn format(&self) -> Option<String> {
+        Some(self.count.to_string())
+    }
+}
+
+fn execute_query<T: Display>(
+    field: &str,
+    id_range: &RangeInclusive<T>,
+    suffix: &str,
+    index: &Index,
+) -> NumHits {
+    let gen_query_inclusive = |from: &T, to: &T| {
+        format!(
+            "{}:[{} TO {}] {}",
+            field,
+            &from.to_string(),
+            &to.to_string(),
+            suffix
+        )
+    };
+
+    let query = gen_query_inclusive(id_range.start(), id_range.end());
+    execute_query_(&query, index)
+}
+
+fn execute_query_(query: &str, index: &Index) -> NumHits {
+    let query_from_text = |text: &str| {
+        QueryParser::for_index(index, vec![])
+            .parse_query(text)
+            .unwrap()
+    };
+    let query = query_from_text(query);
+    let reader = index.reader().unwrap();
+    let searcher = reader.searcher();
+    let num_hits = searcher
+        .search(&query, &(TopDocs::with_limit(10).order_by_score(), Count))
+        .unwrap()
+        .1;
+    NumHits { count: num_hits }
+}

benches/regex_all_terms.rs

@@ -0,0 +1,113 @@
+// Benchmarks regex query that matches all terms in a synthetic index.
+//
+// Corpus model:
+// - N unique terms: t000000, t000001, ...
+// - M docs
+// - K tokens per doc: doc i gets terms derived from (i, token_index)
+//
+// Query:
+// - Regex "t.*" to match all terms
+//
+// Run with:
+// - cargo bench --bench regex_all_terms
+//
+
+use std::fmt::Write;
+
+use binggan::{black_box, BenchRunner};
+use tantivy::collector::Count;
+use tantivy::query::RegexQuery;
+use tantivy::schema::{Schema, TEXT};
+use tantivy::{doc, Index, ReloadPolicy};
+
+const HEAP_SIZE_BYTES: usize = 200_000_000;
+
+#[derive(Clone, Copy)]
+struct BenchConfig {
+    num_terms: usize,
+    num_docs: usize,
+    tokens_per_doc: usize,
+}
+
+fn main() {
+    let configs = default_configs();
+
+    let mut runner = BenchRunner::new();
+    for config in configs {
+        let (index, text_field) = build_index(config, HEAP_SIZE_BYTES);
+        let reader = index
+            .reader_builder()
+            .reload_policy(ReloadPolicy::Manual)
+            .try_into()
+            .expect("reader");
+        let searcher = reader.searcher();
+        let query = RegexQuery::from_pattern("t.*", text_field).expect("regex query");
+
+        let mut group = runner.new_group();
+        group.set_name(format!(
+            "regex_all_terms_t{}_d{}_k{}",
+            config.num_terms, config.num_docs, config.tokens_per_doc
+        ));
+        group.register("regex_count", move |_| {
+            let count = searcher.search(&query, &Count).expect("search");
+            black_box(count);
+        });
+        group.run();
+    }
+}
+
+fn default_configs() -> Vec<BenchConfig> {
+    vec![
+        BenchConfig {
+            num_terms: 10_000,
+            num_docs: 100_000,
+            tokens_per_doc: 1,
+        },
+        BenchConfig {
+            num_terms: 10_000,
+            num_docs: 100_000,
+            tokens_per_doc: 8,
+        },
+        BenchConfig {
+            num_terms: 100_000,
+            num_docs: 100_000,
+            tokens_per_doc: 1,
+        },
+        BenchConfig {
+            num_terms: 100_000,
+            num_docs: 100_000,
+            tokens_per_doc: 8,
+        },
+    ]
+}
+
+fn build_index(config: BenchConfig, heap_size_bytes: usize) -> (Index, tantivy::schema::Field) {
+    let mut schema_builder = Schema::builder();
+    let text_field = schema_builder.add_text_field("text", TEXT);
+    let schema = schema_builder.build();
+    let index = Index::create_in_ram(schema);
+
+    let term_width = config.num_terms.to_string().len();
+    {
+        let mut writer = index
+            .writer_with_num_threads(1, heap_size_bytes)
+            .expect("writer");
+        let mut buffer = String::new();
+        for doc_id in 0..config.num_docs {
+            buffer.clear();
+            for token_idx in 0..config.tokens_per_doc {
+                if token_idx > 0 {
+                    buffer.push(' ');
+                }
+                let term_id = (doc_id * config.tokens_per_doc + token_idx) % config.num_terms;
+                write!(&mut buffer, "t{term_id:0term_width$}").expect("write token");
+            }
+            writer
+                .add_document(doc!(text_field => buffer.as_str()))
+                .expect("add_document");
+        }
+        writer.commit().expect("commit");
+    }
+
+    (index, text_field)
+}

benches/str_search_and_get.rs

@@ -0,0 +1,421 @@
+// This benchmark compares different approaches for retrieving string values:
+//
+// 1. Fast Field Approach: retrieves string values via term_ords() and ord_to_str()
+//
+// 2. Doc Store Approach: retrieves string values via searcher.doc() and field extraction
+//
+// The benchmark includes various data distributions:
+// - Dense Sequential: Sequential document IDs with dense data
+// - Dense Random: Random document IDs with dense data
+// - Sparse Sequential: Sequential document IDs with sparse data
+// - Sparse Random: Random document IDs with sparse data
+use std::ops::Bound;
+
+use binggan::{black_box, BenchGroup, BenchRunner};
+use rand::prelude::*;
+use rand::rngs::StdRng;
+use rand::SeedableRng;
+use tantivy::collector::{Count, DocSetCollector};
+use tantivy::query::RangeQuery;
+use tantivy::schema::document::TantivyDocument;
+use tantivy::schema::{Schema, Value, FAST, STORED, STRING};
+use tantivy::{doc, Index, ReloadPolicy, Searcher, Term};
+
+#[derive(Clone)]
+struct BenchIndex {
+    #[allow(dead_code)]
+    index: Index,
+    searcher: Searcher,
+}
+
+fn build_shared_indices(num_docs: usize, distribution: &str) -> BenchIndex {
+    // Schema with string fast field and stored field for doc access
+    let mut schema_builder = Schema::builder();
+    let f_str_fast = schema_builder.add_text_field("str_fast", STRING | STORED | FAST);
+    let f_str_stored = schema_builder.add_text_field("str_stored", STRING | STORED);
+    let schema = schema_builder.build();
+    let index = Index::create_in_ram(schema.clone());
+
+    // Populate index with stable RNG for reproducibility.
+    let mut rng = StdRng::from_seed([7u8; 32]);
+
+    {
+        let mut writer = index.writer_with_num_threads(1, 4_000_000_000).unwrap();
+
+        match distribution {
+            "dense_random" => {
+                for _doc_id in 0..num_docs {
+                    let suffix = rng.gen_range(0u64..1000u64);
+                    let str_val = format!("str_{:03}", suffix);
+
+                    writer
+                        .add_document(doc!(
+                            f_str_fast=>str_val.clone(),
+                            f_str_stored=>str_val,
+                        ))
+                        .unwrap();
+                }
+            }
+            "dense_sequential" => {
+                for doc_id in 0..num_docs {
+                    let suffix = doc_id as u64 % 1000;
+                    let str_val = format!("str_{:03}", suffix);
+
+                    writer
+                        .add_document(doc!(
+                            f_str_fast=>str_val.clone(),
+                            f_str_stored=>str_val,
+                        ))
+                        .unwrap();
+                }
+            }
+            "sparse_random" => {
+                for _doc_id in 0..num_docs {
+                    let suffix = rng.gen_range(0u64..1000000u64);
+                    let str_val = format!("str_{:07}", suffix);
+
+                    writer
+                        .add_document(doc!(
+                            f_str_fast=>str_val.clone(),
+                            f_str_stored=>str_val,
+                        ))
+                        .unwrap();
+                }
+            }
+            "sparse_sequential" => {
+                for doc_id in 0..num_docs {
+                    let suffix = doc_id as u64;
+                    let str_val = format!("str_{:07}", suffix);
+
+                    writer
+                        .add_document(doc!(
+                            f_str_fast=>str_val.clone(),
+                            f_str_stored=>str_val,
+                        ))
+                        .unwrap();
+                }
+            }
+            _ => {
+                panic!("Unsupported distribution type");
+            }
+        }
+        writer.commit().unwrap();
+    }
+
+    // Prepare reader/searcher once.
+    let reader = index
+        .reader_builder()
+        .reload_policy(ReloadPolicy::Manual)
+        .try_into()
+        .unwrap();
+    let searcher = reader.searcher();
+
+    BenchIndex { index, searcher }
+}
+
+fn main() {
+    // Prepare corpora with varying scenarios
+    let scenarios = vec![
+        (
+            "dense_random_search_low_range".to_string(),
+            1_000_000,
+            "dense_random",
+            0,
+            9,
+        ),
+        (
+            "dense_random_search_high_range".to_string(),
+            1_000_000,
+            "dense_random",
+            990,
+            999,
+        ),
+        (
+            "dense_sequential_search_low_range".to_string(),
+            1_000_000,
+            "dense_sequential",
+            0,
+            9,
+        ),
+        (
+            "dense_sequential_search_high_range".to_string(),
+            1_000_000,
+            "dense_sequential",
+            990,
+            999,
+        ),
+        (
+            "sparse_random_search_low_range".to_string(),
+            1_000_000,
+            "sparse_random",
+            0,
+            9999,
+        ),
+        (
+            "sparse_random_search_high_range".to_string(),
+            1_000_000,
+            "sparse_random",
+            990_000,
+            999_999,
+        ),
+        (
+            "sparse_sequential_search_low_range".to_string(),
+            1_000_000,
+            "sparse_sequential",
+            0,
+            9999,
+        ),
+        (
+            "sparse_sequential_search_high_range".to_string(),
+            1_000_000,
+            "sparse_sequential",
+            990_000,
+            999_999,
+        ),
+    ];
+
+    let mut runner = BenchRunner::new();
+    for (scenario_id, n, distribution, range_low, range_high) in scenarios {
+        let bench_index = build_shared_indices(n, distribution);
+        let mut group = runner.new_group();
+        group.set_name(scenario_id);
+
+        let field = bench_index.searcher.schema().get_field("str_fast").unwrap();
+
+        let (lower_str, upper_str) =
+            if distribution == "dense_sequential" || distribution == "dense_random" {
+                (
+                    format!("str_{:03}", range_low),
+                    format!("str_{:03}", range_high),
+                )
+            } else {
+                (
+                    format!("str_{:07}", range_low),
+                    format!("str_{:07}", range_high),
+                )
+            };
+
+        let lower_term = Term::from_field_text(field, &lower_str);
+        let upper_term = Term::from_field_text(field, &upper_str);
+
+        let query = RangeQuery::new(Bound::Included(lower_term), Bound::Included(upper_term));
+
+        run_benchmark_tasks(&mut group, &bench_index, query, range_low, range_high);
+
+        group.run();
+    }
+}
+
+/// Run all benchmark tasks for a given range query
+fn run_benchmark_tasks(
+    bench_group: &mut BenchGroup,
+    bench_index: &BenchIndex,
+    query: RangeQuery,
+    range_low: u64,
+    range_high: u64,
+) {
+    // Test count of matching documents
+    add_bench_task_count(
+        bench_group,
+        bench_index,
+        query.clone(),
+        range_low,
+        range_high,
+    );
+
+    // Test fetching all DocIds of matching documents
+    add_bench_task_docset(
+        bench_group,
+        bench_index,
+        query.clone(),
+        range_low,
+        range_high,
+    );
+
+    // Test fetching all string fast field values of matching documents
+    add_bench_task_fetch_all_strings(
+        bench_group,
+        bench_index,
+        query.clone(),
+        range_low,
+        range_high,
+    );
+
+    // Test fetching all string values of matching documents through doc() method
+    add_bench_task_fetch_all_strings_from_doc(
+        bench_group,
+        bench_index,
+        query,
+        range_low,
+        range_high,
+    );
+}
+
+fn add_bench_task_count(
+    bench_group: &mut BenchGroup,
+    bench_index: &BenchIndex,
+    query: RangeQuery,
+    range_low: u64,
+    range_high: u64,
+) {
+    let task_name = format!("string_search_count_[{}-{}]", range_low, range_high);
+
+    let search_task = CountSearchTask {
+        searcher: bench_index.searcher.clone(),
+        query,
+    };
+    bench_group.register(task_name, move |_| black_box(search_task.run()));
+}
+
+fn add_bench_task_docset(
+    bench_group: &mut BenchGroup,
+    bench_index: &BenchIndex,
+    query: RangeQuery,
+    range_low: u64,
+    range_high: u64,
+) {
+    let task_name = format!("string_fetch_all_docset_[{}-{}]", range_low, range_high);
+
+    let search_task = DocSetSearchTask {
+        searcher: bench_index.searcher.clone(),
+        query,
+    };
+    bench_group.register(task_name, move |_| black_box(search_task.run()));
+}
+
+fn add_bench_task_fetch_all_strings(
+    bench_group: &mut BenchGroup,
+    bench_index: &BenchIndex,
+    query: RangeQuery,
+    range_low: u64,
+    range_high: u64,
+) {
+    let task_name = format!(
+        "string_fastfield_fetch_all_strings_[{}-{}]",
+        range_low, range_high
+    );
+
+    let search_task = FetchAllStringsSearchTask {
+        searcher: bench_index.searcher.clone(),
+        query,
+    };
+
+    bench_group.register(task_name, move |_| {
+        let result = black_box(search_task.run());
+        result.len()
+    });
+}
+
+fn add_bench_task_fetch_all_strings_from_doc(
+    bench_group: &mut BenchGroup,
+    bench_index: &BenchIndex,
+    query: RangeQuery,
+    range_low: u64,
+    range_high: u64,
+) {
+    let task_name = format!(
+        "string_doc_fetch_all_strings_[{}-{}]",
+        range_low, range_high
+    );
+
+    let search_task = FetchAllStringsFromDocTask {
+        searcher: bench_index.searcher.clone(),
+        query,
+    };
+
+    bench_group.register(task_name, move |_| {
+        let result = black_box(search_task.run());
+        result.len()
+    });
+}
+
+struct CountSearchTask {
+    searcher: Searcher,
+    query: RangeQuery,
+}
+
+impl CountSearchTask {
+    #[inline(never)]
+    pub fn run(&self) -> usize {
+        self.searcher.search(&self.query, &Count).unwrap()
+    }
+}
+
+struct DocSetSearchTask {
+    searcher: Searcher,
+    query: RangeQuery,
+}
+
+impl DocSetSearchTask {
+    #[inline(never)]
+    pub fn run(&self) -> usize {
+        let result = self.searcher.search(&self.query, &DocSetCollector).unwrap();
+        result.len()
+    }
+}
+
+struct FetchAllStringsSearchTask {
+    searcher: Searcher,
+    query: RangeQuery,
+}
+
+impl FetchAllStringsSearchTask {
+    #[inline(never)]
+    pub fn run(&self) -> Vec<String> {
+        let doc_addresses = self.searcher.search(&self.query, &DocSetCollector).unwrap();
+        let mut docs = doc_addresses.into_iter().collect::<Vec<_>>();
+        docs.sort();
+        let mut strings = Vec::with_capacity(docs.len());
+
+        for doc_address in docs {
+            let segment_reader = &self.searcher.segment_readers()[doc_address.segment_ord as usize];
+            let str_column_opt = segment_reader.fast_fields().str("str_fast");
+
+            if let Ok(Some(str_column)) = str_column_opt {
+                let doc_id = doc_address.doc_id;
+                let term_ord = str_column.term_ords(doc_id).next().unwrap();
+                let mut str_buffer = String::new();
+                if str_column.ord_to_str(term_ord, &mut str_buffer).is_ok() {
+                    strings.push(str_buffer);
+                }
+            }
+        }
+
+        strings
+    }
+}
+
+struct FetchAllStringsFromDocTask {
+    searcher: Searcher,
+    query: RangeQuery,
+}
+
+impl FetchAllStringsFromDocTask {
+    #[inline(never)]
+    pub fn run(&self) -> Vec<String> {
+        let doc_addresses = self.searcher.search(&self.query, &DocSetCollector).unwrap();
+        let mut docs = doc_addresses.into_iter().collect::<Vec<_>>();
+        docs.sort();
+        let mut strings = Vec::with_capacity(docs.len());
+
+        let str_stored_field = self
+            .searcher
+            .schema()
+            .get_field("str_stored")
+            .expect("str_stored field should exist");
+
+        for doc_address in docs {
+            // Get the document from the doc store (row store access)
+            if let Ok(doc) = self.searcher.doc::<TantivyDocument>(doc_address) {
+                // Extract string values from the stored field
+                if let Some(field_value) = doc.get_first(str_stored_field) {
+                    if let Some(text) = field_value.as_value().as_str() {
+                        strings.push(text.to_string());
+                    }
+                }
+            }
+        }
+
+        strings
+    }
+}

bitpacker/Cargo.toml

@@ -18,5 +18,5 @@ homepage = "https://github.com/quickwit-oss/tantivy"
 bitpacking = { version = "0.9.2", default-features = false, features = ["bitpacker1x"] }
 
 [dev-dependencies]
-rand = "0.8"
+rand = "0.9"
 proptest = "1"

bitpacker/benches/bench.rs

@@ -4,8 +4,8 @@ extern crate test;
 
 #[cfg(test)]
 mod tests {
+    use rand::rng;
     use rand::seq::IteratorRandom;
-    use rand::thread_rng;
     use tantivy_bitpacker::{BitPacker, BitUnpacker, BlockedBitpacker};
     use test::Bencher;
 
@@ -27,7 +27,7 @@ mod tests {
         let num_els = 1_000_000u32;
         let bit_unpacker = BitUnpacker::new(bit_width);
         let data = create_bitpacked_data(bit_width, num_els);
-        let idxs: Vec<u32> = (0..num_els).choose_multiple(&mut thread_rng(), 100_000);
+        let idxs: Vec<u32> = (0..num_els).choose_multiple(&mut rng(), 100_000);
         b.iter(|| {
             let mut out = 0u64;
             for &idx in &idxs {

bitpacker/src/filter_vec/avx2.rs

@@ -19,7 +19,7 @@ fn u32_to_i32(val: u32) -> i32 {
 #[inline]
 unsafe fn u32_to_i32_avx2(vals_u32x8s: DataType) -> DataType {
     const HIGHEST_BIT_MASK: DataType = from_u32x8([HIGHEST_BIT; NUM_LANES]);
-    op_xor(vals_u32x8s, HIGHEST_BIT_MASK)
+    unsafe { op_xor(vals_u32x8s, HIGHEST_BIT_MASK) }
 }
 
 pub fn filter_vec_in_place(range: RangeInclusive<u32>, offset: u32, output: &mut Vec<u32>) {
@@ -66,17 +66,19 @@ unsafe fn filter_vec_avx2_aux(
     ]);
     const SHIFT: __m256i = from_u32x8([NUM_LANES as u32; NUM_LANES]);
     for _ in 0..num_words {
-        let word = load_unaligned(input);
-        let word = u32_to_i32_avx2(word);
-        let keeper_bitset = compute_filter_bitset(word, range_simd.clone());
-        let added_len = keeper_bitset.count_ones();
-        let filtered_doc_ids = compact(ids, keeper_bitset);
-        store_unaligned(output_tail as *mut __m256i, filtered_doc_ids);
-        output_tail = output_tail.offset(added_len as isize);
-        ids = op_add(ids, SHIFT);
-        input = input.offset(1);
+        unsafe {
+            let word = load_unaligned(input);
+            let word = u32_to_i32_avx2(word);
+            let keeper_bitset = compute_filter_bitset(word, range_simd.clone());
+            let added_len = keeper_bitset.count_ones();
+            let filtered_doc_ids = compact(ids, keeper_bitset);
+            store_unaligned(output_tail as *mut __m256i, filtered_doc_ids);
+            output_tail = output_tail.offset(added_len as isize);
+            ids = op_add(ids, SHIFT);
+            input = input.offset(1);
+        }
     }
-    output_tail.offset_from(output) as usize
+    unsafe { output_tail.offset_from(output) as usize }
 }
 
 #[inline]
@@ -92,8 +94,7 @@ unsafe fn compute_filter_bitset(val: __m256i, range: std::ops::RangeInclusive<__
     let too_low = op_greater(*range.start(), val);
     let too_high = op_greater(val, *range.end());
     let inside = op_or(too_low, too_high);
-    255 - std::arch::x86_64::_mm256_movemask_ps(std::mem::transmute::<DataType, __m256>(inside))
-        as u8
+    255 - std::arch::x86_64::_mm256_movemask_ps(_mm256_castsi256_ps(inside)) as u8
 }
 
 union U8x32 {

columnar/Cargo.toml

@@ -22,7 +22,7 @@ downcast-rs = "2.0.1"
 [dev-dependencies]
 proptest = "1"
 more-asserts = "0.3.1"
-rand = "0.8"
+rand = "0.9"
 binggan = "0.14.0"
 
 [[bench]]

columnar/benches/bench_column_values_get.rs

@@ -9,7 +9,7 @@ use tantivy_columnar::column_values::{CodecType, serialize_and_load_u64_based_co
 fn get_data() -> Vec<u64> {
     let mut rng = StdRng::seed_from_u64(2u64);
     let mut data: Vec<_> = (100..55_000_u64)
-        .map(|num| num + rng.r#gen::<u8>() as u64)
+        .map(|num| num + rng.random::<u8>() as u64)
         .collect();
     data.push(99_000);
     data.insert(1000, 2000);

columnar/benches/bench_create_column_values.rs

@@ -6,7 +6,7 @@ use tantivy_columnar::column_values::{CodecType, serialize_u64_based_column_valu
 fn get_data() -> Vec<u64> {
     let mut rng = StdRng::seed_from_u64(2u64);
     let mut data: Vec<_> = (100..55_000_u64)
-        .map(|num| num + rng.r#gen::<u8>() as u64)
+        .map(|num| num + rng.random::<u8>() as u64)
         .collect();
     data.push(99_000);
     data.insert(1000, 2000);

columnar/benches/bench_optional_index.rs

@@ -8,7 +8,7 @@ const TOTAL_NUM_VALUES: u32 = 1_000_000;
 fn gen_optional_index(fill_ratio: f64) -> OptionalIndex {
     let mut rng: StdRng = StdRng::from_seed([1u8; 32]);
     let vals: Vec<u32> = (0..TOTAL_NUM_VALUES)
-        .map(|_| rng.gen_bool(fill_ratio))
+        .map(|_| rng.random_bool(fill_ratio))
         .enumerate()
         .filter(|(_pos, val)| *val)
         .map(|(pos, _)| pos as u32)
@@ -25,7 +25,7 @@ fn random_range_iterator(
     let mut rng: StdRng = StdRng::from_seed([1u8; 32]);
     let mut current = start;
     std::iter::from_fn(move || {
-        current += rng.gen_range(avg_step_size - avg_deviation..=avg_step_size + avg_deviation);
+        current += rng.random_range(avg_step_size - avg_deviation..=avg_step_size + avg_deviation);
         if current >= end { None } else { Some(current) }
     })
 }

columnar/benches/bench_values_u128.rs

@@ -39,7 +39,7 @@ fn get_data_50percent_item() -> Vec<u128> {
 
     let mut data = vec![];
     for _ in 0..300_000 {
-        let val = rng.gen_range(1..=100);
+        let val = rng.random_range(1..=100);
         data.push(val);
     }
     data.push(SINGLE_ITEM);

columnar/benches/bench_values_u64.rs

@@ -34,7 +34,7 @@ fn get_data_50percent_item() -> Vec<u128> {
 
     let mut data = vec![];
     for _ in 0..300_000 {
-        let val = rng.gen_range(1..=100);
+        let val = rng.random_range(1..=100);
         data.push(val);
     }
     data.push(SINGLE_ITEM);

columnar/src/block_accessor.rs

@@ -29,12 +29,20 @@ impl<T: PartialOrd + Copy + std::fmt::Debug + Send + Sync + 'static + Default>
         }
     }
     #[inline]
-    pub fn fetch_block_with_missing(&mut self, docs: &[u32], accessor: &Column<T>, missing: T) {
+    pub fn fetch_block_with_missing(
+        &mut self,
+        docs: &[u32],
+        accessor: &Column<T>,
+        missing: Option<T>,
+    ) {
         self.fetch_block(docs, accessor);
         // no missing values
         if accessor.index.get_cardinality().is_full() {
             return;
         }
+        let Some(missing) = missing else {
+            return;
+        };
 
         // We can compare docid_cache length with docs to find missing docs
         // For multi value columns we can't rely on the length and always need to scan

columnar/src/column/mod.rs

@@ -85,8 +85,8 @@ impl<T: PartialOrd + Copy + Debug + Send + Sync + 'static> Column<T> {
     }
 
     #[inline]
-    pub fn first(&self, row_id: RowId) -> Option<T> {
-        self.values_for_doc(row_id).next()
+    pub fn first(&self, doc_id: DocId) -> Option<T> {
+        self.values_for_doc(doc_id).next()
     }
 
     /// Load the first value for each docid in the provided slice.

columnar/src/column_values/u64_based/bitpacked.rs

@@ -41,12 +41,6 @@ fn transform_range_before_linear_transformation(
     if range.is_empty() {
         return None;
     }
-    if stats.min_value > *range.end() {
-        return None;
-    }
-    if stats.max_value < *range.start() {
-        return None;
-    }
     let shifted_range =
         range.start().saturating_sub(stats.min_value)..=range.end().saturating_sub(stats.min_value);
     let start_before_gcd_multiplication: u64 = div_ceil(*shifted_range.start(), stats.gcd);

columnar/src/column_values/u64_based/linear.rs

@@ -268,7 +268,7 @@ mod tests {
 
     #[test]
     fn linear_interpol_fast_field_rand() {
-        let mut rng = rand::thread_rng();
+        let mut rng = rand::rng();
         for _ in 0..50 {
             let mut data = (0..10_000).map(|_| rng.next_u64()).collect::<Vec<_>>();
             create_and_validate::<LinearCodec>(&data, "random");

columnar/src/column_values/u64_based/tests.rs

@@ -122,7 +122,7 @@ pub(crate) fn create_and_validate<TColumnCodec: ColumnCodec>(
     assert_eq!(vals, buffer);
 
     if !vals.is_empty() {
-        let test_rand_idx = rand::thread_rng().gen_range(0..=vals.len() - 1);
+        let test_rand_idx = rand::rng().random_range(0..=vals.len() - 1);
         let expected_positions: Vec<u32> = vals
             .iter()
             .enumerate()

columnar/src/dynamic_column.rs

@@ -3,7 +3,8 @@ use std::sync::Arc;
 use std::{fmt, io};
 
 use common::file_slice::FileSlice;
-use common::{ByteCount, DateTime, HasLen, OwnedBytes};
+use common::{ByteCount, DateTime, OwnedBytes};
+use serde::{Deserialize, Serialize};
 
 use crate::column::{BytesColumn, Column, StrColumn};
 use crate::column_values::{StrictlyMonotonicFn, monotonic_map_column};
@@ -317,10 +318,89 @@ impl DynamicColumnHandle {
     }
 
     pub fn num_bytes(&self) -> ByteCount {
-        self.file_slice.len().into()
+        self.file_slice.num_bytes()
+    }
+
+    /// Legacy helper returning the column space usage.
+    pub fn column_and_dictionary_num_bytes(&self) -> io::Result<ColumnSpaceUsage> {
+        self.space_usage()
+    }
+
+    /// Return the space usage of the column, optionally broken down by dictionary and column
+    /// values.
+    ///
+    /// For dictionary encoded columns (strings and bytes), this splits the total footprint into
+    /// the dictionary and the remaining column data (including index and values).
+    /// For all other column types, the dictionary size is `None` and the column size
+    /// equals the total bytes.
+    pub fn space_usage(&self) -> io::Result<ColumnSpaceUsage> {
+        let total_num_bytes = self.num_bytes();
+        let dynamic_column = self.open()?;
+        let dictionary_num_bytes = match &dynamic_column {
+            DynamicColumn::Bytes(bytes_column) => bytes_column.dictionary().num_bytes(),
+            DynamicColumn::Str(str_column) => str_column.dictionary().num_bytes(),
+            _ => {
+                return Ok(ColumnSpaceUsage::new(self.num_bytes(), None));
+            }
+        };
+        assert!(dictionary_num_bytes <= total_num_bytes);
+        let column_num_bytes =
+            ByteCount::from(total_num_bytes.get_bytes() - dictionary_num_bytes.get_bytes());
+        Ok(ColumnSpaceUsage::new(
+            column_num_bytes,
+            Some(dictionary_num_bytes),
+        ))
     }
 
     pub fn column_type(&self) -> ColumnType {
         self.column_type
     }
 }
+
+/// Represents space usage of a column.
+///
+/// `column_num_bytes` tracks the column payload (index, values and footer).
+/// For dictionary encoded columns, `dictionary_num_bytes` captures the dictionary footprint.
+/// [`ColumnSpaceUsage::total_num_bytes`] returns the sum of both parts.
+#[derive(Clone, Debug, Serialize, Deserialize)]
+pub struct ColumnSpaceUsage {
+    column_num_bytes: ByteCount,
+    dictionary_num_bytes: Option<ByteCount>,
+}
+
+impl ColumnSpaceUsage {
+    pub(crate) fn new(
+        column_num_bytes: ByteCount,
+        dictionary_num_bytes: Option<ByteCount>,
+    ) -> Self {
+        ColumnSpaceUsage {
+            column_num_bytes,
+            dictionary_num_bytes,
+        }
+    }
+
+    pub fn column_num_bytes(&self) -> ByteCount {
+        self.column_num_bytes
+    }
+
+    pub fn dictionary_num_bytes(&self) -> Option<ByteCount> {
+        self.dictionary_num_bytes
+    }
+
+    pub fn total_num_bytes(&self) -> ByteCount {
+        self.column_num_bytes + self.dictionary_num_bytes.unwrap_or_default()
+    }
+
+    /// Merge two space usage values by summing their components.
+    pub fn merge(&self, other: &ColumnSpaceUsage) -> ColumnSpaceUsage {
+        let dictionary_num_bytes = match (self.dictionary_num_bytes, other.dictionary_num_bytes) {
+            (Some(lhs), Some(rhs)) => Some(lhs + rhs),
+            (Some(val), None) | (None, Some(val)) => Some(val),
+            (None, None) => None,
+        };
+        ColumnSpaceUsage {
+            column_num_bytes: self.column_num_bytes + other.column_num_bytes,
+            dictionary_num_bytes,
+        }
+    }
+}

columnar/src/lib.rs

@@ -48,7 +48,7 @@ pub use columnar::{
 use sstable::VoidSSTable;
 pub use value::{NumericalType, NumericalValue};
 
-pub use self::dynamic_column::{DynamicColumn, DynamicColumnHandle};
+pub use self::dynamic_column::{ColumnSpaceUsage, DynamicColumn, DynamicColumnHandle};
 
 pub type RowId = u32;
 pub type DocId = u32;

columnar/src/tests.rs

@@ -60,7 +60,7 @@ fn test_dataframe_writer_bool() {
     let DynamicColumn::Bool(bool_col) = dyn_bool_col else {
         panic!();
     };
-    let vals: Vec<Option<bool>> = (0..5).map(|row_id| bool_col.first(row_id)).collect();
+    let vals: Vec<Option<bool>> = (0..5).map(|doc_id| bool_col.first(doc_id)).collect();
     assert_eq!(&vals, &[None, Some(false), None, Some(true), None,]);
 }
 
@@ -108,7 +108,7 @@ fn test_dataframe_writer_ip_addr() {
     let DynamicColumn::IpAddr(ip_col) = dyn_bool_col else {
         panic!();
     };
-    let vals: Vec<Option<Ipv6Addr>> = (0..5).map(|row_id| ip_col.first(row_id)).collect();
+    let vals: Vec<Option<Ipv6Addr>> = (0..5).map(|doc_id| ip_col.first(doc_id)).collect();
     assert_eq!(
         &vals,
         &[
@@ -169,7 +169,7 @@ fn test_dictionary_encoded_str() {
     let DynamicColumn::Str(str_col) = col_handles[0].open().unwrap() else {
         panic!();
     };
-    let index: Vec<Option<u64>> = (0..5).map(|row_id| str_col.ords().first(row_id)).collect();
+    let index: Vec<Option<u64>> = (0..5).map(|doc_id| str_col.ords().first(doc_id)).collect();
     assert_eq!(index, &[None, Some(0), None, Some(2), Some(1)]);
     assert_eq!(str_col.num_rows(), 5);
     let mut term_buffer = String::new();
@@ -204,7 +204,7 @@ fn test_dictionary_encoded_bytes() {
         panic!();
     };
     let index: Vec<Option<u64>> = (0..5)
-        .map(|row_id| bytes_col.ords().first(row_id))
+        .map(|doc_id| bytes_col.ords().first(doc_id))
         .collect();
     assert_eq!(index, &[None, Some(0), None, Some(2), Some(1)]);
     assert_eq!(bytes_col.num_rows(), 5);

common/Cargo.toml

@@ -21,5 +21,5 @@ serde = { version = "1.0.136", features = ["derive"] }
 [dev-dependencies]
 binggan = "0.14.0"
 proptest = "1.0.0"
-rand = "0.8.4"
+rand = "0.9"
 

common/benches/bench.rs

@@ -1,6 +1,6 @@
 use binggan::{BenchRunner, black_box};
+use rand::rng;
 use rand::seq::IteratorRandom;
-use rand::thread_rng;
 use tantivy_common::{BitSet, TinySet, serialize_vint_u32};
 
 fn bench_vint() {
@@ -17,7 +17,7 @@ fn bench_vint() {
         black_box(out);
     });
 
-    let vals: Vec<u32> = (0..20_000).choose_multiple(&mut thread_rng(), 100_000);
+    let vals: Vec<u32> = (0..20_000).choose_multiple(&mut rng(), 100_000);
     runner.bench_function("bench_vint_rand", move |_| {
         let mut out = 0u64;
         for val in vals.iter().cloned() {

common/src/bitset.rs

@@ -181,6 +181,14 @@ pub struct BitSet {
     len: u64,
     max_value: u32,
 }
+impl std::fmt::Debug for BitSet {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("BitSet")
+            .field("len", &self.len)
+            .field("max_value", &self.max_value)
+            .finish()
+    }
+}
 
 fn num_buckets(max_val: u32) -> u32 {
     max_val.div_ceil(64u32)
@@ -408,7 +416,7 @@ mod tests {
     use std::collections::HashSet;
 
     use ownedbytes::OwnedBytes;
-    use rand::distributions::Bernoulli;
+    use rand::distr::Bernoulli;
     use rand::rngs::StdRng;
     use rand::{Rng, SeedableRng};
 

doc/src/json.md

@@ -60,7 +60,7 @@ At indexing, tantivy will try to interpret number and strings as different type
 priority order.
 
 Numbers will be interpreted as u64, i64 and f64 in that order.
-Strings will be interpreted as rfc3999 dates or simple strings.
+Strings will be interpreted as rfc3339 dates or simple strings.
 
