SegmentReader as trait

A bug was added with the `seek_into_the_danger_zone()` optimization

(Spotted and fixed by Stu)

The contract says seek_into_the_danger_zone returns true if do is part of the docset.

The blanket implementation goes like this.

```
let current_doc = self.doc();
if current_doc < target {
     self.seek(target);
}
self.doc() == target
```

So it will return true if target is TERMINATED, where really TERMINATED does not belong to the docset.


The fix tries to clarify the contracts and fixes the intersection algorithm.
We observe a small but all over the board improvement in intersection performance.

---------

Co-authored-by: Stu Hood <stuhood@gmail.com>
Co-authored-by: Paul Masurel <paul.masurel@datadoghq.com>

Cargo.toml

@@ -27,7 +27,7 @@ regex = { version = "1.5.5", default-features = false, features = [
 aho-corasick = "1.0"
 tantivy-fst = "0.5"
 memmap2 = { version = "0.9.0", optional = true }
-lz4_flex = { version = "0.11", default-features = false, optional = true }
+lz4_flex = { version = "0.12", default-features = false, optional = true }
 zstd = { version = "0.13", optional = true, default-features = false }
 tempfile = { version = "3.12.0", optional = true }
 log = "0.4.16"
@@ -50,7 +50,7 @@ fail = { version = "0.5.0", optional = true }
 time = { version = "0.3.35", features = ["serde-well-known"] }
 smallvec = "1.8.0"
 rayon = "1.5.2"
-lru = "0.12.0"
+lru = "0.16.3"
 fastdivide = "0.4.0"
 itertools = "0.14.0"
 measure_time = "0.9.0"
@@ -76,7 +76,7 @@ winapi = "0.3.9"
 
 [dev-dependencies]
 binggan = "0.14.2"
-rand = "0.8.5"
+rand = "0.9"
 maplit = "1.0.2"
 matches = "0.1.9"
 pretty_assertions = "1.2.1"
@@ -85,7 +85,7 @@ test-log = "0.2.10"
 futures = "0.3.21"
 paste = "1.0.11"
 more-asserts = "0.3.1"
-rand_distr = "0.4.3"
+rand_distr = "0.5"
 time = { version = "0.3.10", features = ["serde-well-known", "macros"] }
 postcard = { version = "1.0.4", features = [
     "use-std",
@@ -189,3 +189,7 @@ harness = false
 [[bench]]
 name = "bool_queries_with_range"
 harness = false
+
+[[bench]]
+name = "str_search_and_get"
+harness = false

benches/agg_bench.rs

@@ -1,8 +1,8 @@
 use binggan::plugins::PeakMemAllocPlugin;
 use binggan::{black_box, InputGroup, PeakMemAlloc, INSTRUMENTED_SYSTEM};
-use rand::distributions::WeightedIndex;
-use rand::prelude::SliceRandom;
+use rand::distr::weighted::WeightedIndex;
 use rand::rngs::StdRng;
+use rand::seq::IndexedRandom;
 use rand::{Rng, SeedableRng};
 use rand_distr::Distribution;
 use serde_json::json;
@@ -532,7 +532,7 @@ fn get_test_index_bench(cardinality: Cardinality) -> tantivy::Result<Index> {
     // Prepare 1000 unique terms sampled using a Zipf distribution.
     // Exponent ~1.1 approximates top-20 terms covering around ~20%.
     let terms_1000: Vec<String> = (1..=1000).map(|i| format!("term_{i}")).collect();
-    let zipf_1000 = rand_distr::Zipf::new(1000, 1.1f64).unwrap();
+    let zipf_1000 = rand_distr::Zipf::new(1000.0, 1.1f64).unwrap();
 
     {
         let mut rng = StdRng::from_seed([1u8; 32]);
@@ -576,8 +576,8 @@ fn get_test_index_bench(cardinality: Cardinality) -> tantivy::Result<Index> {
         }
         let _val_max = 1_000_000.0;
         for _ in 0..doc_with_value {
-            let val: f64 = rng.gen_range(0.0..1_000_000.0);
-            let json = if rng.gen_bool(0.1) {
+            let val: f64 = rng.random_range(0.0..1_000_000.0);
+            let json = if rng.random_bool(0.1) {
                 // 10% are numeric values
                 json!({ "mixed_type": val })
             } else {
@@ -586,7 +586,7 @@ fn get_test_index_bench(cardinality: Cardinality) -> tantivy::Result<Index> {
             index_writer.add_document(doc!(
                 text_field => "cool",
                 json_field => json,
-                text_field_all_unique_terms => format!("unique_term_{}", rng.gen::<u64>()),
+                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_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(),

benches/and_or_queries.rs

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

benches/bool_queries_with_range.rs

@@ -36,13 +36,13 @@ fn build_shared_indices(num_docs: usize, p_title_a: f32, distribution: &str) ->
             "dense" => {
                 for doc_id in 0..num_docs {
                     // Always add title to avoid empty documents
-                    let title_token = if rng.gen_bool(p_title_a as f64) {
+                    let title_token = if rng.random_bool(p_title_a as f64) {
                         "a"
                     } else {
                         "b"
                     };
 
-                    let num_rand = rng.gen_range(0u64..1000u64);
+                    let num_rand = rng.random_range(0u64..1000u64);
 
                     let num_asc = (doc_id / 10000) as u64;
 
@@ -60,13 +60,13 @@ fn build_shared_indices(num_docs: usize, p_title_a: f32, distribution: &str) ->
             "sparse" => {
                 for doc_id in 0..num_docs {
                     // Always add title to avoid empty documents
-                    let title_token = if rng.gen_bool(p_title_a as f64) {
+                    let title_token = if rng.random_bool(p_title_a as f64) {
                         "a"
                     } else {
                         "b"
                     };
 
-                    let num_rand = rng.gen_range(0u64..10000000u64);
+                    let num_rand = rng.random_range(0u64..10000000u64);
 
                     let num_asc = doc_id as u64;
 

benches/range_queries.rs

@@ -33,7 +33,7 @@ fn build_shared_indices(num_docs: usize, distribution: &str) -> BenchIndex {
         match distribution {
             "dense" => {
                 for doc_id in 0..num_docs {
-                    let num_rand = rng.gen_range(0u64..1000u64);
+                    let num_rand = rng.random_range(0u64..1000u64);
                     let num_asc = (doc_id / 10000) as u64;
 
                     writer
@@ -46,7 +46,7 @@ fn build_shared_indices(num_docs: usize, distribution: &str) -> BenchIndex {
             }
             "sparse" => {
                 for doc_id in 0..num_docs {
-                    let num_rand = rng.gen_range(0u64..10000000u64);
+                    let num_rand = rng.random_range(0u64..10000000u64);
                     let num_asc = doc_id as u64;
 
                     writer

benches/range_query.rs

@@ -97,20 +97,20 @@ fn get_index_0_to_100() -> Index {
     let num_vals = 100_000;
     let docs: Vec<_> = (0..num_vals)
         .map(|_i| {
-            let id_name = if rng.gen_bool(0.01) {
+            let id_name = if rng.random_bool(0.01) {
                 "veryfew".to_string() // 1%
-            } else if rng.gen_bool(0.1) {
+            } else if rng.random_bool(0.1) {
                 "few".to_string() // 9%
             } else {
                 "most".to_string() // 90%
             };
             Doc {
                 id_name,
-                id: rng.gen_range(0..100),
+                id: rng.random_range(0..100),
                 // Multiply by 1000, so that we create most buckets in the compact space
                 // The benches depend on this range to select n-percent of elements with the
                 // methods below.
-                ip: Ipv6Addr::from_u128(rng.gen_range(0..100) * 1000),
+                ip: Ipv6Addr::from_u128(rng.random_range(0..100) * 1000),
             }
         })
         .collect();

benches/str_search_and_get.rs

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

bitpacker/Cargo.toml

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

bitpacker/benches/bench.rs

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

columnar/Cargo.toml

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

columnar/benches/bench_column_values_get.rs

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

columnar/benches/bench_create_column_values.rs

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

columnar/benches/bench_optional_index.rs

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

columnar/benches/bench_values_u128.rs

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

columnar/benches/bench_values_u64.rs

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

columnar/src/column_values/u64_based/linear.rs

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

columnar/src/column_values/u64_based/tests.rs

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

common/Cargo.toml

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

common/benches/bench.rs

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

common/src/bitset.rs

@@ -416,7 +416,7 @@ mod tests {
     use std::collections::HashSet;
 
     use ownedbytes::OwnedBytes;
-    use rand::distributions::Bernoulli;
+    use rand::distr::Bernoulli;
     use rand::rngs::StdRng;
     use rand::{Rng, SeedableRng};
 

examples/custom_collector.rs

@@ -70,7 +70,7 @@ impl Collector for StatsCollector {
     fn for_segment(
         &self,
         _segment_local_id: u32,
-        segment_reader: &SegmentReader,
+        segment_reader: &dyn SegmentReader,
     ) -> tantivy::Result<StatsSegmentCollector> {
         let fast_field_reader = segment_reader.fast_fields().u64(&self.field)?;
         Ok(StatsSegmentCollector {

examples/faceted_search_with_tweaked_score.rs

@@ -65,7 +65,7 @@ fn main() -> tantivy::Result<()> {
         );
         let top_docs_by_custom_score =
             // Call TopDocs with a custom tweak score
-            TopDocs::with_limit(2).tweak_score(move |segment_reader: &SegmentReader| {
+            TopDocs::with_limit(2).tweak_score(move |segment_reader: &dyn SegmentReader| {
                 let ingredient_reader = segment_reader.facet_reader("ingredient").unwrap();
                 let facet_dict = ingredient_reader.facet_dict();
 

examples/warmer.rs

@@ -43,7 +43,7 @@ impl DynamicPriceColumn {
         }
     }
 
-    pub fn price_for_segment(&self, segment_reader: &SegmentReader) -> Option<Arc<Vec<Price>>> {
+    pub fn price_for_segment(&self, segment_reader: &dyn SegmentReader) -> Option<Arc<Vec<Price>>> {
         let segment_key = (segment_reader.segment_id(), segment_reader.delete_opstamp());
         self.price_cache.read().unwrap().get(&segment_key).cloned()
     }
@@ -157,7 +157,7 @@ fn main() -> tantivy::Result<()> {
     let query = query_parser.parse_query("cooking")?;
 
     let searcher = reader.searcher();
-    let score_by_price = move |segment_reader: &SegmentReader| {
+    let score_by_price = move |segment_reader: &dyn SegmentReader| {
         let price = price_dynamic_column
             .price_for_segment(segment_reader)
             .unwrap();

src/aggregation/accessor_helpers.rs

@@ -57,7 +57,7 @@ pub(crate) fn get_numeric_or_date_column_types() -> &'static [ColumnType] {
 
