rebasing composite aggregations

Closes #2849

Co-authored-by: Paul Masurel <paul.masurel@datadoghq.com>

.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.

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"
@@ -47,7 +47,7 @@ rustc-hash = "2.0.0"
 thiserror = "2.0.1"
 htmlescape = "0.3.1"
 fail = { version = "0.5.0", optional = true }
-time = { version = "0.3.35", features = ["serde-well-known"] }
+time = { version = "0.3.47", features = ["serde-well-known"] }
 smallvec = "1.8.0"
 rayon = "1.5.2"
 lru = "0.16.3"
@@ -64,8 +64,8 @@ query-grammar = { version = "0.25.0", path = "./query-grammar", package = "tanti
 tantivy-bitpacker = { version = "0.9", path = "./bitpacker" }
 common = { version = "0.10", path = "./common/", package = "tantivy-common" }
 tokenizer-api = { version = "0.6", path = "./tokenizer-api", package = "tantivy-tokenizer-api" }
-sketches-ddsketch = { version = "0.3.0", features = ["use_serde"] }
-hyperloglogplus = { version = "0.4.1", features = ["const-loop"] }
+sketches-ddsketch = { git = "https://github.com/quickwit-oss/rust-sketches-ddsketch.git", rev = "555caf1", features = ["use_serde"] }
+datasketches = "0.2.0"
 futures-util = { version = "0.3.28", optional = true }
 futures-channel = { version = "0.3.28", optional = true }
 fnv = "1.0.7"
@@ -86,7 +86,7 @@ futures = "0.3.21"
 paste = "1.0.11"
 more-asserts = "0.3.1"
 rand_distr = "0.5"
-time = { version = "0.3.10", features = ["serde-well-known", "macros"] }
+time = { version = "0.3.47", features = ["serde-well-known", "macros"] }
 postcard = { version = "1.0.4", features = [
     "use-std",
 ], default-features = false }
@@ -193,3 +193,11 @@ harness = false
 [[bench]]
 name = "str_search_and_get"
 harness = false
+
+[[bench]]
+name = "merge_segments"
+harness = false
+
+[[bench]]
+name = "regex_all_terms"
+harness = false

benches/agg_bench.rs

@@ -10,7 +10,7 @@ use tantivy::aggregation::agg_req::Aggregations;
 use tantivy::aggregation::AggregationCollector;
 use tantivy::query::{AllQuery, TermQuery};
 use tantivy::schema::{IndexRecordOption, Schema, TextFieldIndexing, FAST, STRING};
-use tantivy::{doc, Index, Term};
+use tantivy::{doc, DateTime, Index, Term};
 
 #[global_allocator]
 pub static GLOBAL: &PeakMemAlloc<std::alloc::System> = &INSTRUMENTED_SYSTEM;
@@ -70,6 +70,12 @@ fn bench_agg(mut group: InputGroup<Index>) {
 
     register!(group, terms_many_json_mixed_type_with_avg_sub_agg);
 
+    register!(group, composite_term_many_page_1000);
+    register!(group, composite_term_many_page_1000_with_avg_sub_agg);
+    register!(group, composite_term_few);
+    register!(group, composite_histogram);
+    register!(group, composite_histogram_calendar);
+
     register!(group, cardinality_agg);
     register!(group, terms_status_with_cardinality_agg);
 
@@ -314,6 +320,75 @@ fn terms_many_json_mixed_type_with_avg_sub_agg(index: &Index) {
     execute_agg(index, agg_req);
 }
 
+fn composite_term_few(index: &Index) {
+    let agg_req = json!({
+        "my_ctf": {
+            "composite": {
+                "sources": [
+                    { "text_few_terms": { "terms": { "field": "text_few_terms" } } }
+                ],
+                "size": 1000
+            }
+        },
+    });
+    execute_agg(index, agg_req);
+}
+fn composite_term_many_page_1000(index: &Index) {
+    let agg_req = json!({
+        "my_ctmp1000": {
+            "composite": {
+                "sources": [
+                    { "text_many_terms": { "terms": { "field": "text_many_terms" } } }
+                ],
+                "size": 1000
+            }
+        },
+    });
+    execute_agg(index, agg_req);
+}
+fn composite_term_many_page_1000_with_avg_sub_agg(index: &Index) {
+    let agg_req = json!({
+        "my_ctmp1000wasa": {
+            "composite": {
+                "sources": [
+                    { "text_many_terms": { "terms": { "field": "text_many_terms" } } }
+                ],
+                "size": 1000,
+            },
+            "aggs": {
+                "average_f64": { "avg": { "field": "score_f64" } }
+            }
+        },
+    });
+    execute_agg(index, agg_req);
+}
+fn composite_histogram(index: &Index) {
+    let agg_req = json!({
+        "my_ch": {
+            "composite": {
+                "sources": [
+                    { "f64_histogram": { "histogram": { "field": "score_f64", "interval": 1 } } }
+                ],
+                "size": 1000
+            }
+        },
+    });
+    execute_agg(index, agg_req);
+}
+fn composite_histogram_calendar(index: &Index) {
+    let agg_req = json!({
+        "my_chc": {
+            "composite": {
+                "sources": [
+                    { "time_histogram": { "date_histogram": { "field": "timestamp", "calendar_interval": "month" } } }
+                ],
+                "size": 1000
+            }
+        },
+    });
+    execute_agg(index, agg_req);
+}
+
 fn execute_agg(index: &Index, agg_req: serde_json::Value) {
     let agg_req: Aggregations = serde_json::from_value(agg_req).unwrap();
     let collector = get_collector(agg_req);
@@ -496,6 +571,7 @@ fn get_test_index_bench(cardinality: Cardinality) -> tantivy::Result<Index> {
     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 =
@@ -504,6 +580,7 @@ fn get_test_index_bench(cardinality: Cardinality) -> tantivy::Result<Index> {
     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 date_field = schema_builder.add_date_field("timestamp", FAST);
     // use tmp dir
     let index = if reuse_index {
         Index::create_in_dir("agg_bench", schema_builder.build())?
@@ -523,6 +600,7 @@ fn get_test_index_bench(cardinality: Cardinality) -> tantivy::Result<Index> {
     let log_level_distribution =
         WeightedIndex::new(status_field_data.iter().map(|item| item.1)).unwrap();
 
+    let few_terms_data = ["INFO", "ERROR", "WARN", "DEBUG"];
     let lg_norm = rand_distr::LogNormal::new(2.996f64, 0.979f64).unwrap();
 
     let many_terms_data = (0..150_000)
@@ -558,6 +636,8 @@ fn get_test_index_bench(cardinality: Cardinality) -> tantivy::Result<Index> {
                 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(),
@@ -588,11 +668,13 @@ fn get_test_index_bench(cardinality: Cardinality) -> tantivy::Result<Index> {
                 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,
+                date_field => DateTime::from_timestamp_millis((val * 1_000_000.) as i64),
             ))?;
             if cardinality == Cardinality::OptionalSparse {
                 for _ in 0..20 {

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/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)
+}

columnar/src/lib.rs

@@ -59,7 +59,7 @@ pub struct RowAddr {
     pub row_id: RowId,
 }
 
-pub use sstable::Dictionary;
+pub use sstable::{Dictionary, TermOrdHit};
 pub type Streamer<'a> = sstable::Streamer<'a, VoidSSTable>;
 
 pub use common::DateTime;

common/Cargo.toml

@@ -15,11 +15,10 @@ repository = "https://github.com/quickwit-oss/tantivy"
 byteorder = "1.4.3"
 ownedbytes = { version= "0.9", path="../ownedbytes" }
 async-trait = "0.1"
-time = { version = "0.3.10", features = ["serde-well-known"] }
+time = { version = "0.3.47", features = ["serde-well-known"] }
 serde = { version = "1.0.136", features = ["derive"] }
 
 [dev-dependencies]
 binggan = "0.14.0"
 proptest = "1.0.0"
 rand = "0.9"
-

common/src/writer.rs

@@ -62,7 +62,9 @@ impl<W: TerminatingWrite> TerminatingWrite for CountingWriter<W> {
 pub struct AntiCallToken(());
 
 /// Trait used to indicate when no more write need to be done on a writer
-pub trait TerminatingWrite: Write + Send + Sync {
+///
+/// Thread-safety is enforced at the call sites that require it.
+pub trait TerminatingWrite: Write {
     /// Indicate that the writer will no longer be used. Internally call terminate_ref.
     fn terminate(mut self) -> io::Result<()>
     where Self: Sized {

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.

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,
@@ -704,7 +704,11 @@ fn regex(inp: &str) -> IResult<&str, UserInputLeaf> {
                 many1(alt((preceded(char('\\'), char('/')), none_of("/")))),
                 char('/'),
             ),
-            peek(alt((multispace1, eof))),
+            peek(alt((
+                value((), multispace1),
+                value((), char(')')),
+                value((), eof),
+            ))),
         ),
         |elements| UserInputLeaf::Regex {
             field: None,
@@ -721,8 +725,12 @@ fn regex_infallible(inp: &str) -> JResult<&str, UserInputLeaf> {
             opt_i_err(char('/'), "missing delimiter /"),
         ),
         opt_i_err(
-            peek(alt((multispace1, eof))),
-            "expected whitespace or end of input",
+            peek(alt((
+                value((), multispace1),
+                value((), char(')')),
+                value((), eof),
+            ))),
+            "expected whitespace, closing parenthesis, or end of input",
         ),
     )(inp)
     {
@@ -1323,6 +1331,14 @@ 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]
@@ -1699,6 +1715,10 @@ mod test {
         test_parse_query_to_ast_helper("foo:(A OR B)", "(?\"foo\":A ?\"foo\":B)");
         test_parse_query_to_ast_helper("foo:(A* OR B*)", "(?\"foo\":A* ?\"foo\":B*)");
         test_parse_query_to_ast_helper("foo:(*A OR *B)", "(?\"foo\":*A ?\"foo\":*B)");
+
+        // Regexes between parentheses
+        test_parse_query_to_ast_helper("foo:(/A.*/)", "\"foo\":/A.*/");
+        test_parse_query_to_ast_helper("foo:(/A.*/ OR /B.*/)", "(?\"foo\":/A.*/ ?\"foo\":/B.*/)");
     }
 
     #[test]

query-grammar/src/user_input_ast.rs

@@ -66,6 +66,7 @@ impl UserInputLeaf {
             }
             UserInputLeaf::Range { field, .. } if field.is_none() => *field = Some(default_field),
             UserInputLeaf::Set { field, .. } if field.is_none() => *field = Some(default_field),
+            UserInputLeaf::Regex { field, .. } if field.is_none() => *field = Some(default_field),
             _ => (), // field was already set, do nothing
         }
     }

src/aggregation/agg_data.rs

@@ -10,9 +10,10 @@ use crate::aggregation::accessor_helpers::{
 };
 use crate::aggregation::agg_req::{Aggregation, AggregationVariants, Aggregations};
 use crate::aggregation::bucket::{
-    build_segment_filter_collector, build_segment_range_collector, FilterAggReqData,
-    HistogramAggReqData, HistogramBounds, IncludeExcludeParam, MissingTermAggReqData,
-    RangeAggReqData, SegmentHistogramCollector, TermMissingAgg, TermsAggReqData, TermsAggregation,
+    build_segment_filter_collector, build_segment_range_collector, CompositeAggReqData,
+    CompositeAggregation, CompositeSourceAccessors, FilterAggReqData, HistogramAggReqData,
+    HistogramBounds, IncludeExcludeParam, MissingTermAggReqData, RangeAggReqData,
+    SegmentHistogramCollector, TermMissingAgg, TermsAggReqData, TermsAggregation,
     TermsAggregationInternal,
 };
 use crate::aggregation::metric::{
@@ -73,6 +74,12 @@ impl AggregationsSegmentCtx {
         self.per_request.filter_req_data.push(Some(Box::new(data)));
         self.per_request.filter_req_data.len() - 1
     }
+    pub(crate) fn push_composite_req_data(&mut self, data: CompositeAggReqData) -> usize {
+        self.per_request
+            .composite_req_data
+            .push(Some(Box::new(data)));
+        self.per_request.composite_req_data.len() - 1
+    }
 
     #[inline]
     pub(crate) fn get_term_req_data(&self, idx: usize) -> &TermsAggReqData {
@@ -108,6 +115,12 @@ impl AggregationsSegmentCtx {
             .as_deref()
             .expect("range_req_data slot is empty (taken)")
     }
+    #[inline]
+    pub(crate) fn get_composite_req_data(&self, idx: usize) -> &CompositeAggReqData {
+        self.per_request.composite_req_data[idx]
+            .as_deref()
+            .expect("composite_req_data slot is empty (taken)")
+    }
 
     // ---------- mutable getters ----------
 
@@ -181,6 +194,25 @@ impl AggregationsSegmentCtx {
         debug_assert!(self.per_request.filter_req_data[idx].is_none());
         self.per_request.filter_req_data[idx] = Some(value);
     }
+
+    /// Move out the Composite request at `idx`.
+    #[inline]
+    pub(crate) fn take_composite_req_data(&mut self, idx: usize) -> Box<CompositeAggReqData> {
+        self.per_request.composite_req_data[idx]
+            .take()
+            .expect("composite_req_data slot is empty (taken)")
+    }
+
+    /// Put back a Composite request into an empty slot at `idx`.
+    #[inline]
+    pub(crate) fn put_back_composite_req_data(
+        &mut self,
+        idx: usize,
+        value: Box<CompositeAggReqData>,
+    ) {
+        debug_assert!(self.per_request.composite_req_data[idx].is_none());
+        self.per_request.composite_req_data[idx] = Some(value);
+    }
 }
 
 /// Each type of aggregation has its own request data struct. This struct holds
@@ -208,6 +240,8 @@ pub struct PerRequestAggSegCtx {
     pub top_hits_req_data: Vec<TopHitsAggReqData>,
     /// MissingTermAggReqData contains the request data for a missing term aggregation.
     pub missing_term_req_data: Vec<MissingTermAggReqData>,
+    /// CompositeAggReqData contains the request data for a composite aggregation.
+    pub composite_req_data: Vec<Option<Box<CompositeAggReqData>>>,
 
     /// Request tree used to build collectors.
     pub agg_tree: Vec<AggRefNode>,
@@ -255,6 +289,11 @@ impl PerRequestAggSegCtx {
                 .iter()
                 .map(|t| t.get_memory_consumption())
                 .sum::<usize>()
+            + self
+                .composite_req_data
+                .iter()
+                .map(|b| b.as_ref().map(|d| d.get_memory_consumption()).unwrap_or(0))
+                .sum::<usize>()
             + self.agg_tree.len() * std::mem::size_of::<AggRefNode>()
     }
 
@@ -291,6 +330,11 @@ impl PerRequestAggSegCtx {
                 .expect("filter_req_data slot is empty (taken)")
                 .name
                 .as_str(),
+            AggKind::Composite => self.composite_req_data[idx]
+                .as_deref()
+                .expect("composite_req_data slot is empty (taken)")
+                .name
+                .as_str(),
         }
     }
 
@@ -417,6 +461,11 @@ pub(crate) fn build_segment_agg_collector(
         )?)),
         AggKind::Range => Ok(build_segment_range_collector(req, node)?),
         AggKind::Filter => build_segment_filter_collector(req, node),
+        AggKind::Composite => Ok(Box::new(
+            crate::aggregation::bucket::SegmentCompositeCollector::from_req_and_validate(
+                req, node,
+            )?,
+        )),
     }
 }
 
@@ -447,6 +496,7 @@ pub enum AggKind {
     DateHistogram,
     Range,
     Filter,
+    Composite,
 }
 
 impl AggKind {
@@ -462,6 +512,7 @@ impl AggKind {
             AggKind::DateHistogram => "DateHistogram",
             AggKind::Range => "Range",
             AggKind::Filter => "Filter",
+            AggKind::Composite => "Composite",
         }
     }
 }
@@ -709,6 +760,14 @@ fn build_nodes(
                 children,
             }])
         }
+        AggregationVariants::Composite(composite_req) => Ok(vec![build_composite_node(
+            agg_name,
+            reader,
+            segment_ordinal,
+            data,
+            &req.sub_aggregation,
+            composite_req,
+        )?]),
         AggregationVariants::Filter(filter_req) => {
             // Build the query and evaluator upfront
             let schema = reader.schema();
@@ -743,6 +802,35 @@ fn build_nodes(
     }
 }
 
+fn build_composite_node(
+    agg_name: &str,
+    reader: &SegmentReader,
+    _segment_ordinal: SegmentOrdinal,
+    data: &mut AggregationsSegmentCtx,
+    sub_aggs: &Aggregations,
+    req: &CompositeAggregation,
+) -> crate::Result<AggRefNode> {
+    let mut composite_accessors = Vec::with_capacity(req.sources.len());
+    for source in &req.sources {
+        let source_after_key_opt = req.after.get(source.name()).map(|k| &k.0);
+        let source_accessor =
+            CompositeSourceAccessors::build_for_source(reader, source, source_after_key_opt)?;
+        composite_accessors.push(source_accessor);
+    }
+    let agg = CompositeAggReqData {
+        name: agg_name.to_string(),
+        req: req.clone(),
+        composite_accessors,
+    };
+    let idx = data.push_composite_req_data(agg);
+    let children = build_children(sub_aggs, reader, _segment_ordinal, data)?;
+    Ok(AggRefNode {
+        kind: AggKind::Composite,
+        idx_in_req_data: idx,
+        children,
+    })
+}
+
 fn build_children(
     aggs: &Aggregations,
     reader: &SegmentReader,

src/aggregation/agg_req.rs

@@ -32,8 +32,8 @@ use rustc_hash::FxHashMap;
 use serde::{Deserialize, Serialize};
 
 use super::bucket::{
-    DateHistogramAggregationReq, FilterAggregation, HistogramAggregation, RangeAggregation,
-    TermsAggregation,
+    CompositeAggregation, DateHistogramAggregationReq, FilterAggregation, HistogramAggregation,
+    RangeAggregation, TermsAggregation,
 };
 use super::metric::{
     AverageAggregation, CardinalityAggregationReq, CountAggregation, ExtendedStatsAggregation,
@@ -134,6 +134,9 @@ pub enum AggregationVariants {
     /// Filter documents into a single bucket.
     #[serde(rename = "filter")]
     Filter(FilterAggregation),
+    /// Multi-dimensional, paginable bucket aggregation.
+    #[serde(rename = "composite")]
+    Composite(CompositeAggregation),
 
     // Metric aggregation types
     /// Computes the average of the extracted values.
@@ -180,6 +183,11 @@ impl AggregationVariants {
             AggregationVariants::Histogram(histogram) => vec![histogram.field.as_str()],
             AggregationVariants::DateHistogram(histogram) => vec![histogram.field.as_str()],
             AggregationVariants::Filter(filter) => filter.get_fast_field_names(),
+            AggregationVariants::Composite(composite) => composite
+                .sources
+                .iter()
+                .map(|source| source.field())
+                .collect(),
             AggregationVariants::Average(avg) => vec![avg.field_name()],
             AggregationVariants::Count(count) => vec![count.field_name()],
             AggregationVariants::Max(max) => vec![max.field_name()],
@@ -214,6 +222,12 @@ impl AggregationVariants {
             _ => None,
         }
     }
+    pub(crate) fn as_composite(&self) -> Option<&CompositeAggregation> {
+        match &self {
+            AggregationVariants::Composite(composite) => Some(composite),
+            _ => None,
+        }
+    }
     pub(crate) fn as_percentile(&self) -> Option<&PercentilesAggregationReq> {
         match &self {
             AggregationVariants::Percentiles(percentile_req) => Some(percentile_req),

src/aggregation/agg_result.rs

@@ -9,10 +9,12 @@ use rustc_hash::FxHashMap;
 use serde::{Deserialize, Serialize};
 
 use super::bucket::GetDocCount;
+use super::intermediate_agg_result::CompositeIntermediateKey;
 use super::metric::{
     ExtendedStats, PercentilesMetricResult, SingleMetricResult, Stats, TopHitsMetricResult,
 };
 use super::{AggregationError, Key};
+use crate::aggregation::bucket::AfterKey;
 use crate::TantivyError;
 