 The first working type is picked and is the only term that is emitted for indexing.
 Note this interpretation happens on a per-document basis, and there is no effort to try to sniff
@@ -81,7 +81,7 @@ Will be interpreted as
 (my_path.my_segment, String, 233) or (my_path.my_segment, u64, 233)
 ```
 
-Likewise, we need to emit two tokens if the query contains an rfc3999 date.
+Likewise, we need to emit two tokens if the query contains an rfc3339 date.
 Indeed the date could have been actually a single token inside the text of a document at ingestion time. Generally speaking, we will always at least emit a string token in query parsing, and sometimes more.
 
 If one more json field is defined, things get even more complicated.

examples/geo_json.rs

@@ -1,66 +0,0 @@
-use geo_types::Point;
-use tantivy::collector::TopDocs;
-use tantivy::query::SpatialQuery;
-use tantivy::schema::{Schema, Value, SPATIAL, STORED, TEXT};
-use tantivy::spatial::point::GeoPoint;
-use tantivy::{Index, IndexWriter, TantivyDocument};
-fn main() -> tantivy::Result<()> {
-    let mut schema_builder = Schema::builder();
-    schema_builder.add_json_field("properties", STORED | TEXT);
-    schema_builder.add_spatial_field("geometry", STORED | SPATIAL);
-    let schema = schema_builder.build();
-    let index = Index::create_in_ram(schema.clone());
-    let mut index_writer: IndexWriter = index.writer(50_000_000)?;
-    let doc = TantivyDocument::parse_json(
-        &schema,
-        r#"{
-            "type":"Feature",
-            "geometry":{
-                "type":"Polygon",
-                "coordinates":[[[-99.483911,45.577697],[-99.483869,45.571457],[-99.481739,45.571461],[-99.474881,45.571584],[-99.473167,45.571615],[-99.463394,45.57168],[-99.463391,45.57883],[-99.463368,45.586076],[-99.48177,45.585926],[-99.48384,45.585953],[-99.483885,45.57873],[-99.483911,45.577697]]]
-            },
-            "properties":{
-                "admin_level":"8",
-                "border_type":"city",
-                "boundary":"administrative",
-                "gnis:feature_id":"1267426",
-                "name":"Hosmer",
-                "place":"city",
-                "source":"TIGER/Line® 2008 Place Shapefiles (http://www.census.gov/geo/www/tiger/)",
-                "wikidata":"Q2442118",
-                "wikipedia":"en:Hosmer, South Dakota"
-            }
-        }"#,
-    )?;
-    index_writer.add_document(doc)?;
-    index_writer.commit()?;
-
-    let reader = index.reader()?;
-    let searcher = reader.searcher();
-    let field = schema.get_field("geometry").unwrap();
-    let query = SpatialQuery::new(
-        field,
-        [
-            GeoPoint {
-                lon: -99.49,
-                lat: 45.56,
-            },
-            GeoPoint {
-                lon: -99.45,
-                lat: 45.59,
-            },
-        ],
-        tantivy::query::SpatialQueryType::Intersects,
-    );
-    let hits = searcher.search(&query, &TopDocs::with_limit(10).order_by_score())?;
-    for (_score, doc_address) in &hits {
-        let retrieved_doc: TantivyDocument = searcher.doc(*doc_address)?;
-        if let Some(field_value) = retrieved_doc.get_first(field) {
-            if let Some(geometry_box) = field_value.as_value().into_geometry() {
-                println!("Retrieved geometry: {:?}", geometry_box);
-            }
-        }
-    }
-    assert_eq!(hits.len(), 1);
-    Ok(())
-}

query-grammar/src/query_grammar.rs

@@ -560,7 +560,7 @@ fn range_infallible(inp: &str) -> JResult<&str, UserInputLeaf> {
             (
                 (
                     value((), tag(">=")),
-                    map(word_infallible("", false), |(bound, err)| {
+                    map(word_infallible(")", false), |(bound, err)| {
                         (
                             (
                                 bound
@@ -574,7 +574,7 @@ fn range_infallible(inp: &str) -> JResult<&str, UserInputLeaf> {
                 ),
                 (
                     value((), tag("<=")),
-                    map(word_infallible("", false), |(bound, err)| {
+                    map(word_infallible(")", false), |(bound, err)| {
                         (
                             (
                                 UserInputBound::Unbounded,
@@ -588,7 +588,7 @@ fn range_infallible(inp: &str) -> JResult<&str, UserInputLeaf> {
                 ),
                 (
                     value((), tag(">")),
-                    map(word_infallible("", false), |(bound, err)| {
+                    map(word_infallible(")", false), |(bound, err)| {
                         (
                             (
                                 bound
@@ -602,7 +602,7 @@ fn range_infallible(inp: &str) -> JResult<&str, UserInputLeaf> {
                 ),
                 (
                     value((), tag("<")),
-                    map(word_infallible("", false), |(bound, err)| {
+                    map(word_infallible(")", false), |(bound, err)| {
                         (
                             (
                                 UserInputBound::Unbounded,
@@ -1323,6 +1323,14 @@ mod test {
         test_parse_query_to_ast_helper("<a", "{\"*\" TO \"a\"}");
         test_parse_query_to_ast_helper("<=a", "{\"*\" TO \"a\"]");
         test_parse_query_to_ast_helper("<=bsd", "{\"*\" TO \"bsd\"]");
+
+        test_parse_query_to_ast_helper("(<=42)", "{\"*\" TO \"42\"]");
+        test_parse_query_to_ast_helper("(<=42 )", "{\"*\" TO \"42\"]");
+        test_parse_query_to_ast_helper("(age:>5)", "\"age\":{\"5\" TO \"*\"}");
+        test_parse_query_to_ast_helper(
+            "(title:bar AND age:>12)",
+            "(+\"title\":bar +\"age\":{\"12\" TO \"*\"})",
+        );
     }
 
     #[test]

src/aggregation/agg_data.rs

@@ -1,4 +1,4 @@
-use columnar::{Column, ColumnType, StrColumn};
+use columnar::{Column, ColumnBlockAccessor, ColumnType, StrColumn};
 use common::BitSet;
 use rustc_hash::FxHashSet;
 use serde::Serialize;
@@ -10,16 +10,16 @@ use crate::aggregation::accessor_helpers::{
 };
 use crate::aggregation::agg_req::{Aggregation, AggregationVariants, Aggregations};
 use crate::aggregation::bucket::{
-    FilterAggReqData, HistogramAggReqData, HistogramBounds, IncludeExcludeParam,
-    MissingTermAggReqData, RangeAggReqData, SegmentFilterCollector, SegmentHistogramCollector,
-    SegmentRangeCollector, TermMissingAgg, TermsAggReqData, TermsAggregation,
+    build_segment_filter_collector, build_segment_range_collector, FilterAggReqData,
+    HistogramAggReqData, HistogramBounds, IncludeExcludeParam, MissingTermAggReqData,
+    RangeAggReqData, SegmentHistogramCollector, TermMissingAgg, TermsAggReqData, TermsAggregation,
     TermsAggregationInternal,
 };
 use crate::aggregation::metric::{
-    AverageAggregation, CardinalityAggReqData, CardinalityAggregationReq, CountAggregation,
-    ExtendedStatsAggregation, MaxAggregation, MetricAggReqData, MinAggregation,
-    SegmentCardinalityCollector, SegmentExtendedStatsCollector, SegmentPercentilesCollector,
-    SegmentStatsCollector, StatsAggregation, StatsType, SumAggregation, TopHitsAggReqData,
+    build_segment_stats_collector, AverageAggregation, CardinalityAggReqData,
+    CardinalityAggregationReq, CountAggregation, ExtendedStatsAggregation, MaxAggregation,
+    MetricAggReqData, MinAggregation, SegmentCardinalityCollector, SegmentExtendedStatsCollector,
+    SegmentPercentilesCollector, StatsAggregation, StatsType, SumAggregation, TopHitsAggReqData,
     TopHitsSegmentCollector,
 };
 use crate::aggregation::segment_agg_result::{
@@ -35,6 +35,7 @@ pub struct AggregationsSegmentCtx {
     /// Request data for each aggregation type.
     pub per_request: PerRequestAggSegCtx,
     pub context: AggContextParams,
+    pub column_block_accessor: ColumnBlockAccessor<u64>,
 }
 
 impl AggregationsSegmentCtx {
@@ -107,21 +108,14 @@ impl AggregationsSegmentCtx {
             .as_deref()
             .expect("range_req_data slot is empty (taken)")
     }
-    #[inline]
-    pub(crate) fn get_filter_req_data(&self, idx: usize) -> &FilterAggReqData {
-        self.per_request.filter_req_data[idx]
-            .as_deref()
-            .expect("filter_req_data slot is empty (taken)")
-    }
 
     // ---------- mutable getters ----------
 
     #[inline]
-    pub(crate) fn get_term_req_data_mut(&mut self, idx: usize) -> &mut TermsAggReqData {
-        self.per_request.term_req_data[idx]
-            .as_deref_mut()
-            .expect("term_req_data slot is empty (taken)")
+    pub(crate) fn get_metric_req_data_mut(&mut self, idx: usize) -> &mut MetricAggReqData {
+        &mut self.per_request.stats_metric_req_data[idx]
     }
+
     #[inline]
     pub(crate) fn get_cardinality_req_data_mut(
         &mut self,
@@ -129,10 +123,7 @@ impl AggregationsSegmentCtx {
     ) -> &mut CardinalityAggReqData {
         &mut self.per_request.cardinality_req_data[idx]
     }
-    #[inline]
-    pub(crate) fn get_metric_req_data_mut(&mut self, idx: usize) -> &mut MetricAggReqData {
-        &mut self.per_request.stats_metric_req_data[idx]
-    }
+
     #[inline]
     pub(crate) fn get_histogram_req_data_mut(&mut self, idx: usize) -> &mut HistogramAggReqData {
         self.per_request.histogram_req_data[idx]
@@ -142,21 +133,6 @@ impl AggregationsSegmentCtx {
 
     // ---------- take / put (terms, histogram, range) ----------
 
-    /// Move out the boxed Terms request at `idx`, leaving `None`.
-    #[inline]
-    pub(crate) fn take_term_req_data(&mut self, idx: usize) -> Box<TermsAggReqData> {
-        self.per_request.term_req_data[idx]
-            .take()
-            .expect("term_req_data slot is empty (taken)")
-    }
-
-    /// Put back a Terms request into an empty slot at `idx`.
-    #[inline]
-    pub(crate) fn put_back_term_req_data(&mut self, idx: usize, value: Box<TermsAggReqData>) {
-        debug_assert!(self.per_request.term_req_data[idx].is_none());
-        self.per_request.term_req_data[idx] = Some(value);
-    }
-
     /// Move out the boxed Histogram request at `idx`, leaving `None`.
     #[inline]
     pub(crate) fn take_histogram_req_data(&mut self, idx: usize) -> Box<HistogramAggReqData> {
@@ -320,6 +296,7 @@ impl PerRequestAggSegCtx {
 
     /// Convert the aggregation tree into a serializable struct representation.
     /// Each node contains: { name, kind, children }.
+    #[allow(dead_code)]
     pub fn get_view_tree(&self) -> Vec<AggTreeViewNode> {
         fn node_to_view(node: &AggRefNode, pr: &PerRequestAggSegCtx) -> AggTreeViewNode {
             let mut children: Vec<AggTreeViewNode> =
@@ -345,12 +322,19 @@ impl PerRequestAggSegCtx {
 pub(crate) fn build_segment_agg_collectors_root(
     req: &mut AggregationsSegmentCtx,
 ) -> crate::Result<Box<dyn SegmentAggregationCollector>> {
-    build_segment_agg_collectors(req, &req.per_request.agg_tree.clone())
+    build_segment_agg_collectors_generic(req, &req.per_request.agg_tree.clone())
 }
 
 pub(crate) fn build_segment_agg_collectors(
     req: &mut AggregationsSegmentCtx,
     nodes: &[AggRefNode],
+) -> crate::Result<Box<dyn SegmentAggregationCollector>> {
+    build_segment_agg_collectors_generic(req, nodes)
+}
+
+fn build_segment_agg_collectors_generic(
+    req: &mut AggregationsSegmentCtx,
+    nodes: &[AggRefNode],
 ) -> crate::Result<Box<dyn SegmentAggregationCollector>> {
     let mut collectors = Vec::new();
     for node in nodes.iter() {
@@ -388,6 +372,8 @@ pub(crate) fn build_segment_agg_collector(
             Ok(Box::new(SegmentCardinalityCollector::from_req(
                 req_data.column_type,
                 node.idx_in_req_data,
+                req_data.accessor.clone(),
+                req_data.missing_value_for_accessor,
             )))
         }
         AggKind::StatsKind(stats_type) => {
@@ -398,20 +384,21 @@ pub(crate) fn build_segment_agg_collector(
                 | StatsType::Count
                 | StatsType::Max
                 | StatsType::Min
-                | StatsType::Stats => Ok(Box::new(SegmentStatsCollector::from_req(
-                    node.idx_in_req_data,
-                ))),
-                StatsType::ExtendedStats(sigma) => {
-                    Ok(Box::new(SegmentExtendedStatsCollector::from_req(
-                        req_data.field_type,
-                        sigma,
-                        node.idx_in_req_data,
-                        req_data.missing,
-                    )))
-                }
-                StatsType::Percentiles => Ok(Box::new(
-                    SegmentPercentilesCollector::from_req_and_validate(node.idx_in_req_data)?,
+                | StatsType::Stats => build_segment_stats_collector(req_data),
+                StatsType::ExtendedStats(sigma) => Ok(Box::new(
+                    SegmentExtendedStatsCollector::from_req(req_data, sigma),
                 )),
+                StatsType::Percentiles => {
+                    let req_data = req.get_metric_req_data_mut(node.idx_in_req_data);
+                    Ok(Box::new(
+                        SegmentPercentilesCollector::from_req_and_validate(
+                            req_data.field_type,
+                            req_data.missing_u64,
+                            req_data.accessor.clone(),
+                            node.idx_in_req_data,
+                        ),
+                    ))
+                }
             }
         }
         AggKind::TopHits => {
@@ -428,12 +415,8 @@ pub(crate) fn build_segment_agg_collector(
         AggKind::DateHistogram => Ok(Box::new(SegmentHistogramCollector::from_req_and_validate(
             req, node,
         )?)),
-        AggKind::Range => Ok(Box::new(SegmentRangeCollector::from_req_and_validate(
-            req, node,
-        )?)),
-        AggKind::Filter => Ok(Box::new(SegmentFilterCollector::from_req_and_validate(
-            req, node,
-        )?)),
+        AggKind::Range => Ok(build_segment_range_collector(req, node)?),
+        AggKind::Filter => build_segment_filter_collector(req, node),
     }
 }
 
@@ -493,6 +476,7 @@ pub(crate) fn build_aggregations_data_from_req(
     let mut data = AggregationsSegmentCtx {
         per_request: Default::default(),
         context,
+        column_block_accessor: ColumnBlockAccessor::default(),
     };
 
     for (name, agg) in aggs.iter() {
@@ -521,9 +505,9 @@ fn build_nodes(
             let idx_in_req_data = data.push_range_req_data(RangeAggReqData {
                 accessor,
                 field_type,
-                column_block_accessor: Default::default(),
                 name: agg_name.to_string(),
                 req: range_req.clone(),
+                is_top_level,
             });
             let children = build_children(&req.sub_aggregation, reader, segment_ordinal, data)?;
             Ok(vec![AggRefNode {
@@ -541,9 +525,7 @@ fn build_nodes(
             let idx_in_req_data = data.push_histogram_req_data(HistogramAggReqData {
                 accessor,
                 field_type,
-                column_block_accessor: Default::default(),
                 name: agg_name.to_string(),
-                sub_aggregation_blueprint: None,
                 req: histo_req.clone(),
                 is_date_histogram: false,
                 bounds: HistogramBounds {
@@ -568,9 +550,7 @@ fn build_nodes(
             let idx_in_req_data = data.push_histogram_req_data(HistogramAggReqData {
                 accessor,
                 field_type,
-                column_block_accessor: Default::default(),
                 name: agg_name.to_string(),
-                sub_aggregation_blueprint: None,
                 req: histo_req,
                 is_date_histogram: true,
                 bounds: HistogramBounds {
@@ -650,7 +630,6 @@ fn build_nodes(
             let idx_in_req_data = data.push_metric_req_data(MetricAggReqData {
                 accessor,
                 field_type,
-                column_block_accessor: Default::default(),
                 name: agg_name.to_string(),
                 collecting_for,
                 missing: *missing,
@@ -678,7 +657,6 @@ fn build_nodes(
             let idx_in_req_data = data.push_metric_req_data(MetricAggReqData {
                 accessor,
                 field_type,
-                column_block_accessor: Default::default(),
                 name: agg_name.to_string(),
                 collecting_for: StatsType::Percentiles,
                 missing: percentiles_req.missing,
@@ -753,6 +731,7 @@ fn build_nodes(
                 segment_reader: reader.clone(),
                 evaluator,
                 matching_docs_buffer,
+                is_top_level,
             });
             let children = build_children(&req.sub_aggregation, reader, segment_ordinal, data)?;
             Ok(vec![AggRefNode {
@@ -895,7 +874,7 @@ fn build_terms_or_cardinality_nodes(
         });
     }
 
-    // Add one node per accessor to mirror previous behavior and allow per-type missing handling.
+    // Add one node per accessor
     for (accessor, column_type) in column_and_types {
         let missing_value_for_accessor = if use_special_missing_agg {
             None
@@ -926,11 +905,8 @@ fn build_terms_or_cardinality_nodes(
                     column_type,
                     str_dict_column: str_dict_column.clone(),
                     missing_value_for_accessor,
-                    column_block_accessor: Default::default(),
                     name: agg_name.to_string(),
                     req: TermsAggregationInternal::from_req(req),
-                    // Will be filled later when building collectors
-                    sub_aggregation_blueprint: None,
                     sug_aggregations: sub_aggs.clone(),
                     allowed_term_ids,
                     is_top_level,
@@ -943,7 +919,6 @@ fn build_terms_or_cardinality_nodes(
                     column_type,
                     str_dict_column: str_dict_column.clone(),
                     missing_value_for_accessor,
-                    column_block_accessor: Default::default(),
                     name: agg_name.to_string(),
                     req: req.clone(),
                 });

src/aggregation/agg_result.rs

@@ -10,7 +10,8 @@ use serde::{Deserialize, Serialize};
 
 use super::bucket::GetDocCount;
 use super::metric::{
-    ExtendedStats, PercentilesMetricResult, SingleMetricResult, Stats, TopHitsMetricResult,
+    AverageMetricResult, CardinalityMetricResult, ExtendedStats, PercentilesMetricResult,
+    SingleMetricResult, Stats, TopHitsMetricResult,
 };
 use super::{AggregationError, Key};
 use crate::TantivyError;
@@ -81,8 +82,8 @@ impl AggregationResult {
 #[serde(untagged)]
 /// MetricResult
 pub enum MetricResult {
-    /// Average metric result.
-    Average(SingleMetricResult),
+    /// Average metric result with sum and count for multi-step merging.
+    Average(AverageMetricResult),
     /// Count metric result.
     Count(SingleMetricResult),
     /// Max metric result.
@@ -99,8 +100,8 @@ pub enum MetricResult {
     Percentiles(PercentilesMetricResult),
     /// Top hits metric result
     TopHits(TopHitsMetricResult),
-    /// Cardinality metric result
-    Cardinality(SingleMetricResult),
+    /// Cardinality metric result with HLL sketch for multi-step merging.
+    Cardinality(CardinalityMetricResult),
 }
 
 impl MetricResult {
@@ -119,7 +120,7 @@ impl MetricResult {
             MetricResult::TopHits(_) => Err(TantivyError::AggregationError(
                 AggregationError::InvalidRequest("top_hits can't be used to order".to_string()),
             )),
-            MetricResult::Cardinality(card) => Ok(card.value),
+            MetricResult::Cardinality(card) => Ok(card.value), // CardinalityMetricResult.value
         }
     }
 }

src/aggregation/agg_tests.rs

@@ -2,15 +2,441 @@ use serde_json::Value;
 
 use crate::aggregation::agg_req::{Aggregation, Aggregations};
 use crate::aggregation::agg_result::AggregationResults;
-use crate::aggregation::buf_collector::DOC_BLOCK_SIZE;
 use crate::aggregation::collector::AggregationCollector;
 use crate::aggregation::intermediate_agg_result::IntermediateAggregationResults;
 use crate::aggregation::tests::{get_test_index_2_segments, get_test_index_from_values_and_terms};
 use crate::aggregation::DistributedAggregationCollector;
+use crate::docset::COLLECT_BLOCK_BUFFER_LEN;
 use crate::query::{AllQuery, TermQuery};
 use crate::schema::{IndexRecordOption, Schema, FAST};
 use crate::{Index, IndexWriter, Term};
 
+// The following tests ensure that each bucket aggregation type correctly functions as a
+// sub-aggregation of another bucket aggregation in two scenarios:
+// 1) The parent has more buckets than the child sub-aggregation
+// 2) The child sub-aggregation has more buckets than the parent
+//
+// These scenarios exercise the bucket id mapping and sub-aggregation routing logic.
+
+#[test]
+fn test_terms_as_subagg_parent_more_vs_child_more() -> crate::Result<()> {
+    let index = get_test_index_2_segments(false)?;
+
+    // Case A: parent has more buckets than child
+    // Parent: range with 4 buckets
+    // Child: terms on text -> 2 buckets
+    let agg_parent_more: Aggregations = serde_json::from_value(json!({
+        "parent_range": {
+            "range": {
+                "field": "score",
+                "ranges": [
+                    {"to": 3.0},
+                    {"from": 3.0, "to": 7.0},
+                    {"from": 7.0, "to": 20.0},
+                    {"from": 20.0}
+                ]
+            },
+            "aggs": {
+                "child_terms": {"terms": {"field": "text", "order": {"_key": "asc"}}}
+            }
+        }
+    }))
+    .unwrap();
+
+    let res = crate::aggregation::tests::exec_request(agg_parent_more, &index)?;
+    // Exact expected structure and counts
+    assert_eq!(
+        res["parent_range"]["buckets"],
+        json!([
+            {
+                "key": "*-3",
+                "doc_count": 1,
+                "to": 3.0,
+                "child_terms": {
+                    "buckets": [
+                        {"doc_count": 1, "key": "cool"}
+                    ],
+                    "sum_other_doc_count": 0
+                }
+            },
+            {
+                "key": "3-7",
+                "doc_count": 3,
+                "from": 3.0,
+                "to": 7.0,
+                "child_terms": {
+                    "buckets": [
+                        {"doc_count": 2, "key": "cool"},
+                        {"doc_count": 1, "key": "nohit"}
+                    ],
+                    "sum_other_doc_count": 0
+                }
+            },
+            {
+                "key": "7-20",
+                "doc_count": 3,
+                "from": 7.0,
+                "to": 20.0,
+                "child_terms": {
+                    "buckets": [
+                        {"doc_count": 3, "key": "cool"}
+                    ],
+                    "sum_other_doc_count": 0
+                }
+            },
+            {
+                "key": "20-*",
+                "doc_count": 2,
+                "from": 20.0,
+                "child_terms": {
+                    "buckets": [
+                        {"doc_count": 1, "key": "cool"},
+                        {"doc_count": 1, "key": "nohit"}
+                    ],
+                    "sum_other_doc_count": 0
+                }
+            }
+        ])
+    );
+
+    // Case B: child has more buckets than parent
+    // Parent: histogram on score with large interval -> 1 bucket
+    // Child: terms on text -> 2 buckets (cool/nohit)
+    let agg_child_more: Aggregations = serde_json::from_value(json!({
+        "parent_hist": {
+            "histogram": {"field": "score", "interval": 100.0},
+            "aggs": {
+                "child_terms": {"terms": {"field": "text", "order": {"_key": "asc"}}}
+            }
+        }
+    }))
+    .unwrap();
+
+    let res = crate::aggregation::tests::exec_request(agg_child_more, &index)?;
+    assert_eq!(
+        res["parent_hist"],
+        json!({
+            "buckets": [
+                {
+                    "key": 0.0,
+                    "doc_count": 9,
+                    "child_terms": {
+                        "buckets": [
+                            {"doc_count": 7, "key": "cool"},
+                            {"doc_count": 2, "key": "nohit"}
+                        ],
+                        "sum_other_doc_count": 0
+                    }
+                }
+            ]
+        })
+    );
+
+    Ok(())
+}
+
+#[test]
+fn test_range_as_subagg_parent_more_vs_child_more() -> crate::Result<()> {
+    let index = get_test_index_2_segments(false)?;
+
+    // Case A: parent has more buckets than child
+    // Parent: range with 5 buckets
+    // Child: coarse range with 3 buckets
+    let agg_parent_more: Aggregations = serde_json::from_value(json!({
+        "parent_range": {
+            "range": {
+                "field": "score",
+                "ranges": [
+                    {"to": 3.0},
+                    {"from": 3.0, "to": 7.0},
+                    {"from": 7.0, "to": 11.0},
+                    {"from": 11.0, "to": 20.0},
+                    {"from": 20.0}
+                ]
+            },
+            "aggs": {
+                "child_range": {
+                    "range": {
+                        "field": "score",
+                        "ranges": [
+                            {"to": 3.0},
+                            {"from": 3.0, "to": 20.0}
+                        ]
+                    }
+                }
+            }
+        }
+    }))
+    .unwrap();
+    let res = crate::aggregation::tests::exec_request(agg_parent_more, &index)?;
+    assert_eq!(
+        res["parent_range"]["buckets"],
+        json!([
+            {"key": "*-3", "doc_count": 1, "to": 3.0,
+                "child_range": {"buckets": [
+                    {"key": "*-3", "doc_count": 1, "to": 3.0},
+                    {"key": "3-20", "doc_count": 0, "from": 3.0, "to": 20.0},
+                    {"key": "20-*", "doc_count": 0, "from": 20.0}
+                ]}
+            },
+            {"key": "3-7", "doc_count": 3, "from": 3.0, "to": 7.0,
+                "child_range": {"buckets": [
+                    {"key": "*-3", "doc_count": 0, "to": 3.0},
+                    {"key": "3-20", "doc_count": 3, "from": 3.0, "to": 20.0},
+                    {"key": "20-*", "doc_count": 0, "from": 20.0}
+                ]}
+            },
+            {"key": "7-11", "doc_count": 1, "from": 7.0, "to": 11.0,
+                "child_range": {"buckets": [
+                    {"key": "*-3", "doc_count": 0, "to": 3.0},
+                    {"key": "3-20", "doc_count": 1, "from": 3.0, "to": 20.0},
+                    {"key": "20-*", "doc_count": 0, "from": 20.0}
+                ]}
+            },
+            {"key": "11-20", "doc_count": 2, "from": 11.0, "to": 20.0,
+                "child_range": {"buckets": [
+                    {"key": "*-3", "doc_count": 0, "to": 3.0},
+                    {"key": "3-20", "doc_count": 2, "from": 3.0, "to": 20.0},
+                    {"key": "20-*", "doc_count": 0, "from": 20.0}
+                ]}
+            },
+            {"key": "20-*", "doc_count": 2, "from": 20.0,
+                "child_range": {"buckets": [
+                    {"key": "*-3", "doc_count": 0, "to": 3.0},
+                    {"key": "3-20", "doc_count": 0, "from": 3.0, "to": 20.0},
+                    {"key": "20-*", "doc_count": 2, "from": 20.0}
+                ]}
+            }
+        ])
+    );
+
+    // Case B: child has more buckets than parent
+    // Parent: terms on text (2 buckets)
+    // Child: range with 4 buckets
+    let agg_child_more: Aggregations = serde_json::from_value(json!({
+        "parent_terms": {
+            "terms": {"field": "text"},
+            "aggs": {
+                "child_range": {
+                    "range": {
+                        "field": "score",
+                        "ranges": [
+                            {"to": 3.0},
+                            {"from": 3.0, "to": 7.0},
+                            {"from": 7.0, "to": 20.0}
+                        ]
+                    }
+                }
+            }
+        }
+    }))
+    .unwrap();
+    let res = crate::aggregation::tests::exec_request(agg_child_more, &index)?;
+
+    assert_eq!(
+        res["parent_terms"],
+        json!({
+            "buckets": [
+                {
+                    "key": "cool",
+                    "doc_count": 7,
+                    "child_range": {
+                        "buckets": [
+                            {"key": "*-3", "doc_count": 1, "to": 3.0},
+                            {"key": "3-7", "doc_count": 2, "from": 3.0, "to": 7.0},
+                            {"key": "7-20", "doc_count": 3, "from": 7.0, "to": 20.0},
+                            {"key": "20-*", "doc_count": 1, "from": 20.0}
+                        ]
+                    }
+                },
+                {
+                    "key": "nohit",
+                    "doc_count": 2,
+                    "child_range": {
+                        "buckets": [
+                            {"key": "*-3", "doc_count": 0, "to": 3.0},
+                            {"key": "3-7", "doc_count": 1, "from": 3.0, "to": 7.0},
+                            {"key": "7-20", "doc_count": 0, "from": 7.0, "to": 20.0},
+                            {"key": "20-*", "doc_count": 1, "from": 20.0}
+                        ]
+                    }
+                }
+            ],
+            "doc_count_error_upper_bound": 0,
+            "sum_other_doc_count": 0
+        })
+    );
+
+    Ok(())
+}
+
+#[test]
+fn test_histogram_as_subagg_parent_more_vs_child_more() -> crate::Result<()> {
+    let index = get_test_index_2_segments(false)?;
+
+    // Case A: parent has more buckets than child
+    // Parent: range with several ranges
+    // Child: histogram with large interval (single bucket per parent)
+    let agg_parent_more: Aggregations = serde_json::from_value(json!({
+        "parent_range": {
+            "range": {
+                "field": "score",
+                "ranges": [
+                    {"to": 3.0},
+                    {"from": 3.0, "to": 7.0},
+                    {"from": 7.0, "to": 11.0},
+                    {"from": 11.0, "to": 20.0},
+                    {"from": 20.0}
+                ]
+            },
+            "aggs": {
+                "child_hist": {"histogram": {"field": "score", "interval": 100.0}}
+            }
+        }
+    }))
+    .unwrap();
+    let res = crate::aggregation::tests::exec_request(agg_parent_more, &index)?;
+    assert_eq!(
+        res["parent_range"]["buckets"],
+        json!([
+            {"key": "*-3", "doc_count": 1, "to": 3.0,
+                "child_hist": {"buckets": [ {"key": 0.0, "doc_count": 1} ]}
+            },
+            {"key": "3-7", "doc_count": 3, "from": 3.0, "to": 7.0,
+                "child_hist": {"buckets": [ {"key": 0.0, "doc_count": 3} ]}
+            },
+            {"key": "7-11", "doc_count": 1, "from": 7.0, "to": 11.0,
+                "child_hist": {"buckets": [ {"key": 0.0, "doc_count": 1} ]}
+            },
+            {"key": "11-20", "doc_count": 2, "from": 11.0, "to": 20.0,
+                "child_hist": {"buckets": [ {"key": 0.0, "doc_count": 2} ]}
+            },
+            {"key": "20-*", "doc_count": 2, "from": 20.0,
+                "child_hist": {"buckets": [ {"key": 0.0, "doc_count": 2} ]}
+            }
+        ])
+    );
+
+    // Case B: child has more buckets than parent
+    // Parent: terms on text -> 2 buckets
+    // Child: histogram with small interval -> multiple buckets including empties
+    let agg_child_more: Aggregations = serde_json::from_value(json!({
+        "parent_terms": {
+            "terms": {"field": "text"},
+            "aggs": {
+                "child_hist": {"histogram": {"field": "score", "interval": 10.0}}
+            }
+        }
+    }))
+    .unwrap();
+    let res = crate::aggregation::tests::exec_request(agg_child_more, &index)?;
+    assert_eq!(
+        res["parent_terms"],
+        json!({
+            "buckets": [
+                {
+                    "key": "cool",
+                    "doc_count": 7,
+                    "child_hist": {
+                        "buckets": [
+                            {"key": 0.0, "doc_count": 4},
+                            {"key": 10.0, "doc_count": 2},
+                            {"key": 20.0, "doc_count": 0},
+                            {"key": 30.0, "doc_count": 0},
+                            {"key": 40.0, "doc_count": 1}
+                        ]
+                    }
+                },
+                {
+                    "key": "nohit",
+                    "doc_count": 2,
+                    "child_hist": {
+                        "buckets": [
+                            {"key": 0.0, "doc_count": 1},
+                            {"key": 10.0, "doc_count": 0},
+                            {"key": 20.0, "doc_count": 0},
+                            {"key": 30.0, "doc_count": 0},
+                            {"key": 40.0, "doc_count": 1}
+                        ]
+                    }
+                }
+            ],
+            "doc_count_error_upper_bound": 0,
+            "sum_other_doc_count": 0
+        })
+    );
+
+    Ok(())
+}
+
+#[test]
+fn test_date_histogram_as_subagg_parent_more_vs_child_more() -> crate::Result<()> {
+    let index = get_test_index_2_segments(false)?;
+
+    // Case A: parent has more buckets than child
+    // Parent: range with several buckets
+    // Child: date_histogram with 30d -> single bucket per parent
+    let agg_parent_more: Aggregations = serde_json::from_value(json!({
+        "parent_range": {
+            "range": {
+                "field": "score",
+                "ranges": [
+                    {"to": 3.0},
+                    {"from": 3.0, "to": 7.0},
+                    {"from": 7.0, "to": 11.0},
+                    {"from": 11.0, "to": 20.0},
+                    {"from": 20.0}
+                ]
+            },
+            "aggs": {
+                "child_date_hist": {"date_histogram": {"field": "date", "fixed_interval": "30d"}}
+            }
+        }
+    }))
+    .unwrap();
+    let res = crate::aggregation::tests::exec_request(agg_parent_more, &index)?;
+    let buckets = res["parent_range"]["buckets"].as_array().unwrap();
+    // Verify each parent bucket has exactly one child date bucket with matching doc_count
+    for bucket in buckets {
+        let parent_count = bucket["doc_count"].as_u64().unwrap();
+        let child_buckets = bucket["child_date_hist"]["buckets"].as_array().unwrap();
+        assert_eq!(child_buckets.len(), 1);
+        assert_eq!(child_buckets[0]["doc_count"], parent_count);
+    }
+
+    // Case B: child has more buckets than parent
+    // Parent: terms on text (2 buckets)
+    // Child: date_histogram with 1d -> multiple buckets
+    let agg_child_more: Aggregations = serde_json::from_value(json!({
+        "parent_terms": {
+            "terms": {"field": "text"},
+            "aggs": {
+                "child_date_hist": {"date_histogram": {"field": "date", "fixed_interval": "1d"}}
+            }
+        }
+    }))
+    .unwrap();
+    let res = crate::aggregation::tests::exec_request(agg_child_more, &index)?;
+    let buckets = res["parent_terms"]["buckets"].as_array().unwrap();
+
+    // cool bucket
+    assert_eq!(buckets[0]["key"], "cool");
+    let cool_buckets = buckets[0]["child_date_hist"]["buckets"].as_array().unwrap();
+    assert_eq!(cool_buckets.len(), 3);
+    assert_eq!(cool_buckets[0]["doc_count"], 1); // day 0
+    assert_eq!(cool_buckets[1]["doc_count"], 4); // day 1
+    assert_eq!(cool_buckets[2]["doc_count"], 2); // day 2
+
+    // nohit bucket
+    assert_eq!(buckets[1]["key"], "nohit");
+    let nohit_buckets = buckets[1]["child_date_hist"]["buckets"].as_array().unwrap();
+    assert_eq!(nohit_buckets.len(), 2);
+    assert_eq!(nohit_buckets[0]["doc_count"], 1); // day 1
+    assert_eq!(nohit_buckets[1]["doc_count"], 1); // day 2
+
+    Ok(())
+}
+
 fn get_avg_req(field_name: &str) -> Aggregation {
     serde_json::from_value(json!({
         "avg": {
@@ -25,6 +451,10 @@ fn get_collector(agg_req: Aggregations) -> AggregationCollector {
 }
 
 // *** EVERY BUCKET-TYPE SHOULD BE TESTED HERE ***
+// Note: The flushng part of these  tests are outdated, since the buffering change after converting
+// the collection into one collector per request instead of per bucket.
+//
+// However they are useful as they test a complex aggregation requests.
 fn test_aggregation_flushing(
     merge_segments: bool,
     use_distributed_collector: bool,
@@ -37,8 +467,9 @@ fn test_aggregation_flushing(
 
     let reader = index.reader()?;
 
-    assert_eq!(DOC_BLOCK_SIZE, 64);
-    // In the tree we cache Documents of DOC_BLOCK_SIZE, before passing them down as one block.
+    assert_eq!(COLLECT_BLOCK_BUFFER_LEN, 64);
+    // In the tree we cache documents of COLLECT_BLOCK_BUFFER_LEN before passing them down as one
+    // block.
     //
     // Build a request so that on the first level we have one full cache, which is then flushed.
     // The same cache should have some residue docs at the end, which are flushed (Range 0-70)
@@ -928,10 +1359,10 @@ fn test_aggregation_on_json_object_mixed_types() {
         &serde_json::json!({
           "rangeagg": {
             "buckets": [
-              { "average_in_range": { "value": -20.5 }, "doc_count": 1, "key": "*-3", "to": 3.0 },
-              { "average_in_range": { "value": 10.0 }, "doc_count": 1, "from": 3.0, "key": "3-19", "to": 19.0 },
-              { "average_in_range": { "value": null }, "doc_count": 0, "from": 19.0, "key": "19-20", "to": 20.0 },
-              { "average_in_range": { "value": null }, "doc_count": 0, "from": 20.0, "key": "20-*" }
+              { "average_in_range": { "value": -20.5, "sum": -20.5, "count": 1 }, "doc_count": 1, "key": "*-3", "to": 3.0 },
+              { "average_in_range": { "value": 10.0, "sum": 10.0, "count": 1 }, "doc_count": 1, "from": 3.0, "key": "3-19", "to": 19.0 },
+              { "average_in_range": { "value": null, "sum": 0.0, "count": 0 }, "doc_count": 0, "from": 19.0, "key": "19-20", "to": 20.0 },
+              { "average_in_range": { "value": null, "sum": 0.0, "count": 0 }, "doc_count": 0, "from": 20.0, "key": "20-*" }
             ]
           },
           "termagg": {

src/aggregation/bucket/filter.rs

@@ -6,10 +6,14 @@ use serde::{Deserialize, Deserializer, Serialize, Serializer};
 use crate::aggregation::agg_data::{
     build_segment_agg_collectors, AggRefNode, AggregationsSegmentCtx,
 };
+use crate::aggregation::cached_sub_aggs::{
+    CachedSubAggs, HighCardSubAggCache, LowCardSubAggCache, SubAggCache,
+};
 use crate::aggregation::intermediate_agg_result::{
     IntermediateAggregationResult, IntermediateAggregationResults, IntermediateBucketResult,
 };
-use crate::aggregation::segment_agg_result::{CollectorClone, SegmentAggregationCollector};
+use crate::aggregation::segment_agg_result::{BucketIdProvider, SegmentAggregationCollector};
+use crate::aggregation::BucketId;
 use crate::docset::DocSet;
 use crate::query::{AllQuery, EnableScoring, Query, QueryParser};
 use crate::schema::Schema;
@@ -404,15 +408,18 @@ pub struct FilterAggReqData {
     pub evaluator: DocumentQueryEvaluator,
     /// Reusable buffer for matching documents to minimize allocations during collection
     pub matching_docs_buffer: Vec<DocId>,
+    /// True if this filter aggregation is at the top level of the aggregation tree (not nested).
+    pub is_top_level: bool,
 }
 
 impl FilterAggReqData {
     pub(crate) fn get_memory_consumption(&self) -> usize {
         // Estimate: name + segment reader reference + bitset + buffer capacity
         self.name.len()
-            + std::mem::size_of::<SegmentReader>()
-            + self.evaluator.bitset.len() / 8 // BitSet memory (bits to bytes)
-            + self.matching_docs_buffer.capacity() * std::mem::size_of::<DocId>()