 /// Get fast field reader or empty as default.
 pub(crate) fn get_ff_reader(
-    reader: &SegmentReader,
+    reader: &dyn SegmentReader,
     field_name: &str,
     allowed_column_types: Option<&[ColumnType]>,
 ) -> crate::Result<(columnar::Column<u64>, ColumnType)> {
@@ -74,7 +74,7 @@ pub(crate) fn get_ff_reader(
 }
 
 pub(crate) fn get_dynamic_columns(
-    reader: &SegmentReader,
+    reader: &dyn SegmentReader,
     field_name: &str,
 ) -> crate::Result<Vec<columnar::DynamicColumn>> {
     let ff_fields = reader.fast_fields().dynamic_column_handles(field_name)?;
@@ -90,7 +90,7 @@ pub(crate) fn get_dynamic_columns(
 ///
 /// Is guaranteed to return at least one column.
 pub(crate) fn get_all_ff_reader_or_empty(
-    reader: &SegmentReader,
+    reader: &dyn SegmentReader,
     field_name: &str,
     allowed_column_types: Option<&[ColumnType]>,
     fallback_type: ColumnType,

src/aggregation/agg_data.rs

@@ -469,7 +469,7 @@ impl AggKind {
 /// Build AggregationsData by walking the request tree.
 pub(crate) fn build_aggregations_data_from_req(
     aggs: &Aggregations,
-    reader: &SegmentReader,
+    reader: &dyn SegmentReader,
     segment_ordinal: SegmentOrdinal,
     context: AggContextParams,
 ) -> crate::Result<AggregationsSegmentCtx> {
@@ -489,7 +489,7 @@ pub(crate) fn build_aggregations_data_from_req(
 fn build_nodes(
     agg_name: &str,
     req: &Aggregation,
-    reader: &SegmentReader,
+    reader: &dyn SegmentReader,
     segment_ordinal: SegmentOrdinal,
     data: &mut AggregationsSegmentCtx,
     is_top_level: bool,
@@ -728,7 +728,6 @@ fn build_nodes(
             let idx_in_req_data = data.push_filter_req_data(FilterAggReqData {
                 name: agg_name.to_string(),
                 req: filter_req.clone(),
-                segment_reader: reader.clone(),
                 evaluator,
                 matching_docs_buffer,
                 is_top_level,
@@ -745,7 +744,7 @@ fn build_nodes(
 
 fn build_children(
     aggs: &Aggregations,
-    reader: &SegmentReader,
+    reader: &dyn SegmentReader,
     segment_ordinal: SegmentOrdinal,
     data: &mut AggregationsSegmentCtx,
 ) -> crate::Result<Vec<AggRefNode>> {
@@ -764,7 +763,7 @@ fn build_children(
 }
 
 fn get_term_agg_accessors(
-    reader: &SegmentReader,
+    reader: &dyn SegmentReader,
     field_name: &str,
     missing: &Option<Key>,
 ) -> crate::Result<Vec<(Column<u64>, ColumnType)>> {
@@ -817,7 +816,7 @@ fn build_terms_or_cardinality_nodes(
     agg_name: &str,
     field_name: &str,
     missing: &Option<Key>,
-    reader: &SegmentReader,
+    reader: &dyn SegmentReader,
     segment_ordinal: SegmentOrdinal,
     data: &mut AggregationsSegmentCtx,
     sub_aggs: &Aggregations,

src/aggregation/bucket/filter.rs

@@ -401,8 +401,6 @@ pub struct FilterAggReqData {
     pub name: String,
     /// The filter aggregation
     pub req: FilterAggregation,
-    /// The segment reader
-    pub segment_reader: SegmentReader,
     /// Document evaluator for the filter query (precomputed BitSet)
     /// This is built once when the request data is created
     pub evaluator: DocumentQueryEvaluator,
@@ -414,9 +412,8 @@ pub struct FilterAggReqData {
 
 impl FilterAggReqData {
     pub(crate) fn get_memory_consumption(&self) -> usize {
-        // Estimate: name + segment reader reference + bitset + buffer capacity
+        // Estimate: name + bitset + buffer capacity
         self.name.len()
-        + std::mem::size_of::<SegmentReader>()
         + self.evaluator.bitset.len() / 8 // BitSet memory (bits to bytes)
         + self.matching_docs_buffer.capacity() * std::mem::size_of::<DocId>()
         + std::mem::size_of::<bool>()
@@ -438,7 +435,7 @@ impl DocumentQueryEvaluator {
     pub(crate) fn new(
         query: Box<dyn Query>,
         schema: Schema,
-        segment_reader: &SegmentReader,
+        segment_reader: &dyn SegmentReader,
     ) -> crate::Result<Self> {
         let max_doc = segment_reader.max_doc();
 

src/aggregation/collector.rs

@@ -66,7 +66,7 @@ impl Collector for DistributedAggregationCollector {
     fn for_segment(
         &self,
         segment_local_id: crate::SegmentOrdinal,
-        reader: &crate::SegmentReader,
+        reader: &dyn SegmentReader,
     ) -> crate::Result<Self::Child> {
         AggregationSegmentCollector::from_agg_req_and_reader(
             &self.agg,
@@ -96,7 +96,7 @@ impl Collector for AggregationCollector {
     fn for_segment(
         &self,
         segment_local_id: crate::SegmentOrdinal,
-        reader: &crate::SegmentReader,
+        reader: &dyn SegmentReader,
     ) -> crate::Result<Self::Child> {
         AggregationSegmentCollector::from_agg_req_and_reader(
             &self.agg,
@@ -145,7 +145,7 @@ impl AggregationSegmentCollector {
     /// reader. Also includes validation, e.g. checking field types and existence.
     pub fn from_agg_req_and_reader(
         agg: &Aggregations,
-        reader: &SegmentReader,
+        reader: &dyn SegmentReader,
         segment_ordinal: SegmentOrdinal,
         context: &AggContextParams,
     ) -> crate::Result<Self> {

src/collector/count_collector.rs

@@ -43,7 +43,7 @@ impl Collector for Count {
     fn for_segment(
         &self,
         _: SegmentOrdinal,
-        _: &SegmentReader,
+        _: &dyn SegmentReader,
     ) -> crate::Result<SegmentCountCollector> {
         Ok(SegmentCountCollector::default())
     }

src/collector/docset_collector.rs

@@ -1,7 +1,7 @@
 use std::collections::HashSet;
 
 use super::{Collector, SegmentCollector};
-use crate::{DocAddress, DocId, Score};
+use crate::{DocAddress, DocId, Score, SegmentReader};
 
 /// Collectors that returns the set of DocAddress that matches the query.
 ///
@@ -15,7 +15,7 @@ impl Collector for DocSetCollector {
     fn for_segment(
         &self,
         segment_local_id: crate::SegmentOrdinal,
-        _segment: &crate::SegmentReader,
+        _segment: &dyn SegmentReader,
     ) -> crate::Result<Self::Child> {
         Ok(DocSetChildCollector {
             segment_local_id,

src/collector/facet_collector.rs

@@ -265,7 +265,7 @@ impl Collector for FacetCollector {
     fn for_segment(
         &self,
         _: SegmentOrdinal,
-        reader: &SegmentReader,
+        reader: &dyn SegmentReader,
     ) -> crate::Result<FacetSegmentCollector> {
         let facet_reader = reader.facet_reader(&self.field_name)?;
         let facet_dict = facet_reader.facet_dict();
@@ -486,9 +486,9 @@ mod tests {
     use std::collections::BTreeSet;
 
     use columnar::Dictionary;
-    use rand::distributions::Uniform;
+    use rand::distr::Uniform;
     use rand::prelude::SliceRandom;
-    use rand::{thread_rng, Rng};
+    use rand::{rng, Rng};
 
     use super::{FacetCollector, FacetCounts};
     use crate::collector::facet_collector::compress_mapping;
@@ -731,7 +731,7 @@ mod tests {
         let schema = schema_builder.build();
         let index = Index::create_in_ram(schema);
 
-        let uniform = Uniform::new_inclusive(1, 100_000);
+        let uniform = Uniform::new_inclusive(1, 100_000).unwrap();
         let mut docs: Vec<TantivyDocument> =
             vec![("a", 10), ("b", 100), ("c", 7), ("d", 12), ("e", 21)]
                 .into_iter()
@@ -741,14 +741,11 @@ mod tests {
                     std::iter::repeat_n(doc, count)
                 })
                 .map(|mut doc| {
-                    doc.add_facet(
-                        facet_field,
-                        &format!("/facet/{}", thread_rng().sample(uniform)),
-                    );
+                    doc.add_facet(facet_field, &format!("/facet/{}", rng().sample(uniform)));
                     doc
                 })
                 .collect();
-        docs[..].shuffle(&mut thread_rng());
+        docs[..].shuffle(&mut rng());
 
         let mut index_writer: IndexWriter = index.writer_for_tests().unwrap();
         for doc in docs {
@@ -822,8 +819,8 @@ mod tests {
 #[cfg(all(test, feature = "unstable"))]
 mod bench {
 