 #[derive(Clone, Default, Debug, PartialEq, Serialize, Deserialize)]
@@ -158,6 +160,14 @@ pub enum BucketResult {
     },
     /// This is the filter result - a single bucket with sub-aggregations
     Filter(FilterBucketResult),
+    /// This is the composite result
+    Composite {
+        /// The buckets
+        buckets: Vec<CompositeBucketEntry>,
+        /// The key to start after when paginating
+        #[serde(skip_serializing_if = "FxHashMap::is_empty")]
+        after_key: FxHashMap<String, AfterKey>,
+    },
 }
 
 impl BucketResult {
@@ -179,6 +189,9 @@ impl BucketResult {
                 // Only count sub-aggregation buckets
                 filter_result.sub_aggregations.get_bucket_count()
             }
+            BucketResult::Composite { buckets, .. } => {
+                buckets.iter().map(|bucket| bucket.get_bucket_count()).sum()
+            }
         }
     }
 }
@@ -337,3 +350,87 @@ pub struct FilterBucketResult {
     #[serde(flatten)]
     pub sub_aggregations: AggregationResults,
 }
+
+/// Note the type information loss compared to `CompositeIntermediateKey`.
+/// Pagination is performed using `AfterKey`, which encodes type information.
+#[derive(Clone, Debug, Serialize, Deserialize)]
+#[serde(untagged)]
+pub enum CompositeKey {
+    /// Boolean key
+    Bool(bool),
+    /// String key
+    Str(String),
+    /// `i64` key
+    I64(i64),
+    /// `u64` key
+    U64(u64),
+    /// `f64` key
+    F64(f64),
+    /// Null key
+    Null,
+}
+impl Eq for CompositeKey {}
+impl std::hash::Hash for CompositeKey {
+    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
+        core::mem::discriminant(self).hash(state);
+        match self {
+            Self::Bool(val) => val.hash(state),
+            Self::Str(text) => text.hash(state),
+            Self::F64(val) => val.to_bits().hash(state),
+            Self::U64(val) => val.hash(state),
+            Self::I64(val) => val.hash(state),
+            Self::Null => {}
+        }
+    }
+}
+impl PartialEq for CompositeKey {
+    fn eq(&self, other: &Self) -> bool {
+        match (self, other) {
+            (Self::Bool(l), Self::Bool(r)) => l == r,
+            (Self::Str(l), Self::Str(r)) => l == r,
+            (Self::F64(l), Self::F64(r)) => l.to_bits() == r.to_bits(),
+            (Self::I64(l), Self::I64(r)) => l == r,
+            (Self::U64(l), Self::U64(r)) => l == r,
+            (Self::Null, Self::Null) => true,
+            _ => false,
+        }
+    }
+}
+impl From<CompositeIntermediateKey> for CompositeKey {
+    fn from(value: CompositeIntermediateKey) -> Self {
+        match value {
+            CompositeIntermediateKey::Str(s) => Self::Str(s),
+            CompositeIntermediateKey::IpAddr(s) => {
+                if let Some(ip) = s.to_ipv4_mapped() {
+                    Self::Str(ip.to_string())
+                } else {
+                    Self::Str(s.to_string())
+                }
+            }
+            CompositeIntermediateKey::F64(f) => Self::F64(f),
+            CompositeIntermediateKey::Bool(f) => Self::Bool(f),
+            CompositeIntermediateKey::U64(f) => Self::U64(f),
+            CompositeIntermediateKey::I64(f) => Self::I64(f),
+            CompositeIntermediateKey::DateTime(f) => Self::I64(f / 1_000_000), // ns to ms
+            CompositeIntermediateKey::Null => Self::Null,
+        }
+    }
+}
+
+/// Composite bucket entry with a multi-dimensional key.
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+pub struct CompositeBucketEntry {
+    /// The identifier of the bucket.
+    pub key: FxHashMap<String, CompositeKey>,
+    /// Number of documents in the bucket.
+    pub doc_count: u64,
+    #[serde(flatten)]
+    /// Sub-aggregations in this bucket.
+    pub sub_aggregation: AggregationResults,
+}
+
+impl CompositeBucketEntry {
+    pub(crate) fn get_bucket_count(&self) -> u64 {
+        1 + self.sub_aggregation.get_bucket_count()
+    }
+}

src/aggregation/bucket/composite/accessors.rs

@@ -0,0 +1,548 @@
+use std::net::Ipv6Addr;
+
+use columnar::column_values::CompactSpaceU64Accessor;
+use columnar::{Column, ColumnType, MonotonicallyMappableToU64, StrColumn, TermOrdHit};
+
+use crate::aggregation::accessor_helpers::get_numeric_or_date_column_types;
+use crate::aggregation::bucket::composite::numeric_types::num_proj;
+use crate::aggregation::bucket::composite::numeric_types::num_proj::ProjectedNumber;
+use crate::aggregation::bucket::composite::ToTypePaginationOrder;
+use crate::aggregation::bucket::{
+    parse_into_milliseconds, CalendarInterval, CompositeAggregation, CompositeAggregationSource,
+    MissingOrder, Order,
+};
+use crate::aggregation::intermediate_agg_result::CompositeIntermediateKey;
+use crate::{SegmentReader, TantivyError};
+
+/// Contains all information required by the SegmentCompositeCollector to perform the
+/// composite aggregation on a segment.
+pub struct CompositeAggReqData {
+    /// The name of the aggregation.
+    pub name: String,
+    /// The normalized term aggregation request.
+    pub req: CompositeAggregation,
+    /// Accessors for each source, each source can have multiple accessors (columns).
+    pub composite_accessors: Vec<CompositeSourceAccessors>,
+}
+
+impl CompositeAggReqData {
+    /// Estimate the memory consumption of this struct in bytes.
+    pub fn get_memory_consumption(&self) -> usize {
+        std::mem::size_of::<Self>()
+            + self.composite_accessors.len() * std::mem::size_of::<CompositeSourceAccessors>()
+    }
+}
+
+/// Accessors for a single column in a composite source.
+pub struct CompositeAccessor {
+    /// The fast field column
+    pub column: Column<u64>,
+    /// The column type
+    pub column_type: ColumnType,
+    /// Term dictionary if the column type is Str
+    ///
+    /// Only used by term sources
+    pub str_dict_column: Option<StrColumn>,
+    /// Parsed date interval for date histogram sources
+    pub date_histogram_interval: PrecomputedDateInterval,
+}
+
+/// Accessors to all the columns that belong to the field of a composite source.
+pub struct CompositeSourceAccessors {
+    /// The accessors for this source
+    pub accessors: Vec<CompositeAccessor>,
+    /// The key after which to start collecting results. Applies to the first
+    /// column of the source.
+    pub after_key: PrecomputedAfterKey,
+
+    /// The column index the after_key applies to. The after_key only applies to
+    /// one column. Columns before should be skipped. Columns after should be
+    /// kept without comparison to the after_key.
+    pub after_key_accessor_idx: usize,
+
+    /// Whether to skip missing values because of the after_key. Skipping only
+    /// applies if the value for previous columns were exactly equal to the
+    /// corresponding after keys (is_on_after_key).
+    pub skip_missing: bool,
+
+    /// The after key was set to null to indicate that the last collected key
+    /// was a missing value.
+    pub is_after_key_explicit_missing: bool,
+}
+
+impl CompositeSourceAccessors {
+    /// Creates a new set of accessors for the composite source.
+    ///
+    /// Precomputes some values to make collection faster.
+    pub fn build_for_source(
+        reader: &SegmentReader,
+        source: &CompositeAggregationSource,
+        // First option is None when no after key was set in the query, the
+        // second option is None when the after key was set but its value for
+        // this source was set to `null`
+        source_after_key_opt: Option<&CompositeIntermediateKey>,
+    ) -> crate::Result<Self> {
+        let is_after_key_explicit_missing = source_after_key_opt
+            .map(|after_key| matches!(after_key, CompositeIntermediateKey::Null))
+            .unwrap_or(false);
+        let mut skip_missing = false;
+        if let Some(CompositeIntermediateKey::Null) = source_after_key_opt {
+            if !source.missing_bucket() {
+                return Err(TantivyError::InvalidArgument(
+                    "the 'after' key for a source cannot be null when 'missing_bucket' is false"
+                        .to_string(),
+                ));
+            }
+        } else if source_after_key_opt.is_some() {
+            // if missing buckets come first and we have a non null after key, we skip missing
+            if MissingOrder::First == source.missing_order() {
+                skip_missing = true;
+            }
+            if MissingOrder::Default == source.missing_order() && Order::Asc == source.order() {
+                skip_missing = true;
+            }
+        };
+
+        match source {
+            CompositeAggregationSource::Terms(source) => {
+                let allowed_column_types = [
+                    ColumnType::I64,
+                    ColumnType::U64,
+                    ColumnType::F64,
+                    ColumnType::Str,
+                    ColumnType::DateTime,
+                    ColumnType::Bool,
+                    ColumnType::IpAddr,
+                    // ColumnType::Bytes Unsupported
+                ];
+                let mut columns_and_types = reader
+                    .fast_fields()
+                    .u64_lenient_for_type_all(Some(&allowed_column_types), &source.field)?;
+
+                // Sort columns by their pagination order and determine which to skip
+                columns_and_types.sort_by_key(|(_, col_type): &(Column, ColumnType)| {
+                    col_type.column_pagination_order()
+                });
+                if source.order == Order::Desc {
+                    columns_and_types.reverse();
+                }
+                let after_key_accessor_idx = find_first_column_to_collect(
+                    &columns_and_types,
+                    source_after_key_opt,
+                    source.missing_order,
+                    source.order,
+                )?;
+
+                let source_collectors: Vec<CompositeAccessor> = columns_and_types
+                    .into_iter()
+                    .map(|(column, column_type)| {
+                        Ok(CompositeAccessor {
+                            column,
+                            column_type,
+                            str_dict_column: reader.fast_fields().str(&source.field)?,
+                            date_histogram_interval: PrecomputedDateInterval::NotApplicable,
+                        })
+                    })
+                    .collect::<crate::Result<_>>()?;
+
+                let after_key = if let Some(first_col) =
+                    source_collectors.get(after_key_accessor_idx)
+                {
+                    match source_after_key_opt {
+                        Some(after_key) => PrecomputedAfterKey::precompute(
+                            &first_col,
+                            after_key,
+                            &source.field,
+                            source.missing_order,
+                            source.order,
+                        )?,
+                        None => {
+                            precompute_missing_after_key(false, source.missing_order, source.order)
+                        }
+                    }
+                } else {
+                    // if no columns, we don't care about the after_key
+                    PrecomputedAfterKey::Next(0)
+                };
+
+                Ok(CompositeSourceAccessors {
+                    accessors: source_collectors,
+                    is_after_key_explicit_missing,
+                    skip_missing,
+                    after_key,
+                    after_key_accessor_idx,
+                })
+            }
+            CompositeAggregationSource::Histogram(source) => {
+                let column_and_types: Vec<(Column, ColumnType)> =
+                    reader.fast_fields().u64_lenient_for_type_all(
+                        Some(get_numeric_or_date_column_types()),
+                        &source.field,
+                    )?;
+                let source_collectors: Vec<CompositeAccessor> = column_and_types
+                    .into_iter()
+                    .map(|(column, column_type)| {
+                        Ok(CompositeAccessor {
+                            column,
+                            column_type,
+                            str_dict_column: None,
+                            date_histogram_interval: PrecomputedDateInterval::NotApplicable,
+                        })
+                    })
+                    .collect::<crate::Result<_>>()?;
+                let after_key = match source_after_key_opt {
+                    Some(CompositeIntermediateKey::F64(key)) => {
+                        let normalized_key = *key / source.interval;
+                        num_proj::f64_to_i64(normalized_key).into()
+                    }
+                    Some(CompositeIntermediateKey::Null) => {
+                        precompute_missing_after_key(true, source.missing_order, source.order)
+                    }
+                    None => precompute_missing_after_key(true, source.missing_order, source.order),
+                    _ => {
+                        return Err(crate::TantivyError::InvalidArgument(
+                            "After key type invalid for interval composite source".to_string(),
+                        ));
+                    }
+                };
+                Ok(CompositeSourceAccessors {
+                    accessors: source_collectors,
+                    is_after_key_explicit_missing,
+                    skip_missing,
+                    after_key,
+                    after_key_accessor_idx: 0,
+                })
+            }
+            CompositeAggregationSource::DateHistogram(source) => {
+                let column_and_types = reader
+                    .fast_fields()
+                    .u64_lenient_for_type_all(Some(&[ColumnType::DateTime]), &source.field)?;
+                let date_histogram_interval =
+                    PrecomputedDateInterval::from_date_histogram_source_intervals(
+                        &source.fixed_interval,
+                        source.calendar_interval,
+                    )?;
+                let source_collectors: Vec<CompositeAccessor> = column_and_types
+                    .into_iter()
+                    .map(|(column, column_type)| {
+                        Ok(CompositeAccessor {
+                            column,
+                            column_type,
+                            str_dict_column: None,
+                            date_histogram_interval,
+                        })
+                    })
+                    .collect::<crate::Result<_>>()?;
+                let after_key = match source_after_key_opt {
+                    Some(CompositeIntermediateKey::DateTime(key)) => {
+                        PrecomputedAfterKey::Exact(key.to_u64())
+                    }
+                    Some(CompositeIntermediateKey::Null) => {
+                        precompute_missing_after_key(true, source.missing_order, source.order)
+                    }
+                    None => precompute_missing_after_key(true, source.missing_order, source.order),
+                    _ => {
+                        return Err(crate::TantivyError::InvalidArgument(
+                            "After key type invalid for interval composite source".to_string(),
+                        ));
+                    }
+                };
+                Ok(CompositeSourceAccessors {
+                    accessors: source_collectors,
+                    is_after_key_explicit_missing,
+                    skip_missing,
+                    after_key,
+                    after_key_accessor_idx: 0,
+                })
+            }
+        }
+    }
+}
+
+/// Finds the index of the first column we should start collecting from to
+/// resume the pagination from the after_key.
+fn find_first_column_to_collect<T>(
+    sorted_columns: &[(T, ColumnType)],
+    after_key_opt: Option<&CompositeIntermediateKey>,
+    missing_order: MissingOrder,
+    order: Order,
+) -> crate::Result<usize> {
+    let after_key = match after_key_opt {
+        None => return Ok(0), // No pagination, start from beginning
+        Some(key) => key,
+    };
+    // Handle null after_key (we were on a missing value last time)
+    if matches!(after_key, CompositeIntermediateKey::Null) {
+        return match (missing_order, order) {
+            // Missing values come first, so all columns remain
+            (MissingOrder::First, _) | (MissingOrder::Default, Order::Asc) => Ok(0),
+            // Missing values come last, so all columns are done
+            (MissingOrder::Last, _) | (MissingOrder::Default, Order::Desc) => {
+                Ok(sorted_columns.len())
+            }
+        };
+    }
+    // Find the first column whose type order matches or follows the after_key's
+    // type in the pagination sequence
+    let after_key_column_order = after_key.column_pagination_order();
+    for (idx, (_, col_type)) in sorted_columns.iter().enumerate() {
+        let col_order = col_type.column_pagination_order();
+        let is_first_to_collect = match order {
+            Order::Asc => col_order >= after_key_column_order,
+            Order::Desc => col_order <= after_key_column_order,
+        };
+        if is_first_to_collect {
+            return Ok(idx);
+        }
+    }
+    // All columns are before the after_key, nothing left to collect
+    Ok(sorted_columns.len())
+}
+
+fn precompute_missing_after_key(
+    is_after_key_explicit_missing: bool,
+    missing_order: MissingOrder,
+    order: Order,
+) -> PrecomputedAfterKey {
+    let after_last = PrecomputedAfterKey::AfterLast;
+    let before_first = PrecomputedAfterKey::Next(0);
+    match (is_after_key_explicit_missing, missing_order, order) {
+        (true, MissingOrder::First, Order::Asc) => before_first,
+        (true, MissingOrder::First, Order::Desc) => after_last,
+        (true, MissingOrder::Last, Order::Asc) => after_last,
+        (true, MissingOrder::Last, Order::Desc) => before_first,
+        (true, MissingOrder::Default, Order::Asc) => before_first,
+        (true, MissingOrder::Default, Order::Desc) => after_last,
+        (false, _, Order::Asc) => before_first,
+        (false, _, Order::Desc) => after_last,
+    }
+}
+
+/// A parsed representation of the date interval for date histogram sources
+#[derive(Clone, Copy, Debug)]
+pub enum PrecomputedDateInterval {
+    /// This is not a date histogram source
+    NotApplicable,
+    /// Source was configured with a fixed interval
+    FixedNanoseconds(i64),
+    /// Source was configured with a calendar interval
+    Calendar(CalendarInterval),
+}
+
+impl PrecomputedDateInterval {
+    /// Validates the date histogram source interval fields and parses a date interval from them.
+    pub fn from_date_histogram_source_intervals(
+        fixed_interval: &Option<String>,
+        calendar_interval: Option<CalendarInterval>,
+    ) -> crate::Result<Self> {
+        match (fixed_interval, calendar_interval) {
+            (Some(_), Some(_)) | (None, None) => Err(TantivyError::InvalidArgument(
+                "date histogram source must one and only one of fixed_interval or \
+                 calendar_interval set"
+                    .to_string(),
+            )),
+            (Some(fixed_interval), None) => {
+                let fixed_interval_ms = parse_into_milliseconds(&fixed_interval)?;
+                Ok(PrecomputedDateInterval::FixedNanoseconds(
+                    fixed_interval_ms * 1_000_000,
+                ))
+            }
+            (None, Some(calendar_interval)) => {
+                Ok(PrecomputedDateInterval::Calendar(calendar_interval))
+            }
+        }
+    }
+}
+
+/// The after key projected to the u64 column space
+///
+/// Some column types (term, IP) might not have an exact representation of the
+/// specified after key
+#[derive(Debug)]
+pub enum PrecomputedAfterKey {
+    /// The after key could be exactly represented in the column space.
+    Exact(u64),
+    /// The after key could not be exactly represented exactly represented, so
+    /// this is the next closest one.
+    Next(u64),
+    /// The after key could not be represented in the column space, it is
+    /// greater than all value
+    AfterLast,
+}
+
+impl From<TermOrdHit> for PrecomputedAfterKey {
+    fn from(hit: TermOrdHit) -> Self {
+        match hit {
+            TermOrdHit::Exact(ord) => PrecomputedAfterKey::Exact(ord),
+            // TermOrdHit represents AfterLast as Next(u64::MAX), we keep it as is
+            TermOrdHit::Next(ord) => PrecomputedAfterKey::Next(ord),
+        }
+    }
+}
+
+impl<T: MonotonicallyMappableToU64> From<ProjectedNumber<T>> for PrecomputedAfterKey {
+    fn from(num: ProjectedNumber<T>) -> Self {
+        match num {
+            ProjectedNumber::Exact(number) => PrecomputedAfterKey::Exact(number.to_u64()),
+            ProjectedNumber::Next(number) => PrecomputedAfterKey::Next(number.to_u64()),
+            ProjectedNumber::AfterLast => PrecomputedAfterKey::AfterLast,
+        }
+    }
+}
+
+// /!\ These operators only makes sense if both values are in the same column space
+impl PrecomputedAfterKey {
+    pub fn equals(&self, column_value: u64) -> bool {
+        match self {
+            PrecomputedAfterKey::Exact(v) => *v == column_value,
+            PrecomputedAfterKey::Next(_) => false,
+            PrecomputedAfterKey::AfterLast => false,
+        }
+    }
+
+    pub fn gt(&self, column_value: u64) -> bool {
+        match self {
+            PrecomputedAfterKey::Exact(v) => *v > column_value,
+            PrecomputedAfterKey::Next(v) => *v > column_value,
+            PrecomputedAfterKey::AfterLast => true,
+        }
+    }
+
+    pub fn lt(&self, column_value: u64) -> bool {
+        match self {
+            PrecomputedAfterKey::Exact(v) => *v < column_value,
+            // a value equal to the next is greater than the after key
+            PrecomputedAfterKey::Next(v) => *v <= column_value,
+            PrecomputedAfterKey::AfterLast => false,
+        }
+    }
+
+    fn precompute_ip_addr(column: &Column<u64>, key: &Ipv6Addr) -> crate::Result<Self> {
+        // For IP addresses we need to find the compact space value.
+        // We try to convert via the column's min/max range scan.
+        // Since CompactSpaceU64Accessor::u128_to_compact is not public,
+        // we search linearly for the exact u64 value by scanning column values.
+        let ip_u128 = key.to_bits();
+
+        // Scan for matching value - IP columns are typically small
+        let num_vals = column.values.num_vals();
+        let mut found_exact = false;
+        let mut exact_compact = 0u64;
+        let mut best_next: Option<u64> = None;
+
+        for doc_id in 0..num_vals {
+            let val = column.values.get_val(doc_id);
+            // We need the CompactSpaceU64Accessor to convert compact to u128
+            let compact_accessor = column
+                .values
+                .clone()
+                .downcast_arc::<CompactSpaceU64Accessor>()
+                .map_err(|_| {
+                    TantivyError::AggregationError(
+                        crate::aggregation::AggregationError::InternalError(
+                            "type mismatch: could not downcast to CompactSpaceU64Accessor"
+                                .to_string(),
+                        ),
+                    )
+                })?;
+            let val_u128 = compact_accessor.compact_to_u128(val as u32);
+            if val_u128 == ip_u128 {
+                found_exact = true;
+                exact_compact = val;
+                break;
+            } else if val_u128 > ip_u128 {
+                match best_next {
+                    None => best_next = Some(val),
+                    Some(current_best) => {
+                        let current_u128 = compact_accessor.compact_to_u128(current_best as u32);
+                        if val_u128 < current_u128 {
+                            best_next = Some(val);
+                        }
+                    }
+                }
+            }
+        }
+
+        if found_exact {
+            Ok(PrecomputedAfterKey::Exact(exact_compact))
+        } else if let Some(next) = best_next {
+            Ok(PrecomputedAfterKey::Next(next))
+        } else {
+            Ok(PrecomputedAfterKey::AfterLast)
+        }
+    }
+
+    fn precompute_term_ord(
+        str_dict_column: &Option<StrColumn>,
+        key: &str,
+        field: &str,
+    ) -> crate::Result<Self> {
+        let dict = str_dict_column
+            .as_ref()
+            .expect("dictionary missing for str accessor")
+            .dictionary();
+        let next_ord = dict.term_ord_or_next(key).map_err(|_| {
+            TantivyError::InvalidArgument(format!(
+                "failed to lookup after_key '{}' for field '{}'",
+                key, field
+            ))
+        })?;
+        Ok(next_ord.into())
+    }
+
+    /// Projects the after key into the column space of the given accessor.
+    ///
+    /// The computed after key will not take care of skipping entire columns
+    /// when the after key type is ordered after the accessor's type, that
+    /// should be performed earlier.
+    pub fn precompute(
+        composite_accessor: &CompositeAccessor,
+        source_after_key: &CompositeIntermediateKey,
+        field: &str,
+        missing_order: MissingOrder,
+        order: Order,
+    ) -> crate::Result<Self> {
+        use CompositeIntermediateKey as CIKey;
+        let precomputed_key = match (composite_accessor.column_type, source_after_key) {
+            (ColumnType::Bytes, _) => panic!("unsupported"),
+            // null after key
+            (_, CIKey::Null) => precompute_missing_after_key(false, missing_order, order),
+            // numerical
+            (ColumnType::I64, CIKey::I64(k)) => PrecomputedAfterKey::Exact(k.to_u64()),
+            (ColumnType::I64, CIKey::U64(k)) => num_proj::u64_to_i64(*k).into(),
+            (ColumnType::I64, CIKey::F64(k)) => num_proj::f64_to_i64(*k).into(),
+            (ColumnType::U64, CIKey::I64(k)) => num_proj::i64_to_u64(*k).into(),
+            (ColumnType::U64, CIKey::U64(k)) => PrecomputedAfterKey::Exact(*k),
+            (ColumnType::U64, CIKey::F64(k)) => num_proj::f64_to_u64(*k).into(),
+            (ColumnType::F64, CIKey::I64(k)) => num_proj::i64_to_f64(*k).into(),
+            (ColumnType::F64, CIKey::U64(k)) => num_proj::u64_to_f64(*k).into(),
+            (ColumnType::F64, CIKey::F64(k)) => PrecomputedAfterKey::Exact(k.to_u64()),
+            // boolean
+            (ColumnType::Bool, CIKey::Bool(key)) => PrecomputedAfterKey::Exact(key.to_u64()),
+            // string
+            (ColumnType::Str, CIKey::Str(key)) => PrecomputedAfterKey::precompute_term_ord(
+                &composite_accessor.str_dict_column,
+                key,
+                field,
+            )?,
+            // date time
+            (ColumnType::DateTime, CIKey::DateTime(key)) => {
+                PrecomputedAfterKey::Exact(key.to_u64())
+            }
+            // ip address
+            (ColumnType::IpAddr, CIKey::IpAddr(key)) => {
+                PrecomputedAfterKey::precompute_ip_addr(&composite_accessor.column, key)?
+            }
+            // assume the column's type is ordered after the after_key's type
+            _ => PrecomputedAfterKey::keep_all(order),
+        };
+        Ok(precomputed_key)
+    }
+
+    fn keep_all(order: Order) -> Self {
+        match order {
+            Order::Asc => PrecomputedAfterKey::Next(0),
+            Order::Desc => PrecomputedAfterKey::Next(u64::MAX),
+        }
+    }
+}