+        + std::mem::size_of::<SegmentReader>()
+        + self.evaluator.bitset.len() / 8 // BitSet memory (bits to bytes)
+        + self.matching_docs_buffer.capacity() * std::mem::size_of::<DocId>()
+        + std::mem::size_of::<bool>()
     }
 }
 
@@ -489,17 +496,24 @@ impl Debug for DocumentQueryEvaluator {
     }
 }
 
-/// Segment collector for filter aggregation
-pub struct SegmentFilterCollector {
-    /// Document count in this bucket
+#[derive(Debug, Clone, PartialEq, Copy)]
+struct DocCount {
     doc_count: u64,
+    bucket_id: BucketId,
+}
+
+/// Segment collector for filter aggregation
+pub struct SegmentFilterCollector<C: SubAggCache> {
+    /// Document counts per parent bucket
+    parent_buckets: Vec<DocCount>,
     /// Sub-aggregation collectors
-    sub_aggregations: Option<Box<dyn SegmentAggregationCollector>>,
+    sub_aggregations: Option<CachedSubAggs<C>>,
+    bucket_id_provider: BucketIdProvider,
     /// Accessor index for this filter aggregation (to access FilterAggReqData)
     accessor_idx: usize,
 }
 
-impl SegmentFilterCollector {
+impl<C: SubAggCache> SegmentFilterCollector<C> {
     /// Create a new filter segment collector following the new agg_data pattern
     pub(crate) fn from_req_and_validate(
         req: &mut AggregationsSegmentCtx,
@@ -511,47 +525,75 @@ impl SegmentFilterCollector {
         } else {
             None
         };
+        let sub_agg_collector = sub_agg_collector.map(CachedSubAggs::new);
 
         Ok(SegmentFilterCollector {
-            doc_count: 0,
+            parent_buckets: Vec::new(),
             sub_aggregations: sub_agg_collector,
             accessor_idx: node.idx_in_req_data,
+            bucket_id_provider: BucketIdProvider::default(),
         })
     }
 }
 
-impl Debug for SegmentFilterCollector {
+pub(crate) fn build_segment_filter_collector(
+    req: &mut AggregationsSegmentCtx,
+    node: &AggRefNode,
+) -> crate::Result<Box<dyn SegmentAggregationCollector>> {
+    let is_top_level = req.per_request.filter_req_data[node.idx_in_req_data]
+        .as_ref()
+        .expect("filter_req_data slot is empty")
+        .is_top_level;
+
+    if is_top_level {
+        Ok(Box::new(
+            SegmentFilterCollector::<LowCardSubAggCache>::from_req_and_validate(req, node)?,
+        ))
+    } else {
+        Ok(Box::new(
+            SegmentFilterCollector::<HighCardSubAggCache>::from_req_and_validate(req, node)?,
+        ))
+    }
+}
+
+impl<C: SubAggCache> Debug for SegmentFilterCollector<C> {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         f.debug_struct("SegmentFilterCollector")
-            .field("doc_count", &self.doc_count)
+            .field("buckets", &self.parent_buckets)
             .field("has_sub_aggs", &self.sub_aggregations.is_some())
             .field("accessor_idx", &self.accessor_idx)
             .finish()
     }
 }
 
-impl CollectorClone for SegmentFilterCollector {
-    fn clone_box(&self) -> Box<dyn SegmentAggregationCollector> {
-        // For now, panic - this needs proper implementation with weight recreation
-        panic!("SegmentFilterCollector cloning not yet implemented - requires weight recreation")
-    }
-}
-
-impl SegmentAggregationCollector for SegmentFilterCollector {
+impl<C: SubAggCache> SegmentAggregationCollector for SegmentFilterCollector<C> {
     fn add_intermediate_aggregation_result(
-        self: Box<Self>,
+        &mut self,
         agg_data: &AggregationsSegmentCtx,
         results: &mut IntermediateAggregationResults,
+        parent_bucket_id: BucketId,
     ) -> crate::Result<()> {
         let mut sub_results = IntermediateAggregationResults::default();
+        let bucket_opt = self.parent_buckets.get(parent_bucket_id as usize);
 
-        if let Some(sub_aggs) = self.sub_aggregations {
-            sub_aggs.add_intermediate_aggregation_result(agg_data, &mut sub_results)?;
+        if let Some(sub_aggs) = &mut self.sub_aggregations {
+            sub_aggs
+                .get_sub_agg_collector()
+                .add_intermediate_aggregation_result(
+                    agg_data,
+                    &mut sub_results,
+                    // Here we create a new bucket ID for sub-aggregations if the bucket doesn't
+                    // exist, so that sub-aggregations can still produce results (e.g., zero doc
+                    // count)
+                    bucket_opt
+                        .map(|bucket| bucket.bucket_id)
+                        .unwrap_or(self.bucket_id_provider.next_bucket_id()),
+                )?;
         }
 
         // Create the filter bucket result
         let filter_bucket_result = IntermediateBucketResult::Filter {
-            doc_count: self.doc_count,
+            doc_count: bucket_opt.map(|b| b.doc_count).unwrap_or(0),
             sub_aggregations: sub_results,
         };
 
@@ -570,32 +612,17 @@ impl SegmentAggregationCollector for SegmentFilterCollector {
         Ok(())
     }
 
-    fn collect(&mut self, doc: DocId, agg_data: &mut AggregationsSegmentCtx) -> crate::Result<()> {
-        // Access the evaluator from FilterAggReqData
-        let req_data = agg_data.get_filter_req_data(self.accessor_idx);
-
-        // O(1) BitSet lookup to check if document matches filter
-        if req_data.evaluator.matches_document(doc) {
-            self.doc_count += 1;
-
-            // If we have sub-aggregations, collect on them for this filtered document
-            if let Some(sub_aggs) = &mut self.sub_aggregations {
-                sub_aggs.collect(doc, agg_data)?;
-            }
-        }
-        Ok(())
-    }
-
-    #[inline]
-    fn collect_block(
+    fn collect(
         &mut self,
-        docs: &[DocId],
+        parent_bucket_id: BucketId,
+        docs: &[crate::DocId],
         agg_data: &mut AggregationsSegmentCtx,
     ) -> crate::Result<()> {
         if docs.is_empty() {
             return Ok(());
         }
 
+        let mut bucket = self.parent_buckets[parent_bucket_id as usize];
         // Take the request data to avoid borrow checker issues with sub-aggregations
         let mut req = agg_data.take_filter_req_data(self.accessor_idx);
 
@@ -604,18 +631,24 @@ impl SegmentAggregationCollector for SegmentFilterCollector {
         req.evaluator
             .filter_batch(docs, &mut req.matching_docs_buffer);
 
-        self.doc_count += req.matching_docs_buffer.len() as u64;
+        bucket.doc_count += req.matching_docs_buffer.len() as u64;
 
         // Batch process sub-aggregations if we have matches
         if !req.matching_docs_buffer.is_empty() {
             if let Some(sub_aggs) = &mut self.sub_aggregations {
-                // Use collect_block for better sub-aggregation performance
-                sub_aggs.collect_block(&req.matching_docs_buffer, agg_data)?;
+                for &doc_id in &req.matching_docs_buffer {
+                    sub_aggs.push(bucket.bucket_id, doc_id);
+                }
             }
         }
 
         // Put the request data back
         agg_data.put_back_filter_req_data(self.accessor_idx, req);
+        if let Some(sub_aggs) = &mut self.sub_aggregations {
+            sub_aggs.check_flush_local(agg_data)?;
+        }
+        // put back bucket
+        self.parent_buckets[parent_bucket_id as usize] = bucket;
 
         Ok(())
     }
@@ -626,6 +659,21 @@ impl SegmentAggregationCollector for SegmentFilterCollector {
         }
         Ok(())
     }
+
+    fn prepare_max_bucket(
+        &mut self,
+        max_bucket: BucketId,
+        _agg_data: &AggregationsSegmentCtx,
+    ) -> crate::Result<()> {
+        while self.parent_buckets.len() <= max_bucket as usize {
+            let bucket_id = self.bucket_id_provider.next_bucket_id();
+            self.parent_buckets.push(DocCount {
+                doc_count: 0,
+                bucket_id,
+            });
+        }
+        Ok(())
+    }
 }
 
 /// Intermediate result for filter aggregation
@@ -790,7 +838,7 @@ mod tests {
         let expected = json!({
             "electronics": {
                 "doc_count": 2,
-                "avg_price": { "value": 899.0 }  // (999 + 799) / 2
+                "avg_price": { "value": 899.0, "sum": 1798.0, "count": 2 }  // (999 + 799) / 2
             }
         });
 
@@ -820,7 +868,7 @@ mod tests {
         let expected = json!({
             "furniture": {
                 "doc_count": 0,
-                "avg_price": { "value": null }
+                "avg_price": { "value": null, "sum": 0.0, "count": 0 }
             }
         });
 
@@ -856,7 +904,7 @@ mod tests {
         let expected = json!({
             "electronics": {
                 "doc_count": 2,
-                "avg_price": { "value": 899.0 }
+                "avg_price": { "value": 899.0, "sum": 1798.0, "count": 2 }
             },
             "in_stock": {
                 "doc_count": 3,  // apple, samsung, penguin
@@ -952,7 +1000,7 @@ mod tests {
         let expected = json!({
             "premium_electronics": {
                 "doc_count": 1,  // Only apple (999) is >= 800 in tantivy's range semantics
-                "avg_rating": { "value": 4.5 }
+                "avg_rating": { "value": 4.5, "sum": 4.5, "count": 1 }
             }
         });
 
@@ -984,7 +1032,7 @@ mod tests {
         let expected = json!({
             "in_stock": {
                 "doc_count": 3,  // apple, samsung, penguin
-                "avg_price": { "value": 607.67 }  // (999 + 799 + 25) / 3 ≈ 607.67
+                "avg_price": { "value": 607.67, "sum": 1823.0, "count": 3 }  // (999 + 799 + 25) / 3 ≈ 607.67
             },
             "out_of_stock": {
                 "doc_count": 1,  // nike
@@ -1135,7 +1183,7 @@ mod tests {
                 "doc_count": 4,
                 "electronics_branch": {
                     "doc_count": 2,
-                    "avg_price": { "value": 899.0 }
+                    "avg_price": { "value": 899.0, "sum": 1798.0, "count": 2 }
                 },
                 "in_stock_branch": {
                     "doc_count": 3,
@@ -1211,7 +1259,7 @@ mod tests {
                     "doc_count": 2,  // apple (999), samsung (799)
                     "electronics": {
                         "doc_count": 2,  // both are electronics
-                        "avg_rating": { "value": 4.35 }  // (4.5 + 4.2) / 2
+                        "avg_rating": { "value": 4.35, "sum": 8.7, "count": 2 }  // (4.5 + 4.2) / 2
                     },
                     "in_stock": {
                         "doc_count": 2,  // both are in stock
@@ -1273,12 +1321,12 @@ mod tests {
                         {
                             "key": "samsung",
                             "doc_count": 1,
-                            "avg_price": { "value": 799.0 }
+                            "avg_price": { "value": 799.0, "sum": 799.0, "count": 1 }
                         },
                         {
                             "key": "apple",
                             "doc_count": 1,
-                            "avg_price": { "value": 999.0 }
+                            "avg_price": { "value": 999.0, "sum": 999.0, "count": 1 }
                         }
                     ],
                     "sum_other_doc_count": 0,
@@ -1322,7 +1370,7 @@ mod tests {
                     "sum": 1798.0,
                     "avg": 899.0
                 },
-                "rating_avg": { "value": 4.35 },
+                "rating_avg": { "value": 4.35, "sum": 8.7, "count": 2 },
                 "count": { "value": 2.0 }
             }
         });
@@ -1363,7 +1411,7 @@ mod tests {
         let expected = json!({
             "electronics": {
                 "doc_count": 0,
-                "avg_price": { "value": null }
+                "avg_price": { "value": null, "sum": 0.0, "count": 0 }
             }
         });
 
@@ -1519,9 +1567,9 @@ mod tests {
         let searcher = reader.searcher();
 
         let agg = json!({
-            "test": {
-                "filter": deserialized,
-                "aggs": { "count": { "value_count": { "field": "brand" } } }
+                "test": {
+                    "filter": deserialized,
+                    "aggs": { "count": { "value_count": { "field": "brand" } } }
             }
         });
 
@@ -1650,13 +1698,15 @@ mod tests {
         let filter_expected = json!({
             "electronics": {
                 "doc_count": 2,
-                "avg_price": { "value": 899.0 }
+                "avg_price": { "value": 899.0, "sum": 1798.0, "count": 2 }
             }
         });
 
         let separate_expected = json!({
             "result": {
-                "value": 899.0
+                "value": 899.0,
+                "sum": 1798.0,
+                "count": 2
             }
         });
 

src/aggregation/bucket/histogram/histogram.rs

@@ -1,6 +1,6 @@
 use std::cmp::Ordering;
 
-use columnar::{Column, ColumnBlockAccessor, ColumnType};
+use columnar::{Column, ColumnType};
 use rustc_hash::FxHashMap;
 use serde::{Deserialize, Serialize};
 use tantivy_bitpacker::minmax;
@@ -8,14 +8,14 @@ use tantivy_bitpacker::minmax;
 use crate::aggregation::agg_data::{
     build_segment_agg_collectors, AggRefNode, AggregationsSegmentCtx,
 };
-use crate::aggregation::agg_limits::MemoryConsumption;
 use crate::aggregation::agg_req::Aggregations;
 use crate::aggregation::agg_result::BucketEntry;
+use crate::aggregation::cached_sub_aggs::{CachedSubAggs, HighCardCachedSubAggs};
 use crate::aggregation::intermediate_agg_result::{
     IntermediateAggregationResult, IntermediateAggregationResults, IntermediateBucketResult,
     IntermediateHistogramBucketEntry,
 };
-use crate::aggregation::segment_agg_result::SegmentAggregationCollector;
+use crate::aggregation::segment_agg_result::{BucketIdProvider, SegmentAggregationCollector};
 use crate::aggregation::*;
 use crate::TantivyError;
 
@@ -26,13 +26,8 @@ pub struct HistogramAggReqData {
     pub accessor: Column<u64>,
     /// The field type of the fast field.
     pub field_type: ColumnType,
-    /// The column block accessor to access the fast field values.
-    pub column_block_accessor: ColumnBlockAccessor<u64>,
     /// The name of the aggregation.
     pub name: String,
-    /// The sub aggregation blueprint, used to create sub aggregations for each bucket.
-    /// Will be filled during initialization of the collector.
-    pub sub_aggregation_blueprint: Option<Box<dyn SegmentAggregationCollector>>,
     /// The histogram aggregation request.
     pub req: HistogramAggregation,
     /// True if this is a date_histogram aggregation.
@@ -257,18 +252,24 @@ impl HistogramBounds {
 pub(crate) struct SegmentHistogramBucketEntry {
     pub key: f64,
     pub doc_count: u64,
+    pub bucket_id: BucketId,
 }
 
 impl SegmentHistogramBucketEntry {
     pub(crate) fn into_intermediate_bucket_entry(
         self,
-        sub_aggregation: Option<Box<dyn SegmentAggregationCollector>>,
+        sub_aggregation: &mut Option<HighCardCachedSubAggs>,
         agg_data: &AggregationsSegmentCtx,
     ) -> crate::Result<IntermediateHistogramBucketEntry> {
         let mut sub_aggregation_res = IntermediateAggregationResults::default();
         if let Some(sub_aggregation) = sub_aggregation {
             sub_aggregation
-                .add_intermediate_aggregation_result(agg_data, &mut sub_aggregation_res)?;
+                .get_sub_agg_collector()
+                .add_intermediate_aggregation_result(
+                    agg_data,
+                    &mut sub_aggregation_res,
+                    self.bucket_id,
+                )?;
         }
         Ok(IntermediateHistogramBucketEntry {
             key: self.key,
@@ -278,27 +279,38 @@ impl SegmentHistogramBucketEntry {
     }
 }
 
+#[derive(Clone, Debug, Default)]
+struct HistogramBuckets {
+    pub buckets: FxHashMap<i64, SegmentHistogramBucketEntry>,
+}
+
 /// The collector puts values from the fast field into the correct buckets and does a conversion to
 /// the correct datatype.
-#[derive(Clone, Debug)]
+#[derive(Debug)]
 pub struct SegmentHistogramCollector {
     /// The buckets containing the aggregation data.
-    buckets: FxHashMap<i64, SegmentHistogramBucketEntry>,
-    sub_aggregations: FxHashMap<i64, Box<dyn SegmentAggregationCollector>>,
+    /// One Histogram bucket per parent bucket id.
+    parent_buckets: Vec<HistogramBuckets>,
+    sub_agg: Option<HighCardCachedSubAggs>,
     accessor_idx: usize,
+    bucket_id_provider: BucketIdProvider,
 }
 
 impl SegmentAggregationCollector for SegmentHistogramCollector {
     fn add_intermediate_aggregation_result(
-        self: Box<Self>,
+        &mut self,
         agg_data: &AggregationsSegmentCtx,
         results: &mut IntermediateAggregationResults,
+        parent_bucket_id: BucketId,
     ) -> crate::Result<()> {
         let name = agg_data
             .get_histogram_req_data(self.accessor_idx)
             .name
             .clone();
-        let bucket = self.into_intermediate_bucket_result(agg_data)?;
+        // TODO: avoid prepare_max_bucket here and handle empty buckets.
+        self.prepare_max_bucket(parent_bucket_id, agg_data)?;
+        let histogram = std::mem::take(&mut self.parent_buckets[parent_bucket_id as usize]);
+        let bucket = self.add_intermediate_bucket_result(agg_data, histogram)?;
         results.push(name, IntermediateAggregationResult::Bucket(bucket))?;
 
         Ok(())
@@ -307,44 +319,40 @@ impl SegmentAggregationCollector for SegmentHistogramCollector {
     #[inline]
     fn collect(
         &mut self,
-        doc: crate::DocId,
-        agg_data: &mut AggregationsSegmentCtx,
-    ) -> crate::Result<()> {
-        self.collect_block(&[doc], agg_data)
-    }
-
-    #[inline]
-    fn collect_block(
-        &mut self,
+        parent_bucket_id: BucketId,
         docs: &[crate::DocId],
         agg_data: &mut AggregationsSegmentCtx,
     ) -> crate::Result<()> {
-        let mut req = agg_data.take_histogram_req_data(self.accessor_idx);
+        let req = agg_data.take_histogram_req_data(self.accessor_idx);
         let mem_pre = self.get_memory_consumption();
+        let buckets = &mut self.parent_buckets[parent_bucket_id as usize].buckets;
 
         let bounds = req.bounds;
         let interval = req.req.interval;
         let offset = req.offset;
         let get_bucket_pos = |val| get_bucket_pos_f64(val, interval, offset) as i64;
 
-        req.column_block_accessor.fetch_block(docs, &req.accessor);
-        for (doc, val) in req
+        agg_data
+            .column_block_accessor
+            .fetch_block(docs, &req.accessor);
+        for (doc, val) in agg_data
             .column_block_accessor
             .iter_docid_vals(docs, &req.accessor)
         {
-            let val = f64_from_fastfield_u64(val, &req.field_type);
+            let val = f64_from_fastfield_u64(val, req.field_type);
             let bucket_pos = get_bucket_pos(val);
             if bounds.contains(val) {
-                let bucket = self.buckets.entry(bucket_pos).or_insert_with(|| {
+                let bucket = buckets.entry(bucket_pos).or_insert_with(|| {
                     let key = get_bucket_key_from_pos(bucket_pos as f64, interval, offset);
-                    SegmentHistogramBucketEntry { key, doc_count: 0 }
+                    SegmentHistogramBucketEntry {
+                        key,
+                        doc_count: 0,
+                        bucket_id: self.bucket_id_provider.next_bucket_id(),
+                    }
                 });
                 bucket.doc_count += 1;
-                if let Some(sub_aggregation_blueprint) = req.sub_aggregation_blueprint.as_ref() {
-                    self.sub_aggregations
-                        .entry(bucket_pos)
-                        .or_insert_with(|| sub_aggregation_blueprint.clone())
-                        .collect(doc, agg_data)?;
+                if let Some(sub_agg) = &mut self.sub_agg {
+                    sub_agg.push(bucket.bucket_id, doc);
                 }
             }
         }
@@ -358,14 +366,30 @@ impl SegmentAggregationCollector for SegmentHistogramCollector {
                 .add_memory_consumed(mem_delta as u64)?;
         }
 
+        if let Some(sub_agg) = &mut self.sub_agg {
+            sub_agg.check_flush_local(agg_data)?;
+        }
+
         Ok(())
     }
 
     fn flush(&mut self, agg_data: &mut AggregationsSegmentCtx) -> crate::Result<()> {
-        for sub_aggregation in self.sub_aggregations.values_mut() {
+        if let Some(sub_aggregation) = &mut self.sub_agg {
             sub_aggregation.flush(agg_data)?;
         }
+        Ok(())
+    }
 
+    fn prepare_max_bucket(
+        &mut self,
+        max_bucket: BucketId,
+        _agg_data: &AggregationsSegmentCtx,
+    ) -> crate::Result<()> {
+        while self.parent_buckets.len() <= max_bucket as usize {
+            self.parent_buckets.push(HistogramBuckets {
+                buckets: FxHashMap::default(),
+            });
+        }
         Ok(())
     }
 }
@@ -373,22 +397,19 @@ impl SegmentAggregationCollector for SegmentHistogramCollector {
 impl SegmentHistogramCollector {
     fn get_memory_consumption(&self) -> usize {
         let self_mem = std::mem::size_of::<Self>();
-        let sub_aggs_mem = self.sub_aggregations.memory_consumption();
-        let buckets_mem = self.buckets.memory_consumption();
-        self_mem + sub_aggs_mem + buckets_mem
+        let buckets_mem = self.parent_buckets.len() * std::mem::size_of::<HistogramBuckets>();
+        self_mem + buckets_mem
     }
     /// Converts the collector result into a intermediate bucket result.
-    pub fn into_intermediate_bucket_result(
-        self,
+    fn add_intermediate_bucket_result(
+        &mut self,
         agg_data: &AggregationsSegmentCtx,
+        histogram: HistogramBuckets,
     ) -> crate::Result<IntermediateBucketResult> {
-        let mut buckets = Vec::with_capacity(self.buckets.len());
+        let mut buckets = Vec::with_capacity(histogram.buckets.len());
 
-        for (bucket_pos, bucket) in self.buckets {
-            let bucket_res = bucket.into_intermediate_bucket_entry(
-                self.sub_aggregations.get(&bucket_pos).cloned(),
-                agg_data,
-            );
+        for bucket in histogram.buckets.into_values() {
+            let bucket_res = bucket.into_intermediate_bucket_entry(&mut self.sub_agg, agg_data);
 
             buckets.push(bucket_res?);
         }
@@ -408,7 +429,7 @@ impl SegmentHistogramCollector {
         agg_data: &mut AggregationsSegmentCtx,
         node: &AggRefNode,
     ) -> crate::Result<Self> {
-        let blueprint = if !node.children.is_empty() {
+        let sub_agg = if !node.children.is_empty() {
             Some(build_segment_agg_collectors(agg_data, &node.children)?)
         } else {
             None
@@ -423,13 +444,13 @@ impl SegmentHistogramCollector {
             max: f64::MAX,
         });
         req_data.offset = req_data.req.offset.unwrap_or(0.0);
-
-        req_data.sub_aggregation_blueprint = blueprint;
+        let sub_agg = sub_agg.map(CachedSubAggs::new);
 
         Ok(Self {
-            buckets: Default::default(),
-            sub_aggregations: Default::default(),
+            parent_buckets: Default::default(),
+            sub_agg,
             accessor_idx: node.idx_in_req_data,
+            bucket_id_provider: BucketIdProvider::default(),
         })
     }
 }
@@ -1201,7 +1222,9 @@ mod tests {
             res["histogram"]["buckets"][0],
             json!({
                 "avg": {
-                    "value": Value::Null
+                    "value": Value::Null,
+                    "sum": 0.0,
+                    "count": 0
                 },
                 "doc_count": 0,
                 "key": 2.0,

src/aggregation/bucket/range.rs

@@ -1,18 +1,22 @@
 use std::fmt::Debug;
 use std::ops::Range;
 
-use columnar::{Column, ColumnBlockAccessor, ColumnType};
+use columnar::{Column, ColumnType};
 use rustc_hash::FxHashMap;
 use serde::{Deserialize, Serialize};
 
 use crate::aggregation::agg_data::{
     build_segment_agg_collectors, AggRefNode, AggregationsSegmentCtx,
 };
+use crate::aggregation::agg_limits::AggregationLimitsGuard;
+use crate::aggregation::cached_sub_aggs::{
+    CachedSubAggs, HighCardSubAggCache, LowCardCachedSubAggs, LowCardSubAggCache, SubAggCache,
+};
 use crate::aggregation::intermediate_agg_result::{
     IntermediateAggregationResult, IntermediateAggregationResults, IntermediateBucketResult,
     IntermediateRangeBucketEntry, IntermediateRangeBucketResult,
 };
-use crate::aggregation::segment_agg_result::SegmentAggregationCollector;
+use crate::aggregation::segment_agg_result::{BucketIdProvider, SegmentAggregationCollector};
 use crate::aggregation::*;
 use crate::TantivyError;
 
@@ -23,12 +27,12 @@ pub struct RangeAggReqData {
     pub accessor: Column<u64>,
     /// The type of the fast field.
     pub field_type: ColumnType,
-    /// The column block accessor to access the fast field values.
-    pub column_block_accessor: ColumnBlockAccessor<u64>,
     /// The range aggregation request.
     pub req: RangeAggregation,
     /// The name of the aggregation.
     pub name: String,
+    /// Whether this is a top-level aggregation.
+    pub is_top_level: bool,
 }
 
 impl RangeAggReqData {
@@ -151,19 +155,47 @@ pub(crate) struct SegmentRangeAndBucketEntry {
 
 /// The collector puts values from the fast field into the correct buckets and does a conversion to
 /// the correct datatype.
-#[derive(Clone, Debug)]
-pub struct SegmentRangeCollector {
+pub struct SegmentRangeCollector<C: SubAggCache> {
     /// The buckets containing the aggregation data.
-    buckets: Vec<SegmentRangeAndBucketEntry>,
+    /// One for each ParentBucketId
+    parent_buckets: Vec<Vec<SegmentRangeAndBucketEntry>>,
     column_type: ColumnType,
     pub(crate) accessor_idx: usize,
+    sub_agg: Option<CachedSubAggs<C>>,
+    /// Here things get a bit weird. We need to assign unique bucket ids across all
+    /// parent buckets. So we keep track of the next available bucket id here.
+    /// This allows a kind of flattening of the bucket ids across all parent buckets.
+    /// E.g. in nested aggregations:
+    /// Term Agg -> Range aggregation -> Stats aggregation
+    /// E.g. the Term Agg creates 3 buckets ["INFO", "ERROR", "WARN"], each of these has a Range
+    /// aggregation with 4 buckets. The Range aggregation will create buckets with ids:
+    /// - INFO: 0,1,2,3
+    /// - ERROR: 4,5,6,7
+    /// - WARN: 8,9,10,11
+    ///
+    /// This allows the Stats aggregation to have unique bucket ids to refer to.
+    bucket_id_provider: BucketIdProvider,
+    limits: AggregationLimitsGuard,
 }
 
+impl<C: SubAggCache> Debug for SegmentRangeCollector<C> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("SegmentRangeCollector")
+            .field("parent_buckets_len", &self.parent_buckets.len())
+            .field("column_type", &self.column_type)
+            .field("accessor_idx", &self.accessor_idx)
+            .field("has_sub_agg", &self.sub_agg.is_some())
+            .finish()
+    }
+}
+
+/// TODO: Bad naming, there's also SegmentRangeAndBucketEntry
 #[derive(Clone)]
 pub(crate) struct SegmentRangeBucketEntry {
     pub key: Key,
     pub doc_count: u64,
-    pub sub_aggregation: Option<Box<dyn SegmentAggregationCollector>>,
+    // pub sub_aggregation: Option<Box<dyn SegmentAggregationCollector>>,
+    pub bucket_id: BucketId,
     /// The from range of the bucket. Equals `f64::MIN` when `None`.
     pub from: Option<f64>,
     /// The to range of the bucket. Equals `f64::MAX` when `None`. Open interval, `to` is not
@@ -184,48 +216,50 @@ impl Debug for SegmentRangeBucketEntry {
 impl SegmentRangeBucketEntry {
     pub(crate) fn into_intermediate_bucket_entry(
         self,
-        agg_data: &AggregationsSegmentCtx,
     ) -> crate::Result<IntermediateRangeBucketEntry> {
-        let mut sub_aggregation_res = IntermediateAggregationResults::default();
-        if let Some(sub_aggregation) = self.sub_aggregation {
-            sub_aggregation
-                .add_intermediate_aggregation_result(agg_data, &mut sub_aggregation_res)?
-        } else {
-            Default::default()
-        };
+        let sub_aggregation = IntermediateAggregationResults::default();
 
         Ok(IntermediateRangeBucketEntry {
             key: self.key.into(),
             doc_count: self.doc_count,
-            sub_aggregation: sub_aggregation_res,
+            sub_aggregation_res: sub_aggregation,
             from: self.from,
             to: self.to,
         })
     }
 }
 
-impl SegmentAggregationCollector for SegmentRangeCollector {
+impl<C: SubAggCache> SegmentAggregationCollector for SegmentRangeCollector<C> {
     fn add_intermediate_aggregation_result(
-        self: Box<Self>,
+        &mut self,
         agg_data: &AggregationsSegmentCtx,
         results: &mut IntermediateAggregationResults,
+        parent_bucket_id: BucketId,
     ) -> crate::Result<()> {
+        self.prepare_max_bucket(parent_bucket_id, agg_data)?;
         let field_type = self.column_type;
         let name = agg_data
             .get_range_req_data(self.accessor_idx)
             .name
             .to_string();
 
-        let buckets: FxHashMap<SerializedKey, IntermediateRangeBucketEntry> = self
-            .buckets
+        let buckets = std::mem::take(&mut self.parent_buckets[parent_bucket_id as usize]);
+
+        let buckets: FxHashMap<SerializedKey, IntermediateRangeBucketEntry> = buckets
             .into_iter()
-            .map(move |range_bucket| {
-                Ok((
-                    range_to_string(&range_bucket.range, &field_type)?,
-                    range_bucket
-                        .bucket
-                        .into_intermediate_bucket_entry(agg_data)?,
-                ))
+            .map(|range_bucket| {
+                let bucket_id = range_bucket.bucket.bucket_id;
+                let mut agg = range_bucket.bucket.into_intermediate_bucket_entry()?;
+                if let Some(sub_aggregation) = &mut self.sub_agg {
+                    sub_aggregation
+                        .get_sub_agg_collector()
+                        .add_intermediate_aggregation_result(
+                            agg_data,
+                            &mut agg.sub_aggregation_res,
+                            bucket_id,
+                        )?;
+                }
+                Ok((range_to_string(&range_bucket.range, &field_type)?, agg))
             })
             .collect::<crate::Result<_>>()?;
 
@@ -242,73 +276,114 @@ impl SegmentAggregationCollector for SegmentRangeCollector {
     #[inline]
     fn collect(
         &mut self,
-        doc: crate::DocId,
-        agg_data: &mut AggregationsSegmentCtx,
-    ) -> crate::Result<()> {
-        self.collect_block(&[doc], agg_data)
-    }
-
-    #[inline]
-    fn collect_block(
-        &mut self,
+        parent_bucket_id: BucketId,
         docs: &[crate::DocId],
         agg_data: &mut AggregationsSegmentCtx,
     ) -> crate::Result<()> {
-        // Take request data to avoid borrow conflicts during sub-aggregation
-        let mut req = agg_data.take_range_req_data(self.accessor_idx);
+        let req = agg_data.take_range_req_data(self.accessor_idx);
 
-        req.column_block_accessor.fetch_block(docs, &req.accessor);
+        agg_data
+            .column_block_accessor
+            .fetch_block(docs, &req.accessor);
 
-        for (doc, val) in req
+        let buckets = &mut self.parent_buckets[parent_bucket_id as usize];
+
+        for (doc, val) in agg_data
             .column_block_accessor
             .iter_docid_vals(docs, &req.accessor)
         {
-            let bucket_pos = self.get_bucket_pos(val);
-            let bucket = &mut self.buckets[bucket_pos];
+            let bucket_pos = get_bucket_pos(val, buckets);
+            let bucket = &mut buckets[bucket_pos];
             bucket.bucket.doc_count += 1;
-            if let Some(sub_agg) = bucket.bucket.sub_aggregation.as_mut() {
-                sub_agg.collect(doc, agg_data)?;
+            if let Some(sub_agg) = self.sub_agg.as_mut() {
+                sub_agg.push(bucket.bucket.bucket_id, doc);
             }
         }
 
         agg_data.put_back_range_req_data(self.accessor_idx, req);
+        if let Some(sub_agg) = self.sub_agg.as_mut() {
+            sub_agg.check_flush_local(agg_data)?;
+        }
 
         Ok(())
     }
 
     fn flush(&mut self, agg_data: &mut AggregationsSegmentCtx) -> crate::Result<()> {
-        for bucket in self.buckets.iter_mut() {
-            if let Some(sub_agg) = bucket.bucket.sub_aggregation.as_mut() {
-                sub_agg.flush(agg_data)?;
-            }
+        if let Some(sub_agg) = self.sub_agg.as_mut() {
+            sub_agg.flush(agg_data)?;
         }
         Ok(())
     }
+
+    fn prepare_max_bucket(
+        &mut self,
+        max_bucket: BucketId,
+        agg_data: &AggregationsSegmentCtx,
+    ) -> crate::Result<()> {
+        while self.parent_buckets.len() <= max_bucket as usize {
+            let new_buckets = self.create_new_buckets(agg_data)?;
+            self.parent_buckets.push(new_buckets);
+        }
+
+        Ok(())
+    }
+}
+/// Build a concrete `SegmentRangeCollector` with either a Vec- or HashMap-backed
+/// bucket storage, depending on the column type and aggregation level.
+pub(crate) fn build_segment_range_collector(
+    agg_data: &mut AggregationsSegmentCtx,
+    node: &AggRefNode,
+) -> crate::Result<Box<dyn SegmentAggregationCollector>> {
+    let accessor_idx = node.idx_in_req_data;
+    let req_data = agg_data.get_range_req_data(node.idx_in_req_data);
+    let field_type = req_data.field_type;
+
+    // TODO: A better metric instead of is_top_level would be the number of buckets expected.
+    // E.g. If range agg is not top level, but the parent is a bucket agg with less than 10 buckets,
+    // we can are still in low cardinality territory.
+    let is_low_card = req_data.is_top_level && req_data.req.ranges.len() <= 64;
+
+    let sub_agg = if !node.children.is_empty() {
+        Some(build_segment_agg_collectors(agg_data, &node.children)?)
+    } else {
+        None
+    };
+
+    if is_low_card {
+        Ok(Box::new(SegmentRangeCollector::<LowCardSubAggCache> {
+            sub_agg: sub_agg.map(LowCardCachedSubAggs::new),
+            column_type: field_type,
+            accessor_idx,
+            parent_buckets: Vec::new(),
+            bucket_id_provider: BucketIdProvider::default(),
+            limits: agg_data.context.limits.clone(),
+        }))
+    } else {
+        Ok(Box::new(SegmentRangeCollector::<HighCardSubAggCache> {
+            sub_agg: sub_agg.map(CachedSubAggs::new),
+            column_type: field_type,
+            accessor_idx,
+            parent_buckets: Vec::new(),
+            bucket_id_provider: BucketIdProvider::default(),
+            limits: agg_data.context.limits.clone(),
+        }))
+    }
 }
 
-impl SegmentRangeCollector {
-    pub(crate) fn from_req_and_validate(
-        req_data: &mut AggregationsSegmentCtx,
-        node: &AggRefNode,
-    ) -> crate::Result<Self> {
-        let accessor_idx = node.idx_in_req_data;
-        let (field_type, ranges) = {
-            let req_view = req_data.get_range_req_data(node.idx_in_req_data);
-            (req_view.field_type, req_view.req.ranges.clone())
-        };
-
+impl<C: SubAggCache> SegmentRangeCollector<C> {
+    pub(crate) fn create_new_buckets(
+        &mut self,
+        agg_data: &AggregationsSegmentCtx,
+    ) -> crate::Result<Vec<SegmentRangeAndBucketEntry>> {
+        let field_type = self.column_type;
+        let req_data = agg_data.get_range_req_data(self.accessor_idx);
         // The range input on the request is f64.
         // We need to convert to u64 ranges, because we read the values as u64.
         // The mapping from the conversion is monotonic so ordering is preserved.
-        let sub_agg_prototype = if !node.children.is_empty() {
-            Some(build_segment_agg_collectors(req_data, &node.children)?)
-        } else {
-            None
-        };
-
-        let buckets: Vec<_> = extend_validate_ranges(&ranges, &field_type)?
+        let buckets: Vec<_> = extend_validate_ranges(&req_data.req.ranges, &field_type)?
             .iter()
             .map(|range| {
+                let bucket_id = self.bucket_id_provider.next_bucket_id();
                 let key = range
                     .key
                     .clone()
@@ -317,20 +392,20 @@ impl SegmentRangeCollector {
                 let to = if range.range.end == u64::MAX {
                     None
                 } else {
-                    Some(f64_from_fastfield_u64(range.range.end, &field_type))
+                    Some(f64_from_fastfield_u64(range.range.end, field_type))
                 };
                 let from = if range.range.start == u64::MIN {
                     None
                 } else {
-                    Some(f64_from_fastfield_u64(range.range.start, &field_type))
+                    Some(f64_from_fastfield_u64(range.range.start, field_type))
                 };
-                let sub_aggregation = sub_agg_prototype.clone();
+                // let sub_aggregation = sub_agg_prototype.clone();
 
                 Ok(SegmentRangeAndBucketEntry {
                     range: range.range.clone(),
                     bucket: SegmentRangeBucketEntry {
                         doc_count: 0,
-                        sub_aggregation,
+                        bucket_id,
                         key,
                         from,
                         to,
@@ -339,27 +414,20 @@ impl SegmentRangeCollector {
             })
             .collect::<crate::Result<_>>()?;
 
-        req_data.context.limits.add_memory_consumed(
+        self.limits.add_memory_consumed(
             buckets.len() as u64 * std::mem::size_of::<SegmentRangeAndBucketEntry>() as u64,
         )?;
-
-        Ok(SegmentRangeCollector {
-            buckets,
-            column_type: field_type,
-            accessor_idx,
-        })
-    }
-
-    #[inline]
-    fn get_bucket_pos(&self, val: u64) -> usize {
-        let pos = self
-            .buckets
-            .binary_search_by_key(&val, |probe| probe.range.start)
-            .unwrap_or_else(|pos| pos - 1);
-        debug_assert!(self.buckets[pos].range.contains(&val));
-        pos
+        Ok(buckets)
     }
 }
+#[inline]
+fn get_bucket_pos(val: u64, buckets: &[SegmentRangeAndBucketEntry]) -> usize {
+    let pos = buckets
+        .binary_search_by_key(&val, |probe| probe.range.start)
+        .unwrap_or_else(|pos| pos - 1);
+    debug_assert!(buckets[pos].range.contains(&val));
+    pos
+}
 
 /// Converts the user provided f64 range value to fast field value space.
 ///
@@ -456,7 +524,7 @@ pub(crate) fn range_to_string(
             let val = i64::from_u64(val);
             format_date(val)
         } else {
-            Ok(f64_from_fastfield_u64(val, field_type).to_string())
+            Ok(f64_from_fastfield_u64(val, *field_type).to_string())
         }
     };
 
@@ -486,7 +554,7 @@ mod tests {
     pub fn get_collector_from_ranges(
         ranges: Vec<RangeAggregationRange>,
         field_type: ColumnType,
-    ) -> SegmentRangeCollector {
+    ) -> SegmentRangeCollector<HighCardSubAggCache> {
         let req = RangeAggregation {
             field: "dummy".to_string(),
             ranges,
@@ -506,30 +574,33 @@ mod tests {
                 let to = if range.range.end == u64::MAX {
                     None
                 } else {
-                    Some(f64_from_fastfield_u64(range.range.end, &field_type))
+                    Some(f64_from_fastfield_u64(range.range.end, field_type))
                 };
                 let from = if range.range.start == u64::MIN {
                     None
                 } else {
-                    Some(f64_from_fastfield_u64(range.range.start, &field_type))
+                    Some(f64_from_fastfield_u64(range.range.start, field_type))
                 };
                 SegmentRangeAndBucketEntry {