+    use rand::rng;
     use rand::seq::SliceRandom;
-    use rand::thread_rng;
     use test::Bencher;
 
     use crate::collector::FacetCollector;
@@ -846,7 +843,7 @@ mod bench {
             }
         }
         // 40425 docs
-        docs[..].shuffle(&mut thread_rng());
+        docs[..].shuffle(&mut rng());
 
         let mut index_writer: IndexWriter = index.writer_for_tests().unwrap();
         for doc in docs {

src/collector/filter_collector_wrapper.rs

@@ -113,7 +113,7 @@ where
     fn for_segment(
         &self,
         segment_local_id: u32,
-        segment_reader: &SegmentReader,
+        segment_reader: &dyn SegmentReader,
     ) -> crate::Result<Self::Child> {
         let column_opt = segment_reader.fast_fields().column_opt(&self.field)?;
 
@@ -287,7 +287,7 @@ where
     fn for_segment(
         &self,
         segment_local_id: u32,
-        segment_reader: &SegmentReader,
+        segment_reader: &dyn SegmentReader,
     ) -> crate::Result<Self::Child> {
         let column_opt = segment_reader.fast_fields().bytes(&self.field)?;
 

src/collector/histogram_collector.rs

@@ -6,7 +6,7 @@ use fastdivide::DividerU64;
 use crate::collector::{Collector, SegmentCollector};
 use crate::fastfield::{FastFieldNotAvailableError, FastValue};
 use crate::schema::Type;
-use crate::{DocId, Score};
+use crate::{DocId, Score, SegmentReader};
 
 /// Histogram builds an histogram of the values of a fastfield for the
 /// collected DocSet.
@@ -110,7 +110,7 @@ impl Collector for HistogramCollector {
     fn for_segment(
         &self,
         _segment_local_id: crate::SegmentOrdinal,
-        segment: &crate::SegmentReader,
+        segment: &dyn SegmentReader,
     ) -> crate::Result<Self::Child> {
         let column_opt = segment.fast_fields().u64_lenient(&self.field)?;
         let (column, _column_type) = column_opt.ok_or_else(|| FastFieldNotAvailableError {

src/collector/mod.rs

@@ -156,7 +156,7 @@ pub trait Collector: Sync + Send {
     fn for_segment(
         &self,
         segment_local_id: SegmentOrdinal,
-        segment: &SegmentReader,
+        segment: &dyn SegmentReader,
     ) -> crate::Result<Self::Child>;
 
     /// Returns true iff the collector requires to compute scores for documents.
@@ -174,7 +174,7 @@ pub trait Collector: Sync + Send {
         &self,
         weight: &dyn Weight,
         segment_ord: u32,
-        reader: &SegmentReader,
+        reader: &dyn SegmentReader,
     ) -> crate::Result<<Self::Child as SegmentCollector>::Fruit> {
         let with_scoring = self.requires_scoring();
         let mut segment_collector = self.for_segment(segment_ord, reader)?;
@@ -186,7 +186,7 @@ pub trait Collector: Sync + Send {
 pub(crate) fn default_collect_segment_impl<TSegmentCollector: SegmentCollector>(
     segment_collector: &mut TSegmentCollector,
     weight: &dyn Weight,
-    reader: &SegmentReader,
+    reader: &dyn SegmentReader,
     with_scoring: bool,
 ) -> crate::Result<()> {
     match (reader.alive_bitset(), with_scoring) {
@@ -255,7 +255,7 @@ impl<TCollector: Collector> Collector for Option<TCollector> {
     fn for_segment(
         &self,
         segment_local_id: SegmentOrdinal,
-        segment: &SegmentReader,
+        segment: &dyn SegmentReader,
     ) -> crate::Result<Self::Child> {
         Ok(if let Some(inner) = self {
             let inner_segment_collector = inner.for_segment(segment_local_id, segment)?;
@@ -336,7 +336,7 @@ where
     fn for_segment(
         &self,
         segment_local_id: u32,
-        segment: &SegmentReader,
+        segment: &dyn SegmentReader,
     ) -> crate::Result<Self::Child> {
         let left = self.0.for_segment(segment_local_id, segment)?;
         let right = self.1.for_segment(segment_local_id, segment)?;
@@ -407,7 +407,7 @@ where
     fn for_segment(
         &self,
         segment_local_id: u32,
-        segment: &SegmentReader,
+        segment: &dyn SegmentReader,
     ) -> crate::Result<Self::Child> {
         let one = self.0.for_segment(segment_local_id, segment)?;
         let two = self.1.for_segment(segment_local_id, segment)?;
@@ -487,7 +487,7 @@ where
     fn for_segment(
         &self,
         segment_local_id: u32,
-        segment: &SegmentReader,
+        segment: &dyn SegmentReader,
     ) -> crate::Result<Self::Child> {
         let one = self.0.for_segment(segment_local_id, segment)?;
         let two = self.1.for_segment(segment_local_id, segment)?;

src/collector/multi_collector.rs

@@ -24,7 +24,7 @@ impl<TCollector: Collector> Collector for CollectorWrapper<TCollector> {
     fn for_segment(
         &self,
         segment_local_id: u32,
-        reader: &SegmentReader,
+        reader: &dyn SegmentReader,
     ) -> crate::Result<Box<dyn BoxableSegmentCollector>> {
         let child = self.0.for_segment(segment_local_id, reader)?;
         Ok(Box::new(SegmentCollectorWrapper(child)))
@@ -209,7 +209,7 @@ impl Collector for MultiCollector<'_> {
     fn for_segment(
         &self,
         segment_local_id: SegmentOrdinal,
-        segment: &SegmentReader,
+        segment: &dyn SegmentReader,
     ) -> crate::Result<MultiCollectorChild> {
         let children = self
             .collector_wrappers

src/collector/sort_key/order.rs

@@ -5,7 +5,7 @@ use serde::{Deserialize, Serialize};
 
 use crate::collector::{SegmentSortKeyComputer, SortKeyComputer};
 use crate::schema::{OwnedValue, Schema};
-use crate::{DocId, Order, Score};
+use crate::{DocId, Order, Score, SegmentReader};
 
 fn compare_owned_value<const NULLS_FIRST: bool>(lhs: &OwnedValue, rhs: &OwnedValue) -> Ordering {
     match (lhs, rhs) {
@@ -430,7 +430,7 @@ where
 
     fn segment_sort_key_computer(
         &self,
-        segment_reader: &crate::SegmentReader,
+        segment_reader: &dyn SegmentReader,
     ) -> crate::Result<Self::Child> {
         let child = self.0.segment_sort_key_computer(segment_reader)?;
         Ok(SegmentSortKeyComputerWithComparator {
@@ -468,7 +468,7 @@ where
 
     fn segment_sort_key_computer(
         &self,
-        segment_reader: &crate::SegmentReader,
+        segment_reader: &dyn SegmentReader,
     ) -> crate::Result<Self::Child> {
         let child = self.0.segment_sort_key_computer(segment_reader)?;
         Ok(SegmentSortKeyComputerWithComparator {

src/collector/sort_key/sort_by_erased_type.rs

@@ -6,7 +6,7 @@ use crate::collector::sort_key::{
 use crate::collector::{SegmentSortKeyComputer, SortKeyComputer};
 use crate::fastfield::FastFieldNotAvailableError;
 use crate::schema::OwnedValue;
-use crate::{DateTime, DocId, Score};
+use crate::{DateTime, DocId, Score, SegmentReader};
 
 /// Sort by the boxed / OwnedValue representation of either a fast field, or of the score.
 ///
@@ -86,7 +86,7 @@ impl SortKeyComputer for SortByErasedType {
 
     fn segment_sort_key_computer(
         &self,
-        segment_reader: &crate::SegmentReader,
+        segment_reader: &dyn SegmentReader,
     ) -> crate::Result<Self::Child> {
         let inner: Box<dyn ErasedSegmentSortKeyComputer> = match self {
             Self::Field(column_name) => {

src/collector/sort_key/sort_by_score.rs

@@ -1,6 +1,6 @@
 use crate::collector::sort_key::NaturalComparator;
 use crate::collector::{SegmentSortKeyComputer, SortKeyComputer, TopNComputer};
-use crate::{DocAddress, DocId, Score};
+use crate::{DocAddress, DocId, Score, SegmentReader};
 
 /// Sort by similarity score.
 #[derive(Clone, Debug, Copy)]
@@ -19,7 +19,7 @@ impl SortKeyComputer for SortBySimilarityScore {
 
     fn segment_sort_key_computer(
         &self,
-        _segment_reader: &crate::SegmentReader,
+        _segment_reader: &dyn SegmentReader,
     ) -> crate::Result<Self::Child> {
         Ok(SortBySimilarityScore)
     }
@@ -29,7 +29,7 @@ impl SortKeyComputer for SortBySimilarityScore {
         &self,
         k: usize,
         weight: &dyn crate::query::Weight,
-        reader: &crate::SegmentReader,
+        reader: &dyn SegmentReader,
         segment_ord: u32,
     ) -> crate::Result<Vec<(Self::SortKey, DocAddress)>> {
         let mut top_n: TopNComputer<Score, DocId, Self::Comparator> =

src/collector/sort_key/sort_by_static_fast_value.rs

@@ -61,7 +61,7 @@ impl<T: FastValue> SortKeyComputer for SortByStaticFastValue<T> {
 
     fn segment_sort_key_computer(
         &self,
-        segment_reader: &SegmentReader,
+        segment_reader: &dyn SegmentReader,
     ) -> crate::Result<Self::Child> {
         let sort_column_opt = segment_reader.fast_fields().u64_lenient(&self.field)?;
         let (sort_column, _sort_column_type) =

src/collector/sort_key/sort_by_string.rs

@@ -3,7 +3,7 @@ use columnar::StrColumn;
 use crate::collector::sort_key::NaturalComparator;
 use crate::collector::{SegmentSortKeyComputer, SortKeyComputer};
 use crate::termdict::TermOrdinal;
-use crate::{DocId, Score};
+use crate::{DocId, Score, SegmentReader};
 