src/aggregation/bucket/composite/calendar_interval.rs

@@ -0,0 +1,140 @@
+use time::convert::{Day, Nanosecond};
+use time::{Time, UtcDateTime};
+
+const NS_IN_DAY: i64 = Nanosecond::per_t::<i128>(Day) as i64;
+
+/// Computes the timestamp in nanoseconds corresponding to the beginning of the
+/// year (January 1st at midnight UTC).
+pub(super) fn try_year_bucket(timestamp_ns: i64) -> crate::Result<i64> {
+    year_bucket_using_time_crate(timestamp_ns).map_err(|e| {
+        crate::TantivyError::InvalidArgument(format!(
+            "Failed to compute year bucket for timestamp {}: {}",
+            timestamp_ns,
+            e.to_string()
+        ))
+    })
+}
+
+/// Computes the timestamp in nanoseconds corresponding to the beginning of the
+/// month (1st at midnight UTC).
+pub(super) fn try_month_bucket(timestamp_ns: i64) -> crate::Result<i64> {
+    month_bucket_using_time_crate(timestamp_ns).map_err(|e| {
+        crate::TantivyError::InvalidArgument(format!(
+            "Failed to compute month bucket for timestamp {}: {}",
+            timestamp_ns,
+            e.to_string()
+        ))
+    })
+}
+
+/// Computes the timestamp in nanoseconds corresponding to the beginning of the
+/// week (Monday at midnight UTC).
+pub(super) fn week_bucket(timestamp_ns: i64) -> i64 {
+    // 1970-01-01 was a Thursday (weekday = 4)
+    let days_since_epoch = timestamp_ns.div_euclid(NS_IN_DAY);
+    // Find the weekday: 0=Monday, ..., 6=Sunday
+    let weekday = (days_since_epoch + 3).rem_euclid(7);
+    let monday_days_since_epoch = days_since_epoch - weekday;
+    monday_days_since_epoch * NS_IN_DAY
+}
+
+fn year_bucket_using_time_crate(timestamp_ns: i64) -> Result<i64, time::Error> {
+    let timestamp_ns = UtcDateTime::from_unix_timestamp_nanos(timestamp_ns as i128)?
+        .replace_ordinal(1)?
+        .replace_time(Time::MIDNIGHT)
+        .unix_timestamp_nanos();
+    Ok(timestamp_ns as i64)
+}
+
+fn month_bucket_using_time_crate(timestamp_ns: i64) -> Result<i64, time::Error> {
+    let timestamp_ns = UtcDateTime::from_unix_timestamp_nanos(timestamp_ns as i128)?
+        .replace_day(1)?
+        .replace_time(Time::MIDNIGHT)
+        .unix_timestamp_nanos();
+    Ok(timestamp_ns as i64)
+}
+
+#[cfg(test)]
+mod tests {
+    use std::i64;
+
+    use time::format_description::well_known::Iso8601;
+    use time::UtcDateTime;
+
+    use super::*;
+
+    fn ts_ns(iso: &str) -> i64 {
+        UtcDateTime::parse(iso, &Iso8601::DEFAULT)
+            .unwrap()
+            .unix_timestamp_nanos() as i64
+    }
+
+    #[test]
+    fn test_year_bucket() {
+        let ts = ts_ns("1970-01-01T00:00:00Z");
+        let res = try_year_bucket(ts).unwrap();
+        assert_eq!(res, ts_ns("1970-01-01T00:00:00Z"));
+
+        let ts = ts_ns("1970-06-01T10:00:01.010Z");
+        let res = try_year_bucket(ts).unwrap();
+        assert_eq!(res, ts_ns("1970-01-01T00:00:00Z"));
+
+        let ts = ts_ns("2008-12-31T23:59:59.999999999Z"); // leap year
+        let res = try_year_bucket(ts).unwrap();
+        assert_eq!(res, ts_ns("2008-01-01T00:00:00Z"));
+
+        let ts = ts_ns("2008-01-01T00:00:00Z"); // leap year
+        let res = try_year_bucket(ts).unwrap();
+        assert_eq!(res, ts_ns("2008-01-01T00:00:00Z"));
+
+        let ts = ts_ns("2010-12-31T23:59:59.999999999Z");
+        let res = try_year_bucket(ts).unwrap();
+        assert_eq!(res, ts_ns("2010-01-01T00:00:00Z"));
+
+        let ts = ts_ns("1972-06-01T00:10:00Z");
+        let res = try_year_bucket(ts).unwrap();
+        assert_eq!(res, ts_ns("1972-01-01T00:00:00Z"));
+    }
+
+    #[test]
+    fn test_month_bucket() {
+        let ts = ts_ns("1970-01-15T00:00:00Z");
+        let res = try_month_bucket(ts).unwrap();
+        assert_eq!(res, ts_ns("1970-01-01T00:00:00Z"));
+
+        let ts = ts_ns("1970-02-01T00:00:00Z");
+        let res = try_month_bucket(ts).unwrap();
+        assert_eq!(res, ts_ns("1970-02-01T00:00:00Z"));
+
+        let ts = ts_ns("2000-01-31T23:59:59.999999999Z");
+        let res = try_month_bucket(ts).unwrap();
+        assert_eq!(res, ts_ns("2000-01-01T00:00:00Z"));
+    }
+
+    #[test]
+    fn test_week_bucket() {
+        let ts = ts_ns("1970-01-05T00:00:00Z"); // Monday
+        let res = week_bucket(ts);
+        assert_eq!(res, ts_ns("1970-01-05T00:00:00Z"));
+
+        let ts = ts_ns("1970-01-05T23:59:59Z"); // Monday
+        let res = week_bucket(ts);
+        assert_eq!(res, ts_ns("1970-01-05T00:00:00Z"));
+
+        let ts = ts_ns("1970-01-07T01:13:00Z"); // Wednesday
+        let res = week_bucket(ts);
+        assert_eq!(res, ts_ns("1970-01-05T00:00:00Z"));
+
+        let ts = ts_ns("1970-01-11T23:59:59.999999999Z"); // Sunday
+        let res = week_bucket(ts);
+        assert_eq!(res, ts_ns("1970-01-05T00:00:00Z"));
+
+        let ts = ts_ns("2025-10-16T10:41:59.010Z"); // Thursday
+        let res = week_bucket(ts);
+        assert_eq!(res, ts_ns("2025-10-13T00:00:00Z"));
+
+        let ts = ts_ns("1970-01-01T00:00:00Z"); // Thursday
+        let res = week_bucket(ts);
+        assert_eq!(res, ts_ns("1969-12-29T00:00:00Z")); // Negative
+    }
+}

src/aggregation/bucket/composite/collector.rs

@@ -0,0 +1,674 @@
+use std::fmt::Debug;
+use std::mem;
+use std::net::Ipv6Addr;
+
+use columnar::column_values::CompactSpaceU64Accessor;
+use columnar::{
+    Column, ColumnType, Dictionary, MonotonicallyMappableToU128, MonotonicallyMappableToU64,
+    NumericalValue, StrColumn,
+};
+use rustc_hash::FxHashMap;
+use smallvec::SmallVec;
+
+use crate::aggregation::agg_data::{
+    build_segment_agg_collectors, AggRefNode, AggregationsSegmentCtx,
+};
+use crate::aggregation::bucket::composite::accessors::{
+    CompositeAccessor, CompositeAggReqData, PrecomputedDateInterval,
+};
+use crate::aggregation::bucket::composite::calendar_interval;
+use crate::aggregation::bucket::composite::map::{DynArrayHeapMap, MAX_DYN_ARRAY_SIZE};
+use crate::aggregation::bucket::{
+    CalendarInterval, CompositeAggregationSource, MissingOrder, Order,
+};
+use crate::aggregation::cached_sub_aggs::{CachedSubAggs, HighCardSubAggCache};
+use crate::aggregation::intermediate_agg_result::{
+    CompositeIntermediateKey, IntermediateAggregationResult, IntermediateAggregationResults,
+    IntermediateBucketResult, IntermediateCompositeBucketEntry, IntermediateCompositeBucketResult,
+};
+use crate::aggregation::segment_agg_result::{BucketIdProvider, SegmentAggregationCollector};
+use crate::aggregation::BucketId;
+use crate::TantivyError;
+
+#[derive(Clone, Debug)]
+struct CompositeBucketCollector {
+    count: u32,
+    bucket_id: BucketId,
+}
+
+/// Compact sortable representation of a single source value within a composite key.
+///
+/// The struct encodes both the column identity and the fast field value in a way
+/// that preserves the desired sort order via the derived `Ord` implementation
+/// (fields are compared top-to-bottom: `sort_key` first, then `encoded_value`).
+///
+/// ## `sort_key` encoding
+/// - `0` — missing value, sorted first
+/// - `1..=254` — present value; the original accessor index is `sort_key - 1`
+/// - `u8::MAX` (255) — missing value, sorted last
+///
+/// ## `encoded_value` encoding
+/// - `0` when the field is missing
+/// - The raw u64 fast-field representation when order is ascending
+/// - Bitwise NOT of the raw u64 when order is descending
+#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Default, Hash)]
+struct InternalValueRepr {
+    /// Column index biased by +1 (so 0 and u8::MAX are reserved for missing sentinels).
+    sort_key: u8,
+    /// Fast field value, possibly bit-flipped for descending order.
+    encoded_value: u64,
+}
+
+impl InternalValueRepr {
+    #[inline]
+    fn new_term(raw: u64, accessor_idx: u8, order: Order) -> Self {
+        let encoded_value = match order {
+            Order::Asc => raw,
+            Order::Desc => !raw,
+        };
+        InternalValueRepr {
+            sort_key: accessor_idx + 1,
+            encoded_value,
+        }
+    }
+
+    /// For histogram sources the column index is irrelevant (always 1).
+    #[inline]
+    fn new_histogram(raw: u64, order: Order) -> Self {
+        let encoded_value = match order {
+            Order::Asc => raw,
+            Order::Desc => !raw,
+        };
+        InternalValueRepr {
+            sort_key: 1,
+            encoded_value,
+        }
+    }
+
+    #[inline]
+    fn new_missing(order: Order, missing_order: MissingOrder) -> Self {
+        let sort_key = match (missing_order, order) {
+            (MissingOrder::First, _) | (MissingOrder::Default, Order::Asc) => 0,
+            (MissingOrder::Last, _) | (MissingOrder::Default, Order::Desc) => u8::MAX,
+        };
+        InternalValueRepr {
+            sort_key,
+            encoded_value: 0,
+        }
+    }
+
+    /// Decode back to `(accessor_idx, raw_value)`.
+    /// Returns `None` when the value represents a missing field.
+    #[inline]
+    fn decode(self, order: Order) -> Option<(u8, u64)> {
+        if self.sort_key == 0 || self.sort_key == u8::MAX {
+            return None;
+        }
+        let raw = match order {
+            Order::Asc => self.encoded_value,
+            Order::Desc => !self.encoded_value,
+        };
+        Some((self.sort_key - 1, raw))
+    }
+}
+
+/// The collector puts values from the fast field into the correct buckets and
+/// does a conversion to the correct datatype.
+#[derive(Debug)]
+pub struct SegmentCompositeCollector {
+    /// One DynArrayHeapMap per parent bucket.
+    parent_buckets: Vec<DynArrayHeapMap<InternalValueRepr, CompositeBucketCollector>>,
+    accessor_idx: usize,
+    sub_agg: Option<CachedSubAggs<HighCardSubAggCache>>,
+    bucket_id_provider: BucketIdProvider,
+    /// Number of sources, needed when creating new DynArrayHeapMaps.
+    num_sources: usize,
+}
+
+impl SegmentAggregationCollector for SegmentCompositeCollector {
+    fn add_intermediate_aggregation_result(
+        &mut self,
+        agg_data: &AggregationsSegmentCtx,
+        results: &mut IntermediateAggregationResults,
+        parent_bucket_id: BucketId,
+    ) -> crate::Result<()> {
+        let name = agg_data
+            .get_composite_req_data(self.accessor_idx)
+            .name
+            .clone();
+
+        let buckets = self.into_intermediate_bucket_result(agg_data, parent_bucket_id)?;
+        results.push(
+            name,
+            IntermediateAggregationResult::Bucket(IntermediateBucketResult::Composite { buckets }),
+        )?;
+
+        Ok(())
+    }
+
+    fn collect(
+        &mut self,
+        parent_bucket_id: BucketId,
+        docs: &[crate::DocId],
+        agg_data: &mut AggregationsSegmentCtx,
+    ) -> crate::Result<()> {
+        let mem_pre = self.get_memory_consumption();
+        let composite_agg_data = agg_data.take_composite_req_data(self.accessor_idx);
+
+        for doc in docs {
+            let mut sub_level_values = SmallVec::new();
+            recursive_key_visitor(
+                *doc,
+                &composite_agg_data,
+                0,
+                &mut sub_level_values,
+                &mut self.parent_buckets[parent_bucket_id as usize],
+                true,
+                &mut self.sub_agg,
+                &mut self.bucket_id_provider,
+            )?;
+        }
+        agg_data.put_back_composite_req_data(self.accessor_idx, composite_agg_data);
+
+        if let Some(sub_agg) = &mut self.sub_agg {
+            sub_agg.check_flush_local(agg_data)?;
+        }
+
+        let mem_delta = self.get_memory_consumption() - mem_pre;
+        if mem_delta > 0 {
+            agg_data.context.limits.add_memory_consumed(mem_delta)?;
+        }
+
+        Ok(())
+    }
+
+    fn flush(&mut self, agg_data: &mut AggregationsSegmentCtx) -> crate::Result<()> {
+        if let Some(sub_agg) = &mut self.sub_agg {
+            sub_agg.flush(agg_data)?;
+        }
+        Ok(())
+    }
+
+    fn prepare_max_bucket(
+        &mut self,
+        max_bucket: BucketId,
+        _agg_data: &AggregationsSegmentCtx,
+    ) -> crate::Result<()> {
+        let required_len = max_bucket as usize + 1;
+        while self.parent_buckets.len() < required_len {
+            let map = DynArrayHeapMap::try_new(self.num_sources)?;
+            self.parent_buckets.push(map);
+        }
+        Ok(())
+    }
+}
+
+impl SegmentCompositeCollector {
+    fn get_memory_consumption(&self) -> u64 {
+        self.parent_buckets
+            .iter()
+            .map(|m| m.memory_consumption())
+            .sum()
+    }
+
+    pub(crate) fn from_req_and_validate(
+        req_data: &mut AggregationsSegmentCtx,
+        node: &AggRefNode,
+    ) -> crate::Result<Self> {
+        validate_req(req_data, node.idx_in_req_data)?;
+
+        let has_sub_aggregations = !node.children.is_empty();
+        let sub_agg = if has_sub_aggregations {
+            let sub_agg_collector = build_segment_agg_collectors(req_data, &node.children)?;
+            Some(CachedSubAggs::new(sub_agg_collector))
+        } else {
+            None
+        };
+
+        let composite_req_data = req_data.get_composite_req_data(node.idx_in_req_data);
+        let num_sources = composite_req_data.req.sources.len();
+
+        Ok(SegmentCompositeCollector {
+            parent_buckets: vec![DynArrayHeapMap::try_new(num_sources)?],
+            accessor_idx: node.idx_in_req_data,
+            sub_agg,
+            bucket_id_provider: BucketIdProvider::default(),
+            num_sources,
+        })
+    }
+
+    #[inline]
+    fn into_intermediate_bucket_result(
+        &mut self,
+        agg_data: &AggregationsSegmentCtx,
+        parent_bucket_id: BucketId,
+    ) -> crate::Result<IntermediateCompositeBucketResult> {
+        let empty_map = DynArrayHeapMap::try_new(self.num_sources)?;
+        let heap_map = mem::replace(
+            &mut self.parent_buckets[parent_bucket_id as usize],
+            empty_map,
+        );
+
+        let mut dict: FxHashMap<Vec<CompositeIntermediateKey>, IntermediateCompositeBucketEntry> =
+            Default::default();
+        dict.reserve(heap_map.size());
+        let composite_data = agg_data.get_composite_req_data(self.accessor_idx);
+        for (key_internal_repr, agg) in heap_map.into_iter() {
+            let key = resolve_key(&key_internal_repr, composite_data)?;
+            let mut sub_aggregation_res = IntermediateAggregationResults::default();
+            if let Some(sub_agg) = &mut self.sub_agg {
+                sub_agg
+                    .get_sub_agg_collector()
+                    .add_intermediate_aggregation_result(
+                        agg_data,
+                        &mut sub_aggregation_res,
+                        agg.bucket_id,
+                    )?;
+            }
+
+            dict.insert(
+                key,
+                IntermediateCompositeBucketEntry {
+                    doc_count: agg.count,
+                    sub_aggregation: sub_aggregation_res,
+                },
+            );
+        }
+
+        Ok(IntermediateCompositeBucketResult {
+            entries: dict,
+            target_size: composite_data.req.size,
+            orders: composite_data
+                .req
+                .sources
+                .iter()
+                .map(|source| match source {
+                    CompositeAggregationSource::Terms(t) => (t.order, t.missing_order),
+                    CompositeAggregationSource::Histogram(h) => (h.order, h.missing_order),
+                    CompositeAggregationSource::DateHistogram(d) => (d.order, d.missing_order),
+                })
+                .collect(),
+        })
+    }
+}
+
+fn validate_req(req_data: &mut AggregationsSegmentCtx, accessor_idx: usize) -> crate::Result<()> {
+    let composite_data = req_data.get_composite_req_data(accessor_idx);
+    let req = &composite_data.req;
+    if req.sources.is_empty() {
+        return Err(TantivyError::InvalidArgument(
+            "composite aggregation must have at least one source".to_string(),
+        ));
+    }
+    if req.size == 0 {
+        return Err(TantivyError::InvalidArgument(
+            "composite aggregation 'size' must be > 0".to_string(),
+        ));
+    }
+    let column_types_for_sources = composite_data.composite_accessors.iter().map(|item| {
+        item.accessors
+            .iter()
+            .map(|a| a.column_type)
+            .collect::<Vec<_>>()
+    });
+
+    for column_types in column_types_for_sources {
+        if column_types.len() > MAX_DYN_ARRAY_SIZE {
+            return Err(TantivyError::InvalidArgument(format!(
+                "composite aggregation source supports maximum {MAX_DYN_ARRAY_SIZE} sources",
+            )));
+        }
+        if column_types.contains(&ColumnType::Bytes) {
+            return Err(TantivyError::InvalidArgument(
+                "composite aggregation does not support 'bytes' field type".to_string(),
+            ));
+        }
+    }
+    Ok(())
+}
+
+fn collect_bucket_with_limit(
+    doc_id: crate::DocId,
+    limit_num_buckets: usize,
+    buckets: &mut DynArrayHeapMap<InternalValueRepr, CompositeBucketCollector>,
+    key: &[InternalValueRepr],
+    sub_agg: &mut Option<CachedSubAggs<HighCardSubAggCache>>,
+    bucket_id_provider: &mut BucketIdProvider,
+) {
+    let mut record_in_bucket = |bucket: &mut CompositeBucketCollector| {
+        bucket.count += 1;
+        if let Some(sub_agg) = sub_agg {
+            sub_agg.push(bucket.bucket_id, doc_id);
+        }
+    };
+
+    // We still have room for buckets, just insert
+    if buckets.size() < limit_num_buckets {
+        let bucket = buckets.get_or_insert_with(key, || CompositeBucketCollector {
+            count: 0,
+            bucket_id: bucket_id_provider.next_bucket_id(),
+        });
+        record_in_bucket(bucket);
+        return;
+    }
+
+    // Map is full, but we can still update the bucket if it already exists
+    if let Some(bucket) = buckets.get_mut(key) {
+        record_in_bucket(bucket);
+        return;
+    }
+
+    // Check if the item qualifies to enter the top-k, and evict the highest if it does
+    if let Some(highest_key) = buckets.peek_highest() {
+        if key < highest_key {
+            buckets.evict_highest();
+            let bucket = buckets.get_or_insert_with(key, || CompositeBucketCollector {
+                count: 0,
+                bucket_id: bucket_id_provider.next_bucket_id(),
+            });
+            record_in_bucket(bucket);
+        }
+    }
+}
+
+/// Converts the composite key from its internal column space representation
+/// (segment specific) into its intermediate form.
+fn resolve_key(
+    internal_key: &[InternalValueRepr],
+    agg_data: &CompositeAggReqData,
+) -> crate::Result<Vec<CompositeIntermediateKey>> {
+    internal_key
+        .iter()
+        .enumerate()
+        .map(|(idx, val)| {
+            resolve_internal_value_repr(
+                *val,
+                &agg_data.req.sources[idx],
+                &agg_data.composite_accessors[idx].accessors,
+            )
+        })
+        .collect()
+}
+
+fn resolve_internal_value_repr(
+    internal_value_repr: InternalValueRepr,
+    source: &CompositeAggregationSource,
+    composite_accessors: &[CompositeAccessor],
+) -> crate::Result<CompositeIntermediateKey> {
+    let decoded_value_opt = match source {
+        CompositeAggregationSource::Terms(source) => internal_value_repr.decode(source.order),
+        CompositeAggregationSource::Histogram(source) => internal_value_repr.decode(source.order),
+        CompositeAggregationSource::DateHistogram(source) => {
+            internal_value_repr.decode(source.order)
+        }
+    };
+    let Some((decoded_accessor_idx, val)) = decoded_value_opt else {
+        return Ok(CompositeIntermediateKey::Null);
+    };
+    let key = match source {
+        CompositeAggregationSource::Terms(_) => {
+            let CompositeAccessor {
+                column_type,
+                str_dict_column,
+                column,
+                ..
+            } = &composite_accessors[decoded_accessor_idx as usize];
+            resolve_term(val, column_type, str_dict_column, column)?
+        }
+        CompositeAggregationSource::Histogram(source) => {
+            CompositeIntermediateKey::F64(i64::from_u64(val) as f64 * source.interval)
+        }
+        CompositeAggregationSource::DateHistogram(_) => {
+            CompositeIntermediateKey::DateTime(i64::from_u64(val))
+        }
+    };
+
+    Ok(key)
+}
+
+fn resolve_term(
+    val: u64,
+    column_type: &ColumnType,
+    str_dict_column: &Option<StrColumn>,
+    column: &Column,
+) -> crate::Result<CompositeIntermediateKey> {
+    let key = if *column_type == ColumnType::Str {
+        let fallback_dict = Dictionary::empty();
+        let term_dict = str_dict_column
+            .as_ref()
+            .map(|el| el.dictionary())
+            .unwrap_or_else(|| &fallback_dict);
+
+        let mut buffer = Vec::new();
+        term_dict.ord_to_term(val, &mut buffer)?;
+        CompositeIntermediateKey::Str(
+            String::from_utf8(buffer.to_vec()).expect("could not convert to String"),
+        )
+    } else if *column_type == ColumnType::DateTime {
+        let val = i64::from_u64(val);
+        CompositeIntermediateKey::DateTime(val)
+    } else if *column_type == ColumnType::Bool {
+        let val = bool::from_u64(val);
+        CompositeIntermediateKey::Bool(val)
+    } else if *column_type == ColumnType::IpAddr {
+        let compact_space_accessor = column
+            .values
+            .clone()
+            .downcast_arc::<CompactSpaceU64Accessor>()
+            .map_err(|_| {
+                TantivyError::AggregationError(crate::aggregation::AggregationError::InternalError(
+                    "Type mismatch: Could not downcast to CompactSpaceU64Accessor".to_string(),
+                ))
+            })?;
+        let val: u128 = compact_space_accessor.compact_to_u128(val as u32);
+        let val = Ipv6Addr::from_u128(val);
+        CompositeIntermediateKey::IpAddr(val)
+    } else if *column_type == ColumnType::U64 {
+        CompositeIntermediateKey::U64(val)
+    } else if *column_type == ColumnType::I64 {
+        CompositeIntermediateKey::I64(i64::from_u64(val))
+    } else {
+        let val = f64::from_u64(val);
+        let val: NumericalValue = val.into();
+
+        match val.normalize() {
+            NumericalValue::U64(val) => CompositeIntermediateKey::U64(val),
+            NumericalValue::I64(val) => CompositeIntermediateKey::I64(val),
+            NumericalValue::F64(val) => CompositeIntermediateKey::F64(val),
+        }
+    };
+    Ok(key)
+}
+
+/// Depth-first walk of the accessors to build the composite key combinations
+/// and update the buckets.
+fn recursive_key_visitor(
+    doc_id: crate::DocId,
+    composite_agg_data: &CompositeAggReqData,
+    source_idx_for_recursion: usize,
+    sub_level_values: &mut SmallVec<[InternalValueRepr; MAX_DYN_ARRAY_SIZE]>,
+    buckets: &mut DynArrayHeapMap<InternalValueRepr, CompositeBucketCollector>,
+    // whether we need to consider the after_key in the following levels
+    is_on_after_key: bool,
+    sub_agg: &mut Option<CachedSubAggs<HighCardSubAggCache>>,
+    bucket_id_provider: &mut BucketIdProvider,
+) -> crate::Result<()> {
+    if source_idx_for_recursion == composite_agg_data.req.sources.len() {
+        if !is_on_after_key {
+            collect_bucket_with_limit(
+                doc_id,
+                composite_agg_data.req.size as usize,
+                buckets,
+                sub_level_values,
+                sub_agg,
+                bucket_id_provider,
+            );
+        }
+        return Ok(());
+    }
+
+    let current_level_accessors = &composite_agg_data.composite_accessors[source_idx_for_recursion];
+    let current_level_source = &composite_agg_data.req.sources[source_idx_for_recursion];
+    let mut missing = true;
+    for (accessor_idx, accessor) in current_level_accessors.accessors.iter().enumerate() {
+        let values = accessor.column.values_for_doc(doc_id);
+        for value in values {
+            missing = false;
+            match current_level_source {
+                CompositeAggregationSource::Terms(_) => {
+                    let preceeds_after_key_type =
+                        accessor_idx < current_level_accessors.after_key_accessor_idx;
+                    if is_on_after_key && preceeds_after_key_type {
+                        break;
+                    }
+                    let matches_after_key_type =
+                        accessor_idx == current_level_accessors.after_key_accessor_idx;
+
+                    if matches_after_key_type && is_on_after_key {
+                        let should_skip = match current_level_source.order() {
+                            Order::Asc => current_level_accessors.after_key.gt(value),
+                            Order::Desc => current_level_accessors.after_key.lt(value),
+                        };
+                        if should_skip {
+                            continue;
+                        }
+                    }
+                    sub_level_values.push(InternalValueRepr::new_term(
+                        value,
+                        accessor_idx as u8,
+                        current_level_source.order(),
+                    ));
+                    let still_on_after_key =
+                        matches_after_key_type && current_level_accessors.after_key.equals(value);
+                    recursive_key_visitor(
+                        doc_id,
+                        composite_agg_data,
+                        source_idx_for_recursion + 1,
+                        sub_level_values,
+                        buckets,
+                        is_on_after_key && still_on_after_key,
+                        sub_agg,
+                        bucket_id_provider,
+                    )?;
+                    sub_level_values.pop();
+                }
+                CompositeAggregationSource::Histogram(source) => {
+                    let float_value = match accessor.column_type {
+                        ColumnType::U64 => value as f64,
+                        ColumnType::I64 => i64::from_u64(value) as f64,
+                        ColumnType::DateTime => i64::from_u64(value) as f64 / 1_000_000.,
+                        ColumnType::F64 => f64::from_u64(value),
+                        _ => {
+                            panic!(
+                                "unexpected type {:?}. This should not happen",
+                                accessor.column_type
+                            )
+                        }
+                    };
+                    let bucket_index = (float_value / source.interval).floor() as i64;
+                    let bucket_value = i64::to_u64(bucket_index);
+                    if is_on_after_key {
+                        let should_skip = match current_level_source.order() {
+                            Order::Asc => current_level_accessors.after_key.gt(bucket_value),
+                            Order::Desc => current_level_accessors.after_key.lt(bucket_value),
+                        };
+                        if should_skip {
+                            continue;
+                        }
+                    }
+                    sub_level_values.push(InternalValueRepr::new_histogram(
+                        bucket_value,
+                        current_level_source.order(),
+                    ));
+                    let still_on_after_key = current_level_accessors.after_key.equals(bucket_value);
+                    recursive_key_visitor(
+                        doc_id,
+                        composite_agg_data,
+                        source_idx_for_recursion + 1,
+                        sub_level_values,
+                        buckets,
+                        is_on_after_key && still_on_after_key,
+                        sub_agg,
+                        bucket_id_provider,
+                    )?;
+                    sub_level_values.pop();
+                }
+                CompositeAggregationSource::DateHistogram(_) => {
+                    let value_ns = match accessor.column_type {
+                        ColumnType::DateTime => i64::from_u64(value),
+                        _ => {
+                            panic!(
+                                "unexpected type {:?}. This should not happen",
+                                accessor.column_type
+                            )
+                        }
+                    };
+                    let bucket_index = match accessor.date_histogram_interval {
+                        PrecomputedDateInterval::FixedNanoseconds(fixed_interval_ns) => {
+                            (value_ns / fixed_interval_ns) * fixed_interval_ns
+                        }
+                        PrecomputedDateInterval::Calendar(CalendarInterval::Year) => {
+                            calendar_interval::try_year_bucket(value_ns)?
+                        }
+                        PrecomputedDateInterval::Calendar(CalendarInterval::Month) => {
+                            calendar_interval::try_month_bucket(value_ns)?
+                        }
+                        PrecomputedDateInterval::Calendar(CalendarInterval::Week) => {
+                            calendar_interval::week_bucket(value_ns)
+                        }
+                        PrecomputedDateInterval::NotApplicable => {
+                            panic!("interval not precomputed for date histogram source")
+                        }
+                    };
+                    let bucket_value = i64::to_u64(bucket_index);
+                    if is_on_after_key {
+                        let should_skip = match current_level_source.order() {
+                            Order::Asc => current_level_accessors.after_key.gt(bucket_value),
+                            Order::Desc => current_level_accessors.after_key.lt(bucket_value),
+                        };
+                        if should_skip {
+                            continue;
+                        }
+                    }
+                    sub_level_values.push(InternalValueRepr::new_histogram(
+                        bucket_value,
+                        current_level_source.order(),
+                    ));
+                    let still_on_after_key = current_level_accessors.after_key.equals(bucket_value);
+                    recursive_key_visitor(
+                        doc_id,
+                        composite_agg_data,
+                        source_idx_for_recursion + 1,
+                        sub_level_values,
+                        buckets,
+                        is_on_after_key && still_on_after_key,
+                        sub_agg,
+                        bucket_id_provider,
+                    )?;
+                    sub_level_values.pop();
+                }
+            };
+        }
+    }
+    if missing && current_level_source.missing_bucket() {
+        if is_on_after_key && current_level_accessors.skip_missing {
+            return Ok(());
+        }
+        sub_level_values.push(InternalValueRepr::new_missing(
+            current_level_source.order(),
+            current_level_source.missing_order(),
+        ));
+        recursive_key_visitor(
+            doc_id,
+            composite_agg_data,
+            source_idx_for_recursion + 1,
+            sub_level_values,
+            buckets,
+            is_on_after_key && current_level_accessors.is_after_key_explicit_missing,
+            sub_agg,
+            bucket_id_provider,
+        )?;
+        sub_level_values.pop();
+    }
+    Ok(())
+}