                     range: range.range.clone(),
                     bucket: SegmentRangeBucketEntry {
                         doc_count: 0,
-                        sub_aggregation: None,
                         key,
                         from,
                         to,
+                        bucket_id: 0,
                     },
                 }
             })
             .collect();
 
         SegmentRangeCollector {
-            buckets,
+            parent_buckets: vec![buckets],
             column_type: field_type,
             accessor_idx: 0,
+            sub_agg: None,
+            bucket_id_provider: Default::default(),
+            limits: AggregationLimitsGuard::default(),
         }
     }
 
@@ -776,7 +847,7 @@ mod tests {
         let buckets = vec![(10f64..20f64).into(), (30f64..40f64).into()];
         let collector = get_collector_from_ranges(buckets, ColumnType::F64);
 
-        let buckets = collector.buckets;
+        let buckets = collector.parent_buckets[0].clone();
         assert_eq!(buckets[0].range.start, u64::MIN);
         assert_eq!(buckets[0].range.end, 10f64.to_u64());
         assert_eq!(buckets[1].range.start, 10f64.to_u64());
@@ -799,7 +870,7 @@ mod tests {
         ];
         let collector = get_collector_from_ranges(buckets, ColumnType::F64);
 
-        let buckets = collector.buckets;
+        let buckets = collector.parent_buckets[0].clone();
         assert_eq!(buckets[0].range.start, u64::MIN);
         assert_eq!(buckets[0].range.end, 10f64.to_u64());
         assert_eq!(buckets[1].range.start, 10f64.to_u64());
@@ -814,7 +885,7 @@ mod tests {
         let buckets = vec![(-10f64..-1f64).into()];
         let collector = get_collector_from_ranges(buckets, ColumnType::F64);
 
-        let buckets = collector.buckets;
+        let buckets = collector.parent_buckets[0].clone();
         assert_eq!(&buckets[0].bucket.key.to_string(), "*--10");
         assert_eq!(&buckets[buckets.len() - 1].bucket.key.to_string(), "-1-*");
     }
@@ -823,7 +894,7 @@ mod tests {
         let buckets = vec![(0f64..10f64).into()];
         let collector = get_collector_from_ranges(buckets, ColumnType::F64);
 
-        let buckets = collector.buckets;
+        let buckets = collector.parent_buckets[0].clone();
         assert_eq!(&buckets[0].bucket.key.to_string(), "*-0");
         assert_eq!(&buckets[buckets.len() - 1].bucket.key.to_string(), "10-*");
     }
@@ -832,7 +903,7 @@ mod tests {
     fn range_binary_search_test_u64() {
         let check_ranges = |ranges: Vec<RangeAggregationRange>| {
             let collector = get_collector_from_ranges(ranges, ColumnType::U64);
-            let search = |val: u64| collector.get_bucket_pos(val);
+            let search = |val: u64| get_bucket_pos(val, &collector.parent_buckets[0]);
 
             assert_eq!(search(u64::MIN), 0);
             assert_eq!(search(9), 0);
@@ -878,7 +949,7 @@ mod tests {
         let ranges = vec![(10.0..100.0).into()];
 
         let collector = get_collector_from_ranges(ranges, ColumnType::F64);
-        let search = |val: u64| collector.get_bucket_pos(val);
+        let search = |val: u64| get_bucket_pos(val, &collector.parent_buckets[0]);
 
         assert_eq!(search(u64::MIN), 0);
         assert_eq!(search(9f64.to_u64()), 0);
@@ -890,63 +961,3 @@ mod tests {
                                              // the max value
     }
 }
-
-#[cfg(all(test, feature = "unstable"))]
-mod bench {
-
-    use itertools::Itertools;
-    use rand::seq::SliceRandom;
-    use rand::thread_rng;
-
-    use super::*;
-    use crate::aggregation::bucket::range::tests::get_collector_from_ranges;
-
-    const TOTAL_DOCS: u64 = 1_000_000u64;
-    const NUM_DOCS: u64 = 50_000u64;
-
-    fn get_collector_with_buckets(num_buckets: u64, num_docs: u64) -> SegmentRangeCollector {
-        let bucket_size = num_docs / num_buckets;
-        let mut buckets: Vec<RangeAggregationRange> = vec![];
-        for i in 0..num_buckets {
-            let bucket_start = (i * bucket_size) as f64;
-            buckets.push((bucket_start..bucket_start + bucket_size as f64).into())
-        }
-
-        get_collector_from_ranges(buckets, ColumnType::U64)
-    }
-
-    fn get_rand_docs(total_docs: u64, num_docs_returned: u64) -> Vec<u64> {
-        let mut rng = thread_rng();
-
-        let all_docs = (0..total_docs - 1).collect_vec();
-        let mut vals = all_docs
-            .as_slice()
-            .choose_multiple(&mut rng, num_docs_returned as usize)
-            .cloned()
-            .collect_vec();
-        vals.sort();
-        vals
-    }
-
-    fn bench_range_binary_search(b: &mut test::Bencher, num_buckets: u64) {
-        let collector = get_collector_with_buckets(num_buckets, TOTAL_DOCS);
-        let vals = get_rand_docs(TOTAL_DOCS, NUM_DOCS);
-        b.iter(|| {
-            let mut bucket_pos = 0;
-            for val in &vals {
-                bucket_pos = collector.get_bucket_pos(*val);
-            }
-            bucket_pos
-        })
-    }
-
-    #[bench]
-    fn bench_range_100_buckets(b: &mut test::Bencher) {
-        bench_range_binary_search(b, 100)
-    }
-
-    #[bench]
-    fn bench_range_10_buckets(b: &mut test::Bencher) {
-        bench_range_binary_search(b, 10)
-    }
-}

src/aggregation/bucket/term_missing_agg.rs

@@ -5,11 +5,13 @@ use crate::aggregation::agg_data::{
     build_segment_agg_collectors, AggRefNode, AggregationsSegmentCtx,
 };
 use crate::aggregation::bucket::term_agg::TermsAggregation;
+use crate::aggregation::cached_sub_aggs::{CachedSubAggs, HighCardCachedSubAggs};
 use crate::aggregation::intermediate_agg_result::{
     IntermediateAggregationResult, IntermediateAggregationResults, IntermediateBucketResult,
     IntermediateKey, IntermediateTermBucketEntry, IntermediateTermBucketResult,
 };
-use crate::aggregation::segment_agg_result::SegmentAggregationCollector;
+use crate::aggregation::segment_agg_result::{BucketIdProvider, SegmentAggregationCollector};
+use crate::aggregation::BucketId;
 
 /// Special aggregation to handle missing values for term aggregations.
 /// This missing aggregation will check multiple columns for existence.
@@ -35,41 +37,55 @@ impl MissingTermAggReqData {
     }
 }
 
-/// The specialized missing term aggregation.
 #[derive(Default, Debug, Clone)]
-pub struct TermMissingAgg {
+struct MissingCount {
     missing_count: u32,
+    bucket_id: BucketId,
+}
+
+/// The specialized missing term aggregation.
+#[derive(Default, Debug)]
+pub struct TermMissingAgg {
     accessor_idx: usize,
-    sub_agg: Option<Box<dyn SegmentAggregationCollector>>,
+    sub_agg: Option<HighCardCachedSubAggs>,
+    /// Idx = parent bucket id, Value = missing count for that bucket
+    missing_count_per_bucket: Vec<MissingCount>,
+    bucket_id_provider: BucketIdProvider,
 }
 impl TermMissingAgg {
     pub(crate) fn new(
-        req_data: &mut AggregationsSegmentCtx,
+        agg_data: &mut AggregationsSegmentCtx,
         node: &AggRefNode,
     ) -> crate::Result<Self> {
         let has_sub_aggregations = !node.children.is_empty();
         let accessor_idx = node.idx_in_req_data;
         let sub_agg = if has_sub_aggregations {
-            let sub_aggregation = build_segment_agg_collectors(req_data, &node.children)?;
+            let sub_aggregation = build_segment_agg_collectors(agg_data, &node.children)?;
             Some(sub_aggregation)
         } else {
             None
         };
 
+        let sub_agg = sub_agg.map(CachedSubAggs::new);
+        let bucket_id_provider = BucketIdProvider::default();
+
         Ok(Self {
             accessor_idx,
             sub_agg,
-            ..Default::default()
+            missing_count_per_bucket: Vec::new(),
+            bucket_id_provider,
         })
     }
 }
 
 impl SegmentAggregationCollector for TermMissingAgg {
     fn add_intermediate_aggregation_result(
-        self: Box<Self>,
+        &mut self,
         agg_data: &AggregationsSegmentCtx,
         results: &mut IntermediateAggregationResults,
+        parent_bucket_id: BucketId,
     ) -> crate::Result<()> {
+        self.prepare_max_bucket(parent_bucket_id, agg_data)?;
         let req_data = agg_data.get_missing_term_req_data(self.accessor_idx);
         let term_agg = &req_data.req;
         let missing = term_agg
@@ -80,13 +96,16 @@ impl SegmentAggregationCollector for TermMissingAgg {
         let mut entries: FxHashMap<IntermediateKey, IntermediateTermBucketEntry> =
             Default::default();
 
+        let missing_count = &self.missing_count_per_bucket[parent_bucket_id as usize];
         let mut missing_entry = IntermediateTermBucketEntry {
-            doc_count: self.missing_count,
+            doc_count: missing_count.missing_count,
             sub_aggregation: Default::default(),
         };
-        if let Some(sub_agg) = self.sub_agg {
+        if let Some(sub_agg) = &mut self.sub_agg {
             let mut res = IntermediateAggregationResults::default();
-            sub_agg.add_intermediate_aggregation_result(agg_data, &mut res)?;
+            sub_agg
+                .get_sub_agg_collector()
+                .add_intermediate_aggregation_result(agg_data, &mut res, missing_count.bucket_id)?;
             missing_entry.sub_aggregation = res;
         }
         entries.insert(missing.into(), missing_entry);
@@ -109,30 +128,52 @@ impl SegmentAggregationCollector for TermMissingAgg {
 
     fn collect(
         &mut self,
-        doc: crate::DocId,
+        parent_bucket_id: BucketId,
+        docs: &[crate::DocId],
         agg_data: &mut AggregationsSegmentCtx,
     ) -> crate::Result<()> {
+        let bucket = &mut self.missing_count_per_bucket[parent_bucket_id as usize];
         let req_data = agg_data.get_missing_term_req_data(self.accessor_idx);
-        let has_value = req_data
-            .accessors
-            .iter()
-            .any(|(acc, _)| acc.index.has_value(doc));
-        if !has_value {
-            self.missing_count += 1;
-            if let Some(sub_agg) = self.sub_agg.as_mut() {
-                sub_agg.collect(doc, agg_data)?;
+
+        for doc in docs {
+            let doc = *doc;
+            let has_value = req_data
+                .accessors
+                .iter()
+                .any(|(acc, _)| acc.index.has_value(doc));
+            if !has_value {
+                bucket.missing_count += 1;
+
+                if let Some(sub_agg) = self.sub_agg.as_mut() {
+                    sub_agg.push(bucket.bucket_id, doc);
+                }
             }
         }
+
+        if let Some(sub_agg) = self.sub_agg.as_mut() {
+            sub_agg.check_flush_local(agg_data)?;
+        }
         Ok(())
     }
 
-    fn collect_block(
+    fn prepare_max_bucket(
         &mut self,
-        docs: &[crate::DocId],
-        agg_data: &mut AggregationsSegmentCtx,
+        max_bucket: BucketId,
+        _agg_data: &AggregationsSegmentCtx,
     ) -> crate::Result<()> {
-        for doc in docs {
-            self.collect(*doc, agg_data)?;
+        while self.missing_count_per_bucket.len() <= max_bucket as usize {
+            let bucket_id = self.bucket_id_provider.next_bucket_id();
+            self.missing_count_per_bucket.push(MissingCount {
+                missing_count: 0,
+                bucket_id,
+            });
+        }
+        Ok(())
+    }
+
+    fn flush(&mut self, agg_data: &mut AggregationsSegmentCtx) -> crate::Result<()> {
+        if let Some(sub_agg) = self.sub_agg.as_mut() {
+            sub_agg.flush(agg_data)?;
         }
         Ok(())
     }

src/aggregation/buf_collector.rs

@@ -1,87 +0,0 @@
-use super::intermediate_agg_result::IntermediateAggregationResults;
-use super::segment_agg_result::SegmentAggregationCollector;
-use crate::aggregation::agg_data::AggregationsSegmentCtx;
-use crate::DocId;
-
-#[cfg(test)]
-pub(crate) const DOC_BLOCK_SIZE: usize = 64;
-
-#[cfg(not(test))]
-pub(crate) const DOC_BLOCK_SIZE: usize = 256;
-
-pub(crate) type DocBlock = [DocId; DOC_BLOCK_SIZE];
-
-/// BufAggregationCollector buffers documents before calling collect_block().
-#[derive(Clone)]
-pub(crate) struct BufAggregationCollector {
-    pub(crate) collector: Box<dyn SegmentAggregationCollector>,
-    staged_docs: DocBlock,
-    num_staged_docs: usize,
-}
-
-impl std::fmt::Debug for BufAggregationCollector {
-    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
-        f.debug_struct("SegmentAggregationResultsCollector")
-            .field("staged_docs", &&self.staged_docs[..self.num_staged_docs])
-            .field("num_staged_docs", &self.num_staged_docs)
-            .finish()
-    }
-}
-
-impl BufAggregationCollector {
-    pub fn new(collector: Box<dyn SegmentAggregationCollector>) -> Self {
-        Self {
-            collector,
-            num_staged_docs: 0,
-            staged_docs: [0; DOC_BLOCK_SIZE],
-        }
-    }
-}
-
-impl SegmentAggregationCollector for BufAggregationCollector {
-    #[inline]
-    fn add_intermediate_aggregation_result(
-        self: Box<Self>,
-        agg_data: &AggregationsSegmentCtx,
-        results: &mut IntermediateAggregationResults,
-    ) -> crate::Result<()> {
-        Box::new(self.collector).add_intermediate_aggregation_result(agg_data, results)
-    }
-
-    #[inline]
-    fn collect(
-        &mut self,
-        doc: crate::DocId,
-        agg_data: &mut AggregationsSegmentCtx,
-    ) -> crate::Result<()> {
-        self.staged_docs[self.num_staged_docs] = doc;
-        self.num_staged_docs += 1;
-        if self.num_staged_docs == self.staged_docs.len() {
-            self.collector
-                .collect_block(&self.staged_docs[..self.num_staged_docs], agg_data)?;
-            self.num_staged_docs = 0;
-        }
-        Ok(())
-    }
-
-    #[inline]
-    fn collect_block(
-        &mut self,
-        docs: &[crate::DocId],
-        agg_data: &mut AggregationsSegmentCtx,
-    ) -> crate::Result<()> {
-        self.collector.collect_block(docs, agg_data)?;
-        Ok(())
-    }
-
-    #[inline]
-    fn flush(&mut self, agg_data: &mut AggregationsSegmentCtx) -> crate::Result<()> {
-        self.collector
-            .collect_block(&self.staged_docs[..self.num_staged_docs], agg_data)?;
-        self.num_staged_docs = 0;
-
-        self.collector.flush(agg_data)?;
-
-        Ok(())
-    }
-}

src/aggregation/cached_sub_aggs.rs

@@ -0,0 +1,245 @@
+use std::fmt::Debug;
+
+use super::segment_agg_result::SegmentAggregationCollector;
+use crate::aggregation::agg_data::AggregationsSegmentCtx;
+use crate::aggregation::bucket::MAX_NUM_TERMS_FOR_VEC;
+use crate::aggregation::BucketId;
+use crate::DocId;
+
+/// A cache for sub-aggregations, storing doc ids per bucket id.
+/// Depending on the cardinality of the parent aggregation, we use different
+/// storage strategies.
+///
+/// ## Low Cardinality
+/// Cardinality here refers to the number of unique flattened buckets that can be created
+/// by the parent aggregation.
+/// Flattened buckets are the result of combining all buckets per collector
+/// into a single list of buckets, where each bucket is identified by its BucketId.
+///
+/// ## Usage
+/// Since this is caching for sub-aggregations, it is only used by bucket
+/// aggregations.
+///
+/// TODO: consider using a more advanced data structure for high cardinality
+/// aggregations.
+/// What this datastructure does in general is to group docs by bucket id.
+#[derive(Debug)]
+pub(crate) struct CachedSubAggs<C: SubAggCache> {
+    cache: C,
+    sub_agg_collector: Box<dyn SegmentAggregationCollector>,
+    num_docs: usize,
+}
+
+pub type LowCardCachedSubAggs = CachedSubAggs<LowCardSubAggCache>;
+pub type HighCardCachedSubAggs = CachedSubAggs<HighCardSubAggCache>;
+
+const FLUSH_THRESHOLD: usize = 2048;
+
+/// A trait for caching sub-aggregation doc ids per bucket id.
+/// Different implementations can be used depending on the cardinality
+/// of the parent aggregation.
+pub trait SubAggCache: Debug {
+    fn new() -> Self;
+    fn push(&mut self, bucket_id: BucketId, doc_id: DocId);
+    fn flush_local(
+        &mut self,
+        sub_agg: &mut Box<dyn SegmentAggregationCollector>,
+        agg_data: &mut AggregationsSegmentCtx,
+        force: bool,
+    ) -> crate::Result<()>;
+}
+
+impl<Backend: SubAggCache + Debug> CachedSubAggs<Backend> {
+    pub fn new(sub_agg: Box<dyn SegmentAggregationCollector>) -> Self {
+        Self {
+            cache: Backend::new(),
+            sub_agg_collector: sub_agg,
+            num_docs: 0,
+        }
+    }
+
+    pub fn get_sub_agg_collector(&mut self) -> &mut Box<dyn SegmentAggregationCollector> {
+        &mut self.sub_agg_collector
+    }
+
+    #[inline]
+    pub fn push(&mut self, bucket_id: BucketId, doc_id: DocId) {
+        self.cache.push(bucket_id, doc_id);
+        self.num_docs += 1;
+    }
+
+    /// Check if we need to flush based on the number of documents cached.
+    /// If so, flushes the cache to the provided aggregation collector.
+    pub fn check_flush_local(
+        &mut self,
+        agg_data: &mut AggregationsSegmentCtx,
+    ) -> crate::Result<()> {
+        if self.num_docs >= FLUSH_THRESHOLD {
+            self.cache
+                .flush_local(&mut self.sub_agg_collector, agg_data, false)?;
+            self.num_docs = 0;
+        }
+        Ok(())
+    }
+
+    /// Note: this _does_ flush the sub aggregations.
+    pub fn flush(&mut self, agg_data: &mut AggregationsSegmentCtx) -> crate::Result<()> {
+        if self.num_docs != 0 {
+            self.cache
+                .flush_local(&mut self.sub_agg_collector, agg_data, true)?;
+            self.num_docs = 0;
+        }
+        self.sub_agg_collector.flush(agg_data)?;
+        Ok(())
+    }
+}
+
+/// Number of partitions for high cardinality sub-aggregation cache.
+const NUM_PARTITIONS: usize = 16;
+
+#[derive(Debug)]
+pub(crate) struct HighCardSubAggCache {
+    /// This weird partitioning is used to do some cheap grouping on the bucket ids.
+    /// bucket ids are dense, e.g. when we don't detect the cardinality as low cardinality,
+    /// but there are just 16 bucket ids, each bucket id will go to its own partition.
+    ///
+    /// We want to keep this cheap, because high cardinality aggregations can have a lot of
+    /// buckets, and there may be nothing to group.
+    partitions: Box<[PartitionEntry; NUM_PARTITIONS]>,
+}
+
+impl HighCardSubAggCache {
+    #[inline]
+    fn clear(&mut self) {
+        for partition in self.partitions.iter_mut() {
+            partition.clear();
+        }
+    }
+}
+
+#[derive(Debug, Clone, Default)]
+struct PartitionEntry {
+    bucket_ids: Vec<BucketId>,
+    docs: Vec<DocId>,
+}
+
+impl PartitionEntry {
+    #[inline]
+    fn clear(&mut self) {
+        self.bucket_ids.clear();
+        self.docs.clear();
+    }
+}
+
+impl SubAggCache for HighCardSubAggCache {
+    fn new() -> Self {
+        Self {
+            partitions: Box::new(core::array::from_fn(|_| PartitionEntry::default())),
+        }
+    }
+
+    fn push(&mut self, bucket_id: BucketId, doc_id: DocId) {
+        let idx = bucket_id % NUM_PARTITIONS as u32;
+        let slot = &mut self.partitions[idx as usize];
+        slot.bucket_ids.push(bucket_id);
+        slot.docs.push(doc_id);
+    }
+
+    fn flush_local(
+        &mut self,
+        sub_agg: &mut Box<dyn SegmentAggregationCollector>,
+        agg_data: &mut AggregationsSegmentCtx,
+        _force: bool,
+    ) -> crate::Result<()> {
+        let mut max_bucket = 0u32;
+        for partition in self.partitions.iter() {
+            if let Some(&local_max) = partition.bucket_ids.iter().max() {
+                max_bucket = max_bucket.max(local_max);
+            }
+        }
+
+        sub_agg.prepare_max_bucket(max_bucket, agg_data)?;
+
+        for slot in self.partitions.iter() {
+            if !slot.bucket_ids.is_empty() {
+                // Reduce dynamic dispatch overhead by collecting a full partition in one call.
+                sub_agg.collect_multiple(&slot.bucket_ids, &slot.docs, agg_data)?;
+            }
+        }
+
+        self.clear();
+        Ok(())
+    }
+}
+
+#[derive(Debug)]
+pub(crate) struct LowCardSubAggCache {
+    /// Cache doc ids per bucket for sub-aggregations.
+    ///
+    /// The outer Vec is indexed by BucketId.
+    per_bucket_docs: Vec<Vec<DocId>>,
+}
+
+impl LowCardSubAggCache {
+    #[inline]
+    fn clear(&mut self) {
+        for v in &mut self.per_bucket_docs {
+            v.clear();
+        }
+    }
+}
+
+impl SubAggCache for LowCardSubAggCache {
+    fn new() -> Self {
+        Self {
+            per_bucket_docs: Vec::new(),
+        }
+    }
+
+    fn push(&mut self, bucket_id: BucketId, doc_id: DocId) {
+        let idx = bucket_id as usize;
+        if self.per_bucket_docs.len() <= idx {
+            self.per_bucket_docs.resize_with(idx + 1, Vec::new);
+        }
+        self.per_bucket_docs[idx].push(doc_id);
+    }
+
+    fn flush_local(
+        &mut self,
+        sub_agg: &mut Box<dyn SegmentAggregationCollector>,
+        agg_data: &mut AggregationsSegmentCtx,
+        force: bool,
+    ) -> crate::Result<()> {
+        // Pre-aggregated: call collect per bucket.
+        let max_bucket = (self.per_bucket_docs.len() as BucketId).saturating_sub(1);
+        sub_agg.prepare_max_bucket(max_bucket, agg_data)?;
+        // The threshold above which we flush buckets individually.
+        // Note: We need to make sure that we don't lock ourselves into a situation where we hit
+        // the FLUSH_THRESHOLD, but never flush any buckets. (except the final flush)
+        let mut bucket_treshold = FLUSH_THRESHOLD / (self.per_bucket_docs.len().max(1) * 2);
+        const _: () = {
+            // MAX_NUM_TERMS_FOR_VEC threshold is used for term aggregations
+            // Note: There may be other flexible values, for other aggregations, but we can use the
+            // const value here as a upper bound. (better than nothing)
+            let bucket_treshold_limit = FLUSH_THRESHOLD / (MAX_NUM_TERMS_FOR_VEC as usize * 2);
+            assert!(
+                bucket_treshold_limit > 0,
+                "Bucket threshold must be greater than 0"
+            );
+        };
+        if force {
+            bucket_treshold = 0;
+        }
+        for (bucket_id, docs) in self
+            .per_bucket_docs
+            .iter()
+            .enumerate()
+            .filter(|(_, docs)| docs.len() > bucket_treshold)
+        {
+            sub_agg.collect(bucket_id as BucketId, docs, agg_data)?;
+        }
+
+        self.clear();
+        Ok(())
+    }
+}

src/aggregation/collector.rs

@@ -1,9 +1,9 @@
 use super::agg_req::Aggregations;
 use super::agg_result::AggregationResults;
-use super::buf_collector::BufAggregationCollector;
+use super::cached_sub_aggs::LowCardCachedSubAggs;
 use super::intermediate_agg_result::IntermediateAggregationResults;
-use super::segment_agg_result::SegmentAggregationCollector;
 use super::AggContextParams;
+// group buffering strategy is chosen explicitly by callers; no need to hash-group on the fly.
 use crate::aggregation::agg_data::{
     build_aggregations_data_from_req, build_segment_agg_collectors_root, AggregationsSegmentCtx,
 };
@@ -136,7 +136,7 @@ fn merge_fruits(
 /// `AggregationSegmentCollector` does the aggregation collection on a segment.
 pub struct AggregationSegmentCollector {
     aggs_with_accessor: AggregationsSegmentCtx,
-    agg_collector: BufAggregationCollector,
+    agg_collector: LowCardCachedSubAggs,
     error: Option<TantivyError>,
 }
 
@@ -151,8 +151,11 @@ impl AggregationSegmentCollector {
     ) -> crate::Result<Self> {
         let mut agg_data =
             build_aggregations_data_from_req(agg, reader, segment_ordinal, context.clone())?;
-        let result =
-            BufAggregationCollector::new(build_segment_agg_collectors_root(&mut agg_data)?);
+        let mut result =
+            LowCardCachedSubAggs::new(build_segment_agg_collectors_root(&mut agg_data)?);
+        result
+            .get_sub_agg_collector()
+            .prepare_max_bucket(0, &agg_data)?; // prepare for bucket zero
 
         Ok(AggregationSegmentCollector {
             aggs_with_accessor: agg_data,
@@ -170,26 +173,31 @@ impl SegmentCollector for AggregationSegmentCollector {
         if self.error.is_some() {
             return;
         }
-        if let Err(err) = self
+        self.agg_collector.push(0, doc);
+        match self
             .agg_collector
-            .collect(doc, &mut self.aggs_with_accessor)
+            .check_flush_local(&mut self.aggs_with_accessor)
         {
-            self.error = Some(err);
+            Ok(_) => {}
+            Err(e) => {
+                self.error = Some(e);
+            }
         }
     }
-
-    /// The query pushes the documents to the collector via this method.
-    ///
-    /// Only valid for Collectors that ignore docs
     fn collect_block(&mut self, docs: &[DocId]) {
         if self.error.is_some() {
             return;
         }
-        if let Err(err) = self
-            .agg_collector
-            .collect_block(docs, &mut self.aggs_with_accessor)
-        {
-            self.error = Some(err);
+
+        match self.agg_collector.get_sub_agg_collector().collect(
+            0,
+            docs,
+            &mut self.aggs_with_accessor,
+        ) {
+            Ok(_) => {}
+            Err(e) => {
+                self.error = Some(e);
+            }
         }
     }
 
@@ -200,10 +208,13 @@ impl SegmentCollector for AggregationSegmentCollector {
         self.agg_collector.flush(&mut self.aggs_with_accessor)?;
 
         let mut sub_aggregation_res = IntermediateAggregationResults::default();
-        Box::new(self.agg_collector).add_intermediate_aggregation_result(
-            &self.aggs_with_accessor,
-            &mut sub_aggregation_res,
-        )?;
+        self.agg_collector
+            .get_sub_agg_collector()
+            .add_intermediate_aggregation_result(
+                &self.aggs_with_accessor,
+                &mut sub_aggregation_res,
+                0,
+            )?;
 
         Ok(sub_aggregation_res)
     }

src/aggregation/intermediate_agg_result.rs

@@ -19,8 +19,9 @@ use super::bucket::{
     GetDocCount, Order, OrderTarget, RangeAggregation, TermsAggregation,
 };
 use super::metric::{
-    IntermediateAverage, IntermediateCount, IntermediateExtendedStats, IntermediateMax,
-    IntermediateMin, IntermediateStats, IntermediateSum, PercentilesCollector, TopHitsTopNComputer,
+    AverageMetricResult, CardinalityMetricResult, IntermediateAverage, IntermediateCount,
+    IntermediateExtendedStats, IntermediateMax, IntermediateMin, IntermediateStats,
+    IntermediateSum, PercentilesCollector, TopHitsTopNComputer,
 };
 use super::segment_agg_result::AggregationLimitsGuard;
 use super::{format_date, AggregationError, Key, SerializedKey};
@@ -325,7 +326,11 @@ impl IntermediateMetricResult {
     fn into_final_metric_result(self, req: &Aggregation) -> MetricResult {
         match self {
             IntermediateMetricResult::Average(intermediate_avg) => {
-                MetricResult::Average(intermediate_avg.finalize().into())
+                MetricResult::Average(AverageMetricResult {
+                    value: intermediate_avg.finalize(),
+                    sum: intermediate_avg.sum(),
+                    count: intermediate_avg.count(),
+                })
             }
             IntermediateMetricResult::Count(intermediate_count) => {
                 MetricResult::Count(intermediate_count.finalize().into())
@@ -353,7 +358,11 @@ impl IntermediateMetricResult {
                 MetricResult::TopHits(top_hits.into_final_result())
             }
             IntermediateMetricResult::Cardinality(cardinality) => {
-                MetricResult::Cardinality(cardinality.finalize().into())
+                let value = cardinality.finalize();
+                MetricResult::Cardinality(CardinalityMetricResult {
+                    value,
+                    sketch: Some(cardinality),
+                })
             }
         }
     }
@@ -792,7 +801,7 @@ pub struct IntermediateRangeBucketEntry {
     /// The number of documents in the bucket.
     pub doc_count: u64,
     /// The sub_aggregation in this bucket.
-    pub sub_aggregation: IntermediateAggregationResults,
+    pub sub_aggregation_res: IntermediateAggregationResults,
     /// The from range of the bucket. Equals `f64::MIN` when `None`.
     pub from: Option<f64>,
     /// The to range of the bucket. Equals `f64::MAX` when `None`.
@@ -811,7 +820,7 @@ impl IntermediateRangeBucketEntry {
             key: self.key.into(),
             doc_count: self.doc_count,
             sub_aggregation: self
-                .sub_aggregation
+                .sub_aggregation_res
                 .into_final_result_internal(req, limits)?,
             to: self.to,
             from: self.from,
@@ -820,7 +829,7 @@ impl IntermediateRangeBucketEntry {
         };
 
         // If we have a date type on the histogram buckets, we add the `key_as_string` field as
-        // rfc339
+        // rfc3339
         if column_type == Some(ColumnType::DateTime) {
             if let Some(val) = range_bucket_entry.to {
                 let key_as_string = format_date(val as i64)?;
@@ -857,7 +866,8 @@ impl MergeFruits for IntermediateTermBucketEntry {
 impl MergeFruits for IntermediateRangeBucketEntry {
     fn merge_fruits(&mut self, other: IntermediateRangeBucketEntry) -> crate::Result<()> {
         self.doc_count += other.doc_count;
-        self.sub_aggregation.merge_fruits(other.sub_aggregation)?;
+        self.sub_aggregation_res
+            .merge_fruits(other.sub_aggregation_res)?;
         Ok(())
     }
 }
@@ -887,7 +897,7 @@ mod tests {
                 IntermediateRangeBucketEntry {
                     key: IntermediateKey::Str(key.to_string()),
                     doc_count: *doc_count,
-                    sub_aggregation: Default::default(),
+                    sub_aggregation_res: Default::default(),
                     from: None,
                     to: None,
                 },
@@ -920,7 +930,7 @@ mod tests {
                     doc_count: *doc_count,
                     from: None,
                     to: None,
-                    sub_aggregation: get_sub_test_tree(&[(
+                    sub_aggregation_res: get_sub_test_tree(&[(
                         sub_aggregation_key.to_string(),
                         *sub_aggregation_count,
                     )]),

src/aggregation/metric/average.rs

@@ -52,10 +52,8 @@ pub struct IntermediateAverage {
 
 impl IntermediateAverage {
     /// Creates a new [`IntermediateAverage`] instance from a [`SegmentStatsCollector`].
-    pub(crate) fn from_collector(collector: SegmentStatsCollector) -> Self {
-        Self {
-            stats: collector.stats,
-        }
+    pub(crate) fn from_stats(stats: IntermediateStats) -> Self {
+        Self { stats }
     }
     /// Merges the other intermediate result into self.
     pub fn merge_fruits(&mut self, other: IntermediateAverage) {
@@ -65,6 +63,16 @@ impl IntermediateAverage {
     pub fn finalize(&self) -> Option<f64> {
         self.stats.finalize().avg
     }
+
+    /// Returns the sum of all collected values.
+    pub fn sum(&self) -> f64 {
+        self.stats.sum
+    }
+
+    /// Returns the count of all collected values.
+    pub fn count(&self) -> u64 {
+        self.stats.count
+    }
 }
 
 #[cfg(test)]

src/aggregation/metric/cardinality.rs

@@ -2,7 +2,7 @@ use std::collections::hash_map::DefaultHasher;
 use std::hash::{BuildHasher, Hasher};
 
 use columnar::column_values::CompactSpaceU64Accessor;
-use columnar::{Column, ColumnBlockAccessor, ColumnType, Dictionary, StrColumn};
+use columnar::{Column, ColumnType, Dictionary, StrColumn};
 use common::f64_to_u64;
 use hyperloglogplus::{HyperLogLog, HyperLogLogPlus};
 use rustc_hash::FxHashSet;
@@ -106,8 +106,6 @@ pub struct CardinalityAggReqData {
     pub str_dict_column: Option<StrColumn>,
     /// The missing value normalized to the internal u64 representation of the field type.
     pub missing_value_for_accessor: Option<u64>,
-    /// The column block accessor to access the fast field values.
-    pub(crate) column_block_accessor: ColumnBlockAccessor<u64>,
     /// The name of the aggregation.
     pub name: String,
     /// The aggregation request.
@@ -135,45 +133,34 @@ impl CardinalityAggregationReq {
     }
 }
 
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug)]
 pub(crate) struct SegmentCardinalityCollector {
-    cardinality: CardinalityCollector,
-    entries: FxHashSet<u64>,
+    buckets: Vec<SegmentCardinalityCollectorBucket>,
     accessor_idx: usize,
+    /// The column accessor to access the fast field values.
+    accessor: Column<u64>,
+    /// The column_type of the field.
+    column_type: ColumnType,
+    /// The missing value normalized to the internal u64 representation of the field type.
+    missing_value_for_accessor: Option<u64>,
 }
 
-impl SegmentCardinalityCollector {
-    pub fn from_req(column_type: ColumnType, accessor_idx: usize) -> Self {
+#[derive(Clone, Debug, PartialEq, Default)]
+pub(crate) struct SegmentCardinalityCollectorBucket {
+    cardinality: CardinalityCollector,
+    entries: FxHashSet<u64>,
+}
+impl SegmentCardinalityCollectorBucket {
+    pub fn new(column_type: ColumnType) -> Self {
         Self {
             cardinality: CardinalityCollector::new(column_type as u8),
-            entries: Default::default(),
-            accessor_idx,
+            entries: FxHashSet::default(),
         }
     }
-
-    fn fetch_block_with_field(
-        &mut self,
-        docs: &[crate::DocId],
-        agg_data: &mut CardinalityAggReqData,
-    ) {
-        if let Some(missing) = agg_data.missing_value_for_accessor {
-            agg_data.column_block_accessor.fetch_block_with_missing(
-                docs,
-                &agg_data.accessor,
-                missing,
-            );
-        } else {
-            agg_data
-                .column_block_accessor
-                .fetch_block(docs, &agg_data.accessor);
-        }
-    }
-
     fn into_intermediate_metric_result(
         mut self,
-        agg_data: &AggregationsSegmentCtx,
+        req_data: &CardinalityAggReqData,
     ) -> crate::Result<IntermediateMetricResult> {
-        let req_data = &agg_data.get_cardinality_req_data(self.accessor_idx);
         if req_data.column_type == ColumnType::Str {
             let fallback_dict = Dictionary::empty();
             let dict = req_data
@@ -194,6 +181,7 @@ impl SegmentCardinalityCollector {
                     term_ids.push(term_ord as u32);
                 }
             }
+
             term_ids.sort_unstable();
             dict.sorted_ords_to_term_cb(term_ids.iter().map(|term| *term as u64), |term| {
                 self.cardinality.sketch.insert_any(&term);
@@ -227,16 +215,49 @@ impl SegmentCardinalityCollector {
     }
 }
 
+impl SegmentCardinalityCollector {
+    pub fn from_req(
+        column_type: ColumnType,
+        accessor_idx: usize,
+        accessor: Column<u64>,
+        missing_value_for_accessor: Option<u64>,
+    ) -> Self {
+        Self {
+            buckets: vec![SegmentCardinalityCollectorBucket::new(column_type); 1],
+            column_type,
+            accessor_idx,
+            accessor,
+            missing_value_for_accessor,
+        }
+    }
+
+    fn fetch_block_with_field(
+        &mut self,
+        docs: &[crate::DocId],
+        agg_data: &mut AggregationsSegmentCtx,
+    ) {
+        agg_data.column_block_accessor.fetch_block_with_missing(
+            docs,
+            &self.accessor,
+            self.missing_value_for_accessor,
+        );
+    }
+}
+
 impl SegmentAggregationCollector for SegmentCardinalityCollector {
     fn add_intermediate_aggregation_result(
-        self: Box<Self>,
+        &mut self,
         agg_data: &AggregationsSegmentCtx,
         results: &mut IntermediateAggregationResults,
+        parent_bucket_id: BucketId,
     ) -> crate::Result<()> {
+        self.prepare_max_bucket(parent_bucket_id, agg_data)?;
         let req_data = &agg_data.get_cardinality_req_data(self.accessor_idx);
         let name = req_data.name.to_string();
+        // take the bucket in buckets and replace it with a new empty one
+        let bucket = std::mem::take(&mut self.buckets[parent_bucket_id as usize]);
 
-        let intermediate_result = self.into_intermediate_metric_result(agg_data)?;
+        let intermediate_result = bucket.into_intermediate_metric_result(req_data)?;
         results.push(
             name,
             IntermediateAggregationResult::Metric(intermediate_result),
@@ -247,27 +268,20 @@ impl SegmentAggregationCollector for SegmentCardinalityCollector {
 
     fn collect(
         &mut self,
-        doc: crate::DocId,
-        agg_data: &mut AggregationsSegmentCtx,
-    ) -> crate::Result<()> {
-        self.collect_block(&[doc], agg_data)
-    }
-
-    fn collect_block(
-        &mut self,
+        parent_bucket_id: BucketId,
         docs: &[crate::DocId],
         agg_data: &mut AggregationsSegmentCtx,
     ) -> crate::Result<()> {
-        let req_data = agg_data.get_cardinality_req_data_mut(self.accessor_idx);
-        self.fetch_block_with_field(docs, req_data);
+        self.fetch_block_with_field(docs, agg_data);
+        let bucket = &mut self.buckets[parent_bucket_id as usize];
 
-        let col_block_accessor = &req_data.column_block_accessor;
-        if req_data.column_type == ColumnType::Str {
+        let col_block_accessor = &agg_data.column_block_accessor;
+        if self.column_type == ColumnType::Str {
             for term_ord in col_block_accessor.iter_vals() {
-                self.entries.insert(term_ord);
+                bucket.entries.insert(term_ord);
             }
-        } else if req_data.column_type == ColumnType::IpAddr {
-            let compact_space_accessor = req_data
+        } else if self.column_type == ColumnType::IpAddr {
+            let compact_space_accessor = self
                 .accessor
                 .values
                 .clone()
@@ -282,16 +296,29 @@ impl SegmentAggregationCollector for SegmentCardinalityCollector {
                 })?;
             for val in col_block_accessor.iter_vals() {
                 let val: u128 = compact_space_accessor.compact_to_u128(val as u32);
-                self.cardinality.sketch.insert_any(&val);
+                bucket.cardinality.sketch.insert_any(&val);
             }
         } else {
             for val in col_block_accessor.iter_vals() {
-                self.cardinality.sketch.insert_any(&val);
+                bucket.cardinality.sketch.insert_any(&val);
             }
         }
 
         Ok(())
     }
+
+    fn prepare_max_bucket(
+        &mut self,
+        max_bucket: BucketId,
+        _agg_data: &AggregationsSegmentCtx,
+    ) -> crate::Result<()> {
+        if max_bucket as usize >= self.buckets.len() {
+            self.buckets.resize_with(max_bucket as usize + 1, || {
+                SegmentCardinalityCollectorBucket::new(self.column_type)
+            });
+        }
+        Ok(())
+    }
 }
 
 #[derive(Clone, Debug, Serialize, Deserialize)]
@@ -313,7 +340,7 @@ impl PartialEq for CardinalityCollector {
 
 impl CardinalityCollector {
     /// Compute the final cardinality estimate.
-    pub fn finalize(self) -> Option<f64> {
+    pub fn finalize(&self) -> Option<f64> {
         Some(self.sketch.clone().count().trunc())
     }
 

src/aggregation/metric/count.rs

@@ -52,10 +52,8 @@ pub struct IntermediateCount {
 
 impl IntermediateCount {
     /// Creates a new [`IntermediateCount`] instance from a [`SegmentStatsCollector`].
-    pub(crate) fn from_collector(collector: SegmentStatsCollector) -> Self {
-        Self {
-            stats: collector.stats,
-        }
+    pub(crate) fn from_stats(stats: IntermediateStats) -> Self {
+        Self { stats }
     }
     /// Merges the other intermediate result into self.
     pub fn merge_fruits(&mut self, other: IntermediateCount) {

src/aggregation/metric/extended_stats.rs

@@ -8,10 +8,9 @@ use crate::aggregation::agg_data::AggregationsSegmentCtx;