 /// Sort by the first value of a string column.
 ///
@@ -35,7 +35,7 @@ impl SortKeyComputer for SortByString {
 
     fn segment_sort_key_computer(
         &self,
-        segment_reader: &crate::SegmentReader,
+        segment_reader: &dyn SegmentReader,
     ) -> crate::Result<Self::Child> {
         let str_column_opt = segment_reader.fast_fields().str(&self.column_name)?;
         Ok(ByStringColumnSegmentSortKeyComputer { str_column_opt })

src/collector/sort_key/sort_key_computer.rs

@@ -119,7 +119,7 @@ pub trait SortKeyComputer: Sync {
         &self,
         k: usize,
         weight: &dyn crate::query::Weight,
-        reader: &crate::SegmentReader,
+        reader: &dyn SegmentReader,
         segment_ord: u32,
     ) -> crate::Result<Vec<(Self::SortKey, DocAddress)>> {
         let with_scoring = self.requires_scoring();
@@ -135,7 +135,7 @@ pub trait SortKeyComputer: Sync {
     }
 
     /// Builds a child sort key computer for a specific segment.
-    fn segment_sort_key_computer(&self, segment_reader: &SegmentReader) -> Result<Self::Child>;
+    fn segment_sort_key_computer(&self, segment_reader: &dyn SegmentReader) -> Result<Self::Child>;
 }
 
 impl<HeadSortKeyComputer, TailSortKeyComputer> SortKeyComputer
@@ -156,7 +156,7 @@ where
         (self.0.comparator(), self.1.comparator())
     }
 
-    fn segment_sort_key_computer(&self, segment_reader: &SegmentReader) -> Result<Self::Child> {
+    fn segment_sort_key_computer(&self, segment_reader: &dyn SegmentReader) -> Result<Self::Child> {
         Ok((
             self.0.segment_sort_key_computer(segment_reader)?,
             self.1.segment_sort_key_computer(segment_reader)?,
@@ -357,7 +357,7 @@ where
         )
     }
 
-    fn segment_sort_key_computer(&self, segment_reader: &SegmentReader) -> Result<Self::Child> {
+    fn segment_sort_key_computer(&self, segment_reader: &dyn SegmentReader) -> Result<Self::Child> {
         let sort_key_computer1 = self.0.segment_sort_key_computer(segment_reader)?;
         let sort_key_computer2 = self.1.segment_sort_key_computer(segment_reader)?;
         let sort_key_computer3 = self.2.segment_sort_key_computer(segment_reader)?;
@@ -420,7 +420,7 @@ where
         SortKeyComputer4::Comparator,
     );
 
-    fn segment_sort_key_computer(&self, segment_reader: &SegmentReader) -> Result<Self::Child> {
+    fn segment_sort_key_computer(&self, segment_reader: &dyn SegmentReader) -> Result<Self::Child> {
         let sort_key_computer1 = self.0.segment_sort_key_computer(segment_reader)?;
         let sort_key_computer2 = self.1.segment_sort_key_computer(segment_reader)?;
         let sort_key_computer3 = self.2.segment_sort_key_computer(segment_reader)?;
@@ -454,7 +454,7 @@ where
 
 impl<F, SegmentF, TSortKey> SortKeyComputer for F
 where
-    F: 'static + Send + Sync + Fn(&SegmentReader) -> SegmentF,
+    F: 'static + Send + Sync + Fn(&dyn SegmentReader) -> SegmentF,
     SegmentF: 'static + FnMut(DocId) -> TSortKey,
     TSortKey: 'static + PartialOrd + Clone + Send + Sync + std::fmt::Debug,
 {
@@ -462,7 +462,7 @@ where
     type Child = SegmentF;
     type Comparator = NaturalComparator;
 
-    fn segment_sort_key_computer(&self, segment_reader: &SegmentReader) -> Result<Self::Child> {
+    fn segment_sort_key_computer(&self, segment_reader: &dyn SegmentReader) -> Result<Self::Child> {
         Ok((self)(segment_reader))
     }
 }
@@ -509,10 +509,10 @@ mod tests {
 
     #[test]
     fn test_lazy_score_computer() {
-        let score_computer_primary = |_segment_reader: &SegmentReader| |_doc: DocId| 200u32;
+        let score_computer_primary = |_segment_reader: &dyn SegmentReader| |_doc: DocId| 200u32;
         let call_count = Arc::new(AtomicUsize::new(0));
         let call_count_clone = call_count.clone();
-        let score_computer_secondary = move |_segment_reader: &SegmentReader| {
+        let score_computer_secondary = move |_segment_reader: &dyn SegmentReader| {
             let call_count_new_clone = call_count_clone.clone();
             move |_doc: DocId| {
                 call_count_new_clone.fetch_add(1, AtomicOrdering::SeqCst);
@@ -572,10 +572,10 @@ mod tests {
 
     #[test]
     fn test_lazy_score_computer_dynamic_ordering() {
-        let score_computer_primary = |_segment_reader: &SegmentReader| |_doc: DocId| 200u32;
+        let score_computer_primary = |_segment_reader: &dyn SegmentReader| |_doc: DocId| 200u32;
         let call_count = Arc::new(AtomicUsize::new(0));
         let call_count_clone = call_count.clone();
-        let score_computer_secondary = move |_segment_reader: &SegmentReader| {
+        let score_computer_secondary = move |_segment_reader: &dyn SegmentReader| {
             let call_count_new_clone = call_count_clone.clone();
             move |_doc: DocId| {
                 call_count_new_clone.fetch_add(1, AtomicOrdering::SeqCst);

src/collector/sort_key_top_collector.rs

@@ -32,7 +32,11 @@ where TSortKeyComputer: SortKeyComputer + Send + Sync + 'static
         self.sort_key_computer.check_schema(schema)
     }
 
-    fn for_segment(&self, segment_ord: u32, segment_reader: &SegmentReader) -> Result<Self::Child> {
+    fn for_segment(
+        &self,
+        segment_ord: u32,
+        segment_reader: &dyn SegmentReader,
+    ) -> Result<Self::Child> {
         let segment_sort_key_computer = self
             .sort_key_computer
             .segment_sort_key_computer(segment_reader)?;
@@ -63,7 +67,7 @@ where TSortKeyComputer: SortKeyComputer + Send + Sync + 'static
         &self,
         weight: &dyn Weight,
         segment_ord: u32,
-        reader: &SegmentReader,
+        reader: &dyn SegmentReader,
     ) -> crate::Result<Vec<(TSortKeyComputer::SortKey, DocAddress)>> {
         let k = self.doc_range.end;
         let docs = self
@@ -160,7 +164,7 @@ mod tests {
         expected: &[(crate::Score, usize)],
     ) {
         let mut vals: Vec<(crate::Score, usize)> = (0..10).map(|val| (val as f32, val)).collect();
-        vals.shuffle(&mut rand::thread_rng());
+        vals.shuffle(&mut rand::rng());
         let vals_merged = merge_top_k(vals.into_iter(), doc_range, ComparatorEnum::from(order));
         assert_eq!(&vals_merged, expected);
     }

src/collector/tests.rs

@@ -5,7 +5,7 @@ use crate::query::{AllQuery, QueryParser};
 use crate::schema::{Schema, FAST, TEXT};
 use crate::time::format_description::well_known::Rfc3339;
 use crate::time::OffsetDateTime;
-use crate::{DateTime, DocAddress, Index, Searcher, TantivyDocument};
+use crate::{DateTime, DocAddress, Index, Searcher, SegmentReader, TantivyDocument};
 
 pub const TEST_COLLECTOR_WITH_SCORE: TestCollector = TestCollector {
     compute_score: true,
@@ -109,7 +109,7 @@ impl Collector for TestCollector {
     fn for_segment(
         &self,
         segment_id: SegmentOrdinal,
-        _reader: &SegmentReader,
+        _reader: &dyn SegmentReader,
     ) -> crate::Result<TestSegmentCollector> {
         Ok(TestSegmentCollector {
             segment_id,
@@ -180,7 +180,7 @@ impl Collector for FastFieldTestCollector {
     fn for_segment(
         &self,
         _: SegmentOrdinal,
-        segment_reader: &SegmentReader,
+        segment_reader: &dyn SegmentReader,
     ) -> crate::Result<FastFieldSegmentCollector> {
         let reader = segment_reader
             .fast_fields()
@@ -243,7 +243,7 @@ impl Collector for BytesFastFieldTestCollector {
     fn for_segment(
         &self,
         _segment_local_id: u32,
-        segment_reader: &SegmentReader,
+        segment_reader: &dyn SegmentReader,
     ) -> crate::Result<BytesFastFieldSegmentCollector> {
         let column_opt = segment_reader.fast_fields().bytes(&self.field)?;
         Ok(BytesFastFieldSegmentCollector {

src/collector/top_score_collector.rs

@@ -393,7 +393,7 @@ impl TopDocs {
     /// // This is where we build our collector with our custom score.
     /// let top_docs_by_custom_score = TopDocs
     ///         ::with_limit(10)
-    ///          .tweak_score(move |segment_reader: &SegmentReader| {
+    ///          .tweak_score(move |segment_reader: &dyn SegmentReader| {
     ///             // The argument is a function that returns our scoring
     ///             // function.
     ///             //
@@ -442,7 +442,7 @@ pub struct TweakScoreFn<F>(F);
 
 impl<F, TTweakScoreSortKeyFn, TSortKey> SortKeyComputer for TweakScoreFn<F>
 where
-    F: 'static + Send + Sync + Fn(&SegmentReader) -> TTweakScoreSortKeyFn,
+    F: 'static + Send + Sync + Fn(&dyn SegmentReader) -> TTweakScoreSortKeyFn,
     TTweakScoreSortKeyFn: 'static + Fn(DocId, Score) -> TSortKey,
     TweakScoreSegmentSortKeyComputer<TTweakScoreSortKeyFn>:
         SegmentSortKeyComputer<SortKey = TSortKey, SegmentSortKey = TSortKey>,
@@ -458,7 +458,7 @@ where
 