src/aggregation/bucket/composite/map.rs

@@ -0,0 +1,329 @@
+use std::collections::BinaryHeap;
+use std::fmt::Debug;
+use std::hash::Hash;
+
+use rustc_hash::FxHashMap;
+use smallvec::SmallVec;
+
+use crate::TantivyError;
+
+/// Map backed by a hash map for fast access and a binary heap to track the
+/// highest key. The key is an array of fixed size S.
+#[derive(Clone, Debug)]
+struct ArrayHeapMap<K: Ord, V, const S: usize> {
+    pub(crate) buckets: FxHashMap<[K; S], V>,
+    pub(crate) heap: BinaryHeap<[K; S]>,
+}
+
+impl<K: Ord, V, const S: usize> Default for ArrayHeapMap<K, V, S> {
+    fn default() -> Self {
+        ArrayHeapMap {
+            buckets: FxHashMap::default(),
+            heap: BinaryHeap::default(),
+        }
+    }
+}
+
+impl<K: Eq + Hash + Clone + Ord, V, const S: usize> ArrayHeapMap<K, V, S> {
+    /// Panics if the length of `key` is not S.
+    fn get_or_insert_with<F: FnOnce() -> V>(&mut self, key: &[K], f: F) -> &mut V {
+        let key_array: &[K; S] = key.try_into().expect("Key length mismatch");
+        self.buckets.entry(key_array.clone()).or_insert_with(|| {
+            self.heap.push(key_array.clone());
+            f()
+        })
+    }
+
+    /// Panics if the length of `key` is not S.
+    fn get_mut(&mut self, key: &[K]) -> Option<&mut V> {
+        let key_array: &[K; S] = key.try_into().expect("Key length mismatch");
+        self.buckets.get_mut(key_array)
+    }
+
+    fn peek_highest(&self) -> Option<&[K]> {
+        self.heap.peek().map(|k_array| k_array.as_slice())
+    }
+
+    fn evict_highest(&mut self) {
+        if let Some(highest) = self.heap.pop() {
+            self.buckets.remove(&highest);
+        }
+    }
+
+    fn memory_consumption(&self) -> u64 {
+        let key_size = std::mem::size_of::<[K; S]>();
+        let map_size = (key_size + std::mem::size_of::<V>()) * self.buckets.capacity();
+        let heap_size = key_size * self.heap.capacity();
+        (map_size + heap_size) as u64
+    }
+}
+
+impl<K: Copy + Ord + Clone + 'static, V: 'static, const S: usize> ArrayHeapMap<K, V, S> {
+    fn into_iter(self) -> Box<dyn Iterator<Item = (SmallVec<[K; MAX_DYN_ARRAY_SIZE]>, V)>> {
+        Box::new(
+            self.buckets
+                .into_iter()
+                .map(|(k, v)| (SmallVec::from_slice(&k), v)),
+        )
+    }
+}
+
+pub(super) const MAX_DYN_ARRAY_SIZE: usize = 16;
+const MAX_DYN_ARRAY_SIZE_PLUS_ONE: usize = MAX_DYN_ARRAY_SIZE + 1;
+
+/// A map optimized for memory footprint, fast access and efficient eviction of
+/// the highest key.
+///
+/// Keys are inlined arrays of size 1 to [MAX_DYN_ARRAY_SIZE] but for a given
+/// instance the key size is fixed. This allows to avoid heap allocations for the
+/// keys.
+#[derive(Clone, Debug)]
+pub(super) struct DynArrayHeapMap<K: Ord, V>(DynArrayHeapMapInner<K, V>);
+
+/// Wrapper around ArrayHeapMap to dynamically dispatch on the array size.
+#[derive(Clone, Debug)]
+enum DynArrayHeapMapInner<K: Ord, V> {
+    Dim1(ArrayHeapMap<K, V, 1>),
+    Dim2(ArrayHeapMap<K, V, 2>),
+    Dim3(ArrayHeapMap<K, V, 3>),
+    Dim4(ArrayHeapMap<K, V, 4>),
+    Dim5(ArrayHeapMap<K, V, 5>),
+    Dim6(ArrayHeapMap<K, V, 6>),
+    Dim7(ArrayHeapMap<K, V, 7>),
+    Dim8(ArrayHeapMap<K, V, 8>),
+    Dim9(ArrayHeapMap<K, V, 9>),
+    Dim10(ArrayHeapMap<K, V, 10>),
+    Dim11(ArrayHeapMap<K, V, 11>),
+    Dim12(ArrayHeapMap<K, V, 12>),
+    Dim13(ArrayHeapMap<K, V, 13>),
+    Dim14(ArrayHeapMap<K, V, 14>),
+    Dim15(ArrayHeapMap<K, V, 15>),
+    Dim16(ArrayHeapMap<K, V, 16>),
+}
+
+impl<K: Ord, V> DynArrayHeapMap<K, V> {
+    /// Creates a new heap map with dynamic array keys of size `key_dimension`.
+    pub(super) fn try_new(key_dimension: usize) -> crate::Result<Self> {
+        let inner = match key_dimension {
+            0 => {
+                return Err(TantivyError::InvalidArgument(
+                    "DynArrayHeapMap dimension must be at least 1".to_string(),
+                ))
+            }
+            1 => DynArrayHeapMapInner::Dim1(ArrayHeapMap::default()),
+            2 => DynArrayHeapMapInner::Dim2(ArrayHeapMap::default()),
+            3 => DynArrayHeapMapInner::Dim3(ArrayHeapMap::default()),
+            4 => DynArrayHeapMapInner::Dim4(ArrayHeapMap::default()),
+            5 => DynArrayHeapMapInner::Dim5(ArrayHeapMap::default()),
+            6 => DynArrayHeapMapInner::Dim6(ArrayHeapMap::default()),
+            7 => DynArrayHeapMapInner::Dim7(ArrayHeapMap::default()),
+            8 => DynArrayHeapMapInner::Dim8(ArrayHeapMap::default()),
+            9 => DynArrayHeapMapInner::Dim9(ArrayHeapMap::default()),
+            10 => DynArrayHeapMapInner::Dim10(ArrayHeapMap::default()),
+            11 => DynArrayHeapMapInner::Dim11(ArrayHeapMap::default()),
+            12 => DynArrayHeapMapInner::Dim12(ArrayHeapMap::default()),
+            13 => DynArrayHeapMapInner::Dim13(ArrayHeapMap::default()),
+            14 => DynArrayHeapMapInner::Dim14(ArrayHeapMap::default()),
+            15 => DynArrayHeapMapInner::Dim15(ArrayHeapMap::default()),
+            16 => DynArrayHeapMapInner::Dim16(ArrayHeapMap::default()),
+            MAX_DYN_ARRAY_SIZE_PLUS_ONE.. => {
+                return Err(TantivyError::InvalidArgument(format!(
+                    "DynArrayHeapMap supports maximum {MAX_DYN_ARRAY_SIZE} dimensions, got \
+                     {key_dimension}",
+                )))
+            }
+        };
+        Ok(DynArrayHeapMap(inner))
+    }
+
+    /// Number of elements in the map. This is not the dimension of the keys.
+    pub(super) fn size(&self) -> usize {
+        match &self.0 {
+            DynArrayHeapMapInner::Dim1(map) => map.buckets.len(),
+            DynArrayHeapMapInner::Dim2(map) => map.buckets.len(),
+            DynArrayHeapMapInner::Dim3(map) => map.buckets.len(),
+            DynArrayHeapMapInner::Dim4(map) => map.buckets.len(),
+            DynArrayHeapMapInner::Dim5(map) => map.buckets.len(),
+            DynArrayHeapMapInner::Dim6(map) => map.buckets.len(),
+            DynArrayHeapMapInner::Dim7(map) => map.buckets.len(),
+            DynArrayHeapMapInner::Dim8(map) => map.buckets.len(),
+            DynArrayHeapMapInner::Dim9(map) => map.buckets.len(),
+            DynArrayHeapMapInner::Dim10(map) => map.buckets.len(),
+            DynArrayHeapMapInner::Dim11(map) => map.buckets.len(),
+            DynArrayHeapMapInner::Dim12(map) => map.buckets.len(),
+            DynArrayHeapMapInner::Dim13(map) => map.buckets.len(),
+            DynArrayHeapMapInner::Dim14(map) => map.buckets.len(),
+            DynArrayHeapMapInner::Dim15(map) => map.buckets.len(),
+            DynArrayHeapMapInner::Dim16(map) => map.buckets.len(),
+        }
+    }
+}
+
+impl<K: Ord + Hash + Clone, V> DynArrayHeapMap<K, V> {
+    /// Get a mutable reference to the value corresponding to `key` or inserts a new
+    /// value created by calling `f`.
+    ///
+    /// Panics if the length of `key` does not match the key dimension of the map.
+    pub(super) fn get_or_insert_with<F: FnOnce() -> V>(&mut self, key: &[K], f: F) -> &mut V {
+        match &mut self.0 {
+            DynArrayHeapMapInner::Dim1(map) => map.get_or_insert_with(key, f),
+            DynArrayHeapMapInner::Dim2(map) => map.get_or_insert_with(key, f),
+            DynArrayHeapMapInner::Dim3(map) => map.get_or_insert_with(key, f),
+            DynArrayHeapMapInner::Dim4(map) => map.get_or_insert_with(key, f),
+            DynArrayHeapMapInner::Dim5(map) => map.get_or_insert_with(key, f),
+            DynArrayHeapMapInner::Dim6(map) => map.get_or_insert_with(key, f),
+            DynArrayHeapMapInner::Dim7(map) => map.get_or_insert_with(key, f),
+            DynArrayHeapMapInner::Dim8(map) => map.get_or_insert_with(key, f),
+            DynArrayHeapMapInner::Dim9(map) => map.get_or_insert_with(key, f),
+            DynArrayHeapMapInner::Dim10(map) => map.get_or_insert_with(key, f),
+            DynArrayHeapMapInner::Dim11(map) => map.get_or_insert_with(key, f),
+            DynArrayHeapMapInner::Dim12(map) => map.get_or_insert_with(key, f),
+            DynArrayHeapMapInner::Dim13(map) => map.get_or_insert_with(key, f),
+            DynArrayHeapMapInner::Dim14(map) => map.get_or_insert_with(key, f),
+            DynArrayHeapMapInner::Dim15(map) => map.get_or_insert_with(key, f),
+            DynArrayHeapMapInner::Dim16(map) => map.get_or_insert_with(key, f),
+        }
+    }
+
+    /// Returns a mutable reference to the value corresponding to `key`.
+    ///
+    /// Panics if the length of `key` does not match the key dimension of the map.
+    pub fn get_mut(&mut self, key: &[K]) -> Option<&mut V> {
+        match &mut self.0 {
+            DynArrayHeapMapInner::Dim1(map) => map.get_mut(key),
+            DynArrayHeapMapInner::Dim2(map) => map.get_mut(key),
+            DynArrayHeapMapInner::Dim3(map) => map.get_mut(key),
+            DynArrayHeapMapInner::Dim4(map) => map.get_mut(key),
+            DynArrayHeapMapInner::Dim5(map) => map.get_mut(key),
+            DynArrayHeapMapInner::Dim6(map) => map.get_mut(key),
+            DynArrayHeapMapInner::Dim7(map) => map.get_mut(key),
+            DynArrayHeapMapInner::Dim8(map) => map.get_mut(key),
+            DynArrayHeapMapInner::Dim9(map) => map.get_mut(key),
+            DynArrayHeapMapInner::Dim10(map) => map.get_mut(key),
+            DynArrayHeapMapInner::Dim11(map) => map.get_mut(key),
+            DynArrayHeapMapInner::Dim12(map) => map.get_mut(key),
+            DynArrayHeapMapInner::Dim13(map) => map.get_mut(key),
+            DynArrayHeapMapInner::Dim14(map) => map.get_mut(key),
+            DynArrayHeapMapInner::Dim15(map) => map.get_mut(key),
+            DynArrayHeapMapInner::Dim16(map) => map.get_mut(key),
+        }
+    }
+
+    /// Returns a reference to the highest key in the map.
+    pub(super) fn peek_highest(&self) -> Option<&[K]> {
+        match &self.0 {
+            DynArrayHeapMapInner::Dim1(map) => map.peek_highest(),
+            DynArrayHeapMapInner::Dim2(map) => map.peek_highest(),
+            DynArrayHeapMapInner::Dim3(map) => map.peek_highest(),
+            DynArrayHeapMapInner::Dim4(map) => map.peek_highest(),
+            DynArrayHeapMapInner::Dim5(map) => map.peek_highest(),
+            DynArrayHeapMapInner::Dim6(map) => map.peek_highest(),
+            DynArrayHeapMapInner::Dim7(map) => map.peek_highest(),
+            DynArrayHeapMapInner::Dim8(map) => map.peek_highest(),
+            DynArrayHeapMapInner::Dim9(map) => map.peek_highest(),
+            DynArrayHeapMapInner::Dim10(map) => map.peek_highest(),
+            DynArrayHeapMapInner::Dim11(map) => map.peek_highest(),
+            DynArrayHeapMapInner::Dim12(map) => map.peek_highest(),
+            DynArrayHeapMapInner::Dim13(map) => map.peek_highest(),
+            DynArrayHeapMapInner::Dim14(map) => map.peek_highest(),
+            DynArrayHeapMapInner::Dim15(map) => map.peek_highest(),
+            DynArrayHeapMapInner::Dim16(map) => map.peek_highest(),
+        }
+    }
+
+    /// Removes the entry with the highest key from the map.
+    pub(super) fn evict_highest(&mut self) {
+        match &mut self.0 {
+            DynArrayHeapMapInner::Dim1(map) => map.evict_highest(),
+            DynArrayHeapMapInner::Dim2(map) => map.evict_highest(),
+            DynArrayHeapMapInner::Dim3(map) => map.evict_highest(),
+            DynArrayHeapMapInner::Dim4(map) => map.evict_highest(),
+            DynArrayHeapMapInner::Dim5(map) => map.evict_highest(),
+            DynArrayHeapMapInner::Dim6(map) => map.evict_highest(),
+            DynArrayHeapMapInner::Dim7(map) => map.evict_highest(),
+            DynArrayHeapMapInner::Dim8(map) => map.evict_highest(),
+            DynArrayHeapMapInner::Dim9(map) => map.evict_highest(),
+            DynArrayHeapMapInner::Dim10(map) => map.evict_highest(),
+            DynArrayHeapMapInner::Dim11(map) => map.evict_highest(),
+            DynArrayHeapMapInner::Dim12(map) => map.evict_highest(),
+            DynArrayHeapMapInner::Dim13(map) => map.evict_highest(),
+            DynArrayHeapMapInner::Dim14(map) => map.evict_highest(),
+            DynArrayHeapMapInner::Dim15(map) => map.evict_highest(),
+            DynArrayHeapMapInner::Dim16(map) => map.evict_highest(),
+        }
+    }
+
+    pub(crate) fn memory_consumption(&self) -> u64 {
+        match &self.0 {
+            DynArrayHeapMapInner::Dim1(map) => map.memory_consumption(),
+            DynArrayHeapMapInner::Dim2(map) => map.memory_consumption(),
+            DynArrayHeapMapInner::Dim3(map) => map.memory_consumption(),
+            DynArrayHeapMapInner::Dim4(map) => map.memory_consumption(),
+            DynArrayHeapMapInner::Dim5(map) => map.memory_consumption(),
+            DynArrayHeapMapInner::Dim6(map) => map.memory_consumption(),
+            DynArrayHeapMapInner::Dim7(map) => map.memory_consumption(),
+            DynArrayHeapMapInner::Dim8(map) => map.memory_consumption(),
+            DynArrayHeapMapInner::Dim9(map) => map.memory_consumption(),
+            DynArrayHeapMapInner::Dim10(map) => map.memory_consumption(),
+            DynArrayHeapMapInner::Dim11(map) => map.memory_consumption(),
+            DynArrayHeapMapInner::Dim12(map) => map.memory_consumption(),
+            DynArrayHeapMapInner::Dim13(map) => map.memory_consumption(),
+            DynArrayHeapMapInner::Dim14(map) => map.memory_consumption(),
+            DynArrayHeapMapInner::Dim15(map) => map.memory_consumption(),
+            DynArrayHeapMapInner::Dim16(map) => map.memory_consumption(),
+        }
+    }
+}
+
+impl<K: Ord + Clone + Copy + 'static, V: 'static> DynArrayHeapMap<K, V> {
+    /// Turns this map into an iterator over key-value pairs.
+    pub fn into_iter(self) -> impl Iterator<Item = (SmallVec<[K; MAX_DYN_ARRAY_SIZE]>, V)> {
+        match self.0 {
+            DynArrayHeapMapInner::Dim1(map) => map.into_iter(),
+            DynArrayHeapMapInner::Dim2(map) => map.into_iter(),
+            DynArrayHeapMapInner::Dim3(map) => map.into_iter(),
+            DynArrayHeapMapInner::Dim4(map) => map.into_iter(),
+            DynArrayHeapMapInner::Dim5(map) => map.into_iter(),
+            DynArrayHeapMapInner::Dim6(map) => map.into_iter(),
+            DynArrayHeapMapInner::Dim7(map) => map.into_iter(),
+            DynArrayHeapMapInner::Dim8(map) => map.into_iter(),
+            DynArrayHeapMapInner::Dim9(map) => map.into_iter(),
+            DynArrayHeapMapInner::Dim10(map) => map.into_iter(),
+            DynArrayHeapMapInner::Dim11(map) => map.into_iter(),
+            DynArrayHeapMapInner::Dim12(map) => map.into_iter(),
+            DynArrayHeapMapInner::Dim13(map) => map.into_iter(),
+            DynArrayHeapMapInner::Dim14(map) => map.into_iter(),
+            DynArrayHeapMapInner::Dim15(map) => map.into_iter(),
+            DynArrayHeapMapInner::Dim16(map) => map.into_iter(),
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_dyn_array_heap_map() {
+        let mut map = DynArrayHeapMap::<u32, &str>::try_new(2).unwrap();
+        // insert
+        let key1 = [1u32, 2u32];
+        let key2 = [2u32, 1u32];
+        map.get_or_insert_with(&key1, || "a");
+        map.get_or_insert_with(&key2, || "b");
+        assert_eq!(map.size(), 2);
+
+        // evict highest
+        assert_eq!(map.peek_highest(), Some(&key2[..]));
+        map.evict_highest();
+        assert_eq!(map.size(), 1);
+        assert_eq!(map.peek_highest(), Some(&key1[..]));
+
+        // into_iter
+        let mut iter = map.into_iter();
+        let (k, v) = iter.next().unwrap();
+        assert_eq!(k.as_slice(), &key1);
+        assert_eq!(v, "c");
+        assert_eq!(iter.next(), None);
+    }
+}