 use crate::aggregation::intermediate_agg_result::{
     IntermediateAggregationResult, IntermediateAggregationResults, IntermediateMetricResult,
 };
-use crate::aggregation::metric::MetricAggReqData;
 use crate::aggregation::segment_agg_result::SegmentAggregationCollector;
 use crate::aggregation::*;
-use crate::{DocId, TantivyError};
+use crate::TantivyError;
 
 /// A multi-value metric aggregation that computes a collection of extended statistics
 /// on numeric values that are extracted
@@ -318,51 +317,28 @@ impl IntermediateExtendedStats {
     }
 }
 
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug)]
 pub(crate) struct SegmentExtendedStatsCollector {
+    name: String,
     missing: Option<u64>,
     field_type: ColumnType,
-    pub(crate) extended_stats: IntermediateExtendedStats,
-    pub(crate) accessor_idx: usize,
-    val_cache: Vec<u64>,
+    accessor: columnar::Column<u64>,
+    buckets: Vec<IntermediateExtendedStats>,
+    sigma: Option<f64>,
 }
 
 impl SegmentExtendedStatsCollector {
-    pub fn from_req(
-        field_type: ColumnType,
-        sigma: Option<f64>,
-        accessor_idx: usize,
-        missing: Option<f64>,
-    ) -> Self {
-        let missing = missing.and_then(|val| f64_to_fastfield_u64(val, &field_type));
+    pub fn from_req(req: &MetricAggReqData, sigma: Option<f64>) -> Self {
+        let missing = req
+            .missing
+            .and_then(|val| f64_to_fastfield_u64(val, &req.field_type));
         Self {
-            field_type,
-            extended_stats: IntermediateExtendedStats::with_sigma(sigma),
-            accessor_idx,
+            name: req.name.clone(),
+            field_type: req.field_type,
+            accessor: req.accessor.clone(),
             missing,
-            val_cache: Default::default(),
-        }
-    }
-    #[inline]
-    pub(crate) fn collect_block_with_field(
-        &mut self,
-        docs: &[DocId],
-        req_data: &mut MetricAggReqData,
-    ) {
-        if let Some(missing) = self.missing.as_ref() {
-            req_data.column_block_accessor.fetch_block_with_missing(
-                docs,
-                &req_data.accessor,
-                *missing,
-            );
-        } else {
-            req_data
-                .column_block_accessor
-                .fetch_block(docs, &req_data.accessor);
-        }
-        for val in req_data.column_block_accessor.iter_vals() {
-            let val1 = f64_from_fastfield_u64(val, &self.field_type);
-            self.extended_stats.collect(val1);
+            buckets: vec![IntermediateExtendedStats::with_sigma(sigma); 16],
+            sigma,
         }
     }
 }
@@ -370,15 +346,18 @@ impl SegmentExtendedStatsCollector {
 impl SegmentAggregationCollector for SegmentExtendedStatsCollector {
     #[inline]
     fn add_intermediate_aggregation_result(
-        self: Box<Self>,
+        &mut self,
         agg_data: &AggregationsSegmentCtx,
         results: &mut IntermediateAggregationResults,
+        parent_bucket_id: BucketId,
     ) -> crate::Result<()> {
-        let name = agg_data.get_metric_req_data(self.accessor_idx).name.clone();
+        let name = self.name.clone();
+        self.prepare_max_bucket(parent_bucket_id, agg_data)?;
+        let extended_stats = std::mem::take(&mut self.buckets[parent_bucket_id as usize]);
         results.push(
             name,
             IntermediateAggregationResult::Metric(IntermediateMetricResult::ExtendedStats(
-                self.extended_stats,
+                extended_stats,
             )),
         )?;
 
@@ -388,39 +367,36 @@ impl SegmentAggregationCollector for SegmentExtendedStatsCollector {
     #[inline]
     fn collect(
         &mut self,
-        doc: crate::DocId,
+        parent_bucket_id: BucketId,
+        docs: &[crate::DocId],
         agg_data: &mut AggregationsSegmentCtx,
     ) -> crate::Result<()> {
-        let req_data = agg_data.get_metric_req_data(self.accessor_idx);
-        if let Some(missing) = self.missing {
-            let mut has_val = false;
-            for val in req_data.accessor.values_for_doc(doc) {
-                let val1 = f64_from_fastfield_u64(val, &self.field_type);
-                self.extended_stats.collect(val1);
-                has_val = true;
-            }
-            if !has_val {
-                self.extended_stats
-                    .collect(f64_from_fastfield_u64(missing, &self.field_type));
-            }
-        } else {
-            for val in req_data.accessor.values_for_doc(doc) {
-                let val1 = f64_from_fastfield_u64(val, &self.field_type);
-                self.extended_stats.collect(val1);
-            }
+        let mut extended_stats = self.buckets[parent_bucket_id as usize].clone();
+
+        agg_data
+            .column_block_accessor
+            .fetch_block_with_missing(docs, &self.accessor, self.missing);
+        for val in agg_data.column_block_accessor.iter_vals() {
+            let val1 = f64_from_fastfield_u64(val, self.field_type);
+            extended_stats.collect(val1);
         }
 
+        // store back
+        self.buckets[parent_bucket_id as usize] = extended_stats;
+
         Ok(())
     }
 
-    #[inline]
-    fn collect_block(
+    fn prepare_max_bucket(
         &mut self,
-        docs: &[crate::DocId],
-        agg_data: &mut AggregationsSegmentCtx,
+        max_bucket: BucketId,
+        _agg_data: &AggregationsSegmentCtx,
     ) -> crate::Result<()> {
-        let req_data = agg_data.get_metric_req_data_mut(self.accessor_idx);
-        self.collect_block_with_field(docs, req_data);
+        if self.buckets.len() <= max_bucket as usize {
+            self.buckets.resize_with(max_bucket as usize + 1, || {
+                IntermediateExtendedStats::with_sigma(self.sigma)
+            });
+        }
         Ok(())
     }
 }

src/aggregation/metric/max.rs

@@ -52,10 +52,8 @@ pub struct IntermediateMax {
 
 impl IntermediateMax {
     /// Creates a new [`IntermediateMax`] instance from a [`SegmentStatsCollector`].
-    pub(crate) fn from_collector(collector: SegmentStatsCollector) -> Self {
-        Self {
-            stats: collector.stats,
-        }
+    pub(crate) fn from_stats(stats: IntermediateStats) -> Self {
+        Self { stats }
     }
     /// Merges the other intermediate result into self.
     pub fn merge_fruits(&mut self, other: IntermediateMax) {

src/aggregation/metric/min.rs

@@ -52,10 +52,8 @@ pub struct IntermediateMin {
 
 impl IntermediateMin {
     /// Creates a new [`IntermediateMin`] instance from a [`SegmentStatsCollector`].
-    pub(crate) fn from_collector(collector: SegmentStatsCollector) -> Self {
-        Self {
-            stats: collector.stats,
-        }
+    pub(crate) fn from_stats(stats: IntermediateStats) -> Self {
+        Self { stats }
     }
     /// Merges the other intermediate result into self.
     pub fn merge_fruits(&mut self, other: IntermediateMin) {

src/aggregation/metric/mod.rs

@@ -31,7 +31,7 @@ use std::collections::HashMap;
 
 pub use average::*;
 pub use cardinality::*;
-use columnar::{Column, ColumnBlockAccessor, ColumnType};
+use columnar::{Column, ColumnType};
 pub use count::*;
 pub use extended_stats::*;
 pub use max::*;
@@ -55,8 +55,6 @@ pub struct MetricAggReqData {
     pub field_type: ColumnType,
     /// The missing value normalized to the internal u64 representation of the field type.
     pub missing_u64: Option<u64>,
-    /// The column block accessor to access the fast field values.
-    pub column_block_accessor: ColumnBlockAccessor<u64>,
     /// The column accessor to access the fast field values.
     pub accessor: Column<u64>,
     /// Used when converting to intermediate result
@@ -95,6 +93,41 @@ impl From<Option<f64>> for SingleMetricResult {
     }
 }
 
+/// Average metric result with intermediate data for merging.
+///
+/// Unlike [`SingleMetricResult`], this struct includes the raw `sum` and `count`
+/// values that can be used for multi-step query merging.
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+pub struct AverageMetricResult {
+    /// The computed average value. None if no documents matched.
+    pub value: Option<f64>,
+    /// The sum of all values (for multi-step merging).
+    pub sum: f64,
+    /// The count of all values (for multi-step merging).
+    pub count: u64,
+}
+
+/// Cardinality metric result with computed value and raw HLL sketch for multi-step merging.
+///
+/// The `value` field contains the computed cardinality estimate.
+/// The `sketch` field contains the serialized HyperLogLog++ sketch that can be used
+/// for merging results across multiple query steps.
+#[derive(Clone, Debug, Serialize, Deserialize)]
+pub struct CardinalityMetricResult {
+    /// The computed cardinality estimate.
+    pub value: Option<f64>,
+    /// The serialized HyperLogLog++ sketch for multi-step merging.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub sketch: Option<CardinalityCollector>,
+}
+
+impl PartialEq for CardinalityMetricResult {
+    fn eq(&self, other: &Self) -> bool {
+        // Only compare values, not sketch (sketch comparison is complex)
+        self.value == other.value
+    }
+}
+
 /// This is the wrapper of percentile entries, which can be vector or hashmap
 /// depending on if it's keyed or not.
 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
@@ -113,13 +146,26 @@ pub struct PercentileValuesVecEntry {
     value: f64,
 }
 
-/// Single-metric aggregations use this common result structure.
+/// Percentiles metric result with computed values and raw sketch for multi-step merging.
 ///
-/// Main reason to wrap it in value is to match elasticsearch output structure.
-#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+/// The `values` field contains the computed percentile values.
+/// The `sketch` field contains the serialized DDSketch that can be used for merging
+/// results across multiple query steps.
+#[derive(Clone, Debug, Serialize, Deserialize)]
 pub struct PercentilesMetricResult {
-    /// The result of the percentile metric.
+    /// The computed percentile values.
     pub values: PercentileValues,
+    /// The serialized DDSketch for multi-step merging.
+    /// This is the raw sketch data that can be deserialized and merged with other sketches.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub sketch: Option<PercentilesCollector>,
+}
+
+impl PartialEq for PercentilesMetricResult {
+    fn eq(&self, other: &Self) -> bool {
+        // Only compare values, not sketch (sketch comparison is complex)
+        self.values == other.values
+    }
 }
 
 /// The top_hits metric results entry
@@ -200,4 +246,105 @@ mod tests {
         assert_eq!(aggregations_res_json["price_min"]["value"], 0.0);
         assert_eq!(aggregations_res_json["price_sum"]["value"], 15.0);
     }
+
+    #[test]
+    fn test_average_returns_sum_and_count() {
+        let mut schema_builder = Schema::builder();
+        let field_options = NumericOptions::default().set_fast();
+        let field = schema_builder.add_f64_field("price", field_options);
+        let index = Index::create_in_ram(schema_builder.build());
+        let mut index_writer: IndexWriter = index.writer_for_tests().unwrap();
+
+        // Add documents with values 0, 1, 2, 3, 4, 5
+        // sum = 15, count = 6, avg = 2.5
+        for i in 0..6 {
+            index_writer
+                .add_document(doc!(
+                    field => i as f64,
+                ))
+                .unwrap();
+        }
+        index_writer.commit().unwrap();
+
+        let aggregations_json = r#"{ "price_avg": { "avg": { "field": "price" } } }"#;
+        let aggregations: Aggregations = serde_json::from_str(aggregations_json).unwrap();
+        let collector = AggregationCollector::from_aggs(aggregations, Default::default());
+        let reader = index.reader().unwrap();
+        let searcher = reader.searcher();
+        let aggregations_res: AggregationResults = searcher.search(&AllQuery, &collector).unwrap();
+        let aggregations_res_json = serde_json::to_value(aggregations_res).unwrap();
+
+        // Verify all three fields are present and correct
+        assert_eq!(aggregations_res_json["price_avg"]["value"], 2.5);
+        assert_eq!(aggregations_res_json["price_avg"]["sum"], 15.0);
+        assert_eq!(aggregations_res_json["price_avg"]["count"], 6);
+    }
+
+    #[test]
+    fn test_percentiles_returns_sketch() {
+        let mut schema_builder = Schema::builder();
+        let field_options = NumericOptions::default().set_fast();
+        let field = schema_builder.add_f64_field("latency", field_options);
+        let index = Index::create_in_ram(schema_builder.build());
+        let mut index_writer: IndexWriter = index.writer_for_tests().unwrap();
+
+        // Add documents with latency values
+        for i in 0..100 {
+            index_writer
+                .add_document(doc!(
+                    field => i as f64,
+                ))
+                .unwrap();
+        }
+        index_writer.commit().unwrap();
+
+        let aggregations_json =
+            r#"{ "latency_percentiles": { "percentiles": { "field": "latency" } } }"#;
+        let aggregations: Aggregations = serde_json::from_str(aggregations_json).unwrap();
+        let collector = AggregationCollector::from_aggs(aggregations, Default::default());
+        let reader = index.reader().unwrap();
+        let searcher = reader.searcher();
+        let aggregations_res: AggregationResults = searcher.search(&AllQuery, &collector).unwrap();
+        let aggregations_res_json = serde_json::to_value(aggregations_res).unwrap();
+
+        // Verify percentile values are present
+        assert!(aggregations_res_json["latency_percentiles"]["values"].is_object());
+        // Verify sketch is present (serialized DDSketch)
+        assert!(aggregations_res_json["latency_percentiles"]["sketch"].is_object());
+    }
+
+    #[test]
+    fn test_cardinality_returns_sketch() {
+        let mut schema_builder = Schema::builder();
+        let field_options = NumericOptions::default().set_fast();
+        let field = schema_builder.add_u64_field("user_id", field_options);
+        let index = Index::create_in_ram(schema_builder.build());
+        let mut index_writer: IndexWriter = index.writer_for_tests().unwrap();
+
+        // Add documents with some duplicate user_ids
+        for i in 0..50 {
+            index_writer
+                .add_document(doc!(
+                    field => (i % 10) as u64,  // 10 unique values
+                ))
+                .unwrap();
+        }
+        index_writer.commit().unwrap();
+
+        let aggregations_json = r#"{ "unique_users": { "cardinality": { "field": "user_id" } } }"#;
+        let aggregations: Aggregations = serde_json::from_str(aggregations_json).unwrap();
+        let collector = AggregationCollector::from_aggs(aggregations, Default::default());
+        let reader = index.reader().unwrap();
+        let searcher = reader.searcher();
+        let aggregations_res: AggregationResults = searcher.search(&AllQuery, &collector).unwrap();
+        let aggregations_res_json = serde_json::to_value(aggregations_res).unwrap();
+
+        // Verify cardinality value is present and approximately correct
+        let cardinality = aggregations_res_json["unique_users"]["value"]
+            .as_f64()
+            .unwrap();
+        assert!(cardinality >= 9.0 && cardinality <= 11.0); // HLL is approximate
+                                                            // Verify sketch is present (serialized HyperLogLog++)
+        assert!(aggregations_res_json["unique_users"]["sketch"].is_object());
+    }
 }

src/aggregation/metric/percentiles.rs

@@ -7,10 +7,9 @@ use crate::aggregation::agg_data::AggregationsSegmentCtx;
 use crate::aggregation::intermediate_agg_result::{
     IntermediateAggregationResult, IntermediateAggregationResults, IntermediateMetricResult,
 };
-use crate::aggregation::metric::MetricAggReqData;
 use crate::aggregation::segment_agg_result::SegmentAggregationCollector;
 use crate::aggregation::*;
-use crate::{DocId, TantivyError};
+use crate::TantivyError;
 
 /// # Percentiles
 ///
@@ -131,10 +130,16 @@ impl PercentilesAggregationReq {
     }
 }
 
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug)]
 pub(crate) struct SegmentPercentilesCollector {
-    pub(crate) percentiles: PercentilesCollector,
+    pub(crate) buckets: Vec<PercentilesCollector>,
     pub(crate) accessor_idx: usize,
+    /// The type of the field.
+    pub field_type: ColumnType,
+    /// The missing value normalized to the internal u64 representation of the field type.
+    pub missing_u64: Option<u64>,
+    /// The column accessor to access the fast field values.
+    pub accessor: Column<u64>,
 }
 
 #[derive(Clone, Serialize, Deserialize)]
@@ -173,6 +178,9 @@ fn format_percentile(percentile: f64) -> String {
 impl PercentilesCollector {
     /// Convert result into final result. This will query the quantils from the underlying quantil
     /// collector.
+    ///
+    /// The result includes both the computed percentile values and the raw DDSketch
+    /// for multi-step query merging.
     pub fn into_final_result(self, req: &PercentilesAggregationReq) -> PercentilesMetricResult {
         let percentiles: &[f64] = req
             .percents
@@ -205,7 +213,15 @@ impl PercentilesCollector {
                     .collect(),
             )
         };
-        PercentilesMetricResult { values }
+        PercentilesMetricResult {
+            values,
+            sketch: Some(self),
+        }
+    }
+
+    /// Returns a reference to the underlying DDSketch.
+    pub fn sketch(&self) -> &sketches_ddsketch::DDSketch {
+        &self.sketch
     }
 
     fn new() -> Self {
@@ -229,33 +245,18 @@ impl PercentilesCollector {
 }
 
 impl SegmentPercentilesCollector {
-    pub fn from_req_and_validate(accessor_idx: usize) -> crate::Result<Self> {
-        Ok(Self {
-            percentiles: PercentilesCollector::new(),
+    pub fn from_req_and_validate(
+        field_type: ColumnType,
+        missing_u64: Option<u64>,
+        accessor: Column<u64>,
+        accessor_idx: usize,
+    ) -> Self {
+        Self {
+            buckets: Vec::with_capacity(64),
+            field_type,
+            missing_u64,
+            accessor,
             accessor_idx,
-        })
-    }
-    #[inline]
-    pub(crate) fn collect_block_with_field(
-        &mut self,
-        docs: &[DocId],
-        req_data: &mut MetricAggReqData,
-    ) {
-        if let Some(missing) = req_data.missing_u64.as_ref() {
-            req_data.column_block_accessor.fetch_block_with_missing(
-                docs,
-                &req_data.accessor,
-                *missing,
-            );
-        } else {
-            req_data
-                .column_block_accessor
-                .fetch_block(docs, &req_data.accessor);
-        }
-
-        for val in req_data.column_block_accessor.iter_vals() {
-            let val1 = f64_from_fastfield_u64(val, &req_data.field_type);
-            self.percentiles.collect(val1);
         }
     }
 }
@@ -263,12 +264,18 @@ impl SegmentPercentilesCollector {
 impl SegmentAggregationCollector for SegmentPercentilesCollector {
     #[inline]
     fn add_intermediate_aggregation_result(
-        self: Box<Self>,
+        &mut self,
         agg_data: &AggregationsSegmentCtx,
         results: &mut IntermediateAggregationResults,
+        parent_bucket_id: BucketId,
     ) -> crate::Result<()> {
         let name = agg_data.get_metric_req_data(self.accessor_idx).name.clone();
-        let intermediate_metric_result = IntermediateMetricResult::Percentiles(self.percentiles);
+        self.prepare_max_bucket(parent_bucket_id, agg_data)?;
+        // Swap collector with an empty one to avoid cloning
+        let percentiles_collector = std::mem::take(&mut self.buckets[parent_bucket_id as usize]);
+
+        let intermediate_metric_result =
+            IntermediateMetricResult::Percentiles(percentiles_collector);
 
         results.push(
             name,
@@ -281,40 +288,33 @@ impl SegmentAggregationCollector for SegmentPercentilesCollector {
     #[inline]
     fn collect(
         &mut self,
-        doc: crate::DocId,
+        parent_bucket_id: BucketId,
+        docs: &[crate::DocId],
         agg_data: &mut AggregationsSegmentCtx,
     ) -> crate::Result<()> {
-        let req_data = agg_data.get_metric_req_data(self.accessor_idx);
+        let percentiles = &mut self.buckets[parent_bucket_id as usize];
+        agg_data.column_block_accessor.fetch_block_with_missing(
+            docs,
+            &self.accessor,
+            self.missing_u64,
+        );
 
-        if let Some(missing) = req_data.missing_u64 {
-            let mut has_val = false;
-            for val in req_data.accessor.values_for_doc(doc) {
-                let val1 = f64_from_fastfield_u64(val, &req_data.field_type);
-                self.percentiles.collect(val1);
-                has_val = true;
-            }
-            if !has_val {
-                self.percentiles
-                    .collect(f64_from_fastfield_u64(missing, &req_data.field_type));
-            }
-        } else {
-            for val in req_data.accessor.values_for_doc(doc) {
-                let val1 = f64_from_fastfield_u64(val, &req_data.field_type);
-                self.percentiles.collect(val1);
-            }
+        for val in agg_data.column_block_accessor.iter_vals() {
+            let val1 = f64_from_fastfield_u64(val, self.field_type);
+            percentiles.collect(val1);
         }
 
         Ok(())
     }
 
-    #[inline]
-    fn collect_block(
+    fn prepare_max_bucket(
         &mut self,
-        docs: &[crate::DocId],
-        agg_data: &mut AggregationsSegmentCtx,
+        max_bucket: BucketId,
+        _agg_data: &AggregationsSegmentCtx,
     ) -> crate::Result<()> {
-        let req_data = agg_data.get_metric_req_data_mut(self.accessor_idx);
-        self.collect_block_with_field(docs, req_data);
+        while self.buckets.len() <= max_bucket as usize {
+            self.buckets.push(PercentilesCollector::new());
+        }
         Ok(())
     }
 }

src/aggregation/metric/stats.rs

@@ -1,5 +1,6 @@
 use std::fmt::Debug;
 
+use columnar::{Column, ColumnType};
 use serde::{Deserialize, Serialize};
 
 use super::*;
@@ -7,10 +8,9 @@ use crate::aggregation::agg_data::AggregationsSegmentCtx;
 use crate::aggregation::intermediate_agg_result::{
     IntermediateAggregationResult, IntermediateAggregationResults, IntermediateMetricResult,
 };
-use crate::aggregation::metric::MetricAggReqData;
 use crate::aggregation::segment_agg_result::SegmentAggregationCollector;
 use crate::aggregation::*;
-use crate::{DocId, TantivyError};
+use crate::TantivyError;
 
 /// A multi-value metric aggregation that computes a collection of statistics on numeric values that
 /// are extracted from the aggregated documents.
@@ -83,7 +83,7 @@ impl Stats {
 
 /// Intermediate result of the stats aggregation that can be combined with other intermediate
 /// results.
-#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+#[derive(Clone, Copy, Debug, PartialEq, Serialize, Deserialize)]
 pub struct IntermediateStats {
     /// The number of extracted values.
     pub(crate) count: u64,
@@ -187,75 +187,75 @@ pub enum StatsType {
     Percentiles,
 }
 
+fn create_collector<const TYPE_ID: u8>(
+    req: &MetricAggReqData,
+) -> Box<dyn SegmentAggregationCollector> {
+    Box::new(SegmentStatsCollector::<TYPE_ID> {
+        name: req.name.clone(),
+        collecting_for: req.collecting_for,
+        is_number_or_date_type: req.is_number_or_date_type,
+        missing_u64: req.missing_u64,
+        accessor: req.accessor.clone(),
+        buckets: vec![IntermediateStats::default()],
+    })
+}
+
+/// Build a concrete `SegmentStatsCollector` depending on the column type.
+pub(crate) fn build_segment_stats_collector(
+    req: &MetricAggReqData,
+) -> crate::Result<Box<dyn SegmentAggregationCollector>> {
+    match req.field_type {
+        ColumnType::I64 => Ok(create_collector::<{ ColumnType::I64 as u8 }>(req)),
+        ColumnType::U64 => Ok(create_collector::<{ ColumnType::U64 as u8 }>(req)),
+        ColumnType::F64 => Ok(create_collector::<{ ColumnType::F64 as u8 }>(req)),
+        ColumnType::Bool => Ok(create_collector::<{ ColumnType::Bool as u8 }>(req)),
+        ColumnType::DateTime => Ok(create_collector::<{ ColumnType::DateTime as u8 }>(req)),
+        ColumnType::Bytes => Ok(create_collector::<{ ColumnType::Bytes as u8 }>(req)),
+        ColumnType::Str => Ok(create_collector::<{ ColumnType::Str as u8 }>(req)),
+        ColumnType::IpAddr => Ok(create_collector::<{ ColumnType::IpAddr as u8 }>(req)),
+    }
+}
+
+#[repr(C)]
 #[derive(Clone, Debug)]
-pub(crate) struct SegmentStatsCollector {
-    pub(crate) stats: IntermediateStats,
-    pub(crate) accessor_idx: usize,
+pub(crate) struct SegmentStatsCollector<const COLUMN_TYPE_ID: u8> {
+    pub(crate) missing_u64: Option<u64>,
+    pub(crate) accessor: Column<u64>,
+    pub(crate) is_number_or_date_type: bool,
+    pub(crate) buckets: Vec<IntermediateStats>,
+    pub(crate) name: String,
+    pub(crate) collecting_for: StatsType,
 }
 
-impl SegmentStatsCollector {
-    pub fn from_req(accessor_idx: usize) -> Self {
-        Self {
-            stats: IntermediateStats::default(),
-            accessor_idx,
-        }
-    }
-    #[inline]
-    pub(crate) fn collect_block_with_field(
-        &mut self,
-        docs: &[DocId],
-        req_data: &mut MetricAggReqData,
-    ) {
-        if let Some(missing) = req_data.missing_u64.as_ref() {
-            req_data.column_block_accessor.fetch_block_with_missing(
-                docs,
-                &req_data.accessor,
-                *missing,
-            );
-        } else {
-            req_data
-                .column_block_accessor
-                .fetch_block(docs, &req_data.accessor);
-        }
-        if req_data.is_number_or_date_type {
-            for val in req_data.column_block_accessor.iter_vals() {
-                let val1 = f64_from_fastfield_u64(val, &req_data.field_type);
-                self.stats.collect(val1);
-            }
-        } else {
-            for _val in req_data.column_block_accessor.iter_vals() {
-                // we ignore the value and simply record that we got something
-                self.stats.collect(0.0);
-            }
-        }
-    }
-}
-
-impl SegmentAggregationCollector for SegmentStatsCollector {
+impl<const COLUMN_TYPE_ID: u8> SegmentAggregationCollector
+    for SegmentStatsCollector<COLUMN_TYPE_ID>
+{
     #[inline]
     fn add_intermediate_aggregation_result(
-        self: Box<Self>,
+        &mut self,
         agg_data: &AggregationsSegmentCtx,
         results: &mut IntermediateAggregationResults,
+        parent_bucket_id: BucketId,
     ) -> crate::Result<()> {
-        let req = agg_data.get_metric_req_data(self.accessor_idx);
-        let name = req.name.clone();
+        let name = self.name.clone();
 
-        let intermediate_metric_result = match req.collecting_for {
+        self.prepare_max_bucket(parent_bucket_id, agg_data)?;
+        let stats = self.buckets[parent_bucket_id as usize];
+        let intermediate_metric_result = match self.collecting_for {
             StatsType::Average => {
-                IntermediateMetricResult::Average(IntermediateAverage::from_collector(*self))
+                IntermediateMetricResult::Average(IntermediateAverage::from_stats(stats))
             }
             StatsType::Count => {
-                IntermediateMetricResult::Count(IntermediateCount::from_collector(*self))
+                IntermediateMetricResult::Count(IntermediateCount::from_stats(stats))
             }
-            StatsType::Max => IntermediateMetricResult::Max(IntermediateMax::from_collector(*self)),
-            StatsType::Min => IntermediateMetricResult::Min(IntermediateMin::from_collector(*self)),
-            StatsType::Stats => IntermediateMetricResult::Stats(self.stats),
-            StatsType::Sum => IntermediateMetricResult::Sum(IntermediateSum::from_collector(*self)),
+            StatsType::Max => IntermediateMetricResult::Max(IntermediateMax::from_stats(stats)),
+            StatsType::Min => IntermediateMetricResult::Min(IntermediateMin::from_stats(stats)),
+            StatsType::Stats => IntermediateMetricResult::Stats(stats),
+            StatsType::Sum => IntermediateMetricResult::Sum(IntermediateSum::from_stats(stats)),
             _ => {
                 return Err(TantivyError::InvalidArgument(format!(
                     "Unsupported stats type for stats aggregation: {:?}",
-                    req.collecting_for
+                    self.collecting_for
                 )))
             }
         };
@@ -271,41 +271,67 @@ impl SegmentAggregationCollector for SegmentStatsCollector {
     #[inline]
     fn collect(
         &mut self,
-        doc: crate::DocId,
-        agg_data: &mut AggregationsSegmentCtx,
-    ) -> crate::Result<()> {
-        let req_data = agg_data.get_metric_req_data(self.accessor_idx);
-        if let Some(missing) = req_data.missing_u64 {
-            let mut has_val = false;
-            for val in req_data.accessor.values_for_doc(doc) {
-                let val1 = f64_from_fastfield_u64(val, &req_data.field_type);
-                self.stats.collect(val1);
-                has_val = true;
-            }
-            if !has_val {
-                self.stats
-                    .collect(f64_from_fastfield_u64(missing, &req_data.field_type));
-            }
-        } else {
-            for val in req_data.accessor.values_for_doc(doc) {
-                let val1 = f64_from_fastfield_u64(val, &req_data.field_type);
-                self.stats.collect(val1);
-            }
-        }
-
-        Ok(())
-    }
-
-    #[inline]
-    fn collect_block(
-        &mut self,
+        parent_bucket_id: BucketId,
         docs: &[crate::DocId],
         agg_data: &mut AggregationsSegmentCtx,
     ) -> crate::Result<()> {
-        let req_data = agg_data.get_metric_req_data_mut(self.accessor_idx);
-        self.collect_block_with_field(docs, req_data);
+        // TODO: remove once we fetch all values for all bucket ids in one go
+        if docs.len() == 1 && self.missing_u64.is_none() {
+            collect_stats::<COLUMN_TYPE_ID>(
+                &mut self.buckets[parent_bucket_id as usize],
+                self.accessor.values_for_doc(docs[0]),
+                self.is_number_or_date_type,
+            )?;
+
+            return Ok(());
+        }
+        agg_data.column_block_accessor.fetch_block_with_missing(
+            docs,
+            &self.accessor,
+            self.missing_u64,
+        );
+        collect_stats::<COLUMN_TYPE_ID>(
+            &mut self.buckets[parent_bucket_id as usize],
+            agg_data.column_block_accessor.iter_vals(),
+            self.is_number_or_date_type,
+        )?;
+
         Ok(())
     }
+
+    fn prepare_max_bucket(
+        &mut self,
+        max_bucket: BucketId,
+        _agg_data: &AggregationsSegmentCtx,
+    ) -> crate::Result<()> {
+        let required_buckets = (max_bucket as usize) + 1;
+        if self.buckets.len() < required_buckets {
+            self.buckets
+                .resize_with(required_buckets, IntermediateStats::default);
+        }
+        Ok(())
+    }
+}
+
+#[inline]
+fn collect_stats<const COLUMN_TYPE_ID: u8>(
+    stats: &mut IntermediateStats,
+    vals: impl Iterator<Item = u64>,
+    is_number_or_date_type: bool,
+) -> crate::Result<()> {
+    if is_number_or_date_type {
+        for val in vals {
+            let val1 = convert_to_f64::<COLUMN_TYPE_ID>(val);
+            stats.collect(val1);
+        }
+    } else {
+        for _val in vals {
+            // we ignore the value and simply record that we got something
+            stats.collect(0.0);
+        }
+    }
+
+    Ok(())
 }
 
 #[cfg(test)]

src/aggregation/metric/sum.rs

@@ -52,10 +52,8 @@ pub struct IntermediateSum {
 
 impl IntermediateSum {
     /// Creates a new [`IntermediateSum`] instance from a [`SegmentStatsCollector`].
-    pub(crate) fn from_collector(collector: SegmentStatsCollector) -> Self {
-        Self {
-            stats: collector.stats,
-        }
+    pub(crate) fn from_stats(stats: IntermediateStats) -> Self {
+        Self { stats }
     }
     /// Merges the other intermediate result into self.
     pub fn merge_fruits(&mut self, other: IntermediateSum) {

src/aggregation/metric/top_hits.rs

@@ -15,12 +15,11 @@ use crate::aggregation::intermediate_agg_result::{
     IntermediateAggregationResult, IntermediateMetricResult,
 };
 use crate::aggregation::segment_agg_result::SegmentAggregationCollector;
-use crate::aggregation::AggregationError;
+use crate::aggregation::{AggregationError, BucketId};
 use crate::collector::sort_key::ReverseComparator;
 use crate::collector::TopNComputer;
 use crate::schema::OwnedValue;
 use crate::{DocAddress, DocId, SegmentOrdinal};
-// duplicate import removed; already imported above
 
 /// Contains all information required by the TopHitsSegmentCollector to perform the
 /// top_hits aggregation on a segment.
@@ -472,7 +471,10 @@ impl TopHitsTopNComputer {
     /// Create a new TopHitsCollector
     pub fn new(req: &TopHitsAggregationReq) -> Self {
         Self {
-            top_n: TopNComputer::new(req.size + req.from.unwrap_or(0)),
+            top_n: TopNComputer::new_with_comparator(
+                req.size + req.from.unwrap_or(0),
+                ReverseComparator,
+            ),
             req: req.clone(),
         }
     }
@@ -518,7 +520,8 @@ impl TopHitsTopNComputer {
 pub(crate) struct TopHitsSegmentCollector {
     segment_ordinal: SegmentOrdinal,
     accessor_idx: usize,
-    top_n: TopNComputer<Vec<DocValueAndOrder>, DocAddress, ReverseComparator>,
+    buckets: Vec<TopNComputer<Vec<DocValueAndOrder>, DocAddress, ReverseComparator>>,
+    num_hits: usize,
 }
 
 impl TopHitsSegmentCollector {
@@ -527,19 +530,29 @@ impl TopHitsSegmentCollector {
         accessor_idx: usize,
         segment_ordinal: SegmentOrdinal,
     ) -> Self {
+        let num_hits = req.size + req.from.unwrap_or(0);
         Self {
-            top_n: TopNComputer::new(req.size + req.from.unwrap_or(0)),
+            num_hits,
             segment_ordinal,
             accessor_idx,
+            buckets: vec![TopNComputer::new_with_comparator(num_hits, ReverseComparator); 1],
         }
     }
-    fn into_top_hits_collector(
-        self,
+    fn get_top_hits_computer(
+        &mut self,
+        parent_bucket_id: BucketId,
         value_accessors: &HashMap<String, Vec<DynamicColumn>>,
         req: &TopHitsAggregationReq,
     ) -> TopHitsTopNComputer {
+        if parent_bucket_id as usize >= self.buckets.len() {
+            return TopHitsTopNComputer::new(req);
+        }
+        let top_n = std::mem::replace(
+            &mut self.buckets[parent_bucket_id as usize],
+            TopNComputer::new(0),
+        );
         let mut top_hits_computer = TopHitsTopNComputer::new(req);
-        let top_results = self.top_n.into_vec();
+        let top_results = top_n.into_vec();
 
         for res in top_results {
             let doc_value_fields = req.get_document_field_data(value_accessors, res.doc.doc_id);
@@ -554,54 +567,24 @@ impl TopHitsSegmentCollector {
 
         top_hits_computer
     }
-
-    /// TODO add a specialized variant for a single sort field
-    fn collect_with(
-        &mut self,
-        doc_id: crate::DocId,
-        req: &TopHitsAggregationReq,
-        accessors: &[(Column<u64>, ColumnType)],
-    ) -> crate::Result<()> {
-        let sorts: Vec<DocValueAndOrder> = req
-            .sort
-            .iter()
-            .enumerate()
-            .map(|(idx, KeyOrder { order, .. })| {
-                let order = *order;
-                let value = accessors
-                    .get(idx)
-                    .expect("could not find field in accessors")
-                    .0
-                    .values_for_doc(doc_id)
-                    .next();
-                DocValueAndOrder { value, order }
-            })
-            .collect();
-
-        self.top_n.push(
-            sorts,
-            DocAddress {
-                segment_ord: self.segment_ordinal,
-                doc_id,
-            },
-        );
-        Ok(())
-    }
 }
 
 impl SegmentAggregationCollector for TopHitsSegmentCollector {
     fn add_intermediate_aggregation_result(
-        self: Box<Self>,
+        &mut self,
         agg_data: &AggregationsSegmentCtx,
         results: &mut crate::aggregation::intermediate_agg_result::IntermediateAggregationResults,
+        parent_bucket_id: BucketId,
     ) -> crate::Result<()> {
         let req_data = agg_data.get_top_hits_req_data(self.accessor_idx);
 
         let value_accessors = &req_data.value_accessors;
 
-        let intermediate_result = IntermediateMetricResult::TopHits(
-            self.into_top_hits_collector(value_accessors, &req_data.req),
-        );
+        let intermediate_result = IntermediateMetricResult::TopHits(self.get_top_hits_computer(
+            parent_bucket_id,
+            value_accessors,
+            &req_data.req,
+        ));
         results.push(
             req_data.name.to_string(),
             IntermediateAggregationResult::Metric(intermediate_result),
@@ -611,26 +594,56 @@ impl SegmentAggregationCollector for TopHitsSegmentCollector {
     /// TODO: Consider a caching layer to reduce the call overhead
     fn collect(
         &mut self,
-        doc_id: crate::DocId,
-        agg_data: &mut AggregationsSegmentCtx,
-    ) -> crate::Result<()> {
-        let req_data = agg_data.get_top_hits_req_data(self.accessor_idx);
-        self.collect_with(doc_id, &req_data.req, &req_data.accessors)?;
-        Ok(())
-    }
-
-    fn collect_block(
-        &mut self,
+        parent_bucket_id: BucketId,
         docs: &[crate::DocId],
         agg_data: &mut AggregationsSegmentCtx,
     ) -> crate::Result<()> {
+        let top_n = &mut self.buckets[parent_bucket_id as usize];
         let req_data = agg_data.get_top_hits_req_data(self.accessor_idx);
-        // TODO: Consider getting fields with the column block accessor.
-        for doc in docs {
-            self.collect_with(*doc, &req_data.req, &req_data.accessors)?;
+        let req = &req_data.req;
+        let accessors = &req_data.accessors;
+        for &doc_id in docs {
+            // TODO: this is terrible, a new vec is allocated for every doc
+            // We can fetch blocks instead
+            // We don't need to store the order for every value
+            let sorts: Vec<DocValueAndOrder> = req
+                .sort
+                .iter()
+                .enumerate()
+                .map(|(idx, KeyOrder { order, .. })| {
+                    let order = *order;
+                    let value = accessors
+                        .get(idx)
+                        .expect("could not find field in accessors")
+                        .0
+                        .values_for_doc(doc_id)
+                        .next();
+                    DocValueAndOrder { value, order }
+                })
+                .collect();
+
+            top_n.push(
+                sorts,
+                DocAddress {
+                    segment_ord: self.segment_ordinal,
+                    doc_id,
+                },
+            );
         }
         Ok(())
     }
+
+    fn prepare_max_bucket(
+        &mut self,
+        max_bucket: BucketId,
+        _agg_data: &AggregationsSegmentCtx,
+    ) -> crate::Result<()> {
+        self.buckets.resize(
+            (max_bucket as usize) + 1,
+            TopNComputer::new_with_comparator(self.num_hits, ReverseComparator),
+        );
+        Ok(())
+    }
 }
 
 #[cfg(test)]
@@ -746,7 +759,7 @@ mod tests {
                     ],
                     "from": 0,
                 }
-        }
+            }
         }))
         .unwrap();
 
@@ -875,7 +888,7 @@ mod tests {
                         "mixed.*",
                     ],