     fn segment_sort_key_computer(
         &self,
-        segment_reader: &SegmentReader,
+        segment_reader: &dyn SegmentReader,
     ) -> crate::Result<Self::Child> {
         Ok({
             TweakScoreSegmentSortKeyComputer {
@@ -1525,7 +1525,7 @@ mod tests {
         let text_query = query_parser.parse_query("droopy tax")?;
         let collector = TopDocs::with_limit(2)
             .and_offset(1)
-            .order_by(move |_segment_reader: &SegmentReader| move |doc: DocId| doc);
+            .order_by(move |_segment_reader: &dyn SegmentReader| move |doc: DocId| doc);
         let score_docs: Vec<(u32, DocAddress)> =
             index.reader()?.searcher().search(&text_query, &collector)?;
         assert_eq!(
@@ -1543,7 +1543,7 @@ mod tests {
         let text_query = query_parser.parse_query("droopy tax").unwrap();
         let collector = TopDocs::with_limit(2)
             .and_offset(1)
-            .order_by(move |_segment_reader: &SegmentReader| move |doc: DocId| doc);
+            .order_by(move |_segment_reader: &dyn SegmentReader| move |doc: DocId| doc);
         let score_docs: Vec<(u32, DocAddress)> = index
             .reader()
             .unwrap()

src/core/searcher.rs

@@ -4,7 +4,7 @@ use std::{fmt, io};
 
 use crate::collector::Collector;
 use crate::core::Executor;
-use crate::index::{SegmentId, SegmentReader};
+use crate::index::{ArcSegmentReader, SegmentId, SegmentReader};
 use crate::query::{Bm25StatisticsProvider, EnableScoring, Query};
 use crate::schema::document::DocumentDeserialize;
 use crate::schema::{Schema, Term};
@@ -36,7 +36,7 @@ pub struct SearcherGeneration {
 
 impl SearcherGeneration {
     pub(crate) fn from_segment_readers(
-        segment_readers: &[SegmentReader],
+        segment_readers: &[ArcSegmentReader],
         generation_id: u64,
     ) -> Self {
         let mut segment_id_to_del_opstamp = BTreeMap::new();
@@ -133,7 +133,7 @@ impl Searcher {
     pub fn doc_freq(&self, term: &Term) -> crate::Result<u64> {
         let mut total_doc_freq = 0;
         for segment_reader in &self.inner.segment_readers {
-            let inverted_index = segment_reader.inverted_index(term.field())?;
+            let inverted_index = segment_reader.as_ref().inverted_index(term.field())?;
             let doc_freq = inverted_index.doc_freq(term)?;
             total_doc_freq += u64::from(doc_freq);
         }
@@ -146,7 +146,7 @@ impl Searcher {
     pub async fn doc_freq_async(&self, term: &Term) -> crate::Result<u64> {
         let mut total_doc_freq = 0;
         for segment_reader in &self.inner.segment_readers {
-            let inverted_index = segment_reader.inverted_index(term.field())?;
+            let inverted_index = segment_reader.as_ref().inverted_index(term.field())?;
             let doc_freq = inverted_index.doc_freq_async(term).await?;
             total_doc_freq += u64::from(doc_freq);
         }
@@ -154,13 +154,13 @@ impl Searcher {
     }
 
     /// Return the list of segment readers
-    pub fn segment_readers(&self) -> &[SegmentReader] {
+    pub fn segment_readers(&self) -> &[ArcSegmentReader] {
         &self.inner.segment_readers
     }
 
     /// Returns the segment_reader associated with the given segment_ord
-    pub fn segment_reader(&self, segment_ord: u32) -> &SegmentReader {
-        &self.inner.segment_readers[segment_ord as usize]
+    pub fn segment_reader(&self, segment_ord: u32) -> &dyn SegmentReader {
+        self.inner.segment_readers[segment_ord as usize].as_ref()
     }
 
     /// Runs a query on the segment readers wrapped by the searcher.
@@ -229,7 +229,11 @@ impl Searcher {
         let segment_readers = self.segment_readers();
         let fruits = executor.map(
             |(segment_ord, segment_reader)| {
-                collector.collect_segment(weight.as_ref(), segment_ord as u32, segment_reader)
+                collector.collect_segment(
+                    weight.as_ref(),
+                    segment_ord as u32,
+                    segment_reader.as_ref(),
+                )
             },
             segment_readers.iter().enumerate(),
         )?;
@@ -259,7 +263,7 @@ impl From<Arc<SearcherInner>> for Searcher {
 pub(crate) struct SearcherInner {
     schema: Schema,
     index: Index,
-    segment_readers: Vec<SegmentReader>,
+    segment_readers: Vec<ArcSegmentReader>,
     store_readers: Vec<StoreReader>,
     generation: TrackedObject<SearcherGeneration>,
 }
@@ -269,7 +273,7 @@ impl SearcherInner {
     pub(crate) fn new(
         schema: Schema,
         index: Index,
-        segment_readers: Vec<SegmentReader>,
+        segment_readers: Vec<ArcSegmentReader>,
         generation: TrackedObject<SearcherGeneration>,
         doc_store_cache_num_blocks: usize,
     ) -> io::Result<SearcherInner> {
@@ -301,7 +305,7 @@ impl fmt::Debug for Searcher {
         let segment_ids = self
             .segment_readers()
             .iter()
-            .map(SegmentReader::segment_id)
+            .map(|segment_reader| segment_reader.segment_id())
             .collect::<Vec<_>>();
         write!(f, "Searcher({segment_ids:?})")
     }

src/docset.rs

@@ -51,31 +51,55 @@ pub trait DocSet: Send {
         doc
     }
 
-    /// Seeks to the target if possible and returns true if the target is in the DocSet.
+    /// !!!Dragons ahead!!!
+    /// In spirit, this is an approximate and dangerous version of `seek`.
+    ///
+    /// It can leave the DocSet in an `invalid` state and might return a
+    /// lower bound of what the result of Seek would have been.
+    ///
+    ///
+    /// More accurately it returns either:
+    /// - Found if the target is in the docset. In that case, the DocSet is left in a valid state.
+    /// - SeekLowerBound(seek_lower_bound) if the target is not in the docset. In that case, The
+    ///   DocSet can be the left in a invalid state. The DocSet should then only receives call to
+    ///   `seek_danger(..)` until it returns `Found`, and get back to a valid state.
+    ///
+    /// `seek_lower_bound` can be any `DocId` (in the docset or not) as long as it is in
+    /// `(target .. seek_result]` where `seek_result` is the first document in the docset greater
+    /// than to `target`.
+    ///
+    /// `seek_danger` may return `SeekLowerBound(TERMINATED)`.
+    ///
+    /// Calling `seek_danger` with TERMINATED as a target is allowed,
+    /// and should always return NewTarget(TERMINATED) or anything larger as TERMINATED is NOT in
+    /// the DocSet.
     ///
     /// DocSets that already have an efficient `seek` method don't need to implement
-    /// `seek_into_the_danger_zone`. All wrapper DocSets should forward
-    /// `seek_into_the_danger_zone` to the underlying DocSet.
+    /// `seek_danger`.
     ///
-    /// ## API Behaviour
-    /// If `seek_into_the_danger_zone` is returning true, a call to `doc()` has to return target.
-    /// If `seek_into_the_danger_zone` is returning false, a call to `doc()` may return any doc
-    /// between the last doc that matched and target or a doc that is a valid next hit after
-    /// target. The DocSet is considered to be in an invalid state until
-    /// `seek_into_the_danger_zone` returns true again.
-    ///
-    /// `target` needs to be equal or larger than `doc` when in a valid state.
-    ///
-    /// Consecutive calls are not allowed to have decreasing `target` values.
-    ///
-    /// # Warning
-    /// This is an advanced API used by intersection. The API contract is tricky, avoid using it.
-    fn seek_into_the_danger_zone(&mut self, target: DocId) -> bool {
-        let current_doc = self.doc();
-        if current_doc < target {
-            self.seek(target);
+    /// Consecutive calls to seek_danger are guaranteed to have strictly increasing `target`
+    /// values.
+    fn seek_danger(&mut self, target: DocId) -> SeekDangerResult {
+        if target >= TERMINATED {
+            debug_assert!(target == TERMINATED);
+            // No need to advance.
+            return SeekDangerResult::SeekLowerBound(target);
+        }
+
+        // The default implementation does not include any
+        // `danger zone` behavior.
+        //
+        // It does not leave the scorer in an invalid state.
+        // For this reason, we can safely call `self.doc()`.
+        let mut doc = self.doc();
+        if doc < target {
+            doc = self.seek(target);
+        }
+        if doc == target {
+            SeekDangerResult::Found
+        } else {
+            SeekDangerResult::SeekLowerBound(self.doc())
         }
-        self.doc() == target
     }
 
     /// Fills a given mutable buffer with the next doc ids from the
@@ -166,6 +190,17 @@ pub trait DocSet: Send {
     }
 }
 
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum SeekDangerResult {
+    /// The target was found in the DocSet.
+    Found,
+    /// The target was not found in the DocSet.
+    /// We return a range in which the value could be.
+    /// The given target can be any DocId, that is <= than the first document
+    /// in the docset after the target.
+    SeekLowerBound(DocId),
+}
+
 impl DocSet for &mut dyn DocSet {
     fn advance(&mut self) -> u32 {
         (**self).advance()
@@ -175,8 +210,8 @@ impl DocSet for &mut dyn DocSet {
         (**self).seek(target)
     }
 
-    fn seek_into_the_danger_zone(&mut self, target: DocId) -> bool {
-        (**self).seek_into_the_danger_zone(target)
+    fn seek_danger(&mut self, target: DocId) -> SeekDangerResult {
+        (**self).seek_danger(target)
     }
 
     fn doc(&self) -> u32 {
@@ -211,9 +246,9 @@ impl<TDocSet: DocSet + ?Sized> DocSet for Box<TDocSet> {
         unboxed.seek(target)
     }
 