src/aggregation/bucket/composite/numeric_types.rs

@@ -0,0 +1,460 @@
+/// This modules helps comparing numerical values of different types (i64, u64
+/// and f64).
+pub(super) mod num_cmp {
+    use std::cmp::Ordering;
+
+    use crate::TantivyError;
+
+    pub fn cmp_i64_f64(left_i: i64, right_f: f64) -> crate::Result<Ordering> {
+        if right_f.is_nan() {
+            return Err(TantivyError::InvalidArgument(
+                "NaN comparison is not supported".to_string(),
+            ));
+        }
+
+        // If right_f is < i64::MIN then left_i > right_f (i64::MIN=-2^63 can be
+        // exactly represented as f64)
+        if right_f < i64::MIN as f64 {
+            return Ok(Ordering::Greater);
+        }
+        // If right_f is >= i64::MAX then left_i < right_f (i64::MAX=2^63-1 cannot
+        // be exactly represented as f64)
+        if right_f >= i64::MAX as f64 {
+            return Ok(Ordering::Less);
+        }
+
+        // Now right_f is in (i64::MIN, i64::MAX), so `right_f as i64` is
+        // well-defined (truncation toward 0)
+        let right_as_i = right_f as i64;
+
+        let result = match left_i.cmp(&right_as_i) {
+            Ordering::Less => Ordering::Less,
+            Ordering::Greater => Ordering::Greater,
+            Ordering::Equal => {
+                // they have the same integer part, compare the fraction
+                let rem = right_f - (right_as_i as f64);
+                if rem == 0.0 {
+                    Ordering::Equal
+                } else if right_f > 0.0 {
+                    Ordering::Less
+                } else {
+                    Ordering::Greater
+                }
+            }
+        };
+        Ok(result)
+    }
+
+    pub fn cmp_u64_f64(left_u: u64, right_f: f64) -> crate::Result<Ordering> {
+        if right_f.is_nan() {
+            return Err(TantivyError::InvalidArgument(
+                "NaN comparison is not supported".to_string(),
+            ));
+        }
+
+        // Negative floats are always less than any u64 >= 0
+        if right_f < 0.0 {
+            return Ok(Ordering::Greater);
+        }
+
+        // If right_f is >= u64::MAX then left_u < right_f (u64::MAX=2^64-1 cannot be exactly)
+        let max_as_f = u64::MAX as f64;
+        if right_f > max_as_f {
+            return Ok(Ordering::Less);
+        }
+
+        // Now right_f is in (0, u64::MAX), so `right_f as u64` is well-defined
+        // (truncation toward 0)
+        let right_as_u = right_f as u64;
+
+        let result = match left_u.cmp(&right_as_u) {
+            Ordering::Less => Ordering::Less,
+            Ordering::Greater => Ordering::Greater,
+            Ordering::Equal => {
+                // they have the same integer part, compare the fraction
+                let rem = right_f - (right_as_u as f64);
+                if rem == 0.0 {
+                    Ordering::Equal
+                } else {
+                    Ordering::Less
+                }
+            }
+        };
+        Ok(result)
+    }
+
+    pub fn cmp_i64_u64(left_i: i64, right_u: u64) -> Ordering {
+        if left_i < 0 {
+            Ordering::Less
+        } else {
+            let left_as_u = left_i as u64;
+            left_as_u.cmp(&right_u)
+        }
+    }
+}
+
+/// This modules helps projecting numerical values to other numerical types.
+/// When the target value space cannot exactly represent the source value, the
+/// next representable value is returned (or AfterLast if the source value is
+/// larger than the largest representable value).
+///
+/// All functions in this module assume that f64 values are not NaN.
+pub(super) mod num_proj {
+    #[derive(Debug, PartialEq)]
+    pub enum ProjectedNumber<T> {
+        Exact(T),
+        Next(T),
+        AfterLast,
+    }
+
+    pub fn i64_to_u64(value: i64) -> ProjectedNumber<u64> {
+        if value < 0 {
+            ProjectedNumber::Next(0)
+        } else {
+            ProjectedNumber::Exact(value as u64)
+        }
+    }
+
+    pub fn u64_to_i64(value: u64) -> ProjectedNumber<i64> {
+        if value > i64::MAX as u64 {
+            ProjectedNumber::AfterLast
+        } else {
+            ProjectedNumber::Exact(value as i64)
+        }
+    }
+
+    pub fn f64_to_u64(value: f64) -> ProjectedNumber<u64> {
+        if value < 0.0 {
+            ProjectedNumber::Next(0)
+        } else if value > u64::MAX as f64 {
+            ProjectedNumber::AfterLast
+        } else if value.fract() == 0.0 {
+            ProjectedNumber::Exact(value as u64)
+        } else {
+            // casting f64 to u64 truncates toward zero
+            ProjectedNumber::Next(value as u64 + 1)
+        }
+    }
+
+    pub fn f64_to_i64(value: f64) -> ProjectedNumber<i64> {
+        if value < (i64::MIN as f64) {
+            return ProjectedNumber::Next(i64::MIN);
+        } else if value >= (i64::MAX as f64) {
+            return ProjectedNumber::AfterLast;
+        } else if value.fract() == 0.0 {
+            ProjectedNumber::Exact(value as i64)
+        } else if value > 0.0 {
+            // casting f64 to i64 truncates toward zero
+            ProjectedNumber::Next(value as i64 + 1)
+        } else {
+            ProjectedNumber::Next(value as i64)
+        }
+    }
+
+    pub fn i64_to_f64(value: i64) -> ProjectedNumber<f64> {
+        let value_f = value as f64;
+        let k_roundtrip = value_f as i64;
+        if k_roundtrip == value {
+            // between -2^53 and 2^53 all i64 are exactly represented as f64
+            ProjectedNumber::Exact(value_f)
+        } else {
+            // for very large/small i64 values, it is approximated to the closest f64
+            if k_roundtrip > value {
+                ProjectedNumber::Next(value_f)
+            } else {
+                ProjectedNumber::Next(value_f.next_up())
+            }
+        }
+    }
+
+    pub fn u64_to_f64(value: u64) -> ProjectedNumber<f64> {
+        let value_f = value as f64;
+        let k_roundtrip = value_f as u64;
+        if k_roundtrip == value {
+            // between 0 and 2^53 all u64 are exactly represented as f64
+            ProjectedNumber::Exact(value_f)
+        } else if k_roundtrip > value {
+            ProjectedNumber::Next(value_f)
+        } else {
+            ProjectedNumber::Next(value_f.next_up())
+        }
+    }
+}
+
+#[cfg(test)]
+mod num_cmp_tests {
+    use std::cmp::Ordering;
+
+    use super::num_cmp::*;
+
+    #[test]
+    fn test_cmp_u64_f64() {
+        // Basic comparisons
+        assert_eq!(cmp_u64_f64(5, 5.0).unwrap(), Ordering::Equal);
+        assert_eq!(cmp_u64_f64(5, 6.0).unwrap(), Ordering::Less);
+        assert_eq!(cmp_u64_f64(6, 5.0).unwrap(), Ordering::Greater);
+        assert_eq!(cmp_u64_f64(0, 0.0).unwrap(), Ordering::Equal);
+        assert_eq!(cmp_u64_f64(0, 0.1).unwrap(), Ordering::Less);
+
+        // Negative float values should always be less than any u64
+        assert_eq!(cmp_u64_f64(0, -0.1).unwrap(), Ordering::Greater);
+        assert_eq!(cmp_u64_f64(5, -5.0).unwrap(), Ordering::Greater);
+        assert_eq!(cmp_u64_f64(u64::MAX, -1e20).unwrap(), Ordering::Greater);
+
+        // Tests with extreme values
+        assert_eq!(cmp_u64_f64(u64::MAX, 1e20).unwrap(), Ordering::Less);
+
+        // Precision edge cases: large u64 that loses precision when converted to f64
+        // => 2^54, exactly represented as f64
+        let large_f64 = 18_014_398_509_481_984.0;
+        let large_u64 = 18_014_398_509_481_984;
+        // prove that large_u64 is exactly represented as f64
+        assert_eq!(large_u64 as f64, large_f64);
+        assert_eq!(cmp_u64_f64(large_u64, large_f64).unwrap(), Ordering::Equal);
+        // => (2^54 + 1) cannot be exactly represented in f64
+        let large_u64_plus_1 = 18_014_398_509_481_985;
+        // prove that it is represented as f64 by large_f64
+        assert_eq!(large_u64_plus_1 as f64, large_f64);
+        assert_eq!(
+            cmp_u64_f64(large_u64_plus_1, large_f64).unwrap(),
+            Ordering::Greater
+        );
+        // => (2^54 - 1) cannot be exactly represented in f64
+        let large_u64_minus_1 = 18_014_398_509_481_983;
+        // prove that it is also represented as f64 by large_f64
+        assert_eq!(large_u64_minus_1 as f64, large_f64);
+        assert_eq!(
+            cmp_u64_f64(large_u64_minus_1, large_f64).unwrap(),
+            Ordering::Less
+        );
+
+        // NaN comparison results in an error
+        assert!(cmp_u64_f64(0, f64::NAN).is_err());
+    }
+
+    #[test]
+    fn test_cmp_i64_f64() {
+        // Basic comparisons
+        assert_eq!(cmp_i64_f64(5, 5.0).unwrap(), Ordering::Equal);
+        assert_eq!(cmp_i64_f64(5, 6.0).unwrap(), Ordering::Less);
+        assert_eq!(cmp_i64_f64(6, 5.0).unwrap(), Ordering::Greater);
+        assert_eq!(cmp_i64_f64(-5, -5.0).unwrap(), Ordering::Equal);
+        assert_eq!(cmp_i64_f64(-5, -4.0).unwrap(), Ordering::Less);
+        assert_eq!(cmp_i64_f64(-4, -5.0).unwrap(), Ordering::Greater);
+        assert_eq!(cmp_i64_f64(-5, 5.0).unwrap(), Ordering::Less);
+        assert_eq!(cmp_i64_f64(5, -5.0).unwrap(), Ordering::Greater);
+        assert_eq!(cmp_i64_f64(0, -0.1).unwrap(), Ordering::Greater);
+        assert_eq!(cmp_i64_f64(0, 0.1).unwrap(), Ordering::Less);
+        assert_eq!(cmp_i64_f64(-1, -0.5).unwrap(), Ordering::Less);
+        assert_eq!(cmp_i64_f64(-1, 0.0).unwrap(), Ordering::Less);
+        assert_eq!(cmp_i64_f64(0, 0.0).unwrap(), Ordering::Equal);
+
+        // Tests with extreme values
+        assert_eq!(cmp_i64_f64(i64::MAX, 1e20).unwrap(), Ordering::Less);
+        assert_eq!(cmp_i64_f64(i64::MIN, -1e20).unwrap(), Ordering::Greater);
+
+        // Precision edge cases: large i64 that loses precision when converted to f64
+        // => 2^54, exactly represented as f64
+        let large_f64 = 18_014_398_509_481_984.0;
+        let large_i64 = 18_014_398_509_481_984;
+        // prove that large_i64 is exactly represented as f64
+        assert_eq!(large_i64 as f64, large_f64);
+        assert_eq!(cmp_i64_f64(large_i64, large_f64).unwrap(), Ordering::Equal);
+        // => (1_i64 << 54) + 1 cannot be exactly represented in f64
+        let large_i64_plus_1 = 18_014_398_509_481_985;
+        // prove that it is represented as f64 by large_f64
+        assert_eq!(large_i64_plus_1 as f64, large_f64);
+        assert_eq!(
+            cmp_i64_f64(large_i64_plus_1, large_f64).unwrap(),
+            Ordering::Greater
+        );
+        // => (1_i64 << 54) - 1 cannot be exactly represented in f64
+        let large_i64_minus_1 = 18_014_398_509_481_983;
+        // prove that it is also represented as f64 by large_f64
+        assert_eq!(large_i64_minus_1 as f64, large_f64);
+        assert_eq!(
+            cmp_i64_f64(large_i64_minus_1, large_f64).unwrap(),
+            Ordering::Less
+        );
+
+        // Same precision edge case but with negative values
+        // => -2^54, exactly represented as f64
+        let large_neg_f64 = -18_014_398_509_481_984.0;
+        let large_neg_i64 = -18_014_398_509_481_984;
+        // prove that large_neg_i64 is exactly represented as f64
+        assert_eq!(large_neg_i64 as f64, large_neg_f64);
+        assert_eq!(
+            cmp_i64_f64(large_neg_i64, large_neg_f64).unwrap(),
+            Ordering::Equal
+        );
+        // => (-2^54 + 1) cannot be exactly represented in f64
+        let large_neg_i64_plus_1 = -18_014_398_509_481_985;
+        // prove that it is represented as f64 by large_neg_f64
+        assert_eq!(large_neg_i64_plus_1 as f64, large_neg_f64);
+        assert_eq!(
+            cmp_i64_f64(large_neg_i64_plus_1, large_neg_f64).unwrap(),
+            Ordering::Less
+        );
+        // => (-2^54 - 1) cannot be exactly represented in f64
+        let large_neg_i64_minus_1 = -18_014_398_509_481_983;
+        // prove that it is also represented as f64 by large_neg_f64
+        assert_eq!(large_neg_i64_minus_1 as f64, large_neg_f64);
+        assert_eq!(
+            cmp_i64_f64(large_neg_i64_minus_1, large_neg_f64).unwrap(),
+            Ordering::Greater
+        );
+
+        // NaN comparison results in an error
+        assert!(cmp_i64_f64(0, f64::NAN).is_err());
+    }
+
+    #[test]
+    fn test_cmp_i64_u64() {
+        // Test with negative i64 values (should always be less than any u64)
+        assert_eq!(cmp_i64_u64(-1, 0), Ordering::Less);
+        assert_eq!(cmp_i64_u64(i64::MIN, 0), Ordering::Less);
+        assert_eq!(cmp_i64_u64(i64::MIN, u64::MAX), Ordering::Less);
+
+        // Test with positive i64 values
+        assert_eq!(cmp_i64_u64(0, 0), Ordering::Equal);
+        assert_eq!(cmp_i64_u64(1, 0), Ordering::Greater);
+        assert_eq!(cmp_i64_u64(1, 1), Ordering::Equal);
+        assert_eq!(cmp_i64_u64(0, 1), Ordering::Less);
+        assert_eq!(cmp_i64_u64(5, 10), Ordering::Less);
+        assert_eq!(cmp_i64_u64(10, 5), Ordering::Greater);
+
+        // Test with values near i64::MAX and u64 conversion
+        assert_eq!(cmp_i64_u64(i64::MAX, i64::MAX as u64), Ordering::Equal);
+        assert_eq!(cmp_i64_u64(i64::MAX, (i64::MAX as u64) + 1), Ordering::Less);
+        assert_eq!(cmp_i64_u64(i64::MAX, u64::MAX), Ordering::Less);
+    }
+}
+
+#[cfg(test)]
+mod num_proj_tests {
+    use super::num_proj::{self, ProjectedNumber};
+
+    #[test]
+    fn test_i64_to_u64() {
+        assert_eq!(num_proj::i64_to_u64(-1), ProjectedNumber::Next(0));
+        assert_eq!(num_proj::i64_to_u64(i64::MIN), ProjectedNumber::Next(0));
+        assert_eq!(num_proj::i64_to_u64(0), ProjectedNumber::Exact(0));
+        assert_eq!(num_proj::i64_to_u64(42), ProjectedNumber::Exact(42));
+        assert_eq!(
+            num_proj::i64_to_u64(i64::MAX),
+            ProjectedNumber::Exact(i64::MAX as u64)
+        );
+    }
+
+    #[test]
+    fn test_u64_to_i64() {
+        assert_eq!(num_proj::u64_to_i64(0), ProjectedNumber::Exact(0));
+        assert_eq!(num_proj::u64_to_i64(42), ProjectedNumber::Exact(42));
+        assert_eq!(
+            num_proj::u64_to_i64(i64::MAX as u64),
+            ProjectedNumber::Exact(i64::MAX)
+        );
+        assert_eq!(
+            num_proj::u64_to_i64((i64::MAX as u64) + 1),
+            ProjectedNumber::AfterLast
+        );
+        assert_eq!(num_proj::u64_to_i64(u64::MAX), ProjectedNumber::AfterLast);
+    }
+
+    #[test]
+    fn test_f64_to_u64() {
+        assert_eq!(num_proj::f64_to_u64(-1e25), ProjectedNumber::Next(0));
+        assert_eq!(num_proj::f64_to_u64(-0.1), ProjectedNumber::Next(0));
+        assert_eq!(num_proj::f64_to_u64(1e20), ProjectedNumber::AfterLast);
+        assert_eq!(
+            num_proj::f64_to_u64(f64::INFINITY),
+            ProjectedNumber::AfterLast
+        );
+        assert_eq!(num_proj::f64_to_u64(0.0), ProjectedNumber::Exact(0));
+        assert_eq!(num_proj::f64_to_u64(42.0), ProjectedNumber::Exact(42));
+        assert_eq!(num_proj::f64_to_u64(0.5), ProjectedNumber::Next(1));
+        assert_eq!(num_proj::f64_to_u64(42.1), ProjectedNumber::Next(43));
+    }
+
+    #[test]
+    fn test_f64_to_i64() {
+        assert_eq!(num_proj::f64_to_i64(-1e20), ProjectedNumber::Next(i64::MIN));
+        assert_eq!(
+            num_proj::f64_to_i64(f64::NEG_INFINITY),
+            ProjectedNumber::Next(i64::MIN)
+        );
+        assert_eq!(num_proj::f64_to_i64(1e20), ProjectedNumber::AfterLast);
+        assert_eq!(
+            num_proj::f64_to_i64(f64::INFINITY),
+            ProjectedNumber::AfterLast
+        );
+        assert_eq!(num_proj::f64_to_i64(0.0), ProjectedNumber::Exact(0));
+        assert_eq!(num_proj::f64_to_i64(42.0), ProjectedNumber::Exact(42));
+        assert_eq!(num_proj::f64_to_i64(-42.0), ProjectedNumber::Exact(-42));
+        assert_eq!(num_proj::f64_to_i64(0.5), ProjectedNumber::Next(1));
+        assert_eq!(num_proj::f64_to_i64(42.1), ProjectedNumber::Next(43));
+        assert_eq!(num_proj::f64_to_i64(-0.5), ProjectedNumber::Next(0));
+        assert_eq!(num_proj::f64_to_i64(-42.1), ProjectedNumber::Next(-42));
+    }
+
+    #[test]
+    fn test_i64_to_f64() {
+        assert_eq!(num_proj::i64_to_f64(0), ProjectedNumber::Exact(0.0));
+        assert_eq!(num_proj::i64_to_f64(42), ProjectedNumber::Exact(42.0));
+        assert_eq!(num_proj::i64_to_f64(-42), ProjectedNumber::Exact(-42.0));
+
+        let max_exact = 9_007_199_254_740_992; // 2^53
+        assert_eq!(
+            num_proj::i64_to_f64(max_exact),
+            ProjectedNumber::Exact(max_exact as f64)
+        );
+
+        // Test values that cannot be exactly represented as f64 (integers above 2^53)
+        let large_i64 = 9_007_199_254_740_993; // 2^53 + 1
+        let closest_f64 = 9_007_199_254_740_992.0;
+        assert_eq!(large_i64 as f64, closest_f64);
+        if let ProjectedNumber::Next(val) = num_proj::i64_to_f64(large_i64) {
+            // Verify that the returned float is different from the direct cast
+            assert!(val > closest_f64);
+            assert!(val - closest_f64 < 2. * f64::EPSILON * closest_f64);
+        } else {
+            panic!("Expected ProjectedNumber::Next for large_i64");
+        }
+
+        // Test with very large negative value
+        let large_neg_i64 = -9_007_199_254_740_993; // -(2^53 + 1)
+        let closest_neg_f64 = -9_007_199_254_740_992.0;
+        assert_eq!(large_neg_i64 as f64, closest_neg_f64);
+        if let ProjectedNumber::Next(val) = num_proj::i64_to_f64(large_neg_i64) {
+            // Verify that the returned float is the closest representable f64
+            assert_eq!(val, closest_neg_f64);
+        } else {
+            panic!("Expected ProjectedNumber::Next for large_neg_i64");
+        }
+    }
+
+    #[test]
+    fn test_u64_to_f64() {
+        assert_eq!(num_proj::u64_to_f64(0), ProjectedNumber::Exact(0.0));
+        assert_eq!(num_proj::u64_to_f64(42), ProjectedNumber::Exact(42.0));
+
+        // Test the largest u64 value that can be exactly represented as f64 (2^53)
+        let max_exact = 9_007_199_254_740_992; // 2^53
+        assert_eq!(
+            num_proj::u64_to_f64(max_exact),
+            ProjectedNumber::Exact(max_exact as f64)
+        );
+
+        // Test values that cannot be exactly represented as f64 (integers above 2^53)
+        let large_u64 = 9_007_199_254_740_993; // 2^53 + 1
+        let closest_f64 = 9_007_199_254_740_992.0;
+        assert_eq!(large_u64 as f64, closest_f64);
+        if let ProjectedNumber::Next(val) = num_proj::u64_to_f64(large_u64) {
+            // Verify that the returned float is different from the direct cast
+            assert!(val > closest_f64);
+            assert!(val - closest_f64 < 2. * f64::EPSILON * closest_f64);
+        } else {
+            panic!("Expected ProjectedNumber::Next for large_u64");
+        }
+    }
+}