                 }
-        }
+            }
         }))?;
 
         let collector = AggregationCollector::from_aggs(d, Default::default());

src/aggregation/mod.rs

@@ -133,7 +133,7 @@ mod agg_limits;
 pub mod agg_req;
 pub mod agg_result;
 pub mod bucket;
-mod buf_collector;
+pub(crate) mod cached_sub_aggs;
 mod collector;
 mod date;
 mod error;
@@ -162,6 +162,19 @@ use serde::{Deserialize, Deserializer, Serialize};
 
 use crate::tokenizer::TokenizerManager;
 
+/// A bucket id is a dense identifier for a bucket within an aggregation.
+/// It is used to index into a Vec that hold per-bucket data.
+///
+/// For example, in a terms aggregation, each unique term will be assigned a incremental BucketId.
+/// This BucketId will be forwarded to sub-aggregations to identify the parent bucket.
+///
+/// This allows to have a single AggregationCollector instance per aggregation,
+/// that can handle multiple buckets efficiently.
+///
+/// The API to call sub-aggregations is therefore a &[(BucketId, &[DocId])].
+/// For that we'll need a buffer. One Vec per bucket aggregation is needed.
+pub type BucketId = u32;
+
 /// Context parameters for aggregation execution
 ///
 /// This struct holds shared resources needed during aggregation execution:
@@ -335,19 +348,37 @@ impl Display for Key {
     }
 }
 
+pub(crate) fn convert_to_f64<const COLUMN_TYPE_ID: u8>(val: u64) -> f64 {
+    if COLUMN_TYPE_ID == ColumnType::U64 as u8 {
+        val as f64
+    } else if COLUMN_TYPE_ID == ColumnType::I64 as u8
+        || COLUMN_TYPE_ID == ColumnType::DateTime as u8
+    {
+        i64::from_u64(val) as f64
+    } else if COLUMN_TYPE_ID == ColumnType::F64 as u8 {
+        f64::from_u64(val)
+    } else if COLUMN_TYPE_ID == ColumnType::Bool as u8 {
+        val as f64
+    } else {
+        panic!(
+            "ColumnType ID {} cannot be converted to f64 metric",
+            COLUMN_TYPE_ID
+        )
+    }
+}
+
 /// Inverse of `to_fastfield_u64`. Used to convert to `f64` for metrics.
 ///
 /// # Panics
 /// Only `u64`, `f64`, `date`, and `i64` are supported.
-pub(crate) fn f64_from_fastfield_u64(val: u64, field_type: &ColumnType) -> f64 {
+pub(crate) fn f64_from_fastfield_u64(val: u64, field_type: ColumnType) -> f64 {
     match field_type {
-        ColumnType::U64 => val as f64,
-        ColumnType::I64 | ColumnType::DateTime => i64::from_u64(val) as f64,
-        ColumnType::F64 => f64::from_u64(val),
-        ColumnType::Bool => val as f64,
-        _ => {
-            panic!("unexpected type {field_type:?}. This should not happen")
-        }
+        ColumnType::U64 => convert_to_f64::<{ ColumnType::U64 as u8 }>(val),
+        ColumnType::I64 => convert_to_f64::<{ ColumnType::I64 as u8 }>(val),
+        ColumnType::F64 => convert_to_f64::<{ ColumnType::F64 as u8 }>(val),
+        ColumnType::Bool => convert_to_f64::<{ ColumnType::Bool as u8 }>(val),
+        ColumnType::DateTime => convert_to_f64::<{ ColumnType::DateTime as u8 }>(val),
+        _ => panic!("unexpected type {field_type:?}. This should not happen"),
     }
 }
 

src/aggregation/segment_agg_result.rs

@@ -8,25 +8,67 @@ use std::fmt::Debug;
 pub(crate) use super::agg_limits::AggregationLimitsGuard;
 use super::intermediate_agg_result::IntermediateAggregationResults;
 use crate::aggregation::agg_data::AggregationsSegmentCtx;
+use crate::aggregation::BucketId;
+
+/// Monotonically increasing provider of BucketIds.
+#[derive(Debug, Clone, Default)]
+pub struct BucketIdProvider(u32);
+impl BucketIdProvider {
+    /// Get the next BucketId.
+    pub fn next_bucket_id(&mut self) -> BucketId {
+        let bucket_id = self.0;
+        self.0 += 1;
+        bucket_id
+    }
+}
 
 /// A SegmentAggregationCollector is used to collect aggregation results.
-pub trait SegmentAggregationCollector: CollectorClone + Debug {
+pub trait SegmentAggregationCollector: Debug {
     fn add_intermediate_aggregation_result(
-        self: Box<Self>,
+        &mut self,
         agg_data: &AggregationsSegmentCtx,
         results: &mut IntermediateAggregationResults,
+        parent_bucket_id: BucketId,
     ) -> crate::Result<()>;
 
+    /// Note: The caller needs to call `prepare_max_bucket` before calling `collect`.
     fn collect(
         &mut self,
-        doc: crate::DocId,
+        parent_bucket_id: BucketId,
+        docs: &[crate::DocId],
         agg_data: &mut AggregationsSegmentCtx,
     ) -> crate::Result<()>;
 
-    fn collect_block(
+    /// Collect docs for multiple buckets in one call.
+    /// Minimizes dynamic dispatch overhead when collecting many buckets.
+    ///
+    /// Note: The caller needs to call `prepare_max_bucket` before calling `collect`.
+    fn collect_multiple(
         &mut self,
+        bucket_ids: &[BucketId],
         docs: &[crate::DocId],
         agg_data: &mut AggregationsSegmentCtx,
+    ) -> crate::Result<()> {
+        debug_assert_eq!(bucket_ids.len(), docs.len());
+        let mut start = 0;
+        while start < bucket_ids.len() {
+            let bucket_id = bucket_ids[start];
+            let mut end = start + 1;
+            while end < bucket_ids.len() && bucket_ids[end] == bucket_id {
+                end += 1;
+            }
+            self.collect(bucket_id, &docs[start..end], agg_data)?;
+            start = end;
+        }
+        Ok(())
+    }
+
+    /// Prepare the collector for collecting up to BucketId `max_bucket`.
+    /// This is useful so we can split allocation ahead of time of collecting.
+    fn prepare_max_bucket(
+        &mut self,
+        max_bucket: BucketId,
+        agg_data: &AggregationsSegmentCtx,
     ) -> crate::Result<()>;
 
     /// Finalize method. Some Aggregator collect blocks of docs before calling `collect_block`.
@@ -36,26 +78,7 @@ pub trait SegmentAggregationCollector: CollectorClone + Debug {
     }
 }
 
-/// A helper trait to enable cloning of Box<dyn SegmentAggregationCollector>
-pub trait CollectorClone {
-    fn clone_box(&self) -> Box<dyn SegmentAggregationCollector>;
-}
-
-impl<T> CollectorClone for T
-where T: 'static + SegmentAggregationCollector + Clone
-{
-    fn clone_box(&self) -> Box<dyn SegmentAggregationCollector> {
-        Box::new(self.clone())
-    }
-}
-
-impl Clone for Box<dyn SegmentAggregationCollector> {
-    fn clone(&self) -> Box<dyn SegmentAggregationCollector> {
-        self.clone_box()
-    }
-}
-
-#[derive(Clone, Default)]
+#[derive(Default)]
 /// The GenericSegmentAggregationResultsCollector is the generic version of the collector, which
 /// can handle arbitrary complexity of  sub-aggregations. Ideally we never have to pick this one
 /// and can provide specialized versions instead, that remove some of its overhead.
@@ -73,12 +96,13 @@ impl Debug for GenericSegmentAggregationResultsCollector {
 
 impl SegmentAggregationCollector for GenericSegmentAggregationResultsCollector {
     fn add_intermediate_aggregation_result(
-        self: Box<Self>,
+        &mut self,
         agg_data: &AggregationsSegmentCtx,
         results: &mut IntermediateAggregationResults,
+        parent_bucket_id: BucketId,
     ) -> crate::Result<()> {
-        for agg in self.aggs {
-            agg.add_intermediate_aggregation_result(agg_data, results)?;
+        for agg in &mut self.aggs {
+            agg.add_intermediate_aggregation_result(agg_data, results, parent_bucket_id)?;
         }
 
         Ok(())
@@ -86,23 +110,13 @@ impl SegmentAggregationCollector for GenericSegmentAggregationResultsCollector {
 
     fn collect(
         &mut self,
-        doc: crate::DocId,
-        agg_data: &mut AggregationsSegmentCtx,
-    ) -> crate::Result<()> {
-        self.collect_block(&[doc], agg_data)?;
-
-        Ok(())
-    }
-
-    fn collect_block(
-        &mut self,
+        parent_bucket_id: BucketId,
         docs: &[crate::DocId],
         agg_data: &mut AggregationsSegmentCtx,
     ) -> crate::Result<()> {
         for collector in &mut self.aggs {
-            collector.collect_block(docs, agg_data)?;
+            collector.collect(parent_bucket_id, docs, agg_data)?;
         }
-
         Ok(())
     }
 
@@ -112,4 +126,15 @@ impl SegmentAggregationCollector for GenericSegmentAggregationResultsCollector {
         }
         Ok(())
     }
+
+    fn prepare_max_bucket(
+        &mut self,
+        max_bucket: BucketId,
+        agg_data: &AggregationsSegmentCtx,
+    ) -> crate::Result<()> {
+        for collector in &mut self.aggs {
+            collector.prepare_max_bucket(max_bucket, agg_data)?;
+        }
+        Ok(())
+    }
 }

src/collector/facet_collector.rs

@@ -486,9 +486,9 @@ mod tests {
     use std::collections::BTreeSet;
 
     use columnar::Dictionary;
-    use rand::distributions::Uniform;
+    use rand::distr::Uniform;
     use rand::prelude::SliceRandom;
-    use rand::{thread_rng, Rng};
+    use rand::{rng, Rng};
 
     use super::{FacetCollector, FacetCounts};
     use crate::collector::facet_collector::compress_mapping;
@@ -731,7 +731,7 @@ mod tests {
         let schema = schema_builder.build();
         let index = Index::create_in_ram(schema);
 
-        let uniform = Uniform::new_inclusive(1, 100_000);
+        let uniform = Uniform::new_inclusive(1, 100_000).unwrap();
         let mut docs: Vec<TantivyDocument> =
             vec![("a", 10), ("b", 100), ("c", 7), ("d", 12), ("e", 21)]
                 .into_iter()
@@ -741,14 +741,11 @@ mod tests {
                     std::iter::repeat_n(doc, count)
                 })
                 .map(|mut doc| {
-                    doc.add_facet(
-                        facet_field,
-                        &format!("/facet/{}", thread_rng().sample(uniform)),
-                    );
+                    doc.add_facet(facet_field, &format!("/facet/{}", rng().sample(uniform)));
                     doc
                 })
                 .collect();
-        docs[..].shuffle(&mut thread_rng());
+        docs[..].shuffle(&mut rng());
 
         let mut index_writer: IndexWriter = index.writer_for_tests().unwrap();
         for doc in docs {
@@ -822,8 +819,8 @@ mod tests {
 #[cfg(all(test, feature = "unstable"))]
 mod bench {
 
+    use rand::rng;
     use rand::seq::SliceRandom;
-    use rand::thread_rng;
     use test::Bencher;
 
     use crate::collector::FacetCollector;
@@ -846,7 +843,7 @@ mod bench {
             }
         }
         // 40425 docs
-        docs[..].shuffle(&mut thread_rng());
+        docs[..].shuffle(&mut rng());
 
         let mut index_writer: IndexWriter = index.writer_for_tests().unwrap();
         for doc in docs {

src/collector/sort_key/mod.rs

@@ -1,25 +1,48 @@
 mod order;
+mod sort_by_erased_type;
 mod sort_by_score;
 mod sort_by_static_fast_value;
 mod sort_by_string;
 mod sort_key_computer;
 
 pub use order::*;
+pub use sort_by_erased_type::SortByErasedType;
 pub use sort_by_score::SortBySimilarityScore;
 pub use sort_by_static_fast_value::SortByStaticFastValue;
 pub use sort_by_string::SortByString;
 pub use sort_key_computer::{SegmentSortKeyComputer, SortKeyComputer};
 
 #[cfg(test)]
-mod tests {
+pub(crate) mod tests {
+
+    // By spec, regardless of whether ascending or descending order was requested, in presence of a
+    // tie, we sort by ascending doc id/doc address.
+    pub(crate) fn sort_hits<TSortKey: Ord, D: Ord>(
+        hits: &mut [ComparableDoc<TSortKey, D>],
+        order: Order,
+    ) {
+        if order.is_asc() {
+            hits.sort_by(|l, r| l.sort_key.cmp(&r.sort_key).then(l.doc.cmp(&r.doc)));
+        } else {
+            hits.sort_by(|l, r| {
+                l.sort_key
+                    .cmp(&r.sort_key)
+                    .reverse() // This is descending
+                    .then(l.doc.cmp(&r.doc))
+            });
+        }
+    }
+
     use std::collections::HashMap;
     use std::ops::Range;
 
-    use crate::collector::sort_key::{SortBySimilarityScore, SortByStaticFastValue, SortByString};
+    use crate::collector::sort_key::{
+        SortByErasedType, SortBySimilarityScore, SortByStaticFastValue, SortByString,
+    };
     use crate::collector::{ComparableDoc, DocSetCollector, TopDocs};
     use crate::indexer::NoMergePolicy;
     use crate::query::{AllQuery, QueryParser};
-    use crate::schema::{Schema, FAST, TEXT};
+    use crate::schema::{OwnedValue, Schema, FAST, TEXT};
     use crate::{DocAddress, Document, Index, Order, Score, Searcher};
 
     fn make_index() -> crate::Result<Index> {
@@ -294,11 +317,9 @@ mod tests {
                 (SortBySimilarityScore, score_order),
                 (SortByString::for_field("city"), city_order),
             ));
-            Ok(searcher
-                .search(&AllQuery, &top_collector)?
-                .into_iter()
-                .map(|(f, doc)| (f, ids[&doc]))
-                .collect())
+            let results: Vec<((Score, Option<String>), DocAddress)> =
+                searcher.search(&AllQuery, &top_collector)?;
+            Ok(results.into_iter().map(|(f, doc)| (f, ids[&doc])).collect())
         }
 
         assert_eq!(
@@ -323,6 +344,51 @@ mod tests {
         Ok(())
     }
 
+    #[test]
+    fn test_order_by_score_then_owned_value() -> crate::Result<()> {
+        let index = make_index()?;
+
+        type SortKey = (Score, OwnedValue);
+
+        fn query(
+            index: &Index,
+            score_order: Order,
+            city_order: Order,
+        ) -> crate::Result<Vec<(SortKey, u64)>> {
+            let searcher = index.reader()?.searcher();
+            let ids = id_mapping(&searcher);
+
+            let top_collector = TopDocs::with_limit(4).order_by::<(Score, OwnedValue)>((
+                (SortBySimilarityScore, score_order),
+                (SortByErasedType::for_field("city"), city_order),
+            ));
+            let results: Vec<((Score, OwnedValue), DocAddress)> =
+                searcher.search(&AllQuery, &top_collector)?;
+            Ok(results.into_iter().map(|(f, doc)| (f, ids[&doc])).collect())
+        }
+
+        assert_eq!(
+            &query(&index, Order::Asc, Order::Asc)?,
+            &[
+                ((1.0, OwnedValue::Str("austin".to_owned())), 0),
+                ((1.0, OwnedValue::Str("greenville".to_owned())), 1),
+                ((1.0, OwnedValue::Str("tokyo".to_owned())), 2),
+                ((1.0, OwnedValue::Null), 3),
+            ]
+        );
+
+        assert_eq!(
+            &query(&index, Order::Asc, Order::Desc)?,
+            &[
+                ((1.0, OwnedValue::Str("tokyo".to_owned())), 2),
+                ((1.0, OwnedValue::Str("greenville".to_owned())), 1),
+                ((1.0, OwnedValue::Str("austin".to_owned())), 0),
+                ((1.0, OwnedValue::Null), 3),
+            ]
+        );
+        Ok(())
+    }
+
     use proptest::prelude::*;
 
     proptest! {
@@ -372,15 +438,10 @@ mod tests {
 
             // Using the TopDocs collector should always be equivalent to sorting, skipping the
             // offset, and then taking the limit.
-            let sorted_docs: Vec<_> = if order.is_desc() {
-                let mut comparable_docs: Vec<ComparableDoc<_, _, true>> =
+            let sorted_docs: Vec<_> = {
+                let mut comparable_docs: Vec<ComparableDoc<_, _>> =
                     all_results.into_iter().map(|(sort_key, doc)| ComparableDoc { sort_key, doc}).collect();
-                comparable_docs.sort();
-                comparable_docs.into_iter().map(|cd| (cd.sort_key, cd.doc)).collect()
-            } else {
-                let mut comparable_docs: Vec<ComparableDoc<_, _, false>> =
-                    all_results.into_iter().map(|(sort_key, doc)| ComparableDoc { sort_key, doc}).collect();
-                comparable_docs.sort();
+                sort_hits(&mut comparable_docs, order);
                 comparable_docs.into_iter().map(|cd| (cd.sort_key, cd.doc)).collect()
             };
             let expected_docs = sorted_docs.into_iter().skip(offset).take(limit).collect::<Vec<_>>();

src/collector/sort_key/order.rs

@@ -1,36 +1,116 @@
 use std::cmp::Ordering;
 
+use columnar::MonotonicallyMappableToU64;
 use serde::{Deserialize, Serialize};
 
 use crate::collector::{SegmentSortKeyComputer, SortKeyComputer};
-use crate::schema::Schema;
+use crate::schema::{OwnedValue, Schema};
 use crate::{DocId, Order, Score};
 
+fn compare_owned_value<const NULLS_FIRST: bool>(lhs: &OwnedValue, rhs: &OwnedValue) -> Ordering {
+    match (lhs, rhs) {
+        (OwnedValue::Null, OwnedValue::Null) => Ordering::Equal,
+        (OwnedValue::Null, _) => {
+            if NULLS_FIRST {
+                Ordering::Less
+            } else {
+                Ordering::Greater
+            }
+        }
+        (_, OwnedValue::Null) => {
+            if NULLS_FIRST {
+                Ordering::Greater
+            } else {
+                Ordering::Less
+            }
+        }
+        (OwnedValue::Str(a), OwnedValue::Str(b)) => a.cmp(b),
+        (OwnedValue::PreTokStr(a), OwnedValue::PreTokStr(b)) => a.cmp(b),
+        (OwnedValue::U64(a), OwnedValue::U64(b)) => a.cmp(b),
+        (OwnedValue::I64(a), OwnedValue::I64(b)) => a.cmp(b),
+        (OwnedValue::F64(a), OwnedValue::F64(b)) => a.to_u64().cmp(&b.to_u64()),
+        (OwnedValue::Bool(a), OwnedValue::Bool(b)) => a.cmp(b),
+        (OwnedValue::Date(a), OwnedValue::Date(b)) => a.cmp(b),
+        (OwnedValue::Facet(a), OwnedValue::Facet(b)) => a.cmp(b),
+        (OwnedValue::Bytes(a), OwnedValue::Bytes(b)) => a.cmp(b),
+        (OwnedValue::IpAddr(a), OwnedValue::IpAddr(b)) => a.cmp(b),
+        (OwnedValue::U64(a), OwnedValue::I64(b)) => {
+            if *b < 0 {
+                Ordering::Greater
+            } else {
+                a.cmp(&(*b as u64))
+            }
+        }
+        (OwnedValue::I64(a), OwnedValue::U64(b)) => {
+            if *a < 0 {
+                Ordering::Less
+            } else {
+                (*a as u64).cmp(b)
+            }
+        }
+        (OwnedValue::U64(a), OwnedValue::F64(b)) => (*a as f64).to_u64().cmp(&b.to_u64()),
+        (OwnedValue::F64(a), OwnedValue::U64(b)) => a.to_u64().cmp(&(*b as f64).to_u64()),
+        (OwnedValue::I64(a), OwnedValue::F64(b)) => (*a as f64).to_u64().cmp(&b.to_u64()),
+        (OwnedValue::F64(a), OwnedValue::I64(b)) => a.to_u64().cmp(&(*b as f64).to_u64()),
+        (a, b) => {
+            let ord = a.discriminant_value().cmp(&b.discriminant_value());
+            // If the discriminant is equal, it's because a new type was added, but hasn't been
+            // included in this `match` statement.
+            assert!(
+                ord != Ordering::Equal,
+                "Unimplemented comparison for type of {a:?}, {b:?}"
+            );
+            ord
+        }
+    }
+}
+
 /// Comparator trait defining the order in which documents should be ordered.
 pub trait Comparator<T>: Send + Sync + std::fmt::Debug + Default {
     /// Return the order between two values.
     fn compare(&self, lhs: &T, rhs: &T) -> Ordering;
 }
 
-/// With the natural comparator, the top k collector will return
-/// the top documents in decreasing order.
+/// Compare values naturally (e.g. 1 < 2).
+///
+/// When used with `TopDocs`, which reverses the order, this results in a
+/// "Descending" sort (Greatest values first).
+///
+/// `None` (or Null for `OwnedValue`) values are considered to be smaller than any other value,
+/// and will therefore appear last in a descending sort (e.g. `[Some(20), Some(10), None]`).
 #[derive(Debug, Copy, Clone, Default, Serialize, Deserialize)]
 pub struct NaturalComparator;
 
 impl<T: PartialOrd> Comparator<T> for NaturalComparator {
     #[inline(always)]
     fn compare(&self, lhs: &T, rhs: &T) -> Ordering {
-        lhs.partial_cmp(rhs).unwrap()
+        lhs.partial_cmp(rhs).unwrap_or(Ordering::Equal)
     }
 }
 
-/// Sorts document in reverse order.
+/// A (partial) implementation of comparison for OwnedValue.
 ///
-/// If the sort key is None, it will considered as the lowest value, and will therefore appear
-/// first.
+/// Intended for use within columns of homogenous types, and so will panic for OwnedValues with
+/// mismatched types. The one exception is Null, for which we do define all comparisons.
+impl Comparator<OwnedValue> for NaturalComparator {
+    #[inline(always)]
+    fn compare(&self, lhs: &OwnedValue, rhs: &OwnedValue) -> Ordering {
+        compare_owned_value::</* NULLS_FIRST= */ true>(lhs, rhs)
+    }
+}
+
+/// Compare values in reverse (e.g. 2 < 1).
+///
+/// When used with `TopDocs`, which reverses the order, this results in an
+/// "Ascending" sort (Smallest values first).
+///
+/// `None` is considered smaller than `Some` in the underlying comparator, but because the
+/// comparison is reversed, `None` is effectively treated as the lowest value in the resulting
+/// Ascending sort (e.g. `[None, Some(10), Some(20)]`).
 ///
 /// The ReverseComparator does not necessarily imply that the sort order is reversed compared
-/// to the NaturalComparator. In presence of a tie, both version will retain the higher doc ids.
+/// to the NaturalComparator. In presence of a tie on the sort key, documents will always be
+/// sorted by ascending `DocId`/`DocAddress` in TopN results, regardless of the sort key's order.
 #[derive(Debug, Copy, Clone, Default, Serialize, Deserialize)]
 pub struct ReverseComparator;
 
@@ -43,11 +123,15 @@ where NaturalComparator: Comparator<T>
     }
 }
 
-/// Sorts document in reverse order, but considers None as having the lowest value.
+/// Compare values in reverse, but treating `None` as lower than `Some`.
+///
+/// When used with `TopDocs`, which reverses the order, this results in an
+/// "Ascending" sort (Smallest values first), but with `None` values appearing last
+/// (e.g. `[Some(10), Some(20), None]`).
 ///
 /// This is usually what is wanted when sorting by a field in an ascending order.
-/// For instance, in a e-commerce website, if I sort by price ascending, I most likely want the
-/// cheapest items first, and the items without a price at last.
+/// For instance, in an e-commerce website, if sorting by price ascending,
+/// the cheapest items would appear first, and items without a price would appear last.
 #[derive(Debug, Copy, Clone, Default)]
 pub struct ReverseNoneIsLowerComparator;
 
@@ -107,6 +191,84 @@ impl Comparator<String> for ReverseNoneIsLowerComparator {
     }
 }
 
+impl Comparator<OwnedValue> for ReverseNoneIsLowerComparator {
+    #[inline(always)]
+    fn compare(&self, lhs: &OwnedValue, rhs: &OwnedValue) -> Ordering {
+        compare_owned_value::</* NULLS_FIRST= */ false>(rhs, lhs)
+    }
+}
+
+/// Compare values naturally, but treating `None` as higher than `Some`.
+///
+/// When used with `TopDocs`, which reverses the order, this results in a
+/// "Descending" sort (Greatest values first), but with `None` values appearing first
+/// (e.g. `[None, Some(20), Some(10)]`).
+#[derive(Debug, Copy, Clone, Default, Serialize, Deserialize)]
+pub struct NaturalNoneIsHigherComparator;
+
+impl<T> Comparator<Option<T>> for NaturalNoneIsHigherComparator
+where NaturalComparator: Comparator<T>
+{
+    #[inline(always)]
+    fn compare(&self, lhs_opt: &Option<T>, rhs_opt: &Option<T>) -> Ordering {
+        match (lhs_opt, rhs_opt) {
+            (None, None) => Ordering::Equal,
+            (None, Some(_)) => Ordering::Greater,
+            (Some(_), None) => Ordering::Less,
+            (Some(lhs), Some(rhs)) => NaturalComparator.compare(lhs, rhs),
+        }
+    }
+}
+
+impl Comparator<u32> for NaturalNoneIsHigherComparator {
+    #[inline(always)]
+    fn compare(&self, lhs: &u32, rhs: &u32) -> Ordering {
+        NaturalComparator.compare(lhs, rhs)
+    }
+}
+
+impl Comparator<u64> for NaturalNoneIsHigherComparator {
+    #[inline(always)]
+    fn compare(&self, lhs: &u64, rhs: &u64) -> Ordering {
+        NaturalComparator.compare(lhs, rhs)
+    }
+}
+
+impl Comparator<f64> for NaturalNoneIsHigherComparator {
+    #[inline(always)]
+    fn compare(&self, lhs: &f64, rhs: &f64) -> Ordering {
+        NaturalComparator.compare(lhs, rhs)
+    }
+}
+
+impl Comparator<f32> for NaturalNoneIsHigherComparator {
+    #[inline(always)]
+    fn compare(&self, lhs: &f32, rhs: &f32) -> Ordering {
+        NaturalComparator.compare(lhs, rhs)
+    }
+}
+
+impl Comparator<i64> for NaturalNoneIsHigherComparator {
+    #[inline(always)]
+    fn compare(&self, lhs: &i64, rhs: &i64) -> Ordering {
+        NaturalComparator.compare(lhs, rhs)
+    }
+}
+
+impl Comparator<String> for NaturalNoneIsHigherComparator {
+    #[inline(always)]
+    fn compare(&self, lhs: &String, rhs: &String) -> Ordering {
+        NaturalComparator.compare(lhs, rhs)
+    }
+}
+
+impl Comparator<OwnedValue> for NaturalNoneIsHigherComparator {
+    #[inline(always)]
+    fn compare(&self, lhs: &OwnedValue, rhs: &OwnedValue) -> Ordering {
+        compare_owned_value::</* NULLS_FIRST= */ false>(lhs, rhs)
+    }
+}
+
 /// An enum representing the different sort orders.
 #[derive(Debug, Clone, Copy, Eq, PartialEq, Default)]
 pub enum ComparatorEnum {
@@ -115,8 +277,10 @@ pub enum ComparatorEnum {
     Natural,
     /// Reverse order (See [ReverseComparator])
     Reverse,
-    /// Reverse order by treating None as the lowest value.(See [ReverseNoneLowerComparator])
+    /// Reverse order by treating None as the lowest value. (See [ReverseNoneLowerComparator])
     ReverseNoneLower,
+    /// Natural order but treating None as the highest value. (See [NaturalNoneIsHigherComparator])
+    NaturalNoneHigher,
 }
 
 impl From<Order> for ComparatorEnum {
@@ -133,6 +297,7 @@ where
     ReverseNoneIsLowerComparator: Comparator<T>,
     NaturalComparator: Comparator<T>,
     ReverseComparator: Comparator<T>,
+    NaturalNoneIsHigherComparator: Comparator<T>,
 {
     #[inline(always)]
     fn compare(&self, lhs: &T, rhs: &T) -> Ordering {
@@ -140,6 +305,7 @@ where
             ComparatorEnum::Natural => NaturalComparator.compare(lhs, rhs),
             ComparatorEnum::Reverse => ReverseComparator.compare(lhs, rhs),
             ComparatorEnum::ReverseNoneLower => ReverseNoneIsLowerComparator.compare(lhs, rhs),
+            ComparatorEnum::NaturalNoneHigher => NaturalNoneIsHigherComparator.compare(lhs, rhs),
         }
     }
 }
@@ -322,11 +488,12 @@ impl<TSegmentSortKeyComputer, TSegmentSortKey, TComparator> SegmentSortKeyComput
     for SegmentSortKeyComputerWithComparator<TSegmentSortKeyComputer, TComparator>
 where
     TSegmentSortKeyComputer: SegmentSortKeyComputer<SegmentSortKey = TSegmentSortKey>,
-    TSegmentSortKey: PartialOrd + Clone + 'static + Sync + Send,
+    TSegmentSortKey: Clone + 'static + Sync + Send,
     TComparator: Comparator<TSegmentSortKey> + 'static + Sync + Send,
 {
     type SortKey = TSegmentSortKeyComputer::SortKey;
     type SegmentSortKey = TSegmentSortKey;
+    type SegmentComparator = TComparator;
 
     fn segment_sort_key(&mut self, doc: DocId, score: Score) -> Self::SegmentSortKey {
         self.segment_sort_key_computer.segment_sort_key(doc, score)
@@ -346,3 +513,55 @@ where
             .convert_segment_sort_key(sort_key)
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::schema::OwnedValue;
+
+    #[test]
+    fn test_natural_none_is_higher() {
+        let comp = NaturalNoneIsHigherComparator;
+        let null = None;
+        let v1 = Some(1_u64);
+        let v2 = Some(2_u64);
+
+        // NaturalNoneIsGreaterComparator logic:
+        // 1. Delegates to NaturalComparator for non-nulls.
+        // NaturalComparator compare(2, 1) -> 2.cmp(1) -> Greater.
+        assert_eq!(comp.compare(&v2, &v1), Ordering::Greater);
+
+        // 2. Treats None (Null) as Greater than any value.
+        // compare(None, Some(2)) should be Greater.
+        assert_eq!(comp.compare(&null, &v2), Ordering::Greater);
+
+        // compare(Some(1), None) should be Less.
+        assert_eq!(comp.compare(&v1, &null), Ordering::Less);
+
+        // compare(None, None) should be Equal.
+        assert_eq!(comp.compare(&null, &null), Ordering::Equal);
+    }
+
+    #[test]
+    fn test_mixed_ownedvalue_compare() {
+        let u = OwnedValue::U64(10);
+        let i = OwnedValue::I64(10);
+        let f = OwnedValue::F64(10.0);
+
+        let nc = NaturalComparator;
+        assert_eq!(nc.compare(&u, &i), Ordering::Equal);
+        assert_eq!(nc.compare(&u, &f), Ordering::Equal);
+        assert_eq!(nc.compare(&i, &f), Ordering::Equal);
+
+        let u2 = OwnedValue::U64(11);
+        assert_eq!(nc.compare(&u2, &f), Ordering::Greater);
+
+        let s = OwnedValue::Str("a".to_string());
+        // Str < U64
+        assert_eq!(nc.compare(&s, &u), Ordering::Less);
+        // Str < I64
+        assert_eq!(nc.compare(&s, &i), Ordering::Less);
+        // Str < F64
+        assert_eq!(nc.compare(&s, &f), Ordering::Less);
+    }
+}

src/collector/sort_key/sort_by_erased_type.rs

@@ -0,0 +1,361 @@
+use columnar::{ColumnType, MonotonicallyMappableToU64};
+
+use crate::collector::sort_key::{
+    NaturalComparator, SortBySimilarityScore, SortByStaticFastValue, SortByString,
+};
+use crate::collector::{SegmentSortKeyComputer, SortKeyComputer};
+use crate::fastfield::FastFieldNotAvailableError;
+use crate::schema::OwnedValue;
+use crate::{DateTime, DocId, Score};
+
+/// Sort by the boxed / OwnedValue representation of either a fast field, or of the score.
+///
+/// Using the OwnedValue representation allows for type erasure, and can be useful when sort orders
+/// are not known until runtime. But it comes with a performance cost: wherever possible, prefer to
+/// use a SortKeyComputer implementation with a known-type at compile time.
+#[derive(Debug, Clone)]
+pub enum SortByErasedType {
+    /// Sort by a fast field
+    Field(String),
+    /// Sort by score
+    Score,
+}
+
+impl SortByErasedType {
+    /// Creates a new sort key computer which will sort by the given fast field column, with type
+    /// erasure.
+    pub fn for_field(column_name: impl ToString) -> Self {
+        Self::Field(column_name.to_string())
+    }
+
+    /// Creates a new sort key computer which will sort by score, with type erasure.
+    pub fn for_score() -> Self {
+        Self::Score
+    }
+}
+
+trait ErasedSegmentSortKeyComputer: Send + Sync {
+    fn segment_sort_key(&mut self, doc: DocId, score: Score) -> Option<u64>;
+    fn convert_segment_sort_key(&self, sort_key: Option<u64>) -> OwnedValue;
+}
+
+struct ErasedSegmentSortKeyComputerWrapper<C, F> {
+    inner: C,
+    converter: F,
+}
+
+impl<C, F> ErasedSegmentSortKeyComputer for ErasedSegmentSortKeyComputerWrapper<C, F>
+where
+    C: SegmentSortKeyComputer<SegmentSortKey = Option<u64>> + Send + Sync,
+    F: Fn(C::SortKey) -> OwnedValue + Send + Sync + 'static,
+{
+    fn segment_sort_key(&mut self, doc: DocId, score: Score) -> Option<u64> {
+        self.inner.segment_sort_key(doc, score)
+    }
+
+    fn convert_segment_sort_key(&self, sort_key: Option<u64>) -> OwnedValue {
+        let val = self.inner.convert_segment_sort_key(sort_key);
+        (self.converter)(val)
+    }
+}
+
+struct ScoreSegmentSortKeyComputer {
+    segment_computer: SortBySimilarityScore,
+}
+
+impl ErasedSegmentSortKeyComputer for ScoreSegmentSortKeyComputer {
+    fn segment_sort_key(&mut self, doc: DocId, score: Score) -> Option<u64> {
+        let score_value: f64 = self.segment_computer.segment_sort_key(doc, score).into();
+        Some(score_value.to_u64())
+    }
+
+    fn convert_segment_sort_key(&self, sort_key: Option<u64>) -> OwnedValue {
+        let score_value: u64 = sort_key.expect("This implementation always produces a score.");
+        OwnedValue::F64(f64::from_u64(score_value))
+    }
+}
+
+impl SortKeyComputer for SortByErasedType {
+    type SortKey = OwnedValue;
+    type Child = ErasedColumnSegmentSortKeyComputer;
+    type Comparator = NaturalComparator;
+
+    fn requires_scoring(&self) -> bool {
+        matches!(self, Self::Score)
+    }
+
+    fn segment_sort_key_computer(
+        &self,
+        segment_reader: &crate::SegmentReader,
+    ) -> crate::Result<Self::Child> {
+        let inner: Box<dyn ErasedSegmentSortKeyComputer> = match self {
+            Self::Field(column_name) => {
+                let fast_fields = segment_reader.fast_fields();
+                // TODO: We currently double-open the column to avoid relying on the implementation
+                // details of `SortByString` or `SortByStaticFastValue`. Once
+                // https://github.com/quickwit-oss/tantivy/issues/2776 is resolved, we should
+                // consider directly constructing the appropriate `SegmentSortKeyComputer` type for
+                // the column that we open here.
+                let (_column, column_type) =
+                    fast_fields.u64_lenient(column_name)?.ok_or_else(|| {
+                        FastFieldNotAvailableError {
+                            field_name: column_name.to_owned(),
+                        }
+                    })?;
+
+                match column_type {
+                    ColumnType::Str => {
+                        let computer = SortByString::for_field(column_name);
+                        let inner = computer.segment_sort_key_computer(segment_reader)?;
+                        Box::new(ErasedSegmentSortKeyComputerWrapper {
+                            inner,
+                            converter: |val: Option<String>| {
+                                val.map(OwnedValue::Str).unwrap_or(OwnedValue::Null)
+                            },
+                        })
+                    }
+                    ColumnType::U64 => {
+                        let computer = SortByStaticFastValue::<u64>::for_field(column_name);
+                        let inner = computer.segment_sort_key_computer(segment_reader)?;
+                        Box::new(ErasedSegmentSortKeyComputerWrapper {
+                            inner,
+                            converter: |val: Option<u64>| {
+                                val.map(OwnedValue::U64).unwrap_or(OwnedValue::Null)
+                            },
+                        })
+                    }
+                    ColumnType::I64 => {
+                        let computer = SortByStaticFastValue::<i64>::for_field(column_name);
+                        let inner = computer.segment_sort_key_computer(segment_reader)?;
+                        Box::new(ErasedSegmentSortKeyComputerWrapper {
+                            inner,
+                            converter: |val: Option<i64>| {
+                                val.map(OwnedValue::I64).unwrap_or(OwnedValue::Null)
+                            },
+                        })
+                    }
+                    ColumnType::F64 => {
+                        let computer = SortByStaticFastValue::<f64>::for_field(column_name);
+                        let inner = computer.segment_sort_key_computer(segment_reader)?;
+                        Box::new(ErasedSegmentSortKeyComputerWrapper {
+                            inner,
+                            converter: |val: Option<f64>| {
+                                val.map(OwnedValue::F64).unwrap_or(OwnedValue::Null)
+                            },
+                        })
+                    }
+                    ColumnType::Bool => {
+                        let computer = SortByStaticFastValue::<bool>::for_field(column_name);
+                        let inner = computer.segment_sort_key_computer(segment_reader)?;
+                        Box::new(ErasedSegmentSortKeyComputerWrapper {
+                            inner,
+                            converter: |val: Option<bool>| {
+                                val.map(OwnedValue::Bool).unwrap_or(OwnedValue::Null)
+                            },
+                        })
+                    }
+                    ColumnType::DateTime => {
+                        let computer = SortByStaticFastValue::<DateTime>::for_field(column_name);
+                        let inner = computer.segment_sort_key_computer(segment_reader)?;
+                        Box::new(ErasedSegmentSortKeyComputerWrapper {
+                            inner,
+                            converter: |val: Option<DateTime>| {
+                                val.map(OwnedValue::Date).unwrap_or(OwnedValue::Null)
+                            },
+                        })
+                    }
+                    column_type => {
+                        return Err(crate::TantivyError::SchemaError(format!(
+                            "Field `{}` is of type {column_type:?}, which is not supported for \
+                             sorting by owned value yet.",
+                            column_name
+                        )))
+                    }
+                }
+            }
+            Self::Score => Box::new(ScoreSegmentSortKeyComputer {
+                segment_computer: SortBySimilarityScore,
+            }),
+        };
+        Ok(ErasedColumnSegmentSortKeyComputer { inner })
+    }
+}
+
+pub struct ErasedColumnSegmentSortKeyComputer {
+    inner: Box<dyn ErasedSegmentSortKeyComputer>,
+}
+
+impl SegmentSortKeyComputer for ErasedColumnSegmentSortKeyComputer {
+    type SortKey = OwnedValue;
+    type SegmentSortKey = Option<u64>;
+    type SegmentComparator = NaturalComparator;
+
+    #[inline(always)]
+    fn segment_sort_key(&mut self, doc: DocId, score: Score) -> Option<u64> {
+        self.inner.segment_sort_key(doc, score)
+    }
+
+    fn convert_segment_sort_key(&self, segment_sort_key: Self::SegmentSortKey) -> OwnedValue {
+        self.inner.convert_segment_sort_key(segment_sort_key)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::collector::sort_key::{ComparatorEnum, SortByErasedType};
+    use crate::collector::TopDocs;
+    use crate::query::AllQuery;
+    use crate::schema::{OwnedValue, Schema, FAST, TEXT};
+    use crate::Index;
+
+    #[test]
+    fn test_sort_by_owned_u64() {
+        let mut schema_builder = Schema::builder();
+        let id_field = schema_builder.add_u64_field("id", FAST);
+        let schema = schema_builder.build();
+        let index = Index::create_in_ram(schema);
+        let mut writer = index.writer_for_tests().unwrap();
+        writer.add_document(doc!(id_field => 10u64)).unwrap();
+        writer.add_document(doc!(id_field => 2u64)).unwrap();
+        writer.add_document(doc!()).unwrap();
+        writer.commit().unwrap();
+
+        let reader = index.reader().unwrap();
+        let searcher = reader.searcher();
+
+        let collector = TopDocs::with_limit(10)
+            .order_by((SortByErasedType::for_field("id"), ComparatorEnum::Natural));
+        let top_docs = searcher.search(&AllQuery, &collector).unwrap();
+
+        let values: Vec<OwnedValue> = top_docs.into_iter().map(|(key, _)| key).collect();
+
+        assert_eq!(
+            values,
+            vec![OwnedValue::U64(10), OwnedValue::U64(2), OwnedValue::Null]
+        );
+
+        let collector = TopDocs::with_limit(10).order_by((
+            SortByErasedType::for_field("id"),
+            ComparatorEnum::ReverseNoneLower,
+        ));
+        let top_docs = searcher.search(&AllQuery, &collector).unwrap();
+
+        let values: Vec<OwnedValue> = top_docs.into_iter().map(|(key, _)| key).collect();
+
+        assert_eq!(
+            values,
+            vec![OwnedValue::U64(2), OwnedValue::U64(10), OwnedValue::Null]
+        );
+    }
+
+    #[test]
+    fn test_sort_by_owned_string() {
+        let mut schema_builder = Schema::builder();
+        let city_field = schema_builder.add_text_field("city", FAST | TEXT);
+        let schema = schema_builder.build();
+        let index = Index::create_in_ram(schema);
+        let mut writer = index.writer_for_tests().unwrap();
+        writer.add_document(doc!(city_field => "tokyo")).unwrap();
+        writer.add_document(doc!(city_field => "austin")).unwrap();
+        writer.add_document(doc!()).unwrap();
+        writer.commit().unwrap();
+
+        let reader = index.reader().unwrap();
+        let searcher = reader.searcher();
+
+        let collector = TopDocs::with_limit(10).order_by((
+            SortByErasedType::for_field("city"),
+            ComparatorEnum::ReverseNoneLower,
+        ));