-    fn seek_into_the_danger_zone(&mut self, target: DocId) -> bool {
+    fn seek_danger(&mut self, target: DocId) -> SeekDangerResult {
         let unboxed: &mut TDocSet = self.borrow_mut();
-        unboxed.seek_into_the_danger_zone(target)
+        unboxed.seek_danger(target)
     }
 
     fn fill_buffer(&mut self, buffer: &mut [DocId; COLLECT_BLOCK_BUFFER_LEN]) -> usize {

src/fastfield/alive_bitset.rs

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

src/fastfield/mod.rs

@@ -96,7 +96,7 @@ mod tests {
     };
     use crate::time::OffsetDateTime;
     use crate::tokenizer::{LowerCaser, RawTokenizer, TextAnalyzer, TokenizerManager};
-    use crate::{Index, IndexWriter, SegmentReader};
+    use crate::{Index, IndexWriter};
 
     pub static SCHEMA: Lazy<Schema> = Lazy::new(|| {
         let mut schema_builder = Schema::builder();
@@ -430,7 +430,7 @@ mod tests {
             .searcher()
             .segment_readers()
             .iter()
-            .map(SegmentReader::segment_id)
+            .map(|segment_reader| segment_reader.segment_id())
             .collect();
         assert_eq!(segment_ids.len(), 2);
         index_writer.merge(&segment_ids[..]).wait().unwrap();
@@ -879,7 +879,7 @@ mod tests {
         const ONE_HOUR_IN_MICROSECS: i64 = 3_600 * 1_000_000;
         let times: Vec<DateTime> = std::iter::repeat_with(|| {
             // +- One hour.
-            let t = T0 + rng.gen_range(-ONE_HOUR_IN_MICROSECS..ONE_HOUR_IN_MICROSECS);
+            let t = T0 + rng.random_range(-ONE_HOUR_IN_MICROSECS..ONE_HOUR_IN_MICROSECS);
             DateTime::from_timestamp_micros(t)
         })
         .take(1_000)

src/functional_test.rs

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

src/index/index.rs

@@ -14,7 +14,7 @@ use crate::directory::error::OpenReadError;
 use crate::directory::MmapDirectory;
 use crate::directory::{Directory, ManagedDirectory, RamDirectory, INDEX_WRITER_LOCK};
 use crate::error::{DataCorruption, TantivyError};
-use crate::index::{IndexMeta, SegmentId, SegmentMeta, SegmentMetaInventory};
+use crate::index::{IndexMeta, SegmentId, SegmentMeta, SegmentMetaInventory, SegmentReader};
 use crate::indexer::index_writer::{
     IndexWriterOptions, MAX_NUM_THREAD, MEMORY_BUDGET_NUM_BYTES_MIN,
 };
@@ -24,7 +24,7 @@ use crate::reader::{IndexReader, IndexReaderBuilder};
 use crate::schema::document::Document;
 use crate::schema::{Field, FieldType, Schema};
 use crate::tokenizer::{TextAnalyzer, TokenizerManager};
-use crate::SegmentReader;
+use crate::TantivySegmentReader;
 
 fn load_metas(
     directory: &dyn Directory,
@@ -492,7 +492,7 @@ impl Index {
         let segments = self.searchable_segments()?;
         let fields_metadata: Vec<Vec<FieldMetadata>> = segments
             .into_iter()
-            .map(|segment| SegmentReader::open(&segment)?.fields_metadata())
+            .map(|segment| TantivySegmentReader::open(&segment)?.fields_metadata())
             .collect::<Result<_, _>>()?;
         Ok(merge_field_meta_data(fields_metadata))
     }

src/index/inverted_index_reader.rs

@@ -1,4 +1,9 @@
+#[cfg(feature = "quickwit")]
+use std::future::Future;
 use std::io;
+#[cfg(feature = "quickwit")]
+use std::pin::Pin;
+use std::sync::Arc;
 
 use common::json_path_writer::JSON_END_OF_PATH;
 use common::{BinarySerializable, ByteCount};
@@ -27,7 +32,102 @@ use crate::termdict::TermDictionary;
 ///
 /// `InvertedIndexReader` are created by calling
 /// [`SegmentReader::inverted_index()`](crate::SegmentReader::inverted_index).
-pub struct InvertedIndexReader {
+pub trait InvertedIndexReader: Send + Sync {
+    /// Returns the term info associated with the term.
+    fn get_term_info(&self, term: &Term) -> io::Result<Option<TermInfo>>;
+
+    /// Return the term dictionary datastructure.
+    fn terms(&self) -> &TermDictionary;
+
+    /// Return the fields and types encoded in the dictionary in lexicographic order.
+    /// Only valid on JSON fields.
+    ///
+    /// Notice: This requires a full scan and therefore **very expensive**.
+    /// TODO: Move to sstable to use the index.
+    #[doc(hidden)]
+    fn list_encoded_json_fields(&self) -> io::Result<Vec<InvertedIndexFieldSpace>>;
+
+    /// Returns a block postings given a `Term`.
+    /// This method is for an advanced usage only.
+    ///
+    /// Most users should prefer using [`Self::read_postings()`] instead.
+    fn read_block_postings(
+        &self,
+        term: &Term,
+        option: IndexRecordOption,
+    ) -> io::Result<Option<BlockSegmentPostings>>;
+
+    /// Returns a block postings given a `term_info`.
+    /// This method is for an advanced usage only.
+    ///
+    /// Most users should prefer using [`Self::read_postings()`] instead.
+    fn read_block_postings_from_terminfo(
+        &self,
+        term_info: &TermInfo,
+        requested_option: IndexRecordOption,
+    ) -> io::Result<BlockSegmentPostings>;
+
+    /// Returns a posting object given a `term_info`.
+    /// This method is for an advanced usage only.
+    ///
+    /// Most users should prefer using [`Self::read_postings()`] instead.
+    fn read_postings_from_terminfo(
+        &self,
+        term_info: &TermInfo,
+        option: IndexRecordOption,
+    ) -> io::Result<SegmentPostings>;
+
+    /// Returns the total number of tokens recorded for all documents
+    /// (including deleted documents).
+    fn total_num_tokens(&self) -> u64;
+
+    /// Returns the segment postings associated with the term, and with the given option,
+    /// or `None` if the term has never been encountered and indexed.
+    fn read_postings(
+        &self,
+        term: &Term,
+        option: IndexRecordOption,
+    ) -> io::Result<Option<SegmentPostings>>;
+
+    /// Returns the number of documents containing the term.
+    fn doc_freq(&self, term: &Term) -> io::Result<u32>;
+
+    /// Returns the number of documents containing the term asynchronously.
+    #[cfg(feature = "quickwit")]
+    fn doc_freq_async<'a>(&'a self, term: &'a Term) -> BoxFuture<'a, io::Result<u32>>;
+
+    /// Warmup a block postings given a `Term`.
+    /// This method is for an advanced usage only.
+    ///
+    /// returns a boolean, whether the term was found in the dictionary
+    #[cfg(feature = "quickwit")]
+    fn warm_postings<'a>(
+        &'a self,
+        term: &'a Term,
+        with_positions: bool,
+    ) -> BoxFuture<'a, io::Result<bool>>;
+
+    /// Warmup the block postings for all terms.
+    /// This method is for an advanced usage only.
+    ///
+    /// If you know which terms to pre-load, prefer using [`Self::warm_postings`] or
+    /// [`Self::warm_postings`] instead.
+    #[cfg(feature = "quickwit")]
+    fn warm_postings_full<'a>(&'a self, with_positions: bool) -> BoxFuture<'a, io::Result<()>>;
+}
+
+/// Convenient alias for an atomically reference counted inverted index reader handle.
+pub type ArcInvertedIndexReader = Arc<dyn InvertedIndexReader>;
+
+#[cfg(feature = "quickwit")]
+/// Boxed future used by async inverted index reader methods.
+pub type BoxFuture<'a, T> = Pin<Box<dyn Future<Output = T> + Send + 'a>>;
+
+/// The tantivy inverted index reader is in charge of accessing
+/// the inverted index associated with a specific field.
+///
+/// This is the default implementation of [`InvertedIndexReader`].
+pub struct TantivyInvertedIndexReader {
     termdict: TermDictionary,
     postings_file_slice: FileSlice,
     positions_file_slice: FileSlice,
@@ -36,11 +136,16 @@ pub struct InvertedIndexReader {
 }
 
 /// Object that records the amount of space used by a field in an inverted index.
-pub(crate) struct InvertedIndexFieldSpace {
+pub struct InvertedIndexFieldSpace {
+    /// The JSON field name (without the parent field).
     pub field_name: String,
+    /// The field type encoded in the term dictionary.
     pub field_type: Type,
+    /// Total postings size for this field.
     pub postings_size: ByteCount,
+    /// Total positions size for this field.
     pub positions_size: ByteCount,
+    /// Number of terms for this field.
     pub num_terms: u64,
 }
 
@@ -62,16 +167,16 @@ impl InvertedIndexFieldSpace {
     }
 }
 
-impl InvertedIndexReader {
+impl TantivyInvertedIndexReader {
     pub(crate) fn new(
         termdict: TermDictionary,
         postings_file_slice: FileSlice,
         positions_file_slice: FileSlice,
         record_option: IndexRecordOption,
-    ) -> io::Result<InvertedIndexReader> {
+    ) -> io::Result<TantivyInvertedIndexReader> {
         let (total_num_tokens_slice, postings_body) = postings_file_slice.split(8);
         let total_num_tokens = u64::deserialize(&mut total_num_tokens_slice.read_bytes()?)?;
-        Ok(InvertedIndexReader {
+        Ok(TantivyInvertedIndexReader {
             termdict,
             postings_file_slice: postings_body,
             positions_file_slice,
@@ -82,8 +187,8 @@ impl InvertedIndexReader {
 