src/aggregation/bucket/histogram/date_histogram.rs

@@ -207,7 +207,7 @@ fn parse_offset_into_milliseconds(input: &str) -> Result<i64, AggregationError>
     }
 }
 
-fn parse_into_milliseconds(input: &str) -> Result<i64, AggregationError> {
+pub(crate) fn parse_into_milliseconds(input: &str) -> Result<i64, AggregationError> {
     let split_boundary = input
         .as_bytes()
         .iter()

src/aggregation/bucket/mod.rs

@@ -22,6 +22,7 @@
 //! - [Range](RangeAggregation)
 //! - [Terms](TermsAggregation)
 
+mod composite;
 mod filter;
 mod histogram;
 mod range;
@@ -31,6 +32,7 @@ mod term_missing_agg;
 use std::collections::HashMap;
 use std::fmt;
 
+pub use composite::*;
 pub use filter::*;
 pub use histogram::*;
 pub use range::*;

src/aggregation/intermediate_agg_result.rs

@@ -15,8 +15,9 @@ use serde::{Deserialize, Serialize};
 use super::agg_req::{Aggregation, AggregationVariants, Aggregations};
 use super::agg_result::{AggregationResult, BucketResult, MetricResult, RangeBucketEntry};
 use super::bucket::{
-    cut_off_buckets, get_agg_name_and_property, intermediate_histogram_buckets_to_final_buckets,
-    GetDocCount, Order, OrderTarget, RangeAggregation, TermsAggregation,
+    composite_intermediate_key_ordering, cut_off_buckets, get_agg_name_and_property,
+    intermediate_histogram_buckets_to_final_buckets, CompositeAggregation, GetDocCount,
+    MissingOrder, Order, OrderTarget, RangeAggregation, TermsAggregation,
 };
 use super::metric::{
     IntermediateAverage, IntermediateCount, IntermediateExtendedStats, IntermediateMax,
@@ -25,7 +26,7 @@ use super::metric::{
 use super::segment_agg_result::AggregationLimitsGuard;
 use super::{format_date, AggregationError, Key, SerializedKey};
 use crate::aggregation::agg_result::{
-    AggregationResults, BucketEntries, BucketEntry, FilterBucketResult,
+    AggregationResults, BucketEntries, BucketEntry, CompositeBucketEntry, FilterBucketResult,
 };
 use crate::aggregation::bucket::TermsAggregationInternal;
 use crate::aggregation::metric::CardinalityCollector;
@@ -90,6 +91,19 @@ impl From<IntermediateKey> for Key {
 
 impl Eq for IntermediateKey {}
 
+impl std::fmt::Display for IntermediateKey {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            IntermediateKey::Str(val) => f.write_str(val),
+            IntermediateKey::F64(val) => f.write_str(&val.to_string()),
+            IntermediateKey::U64(val) => f.write_str(&val.to_string()),
+            IntermediateKey::I64(val) => f.write_str(&val.to_string()),
+            IntermediateKey::Bool(val) => f.write_str(&val.to_string()),
+            IntermediateKey::IpAddr(val) => f.write_str(&val.to_string()),
+        }
+    }
+}
+
 impl std::hash::Hash for IntermediateKey {
     fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
         core::mem::discriminant(self).hash(state);
@@ -105,6 +119,21 @@ impl std::hash::Hash for IntermediateKey {
 }
 
 impl IntermediateAggregationResults {
+    /// Returns a reference to the intermediate aggregation result for the given key.
+    pub fn get(&self, key: &str) -> Option<&IntermediateAggregationResult> {
+        self.aggs_res.get(key)
+    }
+
+    /// Removes and returns the intermediate aggregation result for the given key.
+    pub fn remove(&mut self, key: &str) -> Option<IntermediateAggregationResult> {
+        self.aggs_res.remove(key)
+    }
+
+    /// Returns an iterator over the keys in the intermediate aggregation results.
+    pub fn keys(&self) -> impl Iterator<Item = &String> {
+        self.aggs_res.keys()
+    }
+
     /// Add a result
     pub fn push(&mut self, key: String, value: IntermediateAggregationResult) -> crate::Result<()> {
         let entry = self.aggs_res.entry(key);
@@ -252,6 +281,11 @@ pub(crate) fn empty_from_req(req: &Aggregation) -> IntermediateAggregationResult
             doc_count: 0,
             sub_aggregations: IntermediateAggregationResults::default(),
         }),
+        Composite(_) => {
+            IntermediateAggregationResult::Bucket(IntermediateBucketResult::Composite {
+                buckets: IntermediateCompositeBucketResult::default(),
+            })
+        }
     }
 }
 
@@ -445,6 +479,11 @@ pub enum IntermediateBucketResult {
         /// Sub-aggregation results
         sub_aggregations: IntermediateAggregationResults,
     },
+    /// Composite aggregation
+    Composite {
+        /// The composite buckets
+        buckets: IntermediateCompositeBucketResult,
+    },
 }
 
 impl IntermediateBucketResult {
@@ -540,6 +579,13 @@ impl IntermediateBucketResult {
                     sub_aggregations: final_sub_aggregations,
                 }))
             }
+            IntermediateBucketResult::Composite { buckets } => {
+                let composite_req = req
+                    .agg
+                    .as_composite()
+                    .expect("unexpected aggregation, expected composite aggregation");
+                buckets.into_final_result(composite_req, req.sub_aggregation(), limits)
+            }
         }
     }
 
@@ -606,6 +652,16 @@ impl IntermediateBucketResult {
                 *doc_count_left += doc_count_right;
                 sub_aggs_left.merge_fruits(sub_aggs_right)?;
             }
+            (
+                IntermediateBucketResult::Composite {
+                    buckets: composite_left,
+                },
+                IntermediateBucketResult::Composite {
+                    buckets: composite_right,
+                },
+            ) => {
+                composite_left.merge_fruits(composite_right)?;
+            }
             (IntermediateBucketResult::Range(_), _) => {
                 panic!("try merge on different types")
             }
@@ -618,6 +674,9 @@ impl IntermediateBucketResult {
             (IntermediateBucketResult::Filter { .. }, _) => {
                 panic!("try merge on different types")
             }
+            (IntermediateBucketResult::Composite { .. }, _) => {
+                panic!("try merge on different types")
+            }
         }
         Ok(())
     }
@@ -639,6 +698,21 @@ pub struct IntermediateTermBucketResult {
 }
 
 impl IntermediateTermBucketResult {
+    /// Returns a reference to the map of bucket entries keyed by [`IntermediateKey`].
+    pub fn entries(&self) -> &FxHashMap<IntermediateKey, IntermediateTermBucketEntry> {
+        &self.entries
+    }
+
+    /// Returns the count of documents not included in the returned buckets.
+    pub fn sum_other_doc_count(&self) -> u64 {
+        self.sum_other_doc_count
+    }
+
+    /// Returns the upper bound of the error on document counts in the returned buckets.
+    pub fn doc_count_error_upper_bound(&self) -> u64 {
+        self.doc_count_error_upper_bound
+    }
+
     pub(crate) fn into_final_result(
         self,
         req: &TermsAggregation,
@@ -820,7 +894,7 @@ 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)?;
@@ -871,6 +945,176 @@ impl MergeFruits for IntermediateHistogramBucketEntry {
     }
 }
 
+/// Entry for the composite bucket.
+pub type IntermediateCompositeBucketEntry = IntermediateTermBucketEntry;
+
+/// The fully typed key for composite aggregation
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+pub enum CompositeIntermediateKey {
+    /// Bool key
+    Bool(bool),
+    /// String key
+    Str(String),
+    /// Float key
+    F64(f64),
+    /// Signed integer key
+    I64(i64),
+    /// Unsigned integer key
+    U64(u64),
+    /// DateTime key, nanoseconds since epoch
+    DateTime(i64),
+    /// IP Address key
+    IpAddr(Ipv6Addr),
+    /// Missing value key
+    Null,
+}
+
+impl Eq for CompositeIntermediateKey {}
+
+impl std::hash::Hash for CompositeIntermediateKey {
+    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
+        core::mem::discriminant(self).hash(state);
+        match self {
+            CompositeIntermediateKey::Bool(val) => val.hash(state),
+            CompositeIntermediateKey::Str(text) => text.hash(state),
+            CompositeIntermediateKey::F64(val) => val.to_bits().hash(state),
+            CompositeIntermediateKey::U64(val) => val.hash(state),
+            CompositeIntermediateKey::I64(val) => val.hash(state),
+            CompositeIntermediateKey::DateTime(val) => val.hash(state),
+            CompositeIntermediateKey::IpAddr(val) => val.hash(state),
+            CompositeIntermediateKey::Null => {}
+        }
+    }
+}
+
+/// Composite aggregation page.
+#[derive(Default, Clone, Debug, PartialEq, Serialize, Deserialize)]
+pub struct IntermediateCompositeBucketResult {
+    pub(crate) entries: FxHashMap<Vec<CompositeIntermediateKey>, IntermediateCompositeBucketEntry>,
+    pub(crate) target_size: u32,
+    pub(crate) orders: Vec<(Order, MissingOrder)>,
+}
+
+impl IntermediateCompositeBucketResult {
+    pub(crate) fn into_final_result(
+        self,
+        req: &CompositeAggregation,
+        sub_aggregation_req: &Aggregations,
+        limits: &mut AggregationLimitsGuard,
+    ) -> crate::Result<BucketResult> {
+        let trimmed_entry_vec =
+            trim_composite_buckets(self.entries, &self.orders, self.target_size)?;
+        let after_key = if trimmed_entry_vec.len() == req.size as usize {
+            trimmed_entry_vec
+                .last()
+                .map(|bucket| {
+                    let (intermediate_key, _entry) = bucket;
+                    intermediate_key
+                        .iter()
+                        .enumerate()
+                        .map(|(idx, intermediate_key)| {
+                            let source = &req.sources[idx];
+                            (source.name().to_string(), intermediate_key.clone().into())
+                        })
+                        .collect()
+                })
+                .unwrap()
+        } else {
+            FxHashMap::default()
+        };
+
+        let buckets = trimmed_entry_vec
+            .into_iter()
+            .map(|(intermediate_key, entry)| {
+                let key = intermediate_key
+                    .into_iter()
+                    .enumerate()
+                    .map(|(idx, intermediate_key)| {
+                        let source = &req.sources[idx];
+                        (source.name().to_string(), intermediate_key.into())
+                    })
+                    .collect();
+                Ok(CompositeBucketEntry {
+                    key,
+                    doc_count: entry.doc_count as u64,
+                    sub_aggregation: entry
+                        .sub_aggregation
+                        .into_final_result_internal(sub_aggregation_req, limits)?,
+                })
+            })
+            .collect::<crate::Result<Vec<_>>>()?;
+
+        Ok(BucketResult::Composite { after_key, buckets })
+    }
+
+    fn merge_fruits(&mut self, other: IntermediateCompositeBucketResult) -> crate::Result<()> {
+        merge_maps(&mut self.entries, other.entries)?;
+        if self.entries.len() as u32 > 2 * self.target_size {
+            self.trim()?;
+        }
+        Ok(())
+    }
+
+    /// Trim the composite buckets to the target size, according to the ordering.
+    pub(crate) fn trim(&mut self) -> crate::Result<()> {
+        if self.entries.len() as u32 <= self.target_size {
+            return Ok(());
+        }
+
+        let sorted_entries = trim_composite_buckets(
+            std::mem::take(&mut self.entries),
+            &self.orders,
+            self.target_size,
+        )?;
+
+        self.entries = sorted_entries.into_iter().collect();
+        Ok(())
+    }
+}
+
+fn trim_composite_buckets(
+    entries: FxHashMap<Vec<CompositeIntermediateKey>, IntermediateCompositeBucketEntry>,
+    orders: &[(Order, MissingOrder)],
+    target_size: u32,
+) -> crate::Result<
+    Vec<(
+        Vec<CompositeIntermediateKey>,
+        IntermediateCompositeBucketEntry,
+    )>,
+> {
+    let mut entries: Vec<_> = entries.into_iter().collect();
+    let mut sort_error: Option<TantivyError> = None;
+    entries.sort_by(|(left_key, _), (right_key, _)| {
+        if sort_error.is_some() {
+            return Ordering::Equal;
+        }
+
+        for idx in 0..orders.len() {
+            match composite_intermediate_key_ordering(
+                &left_key[idx],
+                &right_key[idx],
+                orders[idx].0,
+                orders[idx].1,
+            ) {
+                Ok(ordering) if ordering != Ordering::Equal => return ordering,
+                Ok(_) => continue,
+                Err(err) => {
+                    sort_error = Some(err);
+                    break;
+                }
+            }
+        }
+        Ordering::Equal
+    });
+
+    if let Some(err) = sort_error {
+        return Err(err);
+    }
+
+    entries.truncate(target_size as usize);
+    Ok(entries)
+}
+
 #[cfg(test)]
 mod tests {
     use std::collections::HashMap;

src/aggregation/metric/average.rs

@@ -55,6 +55,12 @@ impl IntermediateAverage {
     pub(crate) fn from_stats(stats: IntermediateStats) -> Self {
         Self { stats }
     }
+
+    /// Returns a reference to the underlying [`IntermediateStats`].
+    pub fn stats(&self) -> &IntermediateStats {
+        &self.stats
+    }
+
     /// Merges the other intermediate result into self.
     pub fn merge_fruits(&mut self, other: IntermediateAverage) {
         self.stats.merge_fruits(other.stats);

src/aggregation/metric/cardinality.rs

@@ -1,12 +1,11 @@
-use std::collections::hash_map::DefaultHasher;
-use std::hash::{BuildHasher, Hasher};
+use std::hash::Hash;
 
 use columnar::column_values::CompactSpaceU64Accessor;
 use columnar::{Column, ColumnType, Dictionary, StrColumn};
 use common::f64_to_u64;
-use hyperloglogplus::{HyperLogLog, HyperLogLogPlus};
+use datasketches::hll::{HllSketch, HllType, HllUnion};
 use rustc_hash::FxHashSet;
-use serde::{Deserialize, Serialize};
+use serde::{Deserialize, Deserializer, Serialize, Serializer};
 
 use crate::aggregation::agg_data::AggregationsSegmentCtx;
 use crate::aggregation::intermediate_agg_result::{
@@ -16,29 +15,17 @@ use crate::aggregation::segment_agg_result::SegmentAggregationCollector;
 use crate::aggregation::*;
 use crate::TantivyError;
 
-#[derive(Clone, Debug, Serialize, Deserialize)]
-struct BuildSaltedHasher {
-    salt: u8,
-}
-
-impl BuildHasher for BuildSaltedHasher {
-    type Hasher = DefaultHasher;
-
-    fn build_hasher(&self) -> Self::Hasher {
-        let mut hasher = DefaultHasher::new();
-        hasher.write_u8(self.salt);
-
-        hasher
-    }
-}
+/// Log2 of the number of registers for the HLL sketch.
+/// 2^11 = 2048 registers, giving ~2.3% relative error and ~1KB per sketch (Hll4).
+const LG_K: u8 = 11;
 
 /// # Cardinality
 ///
 /// The cardinality aggregation allows for computing an estimate
 /// of the number of different values in a data set based on the
-/// HyperLogLog++ algorithm. This is particularly useful for understanding the
-/// uniqueness of values in a large dataset where counting each unique value
-/// individually would be computationally expensive.
+/// Apache DataSketches HyperLogLog algorithm. This is particularly useful for
+/// understanding the uniqueness of values in a large dataset where counting
+/// each unique value individually would be computationally expensive.
 ///
 /// For example, you might use a cardinality aggregation to estimate the number
 /// of unique visitors to a website by aggregating on a field that contains
@@ -184,7 +171,7 @@ impl SegmentCardinalityCollectorBucket {
 
             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);
+                self.cardinality.insert(term);
                 Ok(())
             })?;
             if has_missing {
@@ -195,17 +182,17 @@ impl SegmentCardinalityCollectorBucket {
                     );
                 match missing_key {
                     Key::Str(missing) => {
-                        self.cardinality.sketch.insert_any(&missing);
+                        self.cardinality.insert(missing.as_str());
                     }
                     Key::F64(val) => {
                         let val = f64_to_u64(*val);
-                        self.cardinality.sketch.insert_any(&val);
+                        self.cardinality.insert(val);
                     }
                     Key::U64(val) => {
-                        self.cardinality.sketch.insert_any(&val);
+                        self.cardinality.insert(*val);
                     }
                     Key::I64(val) => {
-                        self.cardinality.sketch.insert_any(&val);
+                        self.cardinality.insert(*val);
                     }
                 }
             }
@@ -296,11 +283,11 @@ impl SegmentAggregationCollector for SegmentCardinalityCollector {
                 })?;
             for val in col_block_accessor.iter_vals() {
                 let val: u128 = compact_space_accessor.compact_to_u128(val as u32);
-                bucket.cardinality.sketch.insert_any(&val);
+                bucket.cardinality.insert(val);
             }
         } else {
             for val in col_block_accessor.iter_vals() {
-                bucket.cardinality.sketch.insert_any(&val);
+                bucket.cardinality.insert(val);
             }
         }
 
@@ -321,11 +308,18 @@ impl SegmentAggregationCollector for SegmentCardinalityCollector {
     }
 }
 