+        let top_docs = searcher.search(&AllQuery, &collector).unwrap();
+
+        let values: Vec<OwnedValue> = top_docs.into_iter().map(|(key, _)| key).collect();
+
+        assert_eq!(
+            values,
+            vec![
+                OwnedValue::Str("austin".to_string()),
+                OwnedValue::Str("tokyo".to_string()),
+                OwnedValue::Null
+            ]
+        );
+    }
+
+    #[test]
+    fn test_sort_by_owned_reverse() {
+        let mut schema_builder = Schema::builder();
+        let id_field = schema_builder.add_u64_field("id", FAST);
+        let schema = schema_builder.build();
+        let index = Index::create_in_ram(schema);
+        let mut writer = index.writer_for_tests().unwrap();
+        writer.add_document(doc!(id_field => 10u64)).unwrap();
+        writer.add_document(doc!(id_field => 2u64)).unwrap();
+        writer.add_document(doc!()).unwrap();
+        writer.commit().unwrap();
+
+        let reader = index.reader().unwrap();
+        let searcher = reader.searcher();
+
+        let collector = TopDocs::with_limit(10)
+            .order_by((SortByErasedType::for_field("id"), ComparatorEnum::Reverse));
+        let top_docs = searcher.search(&AllQuery, &collector).unwrap();
+
+        let values: Vec<OwnedValue> = top_docs.into_iter().map(|(key, _)| key).collect();
+
+        assert_eq!(
+            values,
+            vec![OwnedValue::Null, OwnedValue::U64(2), OwnedValue::U64(10)]
+        );
+    }
+
+    #[test]
+    fn test_sort_by_owned_score() {
+        let mut schema_builder = Schema::builder();
+        let body_field = schema_builder.add_text_field("body", TEXT);
+        let schema = schema_builder.build();
+        let index = Index::create_in_ram(schema);
+        let mut writer = index.writer_for_tests().unwrap();
+        writer.add_document(doc!(body_field => "a a")).unwrap();
+        writer.add_document(doc!(body_field => "a")).unwrap();
+        writer.commit().unwrap();
+
+        let reader = index.reader().unwrap();
+        let searcher = reader.searcher();
+        let query_parser = crate::query::QueryParser::for_index(&index, vec![body_field]);
+        let query = query_parser.parse_query("a").unwrap();
+
+        // Sort by score descending (Natural)
+        let collector = TopDocs::with_limit(10)
+            .order_by((SortByErasedType::for_score(), ComparatorEnum::Natural));
+        let top_docs = searcher.search(&query, &collector).unwrap();
+
+        let values: Vec<f64> = top_docs
+            .into_iter()
+            .map(|(key, _)| match key {
+                OwnedValue::F64(val) => val,
+                _ => panic!("Wrong type {key:?}"),
+            })
+            .collect();
+
+        assert_eq!(values.len(), 2);
+        assert!(values[0] > values[1]);
+
+        // Sort by score ascending (ReverseNoneLower)
+        let collector = TopDocs::with_limit(10).order_by((
+            SortByErasedType::for_score(),
+            ComparatorEnum::ReverseNoneLower,
+        ));
+        let top_docs = searcher.search(&query, &collector).unwrap();
+
+        let values: Vec<f64> = top_docs
+            .into_iter()
+            .map(|(key, _)| match key {
+                OwnedValue::F64(val) => val,
+                _ => panic!("Wrong type {key:?}"),
+            })
+            .collect();
+
+        assert_eq!(values.len(), 2);
+        assert!(values[0] < values[1]);
+    }
+}

src/collector/sort_key/sort_by_score.rs

@@ -63,8 +63,8 @@ impl SortKeyComputer for SortBySimilarityScore {
 
 impl SegmentSortKeyComputer for SortBySimilarityScore {
     type SortKey = Score;
-
     type SegmentSortKey = Score;
+    type SegmentComparator = NaturalComparator;
 
     #[inline(always)]
     fn segment_sort_key(&mut self, _doc: DocId, score: Score) -> Score {

src/collector/sort_key/sort_by_static_fast_value.rs

@@ -34,9 +34,7 @@ impl<T: FastValue> SortByStaticFastValue<T> {
 
 impl<T: FastValue> SortKeyComputer for SortByStaticFastValue<T> {
     type Child = SortByFastValueSegmentSortKeyComputer<T>;
-
     type SortKey = Option<T>;
-
     type Comparator = NaturalComparator;
 
     fn check_schema(&self, schema: &crate::schema::Schema) -> crate::Result<()> {
@@ -84,8 +82,8 @@ pub struct SortByFastValueSegmentSortKeyComputer<T> {
 
 impl<T: FastValue> SegmentSortKeyComputer for SortByFastValueSegmentSortKeyComputer<T> {
     type SortKey = Option<T>;
-
     type SegmentSortKey = Option<u64>;
+    type SegmentComparator = NaturalComparator;
 
     #[inline(always)]
     fn segment_sort_key(&mut self, doc: DocId, _score: Score) -> Self::SegmentSortKey {

src/collector/sort_key/sort_by_string.rs

@@ -30,9 +30,7 @@ impl SortByString {
 
 impl SortKeyComputer for SortByString {
     type SortKey = Option<String>;
-
     type Child = ByStringColumnSegmentSortKeyComputer;
-
     type Comparator = NaturalComparator;
 
     fn segment_sort_key_computer(
@@ -50,8 +48,8 @@ pub struct ByStringColumnSegmentSortKeyComputer {
 
 impl SegmentSortKeyComputer for ByStringColumnSegmentSortKeyComputer {
     type SortKey = Option<String>;
-
     type SegmentSortKey = Option<TermOrdinal>;
+    type SegmentComparator = NaturalComparator;
 
     #[inline(always)]
     fn segment_sort_key(&mut self, doc: DocId, _score: Score) -> Option<TermOrdinal> {
@@ -60,6 +58,8 @@ impl SegmentSortKeyComputer for ByStringColumnSegmentSortKeyComputer {
     }
 
     fn convert_segment_sort_key(&self, term_ord_opt: Option<TermOrdinal>) -> Option<String> {
+        // TODO: Individual lookups to the dictionary like this are very likely to repeatedly
+        // decompress the same blocks. See https://github.com/quickwit-oss/tantivy/issues/2776
         let term_ord = term_ord_opt?;
         let str_column = self.str_column_opt.as_ref()?;
         let mut bytes = Vec::new();

src/collector/sort_key/sort_key_computer.rs

@@ -12,13 +12,21 @@ use crate::{DocAddress, DocId, Result, Score, SegmentReader};
 /// It is the segment local version of the [`SortKeyComputer`].
 pub trait SegmentSortKeyComputer: 'static {
     /// The final score being emitted.
-    type SortKey: 'static + PartialOrd + Send + Sync + Clone;
+    type SortKey: 'static + Send + Sync + Clone;
 
     /// Sort key used by at the segment level by the `SegmentSortKeyComputer`.
     ///
     /// It is typically small like a `u64`, and is meant to be converted
     /// to the final score at the end of the collection of the segment.
-    type SegmentSortKey: 'static + PartialOrd + Clone + Send + Sync + Clone;
+    type SegmentSortKey: 'static + Clone + Send + Sync + Clone;
+
+    /// Comparator type.
+    type SegmentComparator: Comparator<Self::SegmentSortKey> + 'static;
+
+    /// Returns the segment sort key comparator.
+    fn segment_comparator(&self) -> Self::SegmentComparator {
+        Self::SegmentComparator::default()
+    }
 
     /// Computes the sort key for the given document and score.
     fn segment_sort_key(&mut self, doc: DocId, score: Score) -> Self::SegmentSortKey;
@@ -47,7 +55,7 @@ pub trait SegmentSortKeyComputer: 'static {
         left: &Self::SegmentSortKey,
         right: &Self::SegmentSortKey,
     ) -> Ordering {
-        NaturalComparator.compare(left, right)
+        self.segment_comparator().compare(left, right)
     }
 
     /// Implementing this method makes it possible to avoid computing
@@ -81,7 +89,7 @@ pub trait SegmentSortKeyComputer: 'static {
 /// the sort key at a segment scale.
 pub trait SortKeyComputer: Sync {
     /// The sort key type.
-    type SortKey: 'static + Send + Sync + PartialOrd + Clone + std::fmt::Debug;
+    type SortKey: 'static + Send + Sync + Clone + std::fmt::Debug;
     /// Type of the associated [`SegmentSortKeyComputer`].
     type Child: SegmentSortKeyComputer<SortKey = Self::SortKey>;
     /// Comparator type.
@@ -136,10 +144,7 @@ where
     HeadSortKeyComputer: SortKeyComputer,
     TailSortKeyComputer: SortKeyComputer,
 {
-    type SortKey = (
-        <HeadSortKeyComputer::Child as SegmentSortKeyComputer>::SortKey,
-        <TailSortKeyComputer::Child as SegmentSortKeyComputer>::SortKey,
-    );
+    type SortKey = (HeadSortKeyComputer::SortKey, TailSortKeyComputer::SortKey);
     type Child = (HeadSortKeyComputer::Child, TailSortKeyComputer::Child);
 
     type Comparator = (
@@ -188,6 +193,11 @@ where
         TailSegmentSortKeyComputer::SegmentSortKey,
     );
 
+    type SegmentComparator = (
+        HeadSegmentSortKeyComputer::SegmentComparator,
+        TailSegmentSortKeyComputer::SegmentComparator,
+    );
+
     /// A SegmentSortKeyComputer maps to a SegmentSortKey, but it can also decide on
     /// its ordering.
     ///
@@ -269,11 +279,12 @@ impl<T, PreviousScore, NewScore> SegmentSortKeyComputer
     for MappedSegmentSortKeyComputer<T, PreviousScore, NewScore>
 where
     T: SegmentSortKeyComputer<SortKey = PreviousScore>,
-    PreviousScore: 'static + Clone + Send + Sync + PartialOrd,
-    NewScore: 'static + Clone + Send + Sync + PartialOrd,
+    PreviousScore: 'static + Clone + Send + Sync,
+    NewScore: 'static + Clone + Send + Sync,
 {
     type SortKey = NewScore;
     type SegmentSortKey = T::SegmentSortKey;
+    type SegmentComparator = T::SegmentComparator;
 
     fn segment_sort_key(&mut self, doc: DocId, score: Score) -> Self::SegmentSortKey {
         self.sort_key_computer.segment_sort_key(doc, score)
@@ -463,6 +474,7 @@ where
 {
     type SortKey = TSortKey;
     type SegmentSortKey = TSortKey;
+    type SegmentComparator = NaturalComparator;
 
     fn segment_sort_key(&mut self, doc: DocId, _score: Score) -> TSortKey {
         (self)(doc)

src/collector/sort_key_top_collector.rs

@@ -160,7 +160,7 @@ mod tests {
         expected: &[(crate::Score, usize)],
     ) {
         let mut vals: Vec<(crate::Score, usize)> = (0..10).map(|val| (val as f32, val)).collect();
-        vals.shuffle(&mut rand::thread_rng());
+        vals.shuffle(&mut rand::rng());
         let vals_merged = merge_top_k(vals.into_iter(), doc_range, ComparatorEnum::from(order));
         assert_eq!(&vals_merged, expected);
     }

src/collector/top_collector.rs

@@ -1,64 +1,22 @@
-use std::cmp::Ordering;
-
 use serde::{Deserialize, Serialize};
 
 /// Contains a feature (field, score, etc.) of a document along with the document address.
 ///
-/// It guarantees stable sorting: in case of a tie on the feature, the document
-/// address is used.
-///
-/// The REVERSE_ORDER generic parameter controls whether the by-feature order
-/// should be reversed, which is useful for achieving for example largest-first
-/// semantics without having to wrap the feature in a `Reverse`.
-#[derive(Clone, Default, Serialize, Deserialize)]
-pub struct ComparableDoc<T, D, const REVERSE_ORDER: bool = false> {
+/// Used only by TopNComputer, which implements the actual comparison via a `Comparator`.
+#[derive(Clone, Default, Eq, PartialEq, Serialize, Deserialize)]
+pub struct ComparableDoc<T, D> {
     /// The feature of the document. In practice, this is
-    /// is any type that implements `PartialOrd`.
+    /// is a type which can be compared with a `Comparator<T>`.
     pub sort_key: T,
-    /// The document address. In practice, this is any
-    /// type that implements `PartialOrd`, and is guaranteed
-    /// to be unique for each document.
+    /// The document address. In practice, this is either a `DocId` or `DocAddress`.
     pub doc: D,
 }
-impl<T: std::fmt::Debug, D: std::fmt::Debug, const R: bool> std::fmt::Debug
-    for ComparableDoc<T, D, R>
-{
+
+impl<T: std::fmt::Debug, D: std::fmt::Debug> std::fmt::Debug for ComparableDoc<T, D> {
     fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
-        f.debug_struct(format!("ComparableDoc<_, _ {R}").as_str())
+        f.debug_struct("ComparableDoc")
             .field("feature", &self.sort_key)
             .field("doc", &self.doc)
             .finish()
     }
 }
-
-impl<T: PartialOrd, D: PartialOrd, const R: bool> PartialOrd for ComparableDoc<T, D, R> {
-    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
-        Some(self.cmp(other))
-    }
-}
-
-impl<T: PartialOrd, D: PartialOrd, const R: bool> Ord for ComparableDoc<T, D, R> {
-    #[inline]
-    fn cmp(&self, other: &Self) -> Ordering {
-        let by_feature = self
-            .sort_key
-            .partial_cmp(&other.sort_key)
-            .map(|ord| if R { ord.reverse() } else { ord })
-            .unwrap_or(Ordering::Equal);
-
-        let lazy_by_doc_address = || self.doc.partial_cmp(&other.doc).unwrap_or(Ordering::Equal);
-
-        // In case of a tie on the feature, we sort by ascending
-        // `DocAddress` in order to ensure a stable sorting of the
-        // documents.
-        by_feature.then_with(lazy_by_doc_address)
-    }
-}
-
-impl<T: PartialOrd, D: PartialOrd, const R: bool> PartialEq for ComparableDoc<T, D, R> {
-    fn eq(&self, other: &Self) -> bool {
-        self.cmp(other) == Ordering::Equal
-    }
-}
-
-impl<T: PartialOrd, D: PartialOrd, const R: bool> Eq for ComparableDoc<T, D, R> {}

src/collector/top_score_collector.rs

@@ -23,10 +23,9 @@ use crate::{DocAddress, DocId, Order, Score, SegmentReader};
 /// The theoretical complexity for collecting the top `K` out of `N` documents
 /// is `O(N + K)`.
 ///
-/// This collector does not guarantee a stable sorting in case of a tie on the
-/// document score, for stable sorting `PartialOrd` needs to resolve on other fields
-/// like docid in case of score equality.
-/// Only then, it is suitable for pagination.
+/// This collector guarantees a stable sorting in case of a tie on the
+/// document score/sort key: The document address (`DocAddress`) is used as a tie breaker.
+/// In case of a tie on the sort key, documents are always sorted by ascending `DocAddress`.
 ///
 /// ```rust
 /// use tantivy::collector::TopDocs;
@@ -325,7 +324,7 @@ impl TopDocs {
         sort_key_computer: impl SortKeyComputer<SortKey = TSortKey> + Send + 'static,
     ) -> impl Collector<Fruit = Vec<(TSortKey, DocAddress)>>
     where
-        TSortKey: 'static + Clone + Send + Sync + PartialOrd + std::fmt::Debug,
+        TSortKey: 'static + Clone + Send + Sync + std::fmt::Debug,
     {
         TopBySortKeyCollector::new(sort_key_computer, self.doc_range())
     }
@@ -446,7 +445,7 @@ where
     F: 'static + Send + Sync + Fn(&SegmentReader) -> TTweakScoreSortKeyFn,
     TTweakScoreSortKeyFn: 'static + Fn(DocId, Score) -> TSortKey,
     TweakScoreSegmentSortKeyComputer<TTweakScoreSortKeyFn>:
-        SegmentSortKeyComputer<SortKey = TSortKey>,
+        SegmentSortKeyComputer<SortKey = TSortKey, SegmentSortKey = TSortKey>,
     TSortKey: 'static + PartialOrd + Clone + Send + Sync + std::fmt::Debug,
 {
     type SortKey = TSortKey;
@@ -481,6 +480,7 @@ where
 {
     type SortKey = TSortKey;
     type SegmentSortKey = TSortKey;
+    type SegmentComparator = NaturalComparator;
 
     fn segment_sort_key(&mut self, doc: DocId, score: Score) -> TSortKey {
         (self.sort_key_fn)(doc, score)
@@ -500,8 +500,13 @@ where
 ///
 /// For TopN == 0, it will be relative expensive.
 ///
-/// When using the natural comparator, the top N computer returns the top N elements in
-/// descending order, as expected for a top N.
+/// The TopNComputer will tiebreak by using ascending `D` (DocId or DocAddress):
+/// i.e., in case of a tie on the sort key, the `DocId|DocAddress` are always sorted in
+/// ascending order, regardless of the `Comparator` used for the `Score` type.
+///
+/// NOTE: Items must be `push`ed to the TopNComputer in ascending `DocId|DocAddress` order, as the
+/// threshold used to eliminate docs does not include the `DocId` or `DocAddress`: this provides
+/// the ascending `DocId|DocAddress` tie-breaking behavior without additional comparisons.
 #[derive(Serialize, Deserialize)]
 #[serde(from = "TopNComputerDeser<Score, D, C>")]
 pub struct TopNComputer<Score, D, C> {
@@ -580,6 +585,18 @@ where
     }
 }
 
+#[inline(always)]
+fn compare_for_top_k<TSortKey, D: Ord, C: Comparator<TSortKey>>(
+    c: &C,
+    lhs: &ComparableDoc<TSortKey, D>,
+    rhs: &ComparableDoc<TSortKey, D>,
+) -> std::cmp::Ordering {
+    c.compare(&lhs.sort_key, &rhs.sort_key)
+        .reverse() // Reverse here because we want top K.
+        .then_with(|| lhs.doc.cmp(&rhs.doc)) // Regardless of asc/desc, in presence of a tie, we
+                                             // sort by doc id
+}
+
 impl<TSortKey, D, C> TopNComputer<TSortKey, D, C>
 where
     D: Ord,
@@ -600,10 +617,13 @@ where
 
     /// Push a new document to the top n.
     /// If the document is below the current threshold, it will be ignored.
+    ///
+    /// NOTE: `push` must be called in ascending `DocId`/`DocAddress` order.
     #[inline]
     pub fn push(&mut self, sort_key: TSortKey, doc: D) {
         if let Some(last_median) = &self.threshold {
-            if self.comparator.compare(&sort_key, last_median) == Ordering::Less {
+            // See the struct docs for an explanation of why this comparison is strict.
+            if self.comparator.compare(&sort_key, last_median) != Ordering::Greater {
                 return;
             }
         }
@@ -629,9 +649,7 @@ where
     fn truncate_top_n(&mut self) -> TSortKey {
         // Use select_nth_unstable to find the top nth score
         let (_, median_el, _) = self.buffer.select_nth_unstable_by(self.top_n, |lhs, rhs| {
-            self.comparator
-                .compare(&rhs.sort_key, &lhs.sort_key)
-                .then_with(|| lhs.doc.cmp(&rhs.doc))
+            compare_for_top_k(&self.comparator, lhs, rhs)
         });
 
         let median_score = median_el.sort_key.clone();
@@ -646,11 +664,8 @@ where
         if self.buffer.len() > self.top_n {
             self.truncate_top_n();
         }
-        self.buffer.sort_unstable_by(|left, right| {
-            self.comparator
-                .compare(&right.sort_key, &left.sort_key)
-                .then_with(|| left.doc.cmp(&right.doc))
-        });
+        self.buffer
+            .sort_unstable_by(|lhs, rhs| compare_for_top_k(&self.comparator, lhs, rhs));
         self.buffer
     }
 
@@ -755,6 +770,33 @@ mod tests {
         );
     }
 
+    #[test]
+    fn test_topn_computer_duplicates() {
+        let mut computer: TopNComputer<u32, u32, NaturalComparator> =
+            TopNComputer::new_with_comparator(2, NaturalComparator);
+
+        computer.push(1u32, 1u32);
+        computer.push(1u32, 2u32);
+        computer.push(1u32, 3u32);
+        computer.push(1u32, 4u32);
+        computer.push(1u32, 5u32);
+
+        // In the presence of duplicates, DocIds are always ascending order.
+        assert_eq!(
+            computer.into_sorted_vec(),
+            &[
+                ComparableDoc {
+                    sort_key: 1u32,
+                    doc: 1u32,
+                },
+                ComparableDoc {
+                    sort_key: 1u32,
+                    doc: 2u32,
+                }
+            ]
+        );
+    }
+
     #[test]
     fn test_topn_computer_no_panic() {
         for top_n in 0..10 {
@@ -772,14 +814,17 @@ mod tests {
         #[test]
         fn test_topn_computer_asc_prop(
           limit in 0..10_usize,
-          docs in proptest::collection::vec((0..100_u64, 0..100_u64), 0..100_usize),
+          mut docs in proptest::collection::vec((0..100_u64, 0..100_u64), 0..100_usize),
         ) {
+            // NB: TopNComputer must receive inputs in ascending DocId order.
+            docs.sort_by_key(|(_, doc_id)| *doc_id);
             let mut computer: TopNComputer<_, _, ReverseComparator> = TopNComputer::new_with_comparator(limit, ReverseComparator);
             for (feature, doc) in &docs {
                 computer.push(*feature, *doc);
             }
-            let mut comparable_docs: Vec<ComparableDoc<u64, u64>> = docs.into_iter().map(|(sort_key, doc)| ComparableDoc { sort_key, doc }).collect::<Vec<_>>();
-            comparable_docs.sort();
+            let mut comparable_docs: Vec<ComparableDoc<u64, u64>> =
+                docs.into_iter().map(|(sort_key, doc)| ComparableDoc { sort_key, doc }).collect();
+            crate::collector::sort_key::tests::sort_hits(&mut comparable_docs, Order::Asc);
             comparable_docs.truncate(limit);
             prop_assert_eq!(
                 computer.into_sorted_vec(),
@@ -1406,15 +1451,10 @@ mod tests {
 
             // Using the TopDocs collector should always be equivalent to sorting, skipping the
             // offset, and then taking the limit.
-            let sorted_docs: Vec<_> = if order.is_desc() {
-                let mut comparable_docs: Vec<ComparableDoc<_, _, true>> =
+            let sorted_docs: Vec<_> = {
+                let mut comparable_docs: Vec<ComparableDoc<_, _>> =
                     all_results.into_iter().map(|(sort_key, doc)| ComparableDoc { sort_key, doc}).collect();
-                comparable_docs.sort();
-                comparable_docs.into_iter().map(|cd| (cd.sort_key, cd.doc)).collect()
-            } else {
-                let mut comparable_docs: Vec<ComparableDoc<_, _, false>> =
-                    all_results.into_iter().map(|(sort_key, doc)| ComparableDoc { sort_key, doc}).collect();
-                comparable_docs.sort();
+                crate::collector::sort_key::tests::sort_hits(&mut comparable_docs, order);
                 comparable_docs.into_iter().map(|cd| (cd.sort_key, cd.doc)).collect()
             };
             let expected_docs = sorted_docs.into_iter().skip(offset).take(limit).collect::<Vec<_>>();

src/core/executor.rs

@@ -48,7 +48,15 @@ impl Executor {
         F: Sized + Sync + Fn(A) -> crate::Result<R>,
     {
         match self {
-            Executor::SingleThread => args.map(f).collect::<crate::Result<_>>(),
+            Executor::SingleThread => {
+                // Avoid `collect`, since the stacktrace is blown up by it, which makes profiling
+                // harder.
+                let mut result = Vec::with_capacity(args.size_hint().0);
+                for arg in args {
+                    result.push(f(arg)?);
+                }
+                Ok(result)
+            }
             Executor::ThreadPool(pool) => {
                 let args: Vec<A> = args.collect();
                 let num_fruits = args.len();

src/core/json_utils.rs

@@ -227,9 +227,6 @@ pub(crate) fn index_json_value<'a, V: Value<'a>>(
             ReferenceValueLeaf::IpAddr(_) => {
                 unimplemented!("IP address support in dynamic fields is not yet implemented")
             }
-            ReferenceValueLeaf::Geometry(_) => {
-                unimplemented!("Geometry support in dynamic fields is not implemented")
-            }
         },
         ReferenceValue::Array(elements) => {
             for val in elements {
@@ -409,7 +406,7 @@ mod tests {
         let mut term = Term::from_field_json_path(field, "color", false);
         term.append_type_and_str("red");
 
-        assert_eq!(term.serialized_term(), b"\x00\x00\x00\x01jcolor\x00sred")
+        assert_eq!(term.serialized_value_bytes(), b"color\x00sred".to_vec())
     }
 
     #[test]
@@ -419,8 +416,8 @@ mod tests {
         term.append_type_and_fast_value(-4i64);
 
         assert_eq!(
-            term.serialized_term(),
-            b"\x00\x00\x00\x01jcolor\x00i\x7f\xff\xff\xff\xff\xff\xff\xfc"
+            term.serialized_value_bytes(),
+            b"color\x00i\x7f\xff\xff\xff\xff\xff\xff\xfc".to_vec()
         )
     }
 
@@ -431,8 +428,8 @@ mod tests {
         term.append_type_and_fast_value(4u64);
 
         assert_eq!(
-            term.serialized_term(),
-            b"\x00\x00\x00\x01jcolor\x00u\x00\x00\x00\x00\x00\x00\x00\x04"
+            term.serialized_value_bytes(),
+            b"color\x00u\x00\x00\x00\x00\x00\x00\x00\x04".to_vec()
         )
     }
 
@@ -442,8 +439,8 @@ mod tests {
         let mut term = Term::from_field_json_path(field, "color", false);
         term.append_type_and_fast_value(4.0f64);
         assert_eq!(
-            term.serialized_term(),
-            b"\x00\x00\x00\x01jcolor\x00f\xc0\x10\x00\x00\x00\x00\x00\x00"
+            term.serialized_value_bytes(),
+            b"color\x00f\xc0\x10\x00\x00\x00\x00\x00\x00".to_vec()
         )
     }
 
@@ -453,8 +450,8 @@ mod tests {
         let mut term = Term::from_field_json_path(field, "color", false);
         term.append_type_and_fast_value(true);
         assert_eq!(
-            term.serialized_term(),
-            b"\x00\x00\x00\x01jcolor\x00o\x00\x00\x00\x00\x00\x00\x00\x01"
+            term.serialized_value_bytes(),
+            b"color\x00o\x00\x00\x00\x00\x00\x00\x00\x01".to_vec()
         )
     }
 

src/directory/composite_file.rs

@@ -5,7 +5,7 @@ use std::ops::Range;
 use common::{BinarySerializable, CountingWriter, HasLen, VInt};
 
 use crate::directory::{FileSlice, TerminatingWrite, WritePtr};
-use crate::schema::Field;
+use crate::schema::{Field, Schema};
 use crate::space_usage::{FieldUsage, PerFieldSpaceUsage};
 
 #[derive(Eq, PartialEq, Hash, Copy, Ord, PartialOrd, Clone, Debug)]
@@ -167,10 +167,11 @@ impl CompositeFile {
             .map(|byte_range| self.data.slice(byte_range.clone()))
     }
 
-    pub fn space_usage(&self) -> PerFieldSpaceUsage {
+    pub fn space_usage(&self, schema: &Schema) -> PerFieldSpaceUsage {
         let mut fields = Vec::new();
         for (&field_addr, byte_range) in &self.offsets_index {
-            let mut field_usage = FieldUsage::empty(field_addr.field);
+            let field_name = schema.get_field_name(field_addr.field).to_string();
+            let mut field_usage = FieldUsage::empty(field_name);
             field_usage.add_field_idx(field_addr.idx, byte_range.len().into());
             fields.push(field_usage);
         }

src/directory/mmap_directory/mod.rs

@@ -1,3 +1,5 @@
+mod file_watcher;
+
 use std::collections::HashMap;
 use std::fmt;
 use std::fs::{self, File, OpenOptions};
@@ -7,6 +9,7 @@ use std::path::{Path, PathBuf};
 use std::sync::{Arc, RwLock, Weak};
 
 use common::StableDeref;
+use file_watcher::FileWatcher;
 use fs4::fs_std::FileExt;
 #[cfg(all(feature = "mmap", unix))]
 pub use memmap2::Advice;
@@ -18,7 +21,6 @@ use crate::core::META_FILEPATH;
 use crate::directory::error::{
     DeleteError, LockError, OpenDirectoryError, OpenReadError, OpenWriteError,
 };
-use crate::directory::file_watcher::FileWatcher;
 use crate::directory::{
     AntiCallToken, Directory, DirectoryLock, FileHandle, Lock, OwnedBytes, TerminatingWrite,
     WatchCallback, WatchHandle, WritePtr,
@@ -674,7 +676,7 @@ mod tests {
             let num_segments = reader.searcher().segment_readers().len();
             assert!(num_segments <= 4);
             let num_components_except_deletes_and_tempstore =
-                crate::index::SegmentComponent::iterator().len() - 2;
+                crate::index::SegmentComponent::iterator().len() - 1;
             let max_num_mmapped = num_components_except_deletes_and_tempstore * num_segments;
             assert_eventually(|| {
                 let num_mmapped = mmap_directory.get_cache_info().mmapped.len();

src/directory/mod.rs

@@ -5,7 +5,6 @@ mod mmap_directory;
 
 mod directory;
 mod directory_lock;
-mod file_watcher;
 pub mod footer;
 mod managed_directory;
 mod ram_directory;

src/docset.rs

@@ -40,6 +40,8 @@ pub trait DocSet: Send {
     /// of `DocSet` should support it.
     ///
     /// Calling `seek(TERMINATED)` is also legal and is the normal way to consume a `DocSet`.
+    ///
+    /// `target` has to be larger or equal to `.doc()` when calling `seek`.
     fn seek(&mut self, target: DocId) -> DocId {
         let mut doc = self.doc();
         debug_assert!(doc <= target);
@@ -49,6 +51,57 @@ pub trait DocSet: Send {
         doc
     }
 
+    /// !!!Dragons ahead!!!
+    /// In spirit, this is an approximate and dangerous version of `seek`.
+    ///
+    /// It can leave the DocSet in an `invalid` state and might return a
+    /// lower bound of what the result of Seek would have been.
+    ///
+    ///
+    /// More accurately it returns either:
+    /// - Found if the target is in the docset. In that case, the DocSet is left in a valid state.
+    /// - SeekLowerBound(seek_lower_bound) if the target is not in the docset. In that case, The
+    ///   DocSet can be the left in a invalid state. The DocSet should then only receives call to
+    ///   `seek_danger(..)` until it returns `Found`, and get back to a valid state.
+    ///
+    /// `seek_lower_bound` can be any `DocId` (in the docset or not) as long as it is in
+    /// `(target .. seek_result] U {TERMINATED}` where `seek_result` is the first document in the
+    /// docset greater than to `target`.
+    ///
+    /// `seek_danger` may return `SeekLowerBound(TERMINATED)`.
+    ///
+    /// Calling `seek_danger` with TERMINATED as a target is allowed,
+    /// and should always return NewTarget(TERMINATED) or anything larger as TERMINATED is NOT in
+    /// the DocSet.
+    ///
+    /// DocSets that already have an efficient `seek` method don't need to implement
+    /// `seek_danger`.
+    ///
+    /// Consecutive calls to seek_danger are guaranteed to have strictly increasing `target`
+    /// values.
+    fn seek_danger(&mut self, target: DocId) -> SeekDangerResult {
+        if target >= TERMINATED {
+            debug_assert!(target == TERMINATED);
+            // No need to advance.
+            return SeekDangerResult::SeekLowerBound(target);
+        }
+
+        // The default implementation does not include any
+        // `danger zone` behavior.
+        //
+        // It does not leave the scorer in an invalid state.
+        // For this reason, we can safely call `self.doc()`.
+        let mut doc = self.doc();
+        if doc < target {
+            doc = self.seek(target);
+        }
+        if doc == target {
+            SeekDangerResult::Found
+        } else {
+            SeekDangerResult::SeekLowerBound(doc)
+        }
+    }
+
     /// Fills a given mutable buffer with the next doc ids from the
     /// `DocSet`
     ///
@@ -94,6 +147,15 @@ pub trait DocSet: Send {
     /// which would be the number of documents in the DocSet.
     ///
     /// By default this returns `size_hint()`.
+    ///
+    /// DocSets may have vastly different cost depending on their type,
+    /// e.g. an intersection with 10 hits is much cheaper than
+    /// a phrase search with 10 hits, since it needs to load positions.
+    ///
+    /// ### Future Work
+    /// We may want to differentiate `DocSet` costs more more granular, e.g.
+    /// creation_cost, advance_cost, seek_cost on to get a good estimation
+    /// what query types to choose.
     fn cost(&self) -> u64 {
         self.size_hint() as u64
     }
@@ -128,6 +190,17 @@ pub trait DocSet: Send {
     }
 }
 
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum SeekDangerResult {
+    /// The target was found in the DocSet.
+    Found,
+    /// The target was not found in the DocSet.
+    /// We return a range in which the value could be.
+    /// The given target can be any DocId, that is <= than the first document
+    /// in the docset after the target.
+    SeekLowerBound(DocId),
+}
+
 impl DocSet for &mut dyn DocSet {
     fn advance(&mut self) -> u32 {
         (**self).advance()
@@ -137,6 +210,10 @@ impl DocSet for &mut dyn DocSet {
         (**self).seek(target)
     }
 
+    fn seek_danger(&mut self, target: DocId) -> SeekDangerResult {
+        (**self).seek_danger(target)
+    }
+
     fn doc(&self) -> u32 {
         (**self).doc()
     }
@@ -169,6 +246,11 @@ impl<TDocSet: DocSet + ?Sized> DocSet for Box<TDocSet> {
         unboxed.seek(target)
     }
 
+    fn seek_danger(&mut self, target: DocId) -> SeekDangerResult {
+        let unboxed: &mut TDocSet = self.borrow_mut();
+        unboxed.seek_danger(target)
+    }
+
     fn fill_buffer(&mut self, buffer: &mut [DocId; COLLECT_BLOCK_BUFFER_LEN]) -> usize {
         let unboxed: &mut TDocSet = self.borrow_mut();
         unboxed.fill_buffer(buffer)

src/fastfield/alive_bitset.rs

@@ -162,7 +162,7 @@ mod tests {
 mod bench {
 
     use rand::prelude::IteratorRandom;
-    use rand::thread_rng;
+    use rand::rng;
     use test::Bencher;
 
     use super::AliveBitSet;
@@ -176,7 +176,7 @@ mod bench {
     }
 
     fn remove_rand(raw: &mut Vec<u32>) {
-        let i = (0..raw.len()).choose(&mut thread_rng()).unwrap();
+        let i = (0..raw.len()).choose(&mut rng()).unwrap();
         raw.remove(i);
     }
 

src/fastfield/mod.rs

@@ -683,7 +683,7 @@ mod tests {
     }
 
     #[test]
-    fn test_datefastfield() {
+    fn test_datefastfield() -> crate::Result<()> {
         let mut schema_builder = Schema::builder();
         let date_field = schema_builder.add_date_field(
             "date",
@@ -697,28 +697,22 @@ mod tests {
         );
         let schema = schema_builder.build();
         let index = Index::create_in_ram(schema);
-        let mut index_writer = index.writer_for_tests().unwrap();
+        let mut index_writer = index.writer_for_tests()?;
         index_writer.set_merge_policy(Box::new(NoMergePolicy));
-        index_writer
-            .add_document(doc!(
-                date_field => DateTime::from_u64(1i64.to_u64()),
-                multi_date_field => DateTime::from_u64(2i64.to_u64()),
-                multi_date_field => DateTime::from_u64(3i64.to_u64())
-            ))
-            .unwrap();
-        index_writer
-            .add_document(doc!(
-                date_field => DateTime::from_u64(4i64.to_u64())
-            ))
-            .unwrap();
-        index_writer
-            .add_document(doc!(
-                multi_date_field => DateTime::from_u64(5i64.to_u64()),
-                multi_date_field => DateTime::from_u64(6i64.to_u64())
-            ))
-            .unwrap();
-        index_writer.commit().unwrap();
-        let reader = index.reader().unwrap();
+        index_writer.add_document(doc!(
+            date_field => DateTime::from_u64(1i64.to_u64()),
+            multi_date_field => DateTime::from_u64(2i64.to_u64()),
+            multi_date_field => DateTime::from_u64(3i64.to_u64())
+        ))?;
+        index_writer.add_document(doc!(
+            date_field => DateTime::from_u64(4i64.to_u64())
+        ))?;
+        index_writer.add_document(doc!(
+            multi_date_field => DateTime::from_u64(5i64.to_u64()),
+            multi_date_field => DateTime::from_u64(6i64.to_u64())
+        ))?;
+        index_writer.commit()?;
+        let reader = index.reader()?;
         let searcher = reader.searcher();
         assert_eq!(searcher.segment_readers().len(), 1);
         let segment_reader = searcher.segment_reader(0);
@@ -752,6 +746,7 @@ mod tests {
             assert_eq!(dates[0].into_timestamp_nanos(), 5i64);
             assert_eq!(dates[1].into_timestamp_nanos(), 6i64);
         }
+        Ok(())
     }
 
     #[test]
@@ -884,7 +879,7 @@ mod tests {
         const ONE_HOUR_IN_MICROSECS: i64 = 3_600 * 1_000_000;
         let times: Vec<DateTime> = std::iter::repeat_with(|| {
             // +- One hour.
-            let t = T0 + rng.gen_range(-ONE_HOUR_IN_MICROSECS..ONE_HOUR_IN_MICROSECS);
+            let t = T0 + rng.random_range(-ONE_HOUR_IN_MICROSECS..ONE_HOUR_IN_MICROSECS);
             DateTime::from_timestamp_micros(t)
         })
         .take(1_000)

src/fastfield/readers.rs

@@ -8,7 +8,7 @@ use columnar::{
 };
 use common::ByteCount;
 
-use crate::core::json_utils::encode_column_name;
+use crate::core::json_utils::{encode_column_name, json_path_sep_to_dot};
 use crate::directory::FileSlice;
 use crate::schema::{Field, FieldEntry, FieldType, Schema};
 use crate::space_usage::{FieldUsage, PerFieldSpaceUsage};
@@ -39,19 +39,15 @@ impl FastFieldReaders {
         self.resolve_column_name_given_default_field(column_name, default_field_opt)
     }
 
-    pub(crate) fn space_usage(&self, schema: &Schema) -> io::Result<PerFieldSpaceUsage> {
+    pub(crate) fn space_usage(&self) -> io::Result<PerFieldSpaceUsage> {
         let mut per_field_usages: Vec<FieldUsage> = Default::default();
-        for (field, field_entry) in schema.fields() {
-            let column_handles = self.columnar.read_columns(field_entry.name())?;
-            let num_bytes: ByteCount = column_handles
-                .iter()
-                .map(|column_handle| column_handle.num_bytes())
-                .sum();
-            let mut field_usage = FieldUsage::empty(field);
-            field_usage.add_field_idx(0, num_bytes);
+        for (mut field_name, column_handle) in self.columnar.iter_columns()? {
+            json_path_sep_to_dot(&mut field_name);
+            let space_usage = column_handle.space_usage()?;
+            let mut field_usage = FieldUsage::empty(field_name);
+            field_usage.set_column_usage(space_usage);
             per_field_usages.push(field_usage);
         }
-        // TODO fix space usage for JSON fields.
         Ok(PerFieldSpaceUsage::new(per_field_usages))
     }
 

src/fastfield/writer.rs

@@ -189,9 +189,6 @@ impl FastFieldsWriter {
                             .record_str(doc_id, field_name, &token.text);
                     }
                 }
-                ReferenceValueLeaf::Geometry(_) => {
-                    panic!("Geometry fields should not be routed to fast field writer")
-                }
             },
             ReferenceValue::Array(val) => {
                 // TODO: Check this is the correct behaviour we want.
@@ -323,9 +320,6 @@ fn record_json_value_to_columnar_writer<'a, V: Value<'a>>(
                     "Pre-tokenized string support in dynamic fields is not yet implemented"
                 )
             }
-            ReferenceValueLeaf::Geometry(_) => {
-                unimplemented!("Geometry support in dynamic fields is not yet implemented")
-            }
         },
         ReferenceValue::Array(elements) => {
             for el in elements {

src/fieldnorm/reader.rs

@@ -2,7 +2,7 @@ use std::sync::Arc;
 
 use super::{fieldnorm_to_id, id_to_fieldnorm};
 use crate::directory::{CompositeFile, FileSlice, OwnedBytes};
-use crate::schema::Field;
+use crate::schema::{Field, Schema};
 use crate::space_usage::PerFieldSpaceUsage;
 use crate::DocId;
 
@@ -37,8 +37,8 @@ impl FieldNormReaders {
     }
 
     /// Return a break down of the space usage per field.
-    pub fn space_usage(&self) -> PerFieldSpaceUsage {
-        self.data.space_usage()
+    pub fn space_usage(&self, schema: &Schema) -> PerFieldSpaceUsage {
+        self.data.space_usage(schema)
     }
 
     /// Returns a handle to inner file

src/functional_test.rs

@@ -1,6 +1,6 @@
 use std::collections::HashSet;
 
-use rand::{thread_rng, Rng};
+use rand::{rng, Rng};
 
 use crate::indexer::index_writer::MEMORY_BUDGET_NUM_BYTES_MIN;
 use crate::schema::*;
@@ -29,7 +29,7 @@ fn test_functional_store() -> crate::Result<()> {
     let index = Index::create_in_ram(schema);
     let reader = index.reader()?;
 
-    let mut rng = thread_rng();
+    let mut rng = rng();
 
     let mut index_writer: IndexWriter =
         index.writer_with_num_threads(3, 3 * MEMORY_BUDGET_NUM_BYTES_MIN)?;
@@ -38,9 +38,9 @@ fn test_functional_store() -> crate::Result<()> {
 
     let mut doc_id = 0u64;
     for _iteration in 0..get_num_iterations() {
-        let num_docs: usize = rng.gen_range(0..4);
+        let num_docs: usize = rng.random_range(0..4);
         if !doc_set.is_empty() {
-            let doc_to_remove_id = rng.gen_range(0..doc_set.len());
+            let doc_to_remove_id = rng.random_range(0..doc_set.len());
             let removed_doc_id = doc_set.swap_remove(doc_to_remove_id);
             index_writer.delete_term(Term::from_field_u64(id_field, removed_doc_id));
         }
@@ -70,10 +70,10 @@ const LOREM: &str = "Doc Lorem ipsum dolor sit amet, consectetur adipiscing elit
                      cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat \
                      non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.";
 fn get_text() -> String {
-    use rand::seq::SliceRandom;
-    let mut rng = thread_rng();
+    use rand::seq::IndexedRandom;
+    let mut rng = rng();
     let tokens: Vec<_> = LOREM.split(' ').collect();