     /// Creates an empty `InvertedIndexReader` object, which
     /// contains no terms at all.
-    pub fn empty(record_option: IndexRecordOption) -> InvertedIndexReader {
-        InvertedIndexReader {
+    pub fn empty(record_option: IndexRecordOption) -> TantivyInvertedIndexReader {
+        TantivyInvertedIndexReader {
             termdict: TermDictionary::empty(),
             postings_file_slice: FileSlice::empty(),
             positions_file_slice: FileSlice::empty(),
@@ -160,29 +265,6 @@ impl InvertedIndexReader {
         Ok(fields)
     }
 
-    /// Resets the block segment to another position of the postings
-    /// file.
-    ///
-    /// This is useful for enumerating through a list of terms,
-    /// and consuming the associated posting lists while avoiding
-    /// reallocating a [`BlockSegmentPostings`].
-    ///
-    /// # Warning
-    ///
-    /// This does not reset the positions list.
-    pub fn reset_block_postings_from_terminfo(
-        &self,
-        term_info: &TermInfo,
-        block_postings: &mut BlockSegmentPostings,
-    ) -> io::Result<()> {
-        let postings_slice = self
-            .postings_file_slice
-            .slice(term_info.postings_range.clone());
-        let postings_bytes = postings_slice.read_bytes()?;
-        block_postings.reset(term_info.doc_freq, postings_bytes)?;
-        Ok(())
-    }
-
     /// Returns a block postings given a `Term`.
     /// This method is for an advanced usage only.
     ///
@@ -282,7 +364,7 @@ impl InvertedIndexReader {
 }
 
 #[cfg(feature = "quickwit")]
-impl InvertedIndexReader {
+impl TantivyInvertedIndexReader {
     pub(crate) async fn get_term_info_async(&self, term: &Term) -> io::Result<Option<TermInfo>> {
         self.termdict.get_async(term.serialized_value_bytes()).await
     }
@@ -492,3 +574,84 @@ impl InvertedIndexReader {
             .unwrap_or(0u32))
     }
 }
+
+impl InvertedIndexReader for TantivyInvertedIndexReader {
+    fn get_term_info(&self, term: &Term) -> io::Result<Option<TermInfo>> {
+        TantivyInvertedIndexReader::get_term_info(self, term)
+    }
+
+    fn terms(&self) -> &TermDictionary {
+        TantivyInvertedIndexReader::terms(self)
+    }
+
+    fn list_encoded_json_fields(&self) -> io::Result<Vec<InvertedIndexFieldSpace>> {
+        TantivyInvertedIndexReader::list_encoded_json_fields(self)
+    }
+
+    fn read_block_postings(
+        &self,
+        term: &Term,
+        option: IndexRecordOption,
+    ) -> io::Result<Option<BlockSegmentPostings>> {
+        TantivyInvertedIndexReader::read_block_postings(self, term, option)
+    }
+
+    fn read_block_postings_from_terminfo(
+        &self,
+        term_info: &TermInfo,
+        requested_option: IndexRecordOption,
+    ) -> io::Result<BlockSegmentPostings> {
+        TantivyInvertedIndexReader::read_block_postings_from_terminfo(
+            self,
+            term_info,
+            requested_option,
+        )
+    }
+
+    fn read_postings_from_terminfo(
+        &self,
+        term_info: &TermInfo,
+        option: IndexRecordOption,
+    ) -> io::Result<SegmentPostings> {
+        TantivyInvertedIndexReader::read_postings_from_terminfo(self, term_info, option)
+    }
+
+    fn total_num_tokens(&self) -> u64 {
+        TantivyInvertedIndexReader::total_num_tokens(self)
+    }
+
+    fn read_postings(
+        &self,
+        term: &Term,
+        option: IndexRecordOption,
+    ) -> io::Result<Option<SegmentPostings>> {
+        TantivyInvertedIndexReader::read_postings(self, term, option)
+    }
+
+    fn doc_freq(&self, term: &Term) -> io::Result<u32> {
+        TantivyInvertedIndexReader::doc_freq(self, term)
+    }
+
+    #[cfg(feature = "quickwit")]
+    fn doc_freq_async<'a>(&'a self, term: &'a Term) -> BoxFuture<'a, io::Result<u32>> {
+        Box::pin(async move { TantivyInvertedIndexReader::doc_freq_async(self, term).await })
+    }
+
+    #[cfg(feature = "quickwit")]
+    fn warm_postings<'a>(
+        &'a self,
+        term: &'a Term,
+        with_positions: bool,
+    ) -> BoxFuture<'a, io::Result<bool>> {
+        Box::pin(async move {
+            TantivyInvertedIndexReader::warm_postings(self, term, with_positions).await
+        })
+    }
+
+    #[cfg(feature = "quickwit")]
+    fn warm_postings_full<'a>(&'a self, with_positions: bool) -> BoxFuture<'a, io::Result<()>> {
+        Box::pin(async move {
+            TantivyInvertedIndexReader::warm_postings_full(self, with_positions).await
+        })
+    }
+}

src/index/mod.rs

@@ -13,8 +13,13 @@ mod segment_reader;
 pub use self::index::{Index, IndexBuilder};
 pub(crate) use self::index_meta::SegmentMetaInventory;
 pub use self::index_meta::{IndexMeta, IndexSettings, Order, SegmentMeta};
-pub use self::inverted_index_reader::InvertedIndexReader;
+pub use self::inverted_index_reader::{
+    ArcInvertedIndexReader, InvertedIndexFieldSpace, InvertedIndexReader,
+    TantivyInvertedIndexReader,
+};
 pub use self::segment::Segment;
 pub use self::segment_component::SegmentComponent;
 pub use self::segment_id::SegmentId;
-pub use self::segment_reader::{FieldMetadata, SegmentReader};
+pub use self::segment_reader::{
+    ArcSegmentReader, FieldMetadata, SegmentReader, TantivySegmentReader,
+};

src/index/segment_reader.rs

@@ -9,8 +9,10 @@ use itertools::Itertools;
 use crate::directory::{CompositeFile, FileSlice};
 use crate::error::DataCorruption;
 use crate::fastfield::{intersect_alive_bitsets, AliveBitSet, FacetReader, FastFieldReaders};
-use crate::fieldnorm::{FieldNormReader, FieldNormReaders};
-use crate::index::{InvertedIndexReader, Segment, SegmentComponent, SegmentId};
+use crate::fieldnorm::FieldNormReaders;
+use crate::index::{
+    ArcInvertedIndexReader, Segment, SegmentComponent, SegmentId, TantivyInvertedIndexReader,
+};
 use crate::json_utils::json_path_sep_to_dot;
 use crate::schema::{Field, IndexRecordOption, Schema, Type};
 use crate::space_usage::SegmentSpaceUsage;
@@ -18,6 +20,93 @@ use crate::store::StoreReader;
 use crate::termdict::TermDictionary;
 use crate::{DocId, Opstamp};
 
+/// Abstraction over a segment reader for accessing all data structures of a segment.
+///
+/// This trait exists to decouple the query layer from the concrete on-disk layout. Alternative
+/// codecs can implement it to expose their own segment representation.
+pub trait SegmentReader: Send + Sync {
+    /// Highest document id ever attributed in this segment + 1.
+    fn max_doc(&self) -> DocId;
+
+    /// Number of alive documents. Deleted documents are not counted.
+    fn num_docs(&self) -> DocId;
+
+    /// Returns the schema of the index this segment belongs to.
+    fn schema(&self) -> &Schema;
+
+    /// Return the number of documents that have been deleted in the segment.
+    fn num_deleted_docs(&self) -> DocId {
+        self.max_doc() - self.num_docs()
+    }
+
+    /// Returns true if some of the documents of the segment have been deleted.
+    fn has_deletes(&self) -> bool {
+        self.num_deleted_docs() > 0
+    }
+
+    /// Accessor to a segment's fast field reader.
+    fn fast_fields(&self) -> &FastFieldReaders;
+
+    /// Accessor to the `FacetReader` associated with a given `Field`.
+    fn facet_reader(&self, field_name: &str) -> crate::Result<FacetReader> {
+        let schema = self.schema();
+        let field = schema.get_field(field_name)?;
+        let field_entry = schema.get_field_entry(field);
+        if field_entry.field_type().value_type() != Type::Facet {
+            return Err(crate::TantivyError::SchemaError(format!(
+                "`{field_name}` is not a facet field.`"
+            )));
+        }
+        let Some(facet_column) = self.fast_fields().str(field_name)? else {
+            panic!("Facet Field `{field_name}` is missing. This should not happen");
+        };
+        Ok(FacetReader::new(facet_column))
+    }
+
+    /// Accessor to the segment's field norms readers container.
+    fn fieldnorms_readers(&self) -> &FieldNormReaders;
+
+    /// Accessor to the segment's [`StoreReader`](crate::store::StoreReader).
+    fn get_store_reader(&self, cache_num_blocks: usize) -> io::Result<StoreReader>;
+
+    /// Returns a field reader associated with the field given in argument.
+    fn inverted_index(&self, field: Field) -> crate::Result<ArcInvertedIndexReader>;
+
+    /// Returns the list of fields that have been indexed in the segment.
+    fn fields_metadata(&self) -> crate::Result<Vec<FieldMetadata>>;
+
+    /// Returns the segment id
+    fn segment_id(&self) -> SegmentId;
+
+    /// Returns the delete opstamp
+    fn delete_opstamp(&self) -> Option<Opstamp>;
+
+    /// Returns the bitset representing the alive `DocId`s.
+    fn alive_bitset(&self) -> Option<&AliveBitSet>;
+
+    /// Returns true if the `doc` is marked as deleted.
+    fn is_deleted(&self, doc: DocId) -> bool {
+        self.alive_bitset()
+            .map(|alive_bitset| alive_bitset.is_deleted(doc))
+            .unwrap_or(false)
+    }
+
+    /// Returns an iterator that will iterate over the alive document ids
+    fn doc_ids_alive(&self) -> Box<dyn Iterator<Item = DocId> + Send + '_> {
+        if let Some(alive_bitset) = &self.alive_bitset() {
+            Box::new(alive_bitset.iter_alive())
+        } else {
+            Box::new(0u32..self.max_doc())
+        }
+    }
+
+    /// Summarize total space usage of this segment.
+    fn space_usage(&self) -> io::Result<SegmentSpaceUsage>;
+}
+
+/// Convenient alias for an atomically reference counted segment reader handle.
+pub type ArcSegmentReader = Arc<dyn SegmentReader>;
+
 /// Entry point to access all of the datastructures of the `Segment`
 ///
 /// - term dictionary
@@ -29,8 +118,8 @@ use crate::{DocId, Opstamp};
 /// The segment reader has a very low memory footprint,
 /// as close to all of the memory data is mmapped.
 #[derive(Clone)]
-pub struct SegmentReader {
-    inv_idx_reader_cache: Arc<RwLock<HashMap<Field, Arc<InvertedIndexReader>>>>,
+pub struct TantivySegmentReader {
+    inv_idx_reader_cache: Arc<RwLock<HashMap<Field, ArcInvertedIndexReader>>>,
 
     segment_id: SegmentId,
     delete_opstamp: Option<Opstamp>,
@@ -49,98 +138,9 @@ pub struct SegmentReader {
     schema: Schema,
 }
 