-#[derive(Clone, Debug, Serialize, Deserialize)]
-/// The percentiles collector used during segment collection and for merging results.
+#[derive(Clone, Debug)]
+/// The cardinality collector used during segment collection and for merging results.
+/// Uses Apache DataSketches HLL (lg_k=11, Hll4) for compact binary serialization
+/// and cross-language compatibility (e.g. Java `datasketches` library).
 pub struct CardinalityCollector {
-    sketch: HyperLogLogPlus<u64, BuildSaltedHasher>,
+    sketch: HllSketch,
+    /// Salt derived from `ColumnType`, used to differentiate values of different column types
+    /// that map to the same u64 (e.g. bool `false` = 0 vs i64 `0`).
+    /// Not serialized — only needed during insertion, not after sketch registers are populated.
+    salt: u8,
 }
+
 impl Default for CardinalityCollector {
     fn default() -> Self {
         Self::new(0)
@@ -338,25 +332,52 @@ impl PartialEq for CardinalityCollector {
     }
 }
 
-impl CardinalityCollector {
-    /// Compute the final cardinality estimate.
-    pub fn finalize(self) -> Option<f64> {
-        Some(self.sketch.clone().count().trunc())
+impl Serialize for CardinalityCollector {
+    fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
+        let bytes = self.sketch.serialize();
+        serializer.serialize_bytes(&bytes)
     }
+}
 
+impl<'de> Deserialize<'de> for CardinalityCollector {
+    fn deserialize<D: Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error> {
+        let bytes: Vec<u8> = Deserialize::deserialize(deserializer)?;
+        let sketch = HllSketch::deserialize(&bytes).map_err(serde::de::Error::custom)?;
+        Ok(Self { sketch, salt: 0 })
+    }
+}
+
+impl CardinalityCollector {
     fn new(salt: u8) -> Self {
         Self {
-            sketch: HyperLogLogPlus::new(16, BuildSaltedHasher { salt }).unwrap(),
+            sketch: HllSketch::new(LG_K, HllType::Hll4),
+            salt,
         }
     }
 
-    pub(crate) fn merge_fruits(&mut self, right: CardinalityCollector) -> crate::Result<()> {
-        self.sketch.merge(&right.sketch).map_err(|err| {
-            TantivyError::AggregationError(AggregationError::InternalError(format!(
-                "Error while merging cardinality {err:?}"
-            )))
-        })?;
+    /// Insert a value into the HLL sketch, salted by the column type.
+    /// The salt ensures that identical u64 values from different column types
+    /// (e.g. bool `false` vs i64 `0`) are counted as distinct.
+    pub(crate) fn insert<T: Hash>(&mut self, value: T) {
+        self.sketch.update((self.salt, value));
+    }
 
+    /// Compute the final cardinality estimate.
+    pub fn finalize(self) -> Option<f64> {
+        Some(self.sketch.estimate().trunc())
+    }
+
+    /// Serialize the HLL sketch to its compact binary representation.
+    /// The format is cross-language compatible with Apache DataSketches (Java, C++, Python).
+    pub fn to_sketch_bytes(&self) -> Vec<u8> {
+        self.sketch.serialize()
+    }
+
+    pub(crate) fn merge_fruits(&mut self, right: CardinalityCollector) -> crate::Result<()> {
+        let mut union = HllUnion::new(LG_K);
+        union.update(&self.sketch);
+        union.update(&right.sketch);
+        self.sketch = union.get_result(HllType::Hll4);
         Ok(())
     }
 }
@@ -518,4 +539,75 @@ mod tests {
 
         Ok(())
     }
+
+    #[test]
+    fn cardinality_collector_serde_roundtrip() {
+        use super::CardinalityCollector;
+
+        let mut collector = CardinalityCollector::default();
+        collector.insert("hello");
+        collector.insert("world");
+        collector.insert("hello"); // duplicate
+
+        let serialized = serde_json::to_vec(&collector).unwrap();
+        let deserialized: CardinalityCollector = serde_json::from_slice(&serialized).unwrap();
+
+        let original_estimate = collector.finalize().unwrap();
+        let roundtrip_estimate = deserialized.finalize().unwrap();
+        assert_eq!(original_estimate, roundtrip_estimate);
+        assert_eq!(original_estimate, 2.0);
+    }
+
+    #[test]
+    fn cardinality_collector_merge() {
+        use super::CardinalityCollector;
+
+        let mut left = CardinalityCollector::default();
+        left.insert("a");
+        left.insert("b");
+
+        let mut right = CardinalityCollector::default();
+        right.insert("b");
+        right.insert("c");
+
+        left.merge_fruits(right).unwrap();
+        let estimate = left.finalize().unwrap();
+        assert_eq!(estimate, 3.0);
+    }
+
+    #[test]
+    fn cardinality_collector_serialize_deserialize_binary() {
+        use datasketches::hll::HllSketch;
+
+        use super::CardinalityCollector;
+
+        let mut collector = CardinalityCollector::default();
+        collector.insert("apple");
+        collector.insert("banana");
+        collector.insert("cherry");
+
+        let bytes = collector.to_sketch_bytes();
+        let deserialized = HllSketch::deserialize(&bytes).unwrap();
+        assert!((deserialized.estimate() - 3.0).abs() < 0.01);
+    }
+
+    #[test]
+    fn cardinality_collector_salt_differentiates_types() {
+        use super::CardinalityCollector;
+
+        // Without salt, same u64 value from different column types would collide
+        let mut collector_bool = CardinalityCollector::new(5); // e.g. ColumnType::Bool
+        collector_bool.insert(0u64); // false
+        collector_bool.insert(1u64); // true
+
+        let mut collector_i64 = CardinalityCollector::new(2); // e.g. ColumnType::I64
+        collector_i64.insert(0u64);
+        collector_i64.insert(1u64);
+
+        // Merge them
+        collector_bool.merge_fruits(collector_i64).unwrap();
+        let estimate = collector_bool.finalize().unwrap();
+        // Should be 4 because salt makes (5, 0) != (2, 0) and (5, 1) != (2, 1)
+        assert_eq!(estimate, 4.0);
+    }
 }

src/aggregation/metric/mod.rs

@@ -107,8 +107,11 @@ pub enum PercentileValues {
 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
 /// The entry when requesting percentiles with keyed: false
 pub struct PercentileValuesVecEntry {
-    key: f64,
-    value: f64,
+    /// Percentile
+    pub key: f64,
+
+    /// Value at the percentile
+    pub value: f64,
 }
 
 /// Single-metric aggregations use this common result structure.

src/aggregation/metric/percentiles.rs

@@ -222,6 +222,12 @@ impl PercentilesCollector {
         self.sketch.add(val);
     }
 
+    /// Encode the underlying DDSketch to Java-compatible binary format
+    /// for cross-language serialization with Java consumers.
+    pub fn to_sketch_bytes(&self) -> Vec<u8> {
+        self.sketch.to_java_bytes()
+    }
+
     pub(crate) fn merge_fruits(&mut self, right: PercentilesCollector) -> crate::Result<()> {
         self.sketch.merge(&right.sketch).map_err(|err| {
             TantivyError::AggregationError(AggregationError::InternalError(format!(
@@ -325,7 +331,7 @@ mod tests {
     use crate::aggregation::AggregationCollector;
     use crate::query::AllQuery;
     use crate::schema::{Schema, FAST};
-    use crate::Index;
+    use crate::{assert_nearly_equals, Index};
 
     #[test]
     fn test_aggregation_percentiles_empty_index() -> crate::Result<()> {
@@ -608,12 +614,16 @@ mod tests {
         let res = exec_request_with_query(agg_req, &index, None)?;
         assert_eq!(res["range_with_stats"]["buckets"][0]["doc_count"], 3);
 
-        assert_eq!(
-            res["range_with_stats"]["buckets"][0]["percentiles"]["values"]["1.0"],
+        assert_nearly_equals!(
+            res["range_with_stats"]["buckets"][0]["percentiles"]["values"]["1.0"]
+                .as_f64()
+                .unwrap(),
             5.0028295751107414
         );
-        assert_eq!(
-            res["range_with_stats"]["buckets"][0]["percentiles"]["values"]["99.0"],
+        assert_nearly_equals!(
+            res["range_with_stats"]["buckets"][0]["percentiles"]["values"]["99.0"]
+                .as_f64()
+                .unwrap(),
             10.07469668951144
         );
 
@@ -659,8 +669,14 @@ mod tests {
 
         let res = exec_request_with_query(agg_req, &index, None)?;
 
-        assert_eq!(res["percentiles"]["values"]["1.0"], 5.0028295751107414);
-        assert_eq!(res["percentiles"]["values"]["99.0"], 10.07469668951144);
+        assert_nearly_equals!(
+            res["percentiles"]["values"]["1.0"].as_f64().unwrap(),
+            5.0028295751107414
+        );
+        assert_nearly_equals!(
+            res["percentiles"]["values"]["99.0"].as_f64().unwrap(),
+            10.07469668951144
+        );
 
         Ok(())
     }

src/aggregation/metric/stats.rs

@@ -110,6 +110,16 @@ impl Default for IntermediateStats {
 }
 
 impl IntermediateStats {
+    /// Returns the number of values collected.
+    pub fn count(&self) -> u64 {
+        self.count
+    }
+
+    /// Returns the sum of all values collected.
+    pub fn sum(&self) -> f64 {
+        self.sum
+    }
+
     /// Merges the other stats intermediate result into self.
     pub fn merge_fruits(&mut self, other: IntermediateStats) {
         self.count += other.count;

src/collector/sort_key/mod.rs

@@ -1,4 +1,5 @@
 mod order;
+mod sort_by_bytes;
 mod sort_by_erased_type;
 mod sort_by_score;
 mod sort_by_static_fast_value;
@@ -6,6 +7,7 @@ mod sort_by_string;
 mod sort_key_computer;
 
 pub use order::*;
+pub use sort_by_bytes::SortByBytes;
 pub use sort_by_erased_type::SortByErasedType;
 pub use sort_by_score::SortBySimilarityScore;
 pub use sort_by_static_fast_value::SortByStaticFastValue;

src/collector/sort_key/sort_by_bytes.rs

@@ -0,0 +1,168 @@
+use columnar::BytesColumn;
+
+use crate::collector::sort_key::NaturalComparator;
+use crate::collector::{SegmentSortKeyComputer, SortKeyComputer};
+use crate::termdict::TermOrdinal;
+use crate::{DocId, Score};
+
+/// Sort by the first value of a bytes column.
+///
+/// If the field is multivalued, only the first value is considered.
+///
+/// Documents that do not have this value are still considered.
+/// Their sort key will simply be `None`.
+#[derive(Debug, Clone)]
+pub struct SortByBytes {
+    column_name: String,
+}
+
+impl SortByBytes {
+    /// Creates a new sort by bytes sort key computer.
+    pub fn for_field(column_name: impl ToString) -> Self {
+        SortByBytes {
+            column_name: column_name.to_string(),
+        }
+    }
+}
+
+impl SortKeyComputer for SortByBytes {
+    type SortKey = Option<Vec<u8>>;
+    type Child = ByBytesColumnSegmentSortKeyComputer;
+    type Comparator = NaturalComparator;
+
+    fn segment_sort_key_computer(
+        &self,
+        segment_reader: &crate::SegmentReader,
+    ) -> crate::Result<Self::Child> {
+        let bytes_column_opt = segment_reader.fast_fields().bytes(&self.column_name)?;
+        Ok(ByBytesColumnSegmentSortKeyComputer { bytes_column_opt })
+    }
+}
+
+/// Segment-level sort key computer for bytes columns.
+pub struct ByBytesColumnSegmentSortKeyComputer {
+    bytes_column_opt: Option<BytesColumn>,
+}
+
+impl SegmentSortKeyComputer for ByBytesColumnSegmentSortKeyComputer {
+    type SortKey = Option<Vec<u8>>;
+    type SegmentSortKey = Option<TermOrdinal>;
+    type SegmentComparator = NaturalComparator;
+
+    #[inline(always)]
+    fn segment_sort_key(&mut self, doc: DocId, _score: Score) -> Option<TermOrdinal> {
+        let bytes_column = self.bytes_column_opt.as_ref()?;
+        bytes_column.ords().first(doc)
+    }
+
+    fn convert_segment_sort_key(&self, term_ord_opt: Option<TermOrdinal>) -> Option<Vec<u8>> {
+        // 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 bytes_column = self.bytes_column_opt.as_ref()?;
+        let mut bytes = Vec::new();
+        bytes_column
+            .dictionary()
+            .ord_to_term(term_ord, &mut bytes)
+            .ok()?;
+        Some(bytes)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::SortByBytes;
+    use crate::collector::TopDocs;
+    use crate::query::AllQuery;
+    use crate::schema::{BytesOptions, Schema, FAST, INDEXED};
+    use crate::{Index, IndexWriter, Order, TantivyDocument};
+
+    #[test]
+    fn test_sort_by_bytes_asc() -> crate::Result<()> {
+        let mut schema_builder = Schema::builder();
+        let bytes_field = schema_builder
+            .add_bytes_field("data", BytesOptions::default().set_fast().set_indexed());
+        let id_field = schema_builder.add_u64_field("id", FAST | INDEXED);
+        let schema = schema_builder.build();
+        let index = Index::create_in_ram(schema);
+        let mut index_writer: IndexWriter = index.writer_for_tests()?;
+
+        // Insert documents with byte values in non-sorted order
+        let test_data: Vec<(u64, Vec<u8>)> = vec![
+            (1, vec![0x02, 0x00]),
+            (2, vec![0x00, 0x10]),
+            (3, vec![0x01, 0x00]),
+            (4, vec![0x00, 0x20]),
+        ];
+
+        for (id, bytes) in &test_data {
+            let mut doc = TantivyDocument::new();
+            doc.add_u64(id_field, *id);
+            doc.add_bytes(bytes_field, bytes);
+            index_writer.add_document(doc)?;
+        }
+        index_writer.commit()?;
+
+        let reader = index.reader()?;
+        let searcher = reader.searcher();
+
+        // Sort ascending by bytes
+        let top_docs =
+            TopDocs::with_limit(10).order_by((SortByBytes::for_field("data"), Order::Asc));
+        let results: Vec<(Option<Vec<u8>>, _)> = searcher.search(&AllQuery, &top_docs)?;
+
+        // Expected order: [0x00,0x10], [0x00,0x20], [0x01,0x00], [0x02,0x00]
+        let sorted_bytes: Vec<Option<Vec<u8>>> = results.into_iter().map(|(b, _)| b).collect();
+        assert_eq!(
+            sorted_bytes,
+            vec![
+                Some(vec![0x00, 0x10]),
+                Some(vec![0x00, 0x20]),
+                Some(vec![0x01, 0x00]),
+                Some(vec![0x02, 0x00]),
+            ]
+        );
+
+        Ok(())
+    }
+
+    #[test]
+    fn test_sort_by_bytes_desc() -> crate::Result<()> {
+        let mut schema_builder = Schema::builder();
+        let bytes_field = schema_builder
+            .add_bytes_field("data", BytesOptions::default().set_fast().set_indexed());
+        let schema = schema_builder.build();
+        let index = Index::create_in_ram(schema);
+        let mut index_writer: IndexWriter = index.writer_for_tests()?;
+
+        let test_data: Vec<Vec<u8>> = vec![vec![0x00, 0x10], vec![0x02, 0x00], vec![0x01, 0x00]];
+
+        for bytes in &test_data {
+            let mut doc = TantivyDocument::new();
+            doc.add_bytes(bytes_field, bytes);
+            index_writer.add_document(doc)?;
+        }
+        index_writer.commit()?;
+
+        let reader = index.reader()?;
+        let searcher = reader.searcher();
+
+        // Sort descending by bytes
+        let top_docs =
+            TopDocs::with_limit(10).order_by((SortByBytes::for_field("data"), Order::Desc));
+        let results: Vec<(Option<Vec<u8>>, _)> = searcher.search(&AllQuery, &top_docs)?;
+
+        // Expected order (descending): [0x02,0x00], [0x01,0x00], [0x00,0x10]
+        let sorted_bytes: Vec<Option<Vec<u8>>> = results.into_iter().map(|(b, _)| b).collect();
+        assert_eq!(
+            sorted_bytes,
+            vec![
+                Some(vec![0x02, 0x00]),
+                Some(vec![0x01, 0x00]),
+                Some(vec![0x00, 0x10]),
+            ]
+        );
+
+        Ok(())
+    }
+}

src/collector/sort_key/sort_by_erased_type.rs

@@ -1,7 +1,7 @@
 use columnar::{ColumnType, MonotonicallyMappableToU64};
 
 use crate::collector::sort_key::{
-    NaturalComparator, SortBySimilarityScore, SortByStaticFastValue, SortByString,
+    NaturalComparator, SortByBytes, SortBySimilarityScore, SortByStaticFastValue, SortByString,
 };
 use crate::collector::{SegmentSortKeyComputer, SortKeyComputer};
 use crate::fastfield::FastFieldNotAvailableError;
@@ -114,6 +114,16 @@ impl SortKeyComputer for SortByErasedType {
                             },
                         })
                     }
+                    ColumnType::Bytes => {
+                        let computer = SortByBytes::for_field(column_name);
+                        let inner = computer.segment_sort_key_computer(segment_reader)?;
+                        Box::new(ErasedSegmentSortKeyComputerWrapper {
+                            inner,
+                            converter: |val: Option<Vec<u8>>| {
+                                val.map(OwnedValue::Bytes).unwrap_or(OwnedValue::Null)
+                            },
+                        })
+                    }
                     ColumnType::U64 => {
                         let computer = SortByStaticFastValue::<u64>::for_field(column_name);
                         let inner = computer.segment_sort_key_computer(segment_reader)?;
@@ -281,6 +291,65 @@ mod tests {
         );
     }
 
+    #[test]
+    fn test_sort_by_owned_bytes() {
+        let mut schema_builder = Schema::builder();
+        let data_field = schema_builder.add_bytes_field("data", 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!(data_field => vec![0x03u8, 0x00]))
+            .unwrap();
+        writer
+            .add_document(doc!(data_field => vec![0x01u8, 0x00]))
+            .unwrap();
+        writer
+            .add_document(doc!(data_field => vec![0x02u8, 0x00]))
+            .unwrap();
+        writer.add_document(doc!()).unwrap();
+        writer.commit().unwrap();
+
+        let reader = index.reader().unwrap();
+        let searcher = reader.searcher();
+
+        // Sort descending (Natural - highest first)
+        let collector = TopDocs::with_limit(10)
+            .order_by((SortByErasedType::for_field("data"), 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::Bytes(vec![0x03, 0x00]),
+                OwnedValue::Bytes(vec![0x02, 0x00]),
+                OwnedValue::Bytes(vec![0x01, 0x00]),
+                OwnedValue::Null
+            ]
+        );
+
+        // Sort ascending (ReverseNoneLower - lowest first, nulls last)
+        let collector = TopDocs::with_limit(10).order_by((
+            SortByErasedType::for_field("data"),
+            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::Bytes(vec![0x01, 0x00]),
+                OwnedValue::Bytes(vec![0x02, 0x00]),
+                OwnedValue::Bytes(vec![0x03, 0x00]),
+                OwnedValue::Null
+            ]
+        );
+    }
+
     #[test]
     fn test_sort_by_owned_reverse() {
         let mut schema_builder = Schema::builder();

src/directory/mod.rs

@@ -21,7 +21,7 @@ use std::path::PathBuf;
 pub use common::file_slice::{FileHandle, FileSlice};
 pub use common::{AntiCallToken, OwnedBytes, TerminatingWrite};
 
-pub(crate) use self::composite_file::{CompositeFile, CompositeWrite};
+pub use self::composite_file::{CompositeFile, CompositeWrite};
 pub use self::directory::{Directory, DirectoryClone, DirectoryLock};
 pub use self::directory_lock::{Lock, INDEX_WRITER_LOCK, META_LOCK};
 pub use self::ram_directory::RamDirectory;
@@ -52,7 +52,7 @@ pub use self::mmap_directory::MmapDirectory;
 ///
 /// `WritePtr` are required to implement both Write
 /// and Seek.
-pub type WritePtr = BufWriter<Box<dyn TerminatingWrite>>;
+pub type WritePtr = BufWriter<Box<dyn TerminatingWrite + Send + Sync>>;
 
 #[cfg(test)]
 mod tests;

src/indexer/log_merge_policy.rs

@@ -94,7 +94,7 @@ impl MergePolicy for LogMergePolicy {
     fn compute_merge_candidates(&self, segments: &[SegmentMeta]) -> Vec<MergeCandidate> {
         let size_sorted_segments = segments
             .iter()
-            .filter(|seg| seg.num_docs() <= (self.max_docs_before_merge as u32))
+            .filter(|seg| (seg.num_docs() as usize) <= self.max_docs_before_merge)
             .sorted_by_key(|seg| std::cmp::Reverse(seg.max_doc()))
             .collect::<Vec<&SegmentMeta>>();
 
@@ -372,4 +372,21 @@ mod tests {
         assert_eq!(merge_candidates[0].0.len(), 1);
         assert_eq!(merge_candidates[0].0[0], test_input[1].id());
     }
+
+    #[test]
+    fn test_max_docs_before_merge_large_value() {
+        // Regression test: (max_docs_before_merge as u32) truncates values > u32::MAX.
+        // Casting num_docs() to usize instead avoids the truncation.
+        let mut policy = LogMergePolicy::default();
+        policy.set_min_num_segments(2);
+        policy.set_max_docs_before_merge(5_000_000_000usize);
+        let test_input = vec![
+            create_random_segment_meta(100_000),
+            create_random_segment_meta(100_000),
+        ];
+        let result = policy.compute_merge_candidates(&test_input);
+        // Both segments should be eligible (100_000 < 5_000_000_000)
+        assert_eq!(result.len(), 1);
+        assert_eq!(result[0].0.len(), 2);
+    }
 }

src/indexer/segment_updater.rs

@@ -403,7 +403,8 @@ impl SegmentUpdater {
             // from the different drives.
             //
             // Segment 1 from disk 1, Segment 1 from disk 2, etc.
-            committed_segment_metas.sort_by_key(|segment_meta| -(segment_meta.max_doc() as i32));
+            committed_segment_metas
+                .sort_by_key(|segment_meta| std::cmp::Reverse(segment_meta.max_doc()));
             let index_meta = IndexMeta {
                 index_settings: index.settings().clone(),
                 segments: committed_segment_metas,
@@ -705,6 +706,7 @@ mod tests {
     use crate::collector::TopDocs;
     use crate::directory::RamDirectory;
     use crate::fastfield::AliveBitSet;
+    use crate::index::{SegmentId, SegmentMetaInventory};
     use crate::indexer::merge_policy::tests::MergeWheneverPossible;
     use crate::indexer::merger::IndexMerger;
     use crate::indexer::segment_updater::merge_filtered_segments;
@@ -712,6 +714,22 @@ mod tests {
     use crate::schema::*;
     use crate::{Directory, DocAddress, Index, Segment};
 