-    let random_val = rng.gen_range(0..20);
+    let random_val = rng.random_range(0..20);
 
     (0..random_val)
         .map(|_| tokens.choose(&mut rng).unwrap())
@@ -101,7 +101,7 @@ fn test_functional_indexing_unsorted() -> crate::Result<()> {
     let index = Index::create_from_tempdir(schema)?;
     let reader = index.reader()?;
 
-    let mut rng = thread_rng();
+    let mut rng = rng();
 
     let mut index_writer: IndexWriter =
         index.writer_with_num_threads(3, 3 * MEMORY_BUDGET_NUM_BYTES_MIN)?;
@@ -110,7 +110,7 @@ fn test_functional_indexing_unsorted() -> crate::Result<()> {
     let mut uncommitted_docs: HashSet<u64> = HashSet::new();
 
     for _ in 0..get_num_iterations() {
-        let random_val = rng.gen_range(0..20);
+        let random_val = rng.random_range(0..20);
         if random_val == 0 {
             index_writer.commit()?;
             committed_docs.extend(&uncommitted_docs);

src/index/index_meta.rs

@@ -1,8 +1,6 @@
 use std::collections::HashSet;
 use std::fmt;
 use std::path::PathBuf;
-use std::sync::atomic::AtomicBool;
-use std::sync::Arc;
 
 use serde::{Deserialize, Serialize};
 
@@ -13,9 +11,9 @@ use crate::store::Compressor;
 use crate::{Inventory, Opstamp, TrackedObject};
 
 #[derive(Clone, Debug, Serialize, Deserialize)]
-struct DeleteMeta {
+pub struct DeleteMeta {
     num_deleted_docs: u32,
-    opstamp: Opstamp,
+    pub opstamp: Opstamp,
 }
 
 #[derive(Clone, Default)]
@@ -37,7 +35,6 @@ impl SegmentMetaInventory {
         let inner = InnerSegmentMeta {
             segment_id,
             max_doc,
-            include_temp_doc_store: Arc::new(AtomicBool::new(true)),
             deletes: None,
         };
         SegmentMeta::from(self.inventory.track(inner))
@@ -85,15 +82,6 @@ impl SegmentMeta {
         self.tracked.segment_id
     }
 
-    /// Removes the Component::TempStore from the alive list and
-    /// therefore marks the temp docstore file to be deleted by
-    /// the garbage collection.
-    pub fn untrack_temp_docstore(&self) {
-        self.tracked
-            .include_temp_doc_store
-            .store(false, std::sync::atomic::Ordering::Relaxed);
-    }
-
     /// Returns the number of deleted documents.
     pub fn num_deleted_docs(&self) -> u32 {
         self.tracked
@@ -111,20 +99,9 @@ impl SegmentMeta {
     /// is by removing all files that have been created by tantivy
     /// and are not used by any segment anymore.
     pub fn list_files(&self) -> HashSet<PathBuf> {
-        if self
-            .tracked
-            .include_temp_doc_store
-            .load(std::sync::atomic::Ordering::Relaxed)
-        {
-            SegmentComponent::iterator()
-                .map(|component| self.relative_path(*component))
-                .collect::<HashSet<PathBuf>>()
-        } else {
-            SegmentComponent::iterator()
-                .filter(|comp| *comp != &SegmentComponent::TempStore)
-                .map(|component| self.relative_path(*component))
-                .collect::<HashSet<PathBuf>>()
-        }
+        SegmentComponent::iterator()
+            .map(|component| self.relative_path(*component))
+            .collect::<HashSet<PathBuf>>()
     }
 
     /// Returns the relative path of a component of our segment.
@@ -138,11 +115,9 @@ impl SegmentMeta {
             SegmentComponent::Positions => ".pos".to_string(),
             SegmentComponent::Terms => ".term".to_string(),
             SegmentComponent::Store => ".store".to_string(),
-            SegmentComponent::TempStore => ".store.temp".to_string(),
             SegmentComponent::FastFields => ".fast".to_string(),
             SegmentComponent::FieldNorms => ".fieldnorm".to_string(),
             SegmentComponent::Delete => format!(".{}.del", self.delete_opstamp().unwrap_or(0)),
-            SegmentComponent::Spatial => ".spatial".to_string(),
         });
         PathBuf::from(path)
     }
@@ -184,7 +159,6 @@ impl SegmentMeta {
             segment_id: inner_meta.segment_id,
             max_doc,
             deletes: None,
-            include_temp_doc_store: Arc::new(AtomicBool::new(true)),
         });
         SegmentMeta { tracked }
     }
@@ -203,7 +177,6 @@ impl SegmentMeta {
         let tracked = self.tracked.map(move |inner_meta| InnerSegmentMeta {
             segment_id: inner_meta.segment_id,
             max_doc: inner_meta.max_doc,
-            include_temp_doc_store: Arc::new(AtomicBool::new(true)),
             deletes: Some(delete_meta),
         });
         SegmentMeta { tracked }
@@ -214,15 +187,7 @@ impl SegmentMeta {
 struct InnerSegmentMeta {
     segment_id: SegmentId,
     max_doc: u32,
-    deletes: Option<DeleteMeta>,
-    /// If you want to avoid the SegmentComponent::TempStore file to be covered by
-    /// garbage collection and deleted, set this to true. This is used during merge.
-    #[serde(skip)]
-    #[serde(default = "default_temp_store")]
-    pub(crate) include_temp_doc_store: Arc<AtomicBool>,
-}
-fn default_temp_store() -> Arc<AtomicBool> {
-    Arc::new(AtomicBool::new(false))
+    pub deletes: Option<DeleteMeta>,
 }
 
 impl InnerSegmentMeta {
@@ -405,7 +370,10 @@ mod tests {
             schema_builder.build()
         };
         let index_metas = IndexMeta {
-            index_settings: IndexSettings::default(),
+            index_settings: IndexSettings {
+                docstore_compression: Compressor::None,
+                ..Default::default()
+            },
             segments: Vec::new(),
             schema,
             opstamp: 0u64,
@@ -414,7 +382,7 @@ mod tests {
         let json = serde_json::ser::to_string(&index_metas).expect("serialization failed");
         assert_eq!(
             json,
-            r#"{"index_settings":{"docstore_compression":"lz4","docstore_blocksize":16384},"segments":[],"schema":[{"name":"text","type":"text","options":{"indexing":{"record":"position","fieldnorms":true,"tokenizer":"default"},"stored":false,"fast":false}}],"opstamp":0}"#
+            r#"{"index_settings":{"docstore_compression":"none","docstore_blocksize":16384},"segments":[],"schema":[{"name":"text","type":"text","options":{"indexing":{"record":"position","fieldnorms":true,"tokenizer":"default"},"stored":false,"fast":false}}],"opstamp":0}"#
         );
 
         let deser_meta: UntrackedIndexMeta = serde_json::from_str(&json).unwrap();
@@ -495,6 +463,8 @@ mod tests {
     #[test]
     #[cfg(feature = "lz4-compression")]
     fn test_index_settings_default() {
+        use crate::store::Compressor;
+
         let mut index_settings = IndexSettings::default();
         assert_eq!(
             index_settings,

src/index/segment.rs

@@ -46,7 +46,7 @@ impl Segment {
     ///
     /// This method is only used when updating `max_doc` from 0
     /// as we finalize a fresh new segment.
-    pub(crate) fn with_max_doc(self, max_doc: u32) -> Segment {
+    pub fn with_max_doc(self, max_doc: u32) -> Segment {
         Segment {
             index: self.index,
             meta: self.meta.with_max_doc(max_doc),

src/index/segment_component.rs

@@ -23,28 +23,22 @@ pub enum SegmentComponent {
     /// Accessing a document from the store is relatively slow, as it
     /// requires to decompress the entire block it belongs to.
     Store,
-    /// Temporary storage of the documents, before streamed to `Store`.
-    TempStore,
     /// Bitset describing which document of the segment is alive.
     /// (It was representing deleted docs but changed to represent alive docs from v0.17)
     Delete,
-    /// HUSH
-    Spatial,
 }
 
 impl SegmentComponent {
     /// Iterates through the components.
     pub fn iterator() -> slice::Iter<'static, SegmentComponent> {
-        static SEGMENT_COMPONENTS: [SegmentComponent; 9] = [
+        static SEGMENT_COMPONENTS: [SegmentComponent; 7] = [
             SegmentComponent::Postings,
             SegmentComponent::Positions,
             SegmentComponent::FastFields,
             SegmentComponent::FieldNorms,
             SegmentComponent::Terms,
             SegmentComponent::Store,
-            SegmentComponent::TempStore,
             SegmentComponent::Delete,
-            SegmentComponent::Spatial,
         ];
         SEGMENT_COMPONENTS.iter()
     }

src/index/segment_reader.rs

@@ -14,7 +14,6 @@ use crate::index::{InvertedIndexReader, Segment, SegmentComponent, SegmentId};
 use crate::json_utils::json_path_sep_to_dot;
 use crate::schema::{Field, IndexRecordOption, Schema, Type};
 use crate::space_usage::SegmentSpaceUsage;
-use crate::spatial::reader::SpatialReaders;
 use crate::store::StoreReader;
 use crate::termdict::TermDictionary;
 use crate::{DocId, Opstamp};
@@ -44,7 +43,6 @@ pub struct SegmentReader {
     positions_composite: CompositeFile,
     fast_fields_readers: FastFieldReaders,
     fieldnorm_readers: FieldNormReaders,
-    spatial_readers: SpatialReaders,
 
     store_file: FileSlice,
     alive_bitset_opt: Option<AliveBitSet>,
@@ -94,11 +92,6 @@ impl SegmentReader {
         &self.fast_fields_readers
     }
 
-    /// HUSH
-    pub fn spatial_fields(&self) -> &SpatialReaders {
-        &self.spatial_readers
-    }
-
     /// Accessor to the `FacetReader` associated with a given `Field`.
     pub fn facet_reader(&self, field_name: &str) -> crate::Result<FacetReader> {
         let schema = self.schema();
@@ -180,12 +173,6 @@ impl SegmentReader {
         let fast_fields_readers = FastFieldReaders::open(fast_fields_data, schema.clone())?;
         let fieldnorm_data = segment.open_read(SegmentComponent::FieldNorms)?;
         let fieldnorm_readers = FieldNormReaders::open(fieldnorm_data)?;
-        let spatial_readers = if schema.contains_spatial_field() {
-            let spatial_data = segment.open_read(SegmentComponent::Spatial)?;
-            SpatialReaders::open(spatial_data)?
-        } else {
-            SpatialReaders::empty()
-        };
 
         let original_bitset = if segment.meta().has_deletes() {
             let alive_doc_file_slice = segment.open_read(SegmentComponent::Delete)?;
@@ -211,7 +198,6 @@ impl SegmentReader {
             postings_composite,
             fast_fields_readers,
             fieldnorm_readers,
-            spatial_readers,
             segment_id: segment.id(),
             delete_opstamp: segment.meta().delete_opstamp(),
             store_file,
@@ -469,12 +455,11 @@ impl SegmentReader {
     pub fn space_usage(&self) -> io::Result<SegmentSpaceUsage> {
         Ok(SegmentSpaceUsage::new(
             self.num_docs(),
-            self.termdict_composite.space_usage(),
-            self.postings_composite.space_usage(),
-            self.positions_composite.space_usage(),
-            self.fast_fields_readers.space_usage(self.schema())?,
-            self.fieldnorm_readers.space_usage(),
-            self.spatial_readers.space_usage(),
+            self.termdict_composite.space_usage(self.schema()),
+            self.postings_composite.space_usage(self.schema()),
+            self.positions_composite.space_usage(self.schema()),
+            self.fast_fields_readers.space_usage()?,
+            self.fieldnorm_readers.space_usage(self.schema()),
             self.get_store_reader(0)?.space_usage(),
             self.alive_bitset_opt
                 .as_ref()

src/indexer/delete_queue.rs

@@ -4,38 +4,37 @@ use std::sync::{Arc, RwLock, Weak};
 use super::operation::DeleteOperation;
 use crate::Opstamp;
 
-// The DeleteQueue is similar in conceptually to a multiple
-// consumer single producer broadcast channel.
-//
-// All consumer will receive all messages.
-//
-// Consumer of the delete queue are holding a `DeleteCursor`,
-// which points to a specific place of the `DeleteQueue`.
-//
-// New consumer can be created in two ways
-// - calling `delete_queue.cursor()` returns a cursor, that will include all future delete operation
-//   (and some or none of the past operations... The client is in charge of checking the opstamps.).
-// - cloning an existing cursor returns a new cursor, that is at the exact same position, and can
-//   now advance independently from the original cursor.
+/// The DeleteQueue is similar in conceptually to a multiple
+/// consumer single producer broadcast channel.
+///
+/// All consumer will receive all messages.
+///
+/// Consumer of the delete queue are holding a `DeleteCursor`,
+/// which points to a specific place of the `DeleteQueue`.
+///
+/// New consumer can be created in two ways
+/// - calling `delete_queue.cursor()` returns a cursor, that will include all future delete
+///   operation (and some or none of the past operations... The client is in charge of checking the
+///   opstamps.).
+/// - cloning an existing cursor returns a new cursor, that is at the exact same position, and can
+///   now advance independently from the original cursor.
 #[derive(Default)]
 struct InnerDeleteQueue {
     writer: Vec<DeleteOperation>,
     last_block: Weak<Block>,
 }
 
-#[derive(Clone)]
+/// The delete queue is a linked list storing delete operations.
+///
+/// Several consumers can hold a reference to it. Delete operations
+/// get dropped/gc'ed when no more consumers are holding a reference
+/// to them.
+#[derive(Clone, Default)]
 pub struct DeleteQueue {
     inner: Arc<RwLock<InnerDeleteQueue>>,
 }
 
 impl DeleteQueue {
-    // Creates a new delete queue.
-    pub fn new() -> DeleteQueue {
-        DeleteQueue {
-            inner: Arc::default(),
-        }
-    }
-
     fn get_last_block(&self) -> Arc<Block> {
         {
             // try get the last block with simply acquiring the read lock.
@@ -58,10 +57,10 @@ impl DeleteQueue {
         block
     }
 
-    // Creates a new cursor that makes it possible to
-    // consume future delete operations.
-    //
-    // Past delete operations are not accessible.
+    /// Creates a new cursor that makes it possible to
+    /// consume future delete operations.
+    ///
+    /// Past delete operations are not accessible.
     pub fn cursor(&self) -> DeleteCursor {
         let last_block = self.get_last_block();
         let operations_len = last_block.operations.len();
@@ -71,7 +70,7 @@ impl DeleteQueue {
         }
     }
 
-    // Appends a new delete operations.
+    /// Appends a new delete operations.
     pub fn push(&self, delete_operation: DeleteOperation) {
         self.inner
             .write()
@@ -169,6 +168,7 @@ struct Block {
     next: NextBlock,
 }
 
+/// As we process delete operations, keeps track of our position.
 #[derive(Clone)]
 pub struct DeleteCursor {
     block: Arc<Block>,
@@ -261,7 +261,7 @@ mod tests {
 
     #[test]
     fn test_deletequeue() {
-        let delete_queue = DeleteQueue::new();
+        let delete_queue = DeleteQueue::default();
 
         let make_op = |i: usize| DeleteOperation {
             opstamp: i as u64,

src/indexer/index_writer.rs

@@ -128,7 +128,7 @@ fn compute_deleted_bitset(
 /// is `==` target_opstamp.
 /// For instance, there was no delete operation between the state of the `segment_entry` and
 /// the `target_opstamp`, `segment_entry` is not updated.
-pub(crate) fn advance_deletes(
+pub fn advance_deletes(
     mut segment: Segment,
     segment_entry: &mut SegmentEntry,
     target_opstamp: Opstamp,
@@ -218,7 +218,7 @@ fn index_documents<D: Document>(
     let alive_bitset_opt = apply_deletes(&segment_with_max_doc, &mut delete_cursor, &doc_opstamps)?;
 
     let meta = segment_with_max_doc.meta().clone();
-    meta.untrack_temp_docstore();
+
     // update segment_updater inventory to remove tempstore
     let segment_entry = SegmentEntry::new(meta, delete_cursor, alive_bitset_opt);
     segment_updater.schedule_add_segment(segment_entry).wait()?;
@@ -303,7 +303,7 @@ impl<D: Document> IndexWriter<D> {
         let (document_sender, document_receiver) =
             crossbeam_channel::bounded(PIPELINE_MAX_SIZE_IN_DOCS);
 
-        let delete_queue = DeleteQueue::new();
+        let delete_queue = DeleteQueue::default();
 
         let current_opstamp = index.load_metas()?.opstamp;
 

src/indexer/indexing_term.rs

@@ -3,21 +3,21 @@ use std::net::Ipv6Addr;
 use columnar::MonotonicallyMappableToU128;
 
 use crate::fastfield::FastValue;
-use crate::schema::{Field, Type};
+use crate::schema::Field;
 
-/// Term represents the value that the token can take.
-/// It's a serialized representation over different types.
+/// IndexingTerm is used to represent a term during indexing.
+/// It's a serialized representation over field and value.
 ///
-/// It actually wraps a `Vec<u8>`. The first 5 bytes are metadata.
-/// 4 bytes are the field id, and the last byte is the type.
+/// It actually wraps a `Vec<u8>`. The first 4 bytes are the field.
 ///
-/// The serialized value `ValueBytes` is considered everything after the 4 first bytes (term id).
+/// We serialize the field, because we index everything in a single
+/// global term dictionary during indexing.
 #[derive(Clone)]
 pub(crate) struct IndexingTerm<B = Vec<u8>>(B)
 where B: AsRef<[u8]>;
 
 /// The number of bytes used as metadata by `Term`.
-const TERM_METADATA_LENGTH: usize = 5;
+const TERM_METADATA_LENGTH: usize = 4;
 
 impl IndexingTerm {
     /// Create a new Term with a buffer with a given capacity.
@@ -31,10 +31,9 @@ impl IndexingTerm {
     /// Use `clear_with_field_and_type` in that case.
     ///
     /// Sets field and the type.
-    pub(crate) fn set_field_and_type(&mut self, field: Field, typ: Type) {
+    pub(crate) fn set_field(&mut self, field: Field) {
         assert!(self.is_empty());
         self.0[0..4].clone_from_slice(field.field_id().to_be_bytes().as_ref());
-        self.0[4] = typ.to_code();
     }
 
     /// Is empty if there are no value bytes.
@@ -42,10 +41,10 @@ impl IndexingTerm {
         self.0.len() == TERM_METADATA_LENGTH
     }
 
-    /// Removes the value_bytes and set the field and type code.
-    pub(crate) fn clear_with_field_and_type(&mut self, typ: Type, field: Field) {
+    /// Removes the value_bytes and set the field
+    pub(crate) fn clear_with_field(&mut self, field: Field) {
         self.truncate_value_bytes(0);
-        self.set_field_and_type(field, typ);
+        self.set_field(field);
     }
 
     /// Sets a u64 value in the term.
@@ -122,6 +121,23 @@ impl IndexingTerm {
 impl<B> IndexingTerm<B>
 where B: AsRef<[u8]>
 {
+    /// Wraps serialized term bytes.
+    ///
+    /// The input buffer is expected to be the concatenation of the big endian encoded field id
+    /// followed by the serialized value bytes (type tag + payload).
+    #[inline]
+    pub fn wrap(serialized_term: B) -> IndexingTerm<B> {
+        debug_assert!(serialized_term.as_ref().len() >= TERM_METADATA_LENGTH);
+        IndexingTerm(serialized_term)
+    }
+
+    /// Returns the field this term belongs to.
+    #[inline]
+    pub fn field(&self) -> Field {
+        let field_id_bytes: [u8; 4] = self.0.as_ref()[..4].try_into().unwrap();
+        Field::from_field_id(u32::from_be_bytes(field_id_bytes))
+    }
+
     /// Returns the serialized representation of Term.
     /// This includes field_id, value type and value.
     ///
@@ -136,6 +152,7 @@ where B: AsRef<[u8]>
 #[cfg(test)]
 mod tests {
 
+    use super::IndexingTerm;
     use crate::schema::*;
 
     #[test]
@@ -143,42 +160,55 @@ mod tests {
         let mut schema_builder = Schema::builder();
         schema_builder.add_text_field("text", STRING);
         let title_field = schema_builder.add_text_field("title", STRING);
-        let term = Term::from_field_text(title_field, "test");
+        let mut term = IndexingTerm::with_capacity(0);
+        term.set_field(title_field);
+        term.set_bytes(b"test");
         assert_eq!(term.field(), title_field);
-        assert_eq!(term.typ(), Type::Str);
-        assert_eq!(term.value().as_str(), Some("test"))
+        assert_eq!(term.serialized_term(), b"\x00\x00\x00\x01test".to_vec())
     }
 
     /// Size (in bytes) of the buffer of a fast value (u64, i64, f64, or date) term.
     /// <field> + <type byte> + <value len>
     ///
     /// - <field> is a big endian encoded u32 field id
-    /// - <type_byte>'s most significant bit expresses whether the term is a json term or not The
-    ///   remaining 7 bits are used to encode the type of the value. If this is a JSON term, the
-    ///   type is the type of the leaf of the json.
     /// - <value> is,  if this is not the json term, a binary representation specific to the type.
     ///   If it is a JSON Term, then it is prepended with the path that leads to this leaf value.
-    const FAST_VALUE_TERM_LEN: usize = 4 + 1 + 8;
+    const FAST_VALUE_TERM_LEN: usize = 4 + 8;
 
     #[test]
     pub fn test_term_u64() {
         let mut schema_builder = Schema::builder();
         let count_field = schema_builder.add_u64_field("count", INDEXED);
-        let term = Term::from_field_u64(count_field, 983u64);
+        let mut term = IndexingTerm::with_capacity(0);
+        term.set_field(count_field);
+        term.set_u64(983u64);
         assert_eq!(term.field(), count_field);
-        assert_eq!(term.typ(), Type::U64);
         assert_eq!(term.serialized_term().len(), FAST_VALUE_TERM_LEN);
-        assert_eq!(term.value().as_u64(), Some(983u64))
     }
 
     #[test]
     pub fn test_term_bool() {
         let mut schema_builder = Schema::builder();
         let bool_field = schema_builder.add_bool_field("bool", INDEXED);
-        let term = Term::from_field_bool(bool_field, true);
+        let term = {
+            let mut term = IndexingTerm::with_capacity(0);
+            term.set_field(bool_field);
+            term.set_bool(true);
+            term
+        };
         assert_eq!(term.field(), bool_field);
-        assert_eq!(term.typ(), Type::Bool);
         assert_eq!(term.serialized_term().len(), FAST_VALUE_TERM_LEN);
-        assert_eq!(term.value().as_bool(), Some(true))
+    }
+
+    #[test]
+    pub fn indexing_term_wrap_extracts_field() {
+        let field = Field::from_field_id(7u32);
+        let mut term = IndexingTerm::with_capacity(0);
+        term.set_field(field);
+        term.append_bytes(b"abc");
+
+        let wrapped = IndexingTerm::wrap(term.serialized_term());
+        assert_eq!(wrapped.field(), field);
+        assert_eq!(wrapped.serialized_term(), term.serialized_term());
     }
 }

src/indexer/merger.rs

@@ -1,5 +1,3 @@
-use std::collections::HashMap;
-use std::io::{BufWriter, Write};
 use std::sync::Arc;
 
 use columnar::{
@@ -8,7 +6,6 @@ use columnar::{
 use common::ReadOnlyBitSet;
 use itertools::Itertools;
 use measure_time::debug_time;
-use tempfile::NamedTempFile;
 
 use crate::directory::WritePtr;
 use crate::docset::{DocSet, TERMINATED};
@@ -20,8 +17,6 @@ use crate::indexer::doc_id_mapping::{MappingType, SegmentDocIdMapping};
 use crate::indexer::SegmentSerializer;
 use crate::postings::{InvertedIndexSerializer, Postings, SegmentPostings};
 use crate::schema::{value_type_to_column_type, Field, FieldType, Schema};
-use crate::spatial::bkd::LeafPageIterator;
-use crate::spatial::triangle::Triangle;
 use crate::store::StoreWriter;
 use crate::termdict::{TermMerger, TermOrdinal};
 use crate::{DocAddress, DocId, InvertedIndexReader};
@@ -175,7 +170,6 @@ impl IndexMerger {
         let mut readers = vec![];
         for (segment, new_alive_bitset_opt) in segments.iter().zip(alive_bitset_opt) {
             if segment.meta().num_docs() > 0 {
-                dbg!("segment");
                 let reader =
                     SegmentReader::open_with_custom_alive_set(segment, new_alive_bitset_opt)?;
                 readers.push(reader);
@@ -526,89 +520,6 @@ impl IndexMerger {
         Ok(())
     }
 
-    fn write_spatial_fields(
-        &self,
-        serializer: &mut SegmentSerializer,
-        doc_id_mapping: &SegmentDocIdMapping,
-    ) -> crate::Result<()> {
-        /// We need to rebuild a BKD-tree based off the list of triangles.
-        ///
-        /// Because the data can be large, we do this by writing the sequence of triangles to
-        /// disk, and mmapping it as mutable slice, and calling the same code as what
-        /// is done for the segment serialization.
-        ///
-        /// The OS is in charge of deciding how to handle its page cache.
-        /// This is the same as what would have happened with swapping,
-        /// except by explicitly mapping the file, the OS is more likely to
-        /// swap, the memory will not be accounted as anonymous memory,
-        /// swap space is reserved etc.
-        use crate::spatial::bkd::Segment;
-
-        let Some(mut spatial_serializer) = serializer.extract_spatial_serializer() else {
-            // The schema does not contain any spatial field.
-            return Ok(());
-        };
-
-        let mut segment_mappings: Vec<Vec<Option<DocId>>> = Vec::new();
-        for reader in &self.readers {
-            let max_doc = reader.max_doc();
-            segment_mappings.push(vec![None; max_doc as usize]);
-        }
-        for (new_doc_id, old_doc_addr) in doc_id_mapping.iter_old_doc_addrs().enumerate() {
-            segment_mappings[old_doc_addr.segment_ord as usize][old_doc_addr.doc_id as usize] =
-                Some(new_doc_id as DocId);
-        }
-        let mut temp_files: HashMap<Field, NamedTempFile> = HashMap::new();
-
-        for (field, field_entry) in self.schema.fields() {
-            if matches!(field_entry.field_type(), FieldType::Spatial(_)) {
-                temp_files.insert(field, NamedTempFile::new()?);
-            }
-        }
-        for (segment_ord, reader) in self.readers.iter().enumerate() {
-            for (field, temp_file) in &mut temp_files {
-                let mut buf_temp_file = BufWriter::new(temp_file);
-                let spatial_readers = reader.spatial_fields();
-                let Some(spatial_reader) = spatial_readers.get_field(*field)? else {
-                    continue;
-                };
-                let segment = Segment::new(spatial_reader.get_bytes());
-                for triangle_result in LeafPageIterator::new(&segment) {
-                    let triangles = triangle_result?;
-                    for triangle in triangles {
-                        if let Some(new_doc_id) =
-                            segment_mappings[segment_ord][triangle.doc_id as usize]
-                        {
-                            // This is really just a temporary file, not meant to be portable, so we
-                            // use native endianness here.
-                            for &word in &triangle.words {
-                                buf_temp_file.write_all(&word.to_ne_bytes())?;
-                            }
-                            buf_temp_file.write_all(&new_doc_id.to_ne_bytes())?;
-                        }
-                    }
-                }
-                buf_temp_file.flush()?;
-                // No need to fsync here. This file is not here for persistency.
-            }
-        }
-        for (field, temp_file) in temp_files {
-            // Memory map the triangle file.
-            use memmap2::MmapOptions;
-            let mmap = unsafe { MmapOptions::new().map_mut(temp_file.as_file())? };
-            // Cast to &[Triangle] slice
-            let triangle_count = mmap.len() / std::mem::size_of::<Triangle>();
-            let triangles = unsafe {
-                std::slice::from_raw_parts_mut(mmap.as_ptr() as *mut Triangle, triangle_count)
-            };
-            // Get spatial writer and rebuild block kd-tree.
-            spatial_serializer.serialize_field(field, triangles)?;
-        }
-        spatial_serializer.close()?;
-
-        Ok(())
-    }
-
     /// Writes the merged segment by pushing information
     /// to the `SegmentSerializer`.
     ///
@@ -633,10 +544,9 @@ impl IndexMerger {
 
         debug!("write-storagefields");
         self.write_storable_fields(serializer.get_store_writer())?;
-        debug!("write-spatialfields");
-        self.write_spatial_fields(&mut serializer, &doc_id_mapping)?;
         debug!("write-fastfields");
         self.write_fast_fields(serializer.get_fast_field_write(), doc_id_mapping)?;
+
         debug!("close-serializer");
         serializer.close()?;
         Ok(self.max_doc)

src/indexer/mod.rs

@@ -4,6 +4,7 @@
 //! `IndexWriter` is the main entry point for that, which created from
 //! [`Index::writer`](crate::Index::writer).
 
+/// Delete queue implementation for broadcasting delete operations to consumers.
 pub(crate) mod delete_queue;
 pub(crate) mod path_to_unordered_id;
 
@@ -32,12 +33,11 @@ mod stamper;
 use crossbeam_channel as channel;
 use smallvec::SmallVec;
 
-pub use self::index_writer::{IndexWriter, IndexWriterOptions};
+pub use self::index_writer::{advance_deletes, IndexWriter, IndexWriterOptions};
 pub use self::log_merge_policy::LogMergePolicy;
 pub use self::merge_operation::MergeOperation;
 pub use self::merge_policy::{MergeCandidate, MergePolicy, NoMergePolicy};
-use self::operation::AddOperation;
-pub use self::operation::UserOperation;
+pub use self::operation::{AddOperation, DeleteOperation, UserOperation};
 pub use self::prepared_commit::PreparedCommit;
 pub use self::segment_entry::SegmentEntry;
 pub(crate) use self::segment_serializer::SegmentSerializer;

src/indexer/operation.rs

@@ -5,14 +5,20 @@ use crate::Opstamp;
 
 /// Timestamped Delete operation.
 pub struct DeleteOperation {
+    /// Operation stamp.
+    /// It is used to check whether the delete operation
+    /// applies to an added document operation.
     pub opstamp: Opstamp,
+    /// Weight is used to define the set of documents to be deleted.
     pub target: Box<dyn Weight>,
 }
 
 /// Timestamped Add operation.
 #[derive(Eq, PartialEq, Debug)]
 pub struct AddOperation<D: Document = TantivyDocument> {
+    /// Operation stamp.
     pub opstamp: Opstamp,
+    /// Document to be added.
     pub document: D,
 }
 

src/indexer/segment_register.rs

@@ -117,7 +117,7 @@ mod tests {
     #[test]
     fn test_segment_register() {
         let inventory = SegmentMetaInventory::default();
-        let delete_queue = DeleteQueue::new();
+        let delete_queue = DeleteQueue::default();
 
         let mut segment_register = SegmentRegister::default();
         let segment_id_a = SegmentId::generate_random();

src/indexer/segment_serializer.rs

@@ -4,7 +4,6 @@ use crate::directory::WritePtr;
 use crate::fieldnorm::FieldNormsSerializer;
 use crate::index::{Segment, SegmentComponent};
 use crate::postings::InvertedIndexSerializer;
-use crate::spatial::serializer::SpatialSerializer;
 use crate::store::StoreWriter;
 
 /// Segment serializer is in charge of laying out on disk
@@ -13,7 +12,6 @@ pub struct SegmentSerializer {
     segment: Segment,
     pub(crate) store_writer: StoreWriter,
     fast_field_write: WritePtr,
-    spatial_serializer: Option<SpatialSerializer>,
     fieldnorms_serializer: Option<FieldNormsSerializer>,
     postings_serializer: InvertedIndexSerializer,
 }
@@ -37,20 +35,11 @@ impl SegmentSerializer {
         let fieldnorms_write = segment.open_write(SegmentComponent::FieldNorms)?;
         let fieldnorms_serializer = FieldNormsSerializer::from_write(fieldnorms_write)?;
 
-        let spatial_serializer: Option<SpatialSerializer> =
-            if segment.schema().contains_spatial_field() {
-                let spatial_write = segment.open_write(SegmentComponent::Spatial)?;
-                Some(SpatialSerializer::from_write(spatial_write)?)
-            } else {
-                None
-            };
-
         let postings_serializer = InvertedIndexSerializer::open(&mut segment)?;
         Ok(SegmentSerializer {
             segment,
             store_writer,
             fast_field_write,
-            spatial_serializer,
             fieldnorms_serializer: Some(fieldnorms_serializer),
             postings_serializer,
         })
@@ -75,11 +64,6 @@ impl SegmentSerializer {
         &mut self.fast_field_write
     }
 
-    /// Accessor to the `SpatialSerializer`
-    pub fn extract_spatial_serializer(&mut self) -> Option<SpatialSerializer> {
-        self.spatial_serializer.take()
-    }
-
     /// Extract the field norm serializer.
     ///
     /// Note the fieldnorms serializer can only be extracted once.
@@ -97,9 +81,6 @@ impl SegmentSerializer {
         if let Some(fieldnorms_serializer) = self.extract_fieldnorms_serializer() {
             fieldnorms_serializer.close()?;
         }
-        if let Some(spatial_serializer) = self.extract_spatial_serializer() {
-            spatial_serializer.close()?;
-        }
         self.fast_field_write.terminate()?;
         self.postings_serializer.close()?;
         self.store_writer.close()?;

src/indexer/segment_writer.rs

@@ -16,7 +16,6 @@ use crate::postings::{
 };
 use crate::schema::document::{Document, Value};
 use crate::schema::{FieldEntry, FieldType, Schema, DATE_TIME_PRECISION_INDEXED};
-use crate::spatial::writer::SpatialWriter;
 use crate::tokenizer::{FacetTokenizer, PreTokenizedStream, TextAnalyzer, Tokenizer};
 use crate::{DocId, Opstamp, TantivyError};
 
@@ -53,7 +52,6 @@ pub struct SegmentWriter {
     pub(crate) segment_serializer: SegmentSerializer,
     pub(crate) fast_field_writers: FastFieldsWriter,
     pub(crate) fieldnorms_writer: FieldNormsWriter,
-    pub(crate) spatial_writer: SpatialWriter,
     pub(crate) json_path_writer: JsonPathWriter,
     pub(crate) json_positions_per_path: IndexingPositionsPerPath,
     pub(crate) doc_opstamps: Vec<Opstamp>,
@@ -106,7 +104,6 @@ impl SegmentWriter {
             ctx: IndexingContext::new(table_size),
             per_field_postings_writers,
             fieldnorms_writer: FieldNormsWriter::for_schema(&schema),
-            spatial_writer: SpatialWriter::default(),
             json_path_writer: JsonPathWriter::default(),
             json_positions_per_path: IndexingPositionsPerPath::default(),
             segment_serializer,
@@ -133,7 +130,6 @@ impl SegmentWriter {
             self.ctx,
             self.fast_field_writers,
             &self.fieldnorms_writer,
-            &mut self.spatial_writer,
             self.segment_serializer,
         )?;
         Ok(self.doc_opstamps)
@@ -146,7 +142,6 @@ impl SegmentWriter {
             + self.fieldnorms_writer.mem_usage()
             + self.fast_field_writers.mem_usage()
             + self.segment_serializer.mem_usage()
-            + self.spatial_writer.mem_usage()
     }
 
     fn index_document<D: Document>(&mut self, doc: &D) -> crate::Result<()> {
@@ -176,7 +171,7 @@ impl SegmentWriter {
             let (term_buffer, ctx) = (&mut self.term_buffer, &mut self.ctx);
             let postings_writer: &mut dyn PostingsWriter =
                 self.per_field_postings_writers.get_for_field_mut(field);
-            term_buffer.clear_with_field_and_type(field_entry.field_type().value_type(), field);
+            term_buffer.clear_with_field(field);
 
             match field_entry.field_type() {
                 FieldType::Facet(_) => {
@@ -343,13 +338,6 @@ impl SegmentWriter {
                         self.fieldnorms_writer.record(doc_id, field, num_vals);
                     }
                 }
-                FieldType::Spatial(_) => {
-                    for value in values {
-                        if let Some(geometry) = value.as_geometry() {
-                            self.spatial_writer.add_geometry(doc_id, field, *geometry);
-                        }
-                    }
-                }
             }
         }
         Ok(())
@@ -404,16 +392,12 @@ fn remap_and_write(
     ctx: IndexingContext,
     fast_field_writers: FastFieldsWriter,
     fieldnorms_writer: &FieldNormsWriter,
-    spatial_writer: &mut SpatialWriter,
     mut serializer: SegmentSerializer,
 ) -> crate::Result<()> {
     debug!("remap-and-write");
     if let Some(fieldnorms_serializer) = serializer.extract_fieldnorms_serializer() {
         fieldnorms_writer.serialize(fieldnorms_serializer)?;
     }
-    if let Some(spatial_serializer) = serializer.extract_spatial_serializer() {
-        spatial_writer.serialize(spatial_serializer)?;
-    }
     let fieldnorm_data = serializer
         .segment()
         .open_read(SegmentComponent::FieldNorms)?;
@@ -437,10 +421,9 @@ fn remap_and_write(
 #[cfg(test)]
 mod tests {
     use std::collections::BTreeMap;
-    use std::path::{Path, PathBuf};
+    use std::path::Path;
 
     use columnar::ColumnType;
-    use tempfile::TempDir;
 
     use crate::collector::{Count, TopDocs};
     use crate::directory::RamDirectory;
@@ -1083,10 +1066,7 @@ mod tests {
         let mut schema_builder = Schema::builder();
         schema_builder.add_text_field("title", text_options);
         let schema = schema_builder.build();
-        let tempdir = TempDir::new().unwrap();
-        let tempdir_path = PathBuf::from(tempdir.path());
-        Index::create_in_dir(&tempdir_path, schema).unwrap();
-        let index = Index::open_in_dir(tempdir_path).unwrap();
+        let index = Index::create_in_ram(schema);
         let schema = index.schema();
         let mut index_writer = index.writer(50_000_000).unwrap();
         let title = schema.get_field("title").unwrap();

src/lib.rs

@@ -17,6 +17,7 @@
 //!
 //! ```rust
 //! # use std::path::Path;
+//! # use std::fs;
 //! # use tempfile::TempDir;
 //! # use tantivy::collector::TopDocs;
 //! # use tantivy::query::QueryParser;
@@ -27,8 +28,11 @@
 //! #     // Let's create a temporary directory for the
 //! #     // sake of this example
 //! #     if let Ok(dir) = TempDir::new() {
-//! #         run_example(dir.path()).unwrap();
-//! #         dir.close().unwrap();
+//! #         let index_path = dir.path().join("index");
+//! #         // In case the directory already exists, we remove it
+//! #         let _ = fs::remove_dir_all(&index_path);
+//! #         fs::create_dir_all(&index_path).unwrap();
+//! #         run_example(&index_path).unwrap();
 //! #     }
 //! # }
 //! #
@@ -191,7 +195,6 @@ pub mod fieldnorm;
 pub mod index;
 pub mod positions;
 pub mod postings;
-pub mod spatial;
 
 /// Module containing the different query implementations.
 pub mod query;
@@ -204,6 +207,7 @@ mod docset;
 mod reader;
 
 #[cfg(test)]
+#[cfg(feature = "mmap")]
 mod compat_tests;
 
 pub use self::reader::{IndexReader, IndexReaderBuilder, ReloadPolicy, Warmer};
@@ -217,9 +221,7 @@ use once_cell::sync::Lazy;
 use serde::{Deserialize, Serialize};
 
 pub use self::docset::{DocSet, COLLECT_BLOCK_BUFFER_LEN, TERMINATED};
-#[doc(hidden)]
-pub use crate::core::json_utils;
-pub use crate::core::{Executor, Searcher, SearcherGeneration};
+pub use crate::core::{json_utils, Executor, Searcher, SearcherGeneration};
 pub use crate::directory::Directory;
 pub use crate::index::{
     Index, IndexBuilder, IndexMeta, IndexSettings, InvertedIndexReader, Order, Segment,
@@ -375,7 +377,7 @@ pub mod tests {
 
     use common::{BinarySerializable, FixedSize};
     use query_grammar::{UserInputAst, UserInputLeaf, UserInputLiteral};
-    use rand::distributions::{Bernoulli, Uniform};
+    use rand::distr::{Bernoulli, Uniform};
     use rand::rngs::StdRng;
     use rand::{Rng, SeedableRng};
     use time::OffsetDateTime;
@@ -426,7 +428,7 @@ pub mod tests {
     pub fn generate_nonunique_unsorted(max_value: u32, n_elems: usize) -> Vec<u32> {
         let seed: [u8; 32] = [1; 32];
         StdRng::from_seed(seed)
-            .sample_iter(&Uniform::new(0u32, max_value))
+            .sample_iter(&Uniform::new(0u32, max_value).unwrap())
             .take(n_elems)
             .collect::<Vec<u32>>()
     }
@@ -1173,12 +1175,11 @@ pub mod tests {
 
     #[test]
     fn test_validate_checksum() -> crate::Result<()> {
-        let index_path = tempfile::tempdir().expect("dir");
         let mut builder = Schema::builder();
         let body = builder.add_text_field("body", TEXT | STORED);
         let schema = builder.build();
-        let index = Index::create_in_dir(&index_path, schema)?;
-        let mut writer: IndexWriter = index.writer(50_000_000)?;
+        let index = Index::create_in_ram(schema);
+        let mut writer: IndexWriter = index.writer_for_tests()?;
         writer.set_merge_policy(Box::new(NoMergePolicy));
         for _ in 0..5000 {
             writer.add_document(doc!(body => "foo"))?;