+    #[test]
+    fn test_segment_sort_large_max_doc() {
+        // Regression test: -(max_doc as i32) overflows for max_doc >= 2^31.
+        // Using std::cmp::Reverse avoids this.
+        let inventory = SegmentMetaInventory::default();
+        let mut metas = vec![
+            inventory.new_segment_meta(SegmentId::generate_random(), 100),
+            inventory.new_segment_meta(SegmentId::generate_random(), (1u32 << 31) - 1),
+            inventory.new_segment_meta(SegmentId::generate_random(), 50_000),
+        ];
+        metas.sort_by_key(|m| std::cmp::Reverse(m.max_doc()));
+        assert_eq!(metas[0].max_doc(), (1u32 << 31) - 1);
+        assert_eq!(metas[1].max_doc(), 50_000);
+        assert_eq!(metas[2].max_doc(), 100);
+    }
+
     #[test]
     fn test_delete_during_merge() -> crate::Result<()> {
         let mut schema_builder = Schema::builder();

src/lib.rs

@@ -169,8 +169,10 @@ mod macros;
 mod future_result;
 
 // Re-exports
+pub use columnar;
 pub use common::{ByteCount, DateTime};
-pub use {columnar, query_grammar, time};
+pub use query_grammar;
+pub use time;
 
 pub use crate::error::TantivyError;
 pub use crate::future_result::FutureResult;

src/postings/mod.rs

@@ -14,7 +14,8 @@ mod postings;
 mod postings_writer;
 mod recorder;
 mod segment_postings;
-mod serializer;
+/// Serializer module for the inverted index
+pub mod serializer;
 mod skip;
 mod term_info;
 

src/postings/serializer.rs

@@ -11,7 +11,7 @@ use crate::positions::PositionSerializer;
 use crate::postings::compression::{BlockEncoder, VIntEncoder, COMPRESSION_BLOCK_SIZE};
 use crate::postings::skip::SkipSerializer;
 use crate::query::Bm25Weight;
-use crate::schema::{Field, FieldEntry, FieldType, IndexRecordOption, Schema};
+use crate::schema::{Field, FieldEntry, IndexRecordOption, Schema};
 use crate::termdict::TermDictionaryBuilder;
 use crate::{DocId, Score};
 
@@ -80,9 +80,12 @@ impl InvertedIndexSerializer {
         let term_dictionary_write = self.terms_write.for_field(field);
         let postings_write = self.postings_write.for_field(field);
         let positions_write = self.positions_write.for_field(field);
-        let field_type: FieldType = (*field_entry.field_type()).clone();
+        let index_record_option = field_entry
+            .field_type()
+            .index_record_option()
+            .unwrap_or(IndexRecordOption::Basic);
         FieldSerializer::create(
-            &field_type,
+            index_record_option,
             total_num_tokens,
             term_dictionary_write,
             postings_write,
@@ -102,29 +105,27 @@ impl InvertedIndexSerializer {
 
 /// The field serializer is in charge of
 /// the serialization of a specific field.
-pub struct FieldSerializer<'a> {
-    term_dictionary_builder: TermDictionaryBuilder<&'a mut CountingWriter<WritePtr>>,
+pub struct FieldSerializer<'a, W: Write = WritePtr> {
+    term_dictionary_builder: TermDictionaryBuilder<&'a mut CountingWriter<W>>,
     postings_serializer: PostingsSerializer,
-    positions_serializer_opt: Option<PositionSerializer<&'a mut CountingWriter<WritePtr>>>,
+    positions_serializer_opt: Option<PositionSerializer<&'a mut CountingWriter<W>>>,
     current_term_info: TermInfo,
     term_open: bool,
-    postings_write: &'a mut CountingWriter<WritePtr>,
+    postings_write: &'a mut CountingWriter<W>,
     postings_start_offset: u64,
 }
 
-impl<'a> FieldSerializer<'a> {
-    fn create(
-        field_type: &FieldType,
+impl<'a, W: Write> FieldSerializer<'a, W> {
+    /// Creates a new `FieldSerializer` for the given field type.
+    pub fn create(
+        index_record_option: IndexRecordOption,
         total_num_tokens: u64,
-        term_dictionary_write: &'a mut CountingWriter<WritePtr>,
-        postings_write: &'a mut CountingWriter<WritePtr>,
-        positions_write: &'a mut CountingWriter<WritePtr>,
+        term_dictionary_write: &'a mut CountingWriter<W>,
+        postings_write: &'a mut CountingWriter<W>,
+        positions_write: &'a mut CountingWriter<W>,
         fieldnorm_reader: Option<FieldNormReader>,
-    ) -> io::Result<FieldSerializer<'a>> {
+    ) -> io::Result<FieldSerializer<'a, W>> {
         total_num_tokens.serialize(postings_write)?;
-        let index_record_option = field_type
-            .index_record_option()
-            .unwrap_or(IndexRecordOption::Basic);
         let term_dictionary_builder = TermDictionaryBuilder::create(term_dictionary_write)?;
         let average_fieldnorm = fieldnorm_reader
             .as_ref()
@@ -192,6 +193,11 @@ impl<'a> FieldSerializer<'a> {
         Ok(())
     }
 
+    /// Starts the postings for a new term without recording term frequencies.
+    pub fn new_term_without_freq(&mut self, term: &[u8]) -> io::Result<()> {
+        self.new_term(term, 0, false)
+    }
+
     /// Serialize the information that a document contains for the current term:
     /// its term frequency, and the position deltas.
     ///
@@ -297,6 +303,7 @@ impl Block {
     }
 }
 
+/// Serializer for postings lists.
 pub struct PostingsSerializer {
     last_doc_id_encoded: u32,
 
@@ -316,6 +323,9 @@ pub struct PostingsSerializer {
 }
 
 impl PostingsSerializer {
+    /// Creates a new `PostingsSerializer`.
+    /// * avg_fieldnorm - average field norm for the field being serialized.
+    /// * mode - indexing options for the field being serialized.
     pub fn new(
         avg_fieldnorm: Score,
         mode: IndexRecordOption,
@@ -338,6 +348,8 @@ impl PostingsSerializer {
         }
     }
 
+    /// Starts the serialization for a new term.
+    /// * term_doc_freq - the number of documents containing the term.
     pub fn new_term(&mut self, term_doc_freq: u32, record_term_freq: bool) {
         self.bm25_weight = None;
 
@@ -377,6 +389,7 @@ impl PostingsSerializer {
             self.postings_write.extend(block_encoded);
         }
         if self.term_has_freq {
+            // encode the term frequencies
             let (num_bits, block_encoded): (u8, &[u8]) = self
                 .block_encoder
                 .compress_block_unsorted(self.block.term_freqs(), true);
@@ -417,6 +430,9 @@ impl PostingsSerializer {
         self.block.clear();
     }
 
+    /// Register that the given document contains the current term.
+    /// * doc_id - the document id.
+    /// * term_freq - the term frequency within the document.
     pub fn write_doc(&mut self, doc_id: DocId, term_freq: u32) {
         self.block.append_doc(doc_id, term_freq);
         if self.block.is_full() {
@@ -424,6 +440,7 @@ impl PostingsSerializer {
         }
     }
 
+    /// Finish the serialization for this term.
     pub fn close_term(
         &mut self,
         doc_freq: u32,

src/postings/skip.rs

@@ -14,7 +14,11 @@ use crate::{DocId, Score, TERMINATED};
 //   (requiring a 6th bit), but the biggest doc_id we can want to encode is TERMINATED-1, which can
 //   be represented on 31b without delta encoding.
 fn encode_bitwidth(bitwidth: u8, delta_1: bool) -> u8 {
-    assert!(bitwidth < 32);
+    assert!(
+        bitwidth < 32,
+        "bitwidth needs to be less than 32, but got {}",
+        bitwidth
+    );
     bitwidth | ((delta_1 as u8) << 6)
 }
 

src/query/boolean_query/boolean_weight.rs

@@ -291,18 +291,6 @@ impl<TScoreCombiner: ScoreCombiner> BooleanWeight<TScoreCombiner> {
             }
         };
 
-        let exclude_scorer_opt: Option<Box<dyn Scorer>> = if exclude_scorers.is_empty() {
-            None
-        } else {
-            let exclude_specialized_scorer: SpecializedScorer =
-                scorer_union(exclude_scorers, DoNothingCombiner::default, num_docs);
-            Some(into_box_scorer(
-                exclude_specialized_scorer,
-                DoNothingCombiner::default,
-                num_docs,
-            ))
-        };
-
         let include_scorer = match (should_scorers, must_scorers) {
             (ShouldScorersCombinationMethod::Ignored, must_scorers) => {
                 // No SHOULD clauses (or they were absorbed into MUST).
@@ -380,16 +368,23 @@ impl<TScoreCombiner: ScoreCombiner> BooleanWeight<TScoreCombiner> {
                 }
             }
         };
-        if let Some(exclude_scorer) = exclude_scorer_opt {
-            let include_scorer_boxed =
-                into_box_scorer(include_scorer, &score_combiner_fn, num_docs);
-            Ok(SpecializedScorer::Other(Box::new(Exclude::new(
-                include_scorer_boxed,
-                exclude_scorer,
-            ))))
-        } else {
-            Ok(include_scorer)
+        if exclude_scorers.is_empty() {
+            return Ok(include_scorer);
         }
+
+        let include_scorer_boxed = into_box_scorer(include_scorer, &score_combiner_fn, num_docs);
+        let scorer: Box<dyn Scorer> = if exclude_scorers.len() == 1 {
+            let exclude_scorer = exclude_scorers.pop().unwrap();
+            match exclude_scorer.downcast::<TermScorer>() {
+                // Cast to TermScorer succeeded
+                Ok(exclude_scorer) => Box::new(Exclude::new(include_scorer_boxed, *exclude_scorer)),
+                // We get back the original Box<dyn Scorer>
+                Err(exclude_scorer) => Box::new(Exclude::new(include_scorer_boxed, exclude_scorer)),
+            }
+        } else {
+            Box::new(Exclude::new(include_scorer_boxed, exclude_scorers))
+        };
+        Ok(SpecializedScorer::Other(scorer))
     }
 }
 

src/query/exclude.rs

@@ -1,48 +1,71 @@
-use crate::docset::{DocSet, TERMINATED};
+use crate::docset::{DocSet, SeekDangerResult, TERMINATED};
 use crate::query::Scorer;
 use crate::{DocId, Score};
 
-#[inline]
-fn is_within<TDocSetExclude: DocSet>(docset: &mut TDocSetExclude, doc: DocId) -> bool {
-    docset.doc() <= doc && docset.seek(doc) == doc
-}
-
-/// Filters a given `DocSet` by removing the docs from a given `DocSet`.
+/// An exclusion set is a set of documents
+/// that should be excluded from a given DocSet.
 ///
-/// The excluding docset has no impact on scoring.
-pub struct Exclude<TDocSet, TDocSetExclude> {
-    underlying_docset: TDocSet,
-    excluding_docset: TDocSetExclude,
+/// It can be a single DocSet, or a Vec of DocSets.
+pub trait ExclusionSet: Send {
+    /// Returns `true` if the given `doc` is in the exclusion set.
+    fn contains(&mut self, doc: DocId) -> bool;
 }
 
-impl<TDocSet, TDocSetExclude> Exclude<TDocSet, TDocSetExclude>
+impl<TDocSet: DocSet> ExclusionSet for TDocSet {
+    #[inline]
+    fn contains(&mut self, doc: DocId) -> bool {
+        self.seek_danger(doc) == SeekDangerResult::Found
+    }
+}
+
+impl<TDocSet: DocSet> ExclusionSet for Vec<TDocSet> {
+    #[inline]
+    fn contains(&mut self, doc: DocId) -> bool {
+        for docset in self.iter_mut() {
+            if docset.seek_danger(doc) == SeekDangerResult::Found {
+                return true;
+            }
+        }
+        false
+    }
+}
+
+/// Filters a given `DocSet` by removing the docs from an exclusion set.
+///
+/// The excluding docsets have no impact on scoring.
+pub struct Exclude<TDocSet, TExclusionSet> {
+    underlying_docset: TDocSet,
+    exclusion_set: TExclusionSet,
+}
+
+impl<TDocSet, TExclusionSet> Exclude<TDocSet, TExclusionSet>
 where
     TDocSet: DocSet,
-    TDocSetExclude: DocSet,
+    TExclusionSet: ExclusionSet,
 {
     /// Creates a new `ExcludeScorer`
     pub fn new(
         mut underlying_docset: TDocSet,
-        mut excluding_docset: TDocSetExclude,
-    ) -> Exclude<TDocSet, TDocSetExclude> {
+        mut exclusion_set: TExclusionSet,
+    ) -> Exclude<TDocSet, TExclusionSet> {
         while underlying_docset.doc() != TERMINATED {
             let target = underlying_docset.doc();
-            if !is_within(&mut excluding_docset, target) {
+            if !exclusion_set.contains(target) {
                 break;
             }
             underlying_docset.advance();
         }
         Exclude {
             underlying_docset,
-            excluding_docset,
+            exclusion_set,
         }
     }
 }
 
-impl<TDocSet, TDocSetExclude> DocSet for Exclude<TDocSet, TDocSetExclude>
+impl<TDocSet, TExclusionSet> DocSet for Exclude<TDocSet, TExclusionSet>
 where
     TDocSet: DocSet,
-    TDocSetExclude: DocSet,
+    TExclusionSet: ExclusionSet,
 {
     fn advance(&mut self) -> DocId {
         loop {
@@ -50,7 +73,7 @@ where
             if candidate == TERMINATED {
                 return TERMINATED;
             }
-            if !is_within(&mut self.excluding_docset, candidate) {
+            if !self.exclusion_set.contains(candidate) {
                 return candidate;
             }
         }
@@ -61,7 +84,7 @@ where
         if candidate == TERMINATED {
             return TERMINATED;
         }
-        if !is_within(&mut self.excluding_docset, candidate) {
+        if !self.exclusion_set.contains(candidate) {
             return candidate;
         }
         self.advance()
@@ -79,10 +102,10 @@ where
     }
 }
 
-impl<TScorer, TDocSetExclude> Scorer for Exclude<TScorer, TDocSetExclude>
+impl<TScorer, TExclusionSet> Scorer for Exclude<TScorer, TExclusionSet>
 where
     TScorer: Scorer,
-    TDocSetExclude: DocSet + 'static,
+    TExclusionSet: ExclusionSet + 'static,
 {
     #[inline]
     fn score(&mut self) -> Score {

src/query/mod.rs

@@ -43,7 +43,7 @@ pub use self::boost_query::{BoostQuery, BoostWeight};
 pub use self::const_score_query::{ConstScoreQuery, ConstScorer};
 pub use self::disjunction_max_query::DisjunctionMaxQuery;
 pub use self::empty_query::{EmptyQuery, EmptyScorer, EmptyWeight};
-pub use self::exclude::Exclude;
+pub use self::exclude::{Exclude, ExclusionSet};
 pub use self::exist_query::ExistsQuery;
 pub use self::explanation::Explanation;
 #[cfg(test)]

src/query/query_parser/query_parser.rs

@@ -2068,6 +2068,16 @@ mod test {
             format!("Regex(Field(0), {:#?})", expected_regex).as_str(),
             false,
         );
+        let expected_regex2 = tantivy_fst::Regex::new(r".*a").unwrap();
+        test_parse_query_to_logical_ast_helper(
+            "title:(/.*b/ OR /.*a/)",
+            format!(
+                "(Regex(Field(0), {:#?}) Regex(Field(0), {:#?}))",
+                expected_regex, expected_regex2
+            )
+            .as_str(),
+            false,
+        );
 
         // Invalid field
         let err = parse_query_to_logical_ast("float:/.*b/", false).unwrap_err();

src/query/range_query/mod.rs

@@ -19,7 +19,8 @@ pub(crate) fn is_type_valid_for_fastfield_range_query(typ: Type) -> bool {
         | Type::Bool
         | Type::Date
         | Type::Json
-        | Type::IpAddr => true,
-        Type::Facet | Type::Bytes => false,
+        | Type::IpAddr
+        | Type::Bytes => true,
+        Type::Facet => false,
     }
 }

src/query/range_query/range_query_fastfield.rs

@@ -6,8 +6,8 @@ use std::net::Ipv6Addr;
 use std::ops::{Bound, RangeInclusive};
 
 use columnar::{
-    Cardinality, Column, ColumnType, MonotonicallyMappableToU128, MonotonicallyMappableToU64,
-    NumericalType, StrColumn,
+    BytesColumn, Cardinality, Column, ColumnType, MonotonicallyMappableToU128,
+    MonotonicallyMappableToU64, NumericalType, StrColumn,
 };
 use common::bounds::{BoundsRange, TransformBound};
 
@@ -163,6 +163,25 @@ impl Weight for FastFieldRangeWeight {
             };
             let dict = str_dict_column.dictionary();
 
+            let bounds = self.bounds.map_bound(get_value_bytes);
+            // Get term ids for terms
+            let (lower_bound, upper_bound) =
+                dict.term_bounds_to_ord(bounds.lower_bound, bounds.upper_bound)?;
+            let fast_field_reader = reader.fast_fields();
+            let Some((column, _col_type)) =
+                fast_field_reader.u64_lenient_for_type(None, &field_name)?
+            else {
+                return Ok(Box::new(EmptyScorer));
+            };
+            search_on_u64_ff(column, boost, BoundsRange::new(lower_bound, upper_bound))
+        } else if field_type.is_bytes() {
+            let Some(bytes_column): Option<BytesColumn> =
+                reader.fast_fields().bytes(&field_name)?
+            else {
+                return Ok(Box::new(EmptyScorer));
+            };
+            let dict = bytes_column.dictionary();
+
             let bounds = self.bounds.map_bound(get_value_bytes);
             // Get term ids for terms
             let (lower_bound, upper_bound) =
@@ -1402,6 +1421,66 @@ mod tests {
 
         Ok(())
     }
+
+    #[test]
+    fn test_bytes_field_ff_range_query() -> crate::Result<()> {
+        use crate::schema::BytesOptions;
+
+        let mut schema_builder = Schema::builder();
+        let bytes_field = schema_builder
+            .add_bytes_field("data", BytesOptions::default().set_fast().set_indexed());
+        let schema = schema_builder.build();
+        let index = Index::create_in_ram(schema.clone());
+        let mut index_writer: IndexWriter = index.writer_for_tests()?;
+
+        // Insert documents with lexicographically sortable byte values
+        // Using simple byte sequences that have clear ordering
+        let values: Vec<Vec<u8>> = vec![
+            vec![0x00, 0x10],
+            vec![0x00, 0x20],
+            vec![0x00, 0x30],
+            vec![0x01, 0x00],
+            vec![0x01, 0x10],
+            vec![0x02, 0x00],
+        ];
+
+        for value in &values {
+            let mut doc = TantivyDocument::new();
+            doc.add_bytes(bytes_field, value);
+            index_writer.add_document(doc)?;
+        }
+        index_writer.commit()?;
+
+        let reader = index.reader()?;
+        let searcher = reader.searcher();
+
+        // Test: Range query [0x00, 0x20] to [0x01, 0x00] (inclusive)
+        // Should match: [0x00, 0x20], [0x00, 0x30], [0x01, 0x00]
+        let lower = Term::from_field_bytes(bytes_field, &[0x00, 0x20]);
+        let upper = Term::from_field_bytes(bytes_field, &[0x01, 0x00]);
+        let range_query = RangeQuery::new(Bound::Included(lower), Bound::Included(upper));
+        let count = searcher.search(&range_query, &Count)?;
+        assert_eq!(
+            count, 3,
+            "Expected 3 documents in range [0x00,0x20] to [0x01,0x00]"
+        );
+
+        // Test: Range query > [0x01, 0x00] (exclusive lower bound)
+        // Should match: [0x01, 0x10], [0x02, 0x00]
+        let lower = Term::from_field_bytes(bytes_field, &[0x01, 0x00]);
+        let range_query = RangeQuery::new(Bound::Excluded(lower), Bound::Unbounded);
+        let count = searcher.search(&range_query, &Count)?;
+        assert_eq!(count, 2, "Expected 2 documents > [0x01,0x00]");
+
+        // Test: Range query < [0x00, 0x30] (exclusive upper bound)
+        // Should match: [0x00, 0x10], [0x00, 0x20]
+        let upper = Term::from_field_bytes(bytes_field, &[0x00, 0x30]);
+        let range_query = RangeQuery::new(Bound::Unbounded, Bound::Excluded(upper));
+        let count = searcher.search(&range_query, &Count)?;
+        assert_eq!(count, 2, "Expected 2 documents < [0x00,0x30]");
+
+        Ok(())
+    }
 }
 
 #[cfg(test)]

src/schema/field_type.rs

@@ -223,6 +223,11 @@ impl FieldType {
         matches!(self, FieldType::Str(_))
     }
 
+    /// returns true if this is a bytes field
+    pub fn is_bytes(&self) -> bool {
+        matches!(self, FieldType::Bytes(_))
+    }
+
     /// returns true if this is an date field
     pub fn is_date(&self) -> bool {
         matches!(self, FieldType::Date(_))

sstable/src/lib.rs

@@ -51,7 +51,7 @@ mod sstable_index_v3;
 pub use sstable_index_v3::{BlockAddr, SSTableIndex, SSTableIndexBuilder, SSTableIndexV3};
 mod sstable_index_v2;
 pub(crate) mod vint;
-pub use dictionary::Dictionary;
+pub use dictionary::{Dictionary, TermOrdHit};
 pub use streamer::{Streamer, StreamerBuilder};
 
 mod block_reader;
@@ -302,8 +302,9 @@ where
             || self.previous_key[keep_len] < key[keep_len];
         assert!(
             increasing_keys,
-            "Keys should be increasing. ({:?} > {key:?})",
-            self.previous_key
+            "Keys should be increasing. ({:?} > {:?})",
+            String::from_utf8_lossy(&self.previous_key),
+            String::from_utf8_lossy(key),
         );
         self.previous_key.resize(key.len(), 0u8);
         self.previous_key[keep_len..].copy_from_slice(&key[keep_len..]);