-impl SegmentReader {
-    /// Returns the highest document id ever attributed in
-    /// this segment + 1.
-    pub fn max_doc(&self) -> DocId {
-        self.max_doc
-    }
-
-    /// Returns the number of alive documents.
-    /// Deleted documents are not counted.
-    pub fn num_docs(&self) -> DocId {
-        self.num_docs
-    }
-
-    /// Returns the schema of the index this segment belongs to.
-    pub fn schema(&self) -> &Schema {
-        &self.schema
-    }
-
-    /// Return the number of documents that have been
-    /// deleted in the segment.
-    pub fn num_deleted_docs(&self) -> DocId {
-        self.max_doc - self.num_docs
-    }
-
-    /// Returns true if some of the documents of the segment have been deleted.
-    pub fn has_deletes(&self) -> bool {
-        self.num_deleted_docs() > 0
-    }
-
-    /// Accessor to a segment's fast field reader given a field.
-    ///
-    /// Returns the u64 fast value reader if the field
-    /// is a u64 field indexed as "fast".
-    ///
-    /// Return a FastFieldNotAvailableError if the field is not
-    /// declared as a fast field in the schema.
-    ///
-    /// # Panics
-    /// May panic if the index is corrupted.
-    pub fn fast_fields(&self) -> &FastFieldReaders {
-        &self.fast_fields_readers
-    }
-
-    /// Accessor to the `FacetReader` associated with a given `Field`.
-    pub fn facet_reader(&self, field_name: &str) -> crate::Result<FacetReader> {
-        let schema = self.schema();
-        let field = schema.get_field(field_name)?;
-        let field_entry = schema.get_field_entry(field);
-        if field_entry.field_type().value_type() != Type::Facet {
-            return Err(crate::TantivyError::SchemaError(format!(
-                "`{field_name}` is not a facet field.`"
-            )));
-        }
-        let Some(facet_column) = self.fast_fields().str(field_name)? else {
-            panic!("Facet Field `{field_name}` is missing. This should not happen");
-        };
-        Ok(FacetReader::new(facet_column))
-    }
-
-    /// Accessor to the segment's `Field norms`'s reader.
-    ///
-    /// Field norms are the length (in tokens) of the fields.
-    /// It is used in the computation of the [TfIdf](https://fulmicoton.gitbooks.io/tantivy-doc/content/tfidf.html).
-    ///
-    /// They are simply stored as a fast field, serialized in
-    /// the `.fieldnorm` file of the segment.
-    pub fn get_fieldnorms_reader(&self, field: Field) -> crate::Result<FieldNormReader> {
-        self.fieldnorm_readers.get_field(field)?.ok_or_else(|| {
-            let field_name = self.schema.get_field_name(field);
-            let err_msg = format!(
-                "Field norm not found for field {field_name:?}. Was the field set to record norm \
-                 during indexing?"
-            );
-            crate::TantivyError::SchemaError(err_msg)
-        })
-    }
-
-    #[doc(hidden)]
-    pub fn fieldnorms_readers(&self) -> &FieldNormReaders {
-        &self.fieldnorm_readers
-    }
-
-    /// Accessor to the segment's [`StoreReader`](crate::store::StoreReader).
-    ///
-    /// `cache_num_blocks` sets the number of decompressed blocks to be cached in an LRU.
-    /// The size of blocks is configurable, this should be reflexted in the
-    pub fn get_store_reader(&self, cache_num_blocks: usize) -> io::Result<StoreReader> {
-        StoreReader::open(self.store_file.clone(), cache_num_blocks)
-    }
-
+impl TantivySegmentReader {
     /// Open a new segment for reading.
-    pub fn open(segment: &Segment) -> crate::Result<SegmentReader> {
+    pub fn open(segment: &Segment) -> crate::Result<TantivySegmentReader> {
         Self::open_with_custom_alive_set(segment, None)
     }
 
@@ -148,7 +148,7 @@ impl SegmentReader {
     pub fn open_with_custom_alive_set(
         segment: &Segment,
         custom_bitset: Option<AliveBitSet>,
-    ) -> crate::Result<SegmentReader> {
+    ) -> crate::Result<TantivySegmentReader> {
         let termdict_file = segment.open_read(SegmentComponent::Terms)?;
         let termdict_composite = CompositeFile::open(&termdict_file)?;
 
@@ -190,7 +190,7 @@ impl SegmentReader {
             .map(|alive_bitset| alive_bitset.num_alive_docs() as u32)
             .unwrap_or(max_doc);
 
-        Ok(SegmentReader {
+        Ok(TantivySegmentReader {
             inv_idx_reader_cache: Default::default(),
             num_docs,
             max_doc,
@@ -206,6 +206,52 @@ impl SegmentReader {
             schema,
         })
     }
+}
+
+impl SegmentReader for TantivySegmentReader {
+    /// Returns the highest document id ever attributed in
+    /// this segment + 1.
+    fn max_doc(&self) -> DocId {
+        self.max_doc
+    }
+
+    /// Returns the number of alive documents.
+    /// Deleted documents are not counted.
+    fn num_docs(&self) -> DocId {
+        self.num_docs
+    }
+
+    /// Returns the schema of the index this segment belongs to.
+    fn schema(&self) -> &Schema {
+        &self.schema
+    }
+
+    /// Accessor to a segment's fast field reader given a field.
+    ///
+    /// Returns the u64 fast value reader if the field
+    /// is a u64 field indexed as "fast".
+    ///
+    /// Return a FastFieldNotAvailableError if the field is not
+    /// declared as a fast field in the schema.
+    ///
+    /// # Panics
+    /// May panic if the index is corrupted.
+    fn fast_fields(&self) -> &FastFieldReaders {
+        &self.fast_fields_readers
+    }
+
+    #[doc(hidden)]
+    fn fieldnorms_readers(&self) -> &FieldNormReaders {
+        &self.fieldnorm_readers
+    }
+
+    /// Accessor to the segment's [`StoreReader`](crate::store::StoreReader).
+    ///
+    /// `cache_num_blocks` sets the number of decompressed blocks to be cached in an LRU.
+    /// The size of blocks is configurable, this should be reflexted in the
+    fn get_store_reader(&self, cache_num_blocks: usize) -> io::Result<StoreReader> {
+        StoreReader::open(self.store_file.clone(), cache_num_blocks)
+    }
 
     /// Returns a field reader associated with the field given in argument.
     /// If the field was not present in the index during indexing time,
@@ -219,7 +265,7 @@ impl SegmentReader {
     /// is returned.
     /// Similarly, if the field is marked as indexed but no term has been indexed for the given
     /// index, an empty `InvertedIndexReader` is returned (but no warning is logged).
-    pub fn inverted_index(&self, field: Field) -> crate::Result<Arc<InvertedIndexReader>> {
+    fn inverted_index(&self, field: Field) -> crate::Result<ArcInvertedIndexReader> {
         if let Some(inv_idx_reader) = self
             .inv_idx_reader_cache
             .read()
@@ -244,7 +290,7 @@ impl SegmentReader {
             //
             // Returns an empty inverted index.
             let record_option = record_option_opt.unwrap_or(IndexRecordOption::Basic);
-            return Ok(Arc::new(InvertedIndexReader::empty(record_option)));
+            return Ok(Arc::new(TantivyInvertedIndexReader::empty(record_option)));
         }
 
         let record_option = record_option_opt.unwrap();
@@ -268,7 +314,7 @@ impl SegmentReader {
             DataCorruption::comment_only(error_msg)
         })?;
 
-        let inv_idx_reader = Arc::new(InvertedIndexReader::new(
+        let inv_idx_reader: ArcInvertedIndexReader = Arc::new(TantivyInvertedIndexReader::new(
             TermDictionary::open(termdict_file)?,
             postings_file,
             positions_file,
@@ -298,7 +344,7 @@ impl SegmentReader {
     /// Disclaimer: Some fields may not be listed here. For instance, if the schema contains a json
     /// field that is not indexed nor a fast field but is stored, it is possible for the field
     /// to not be listed.
-    pub fn fields_metadata(&self) -> crate::Result<Vec<FieldMetadata>> {
+    fn fields_metadata(&self) -> crate::Result<Vec<FieldMetadata>> {
         let mut indexed_fields: Vec<FieldMetadata> = Vec::new();
         let mut map_to_canonical = FnvHashMap::default();
         for (field, field_entry) in self.schema().fields() {
@@ -420,39 +466,22 @@ impl SegmentReader {
     }
 
     /// Returns the segment id
-    pub fn segment_id(&self) -> SegmentId {
+    fn segment_id(&self) -> SegmentId {
         self.segment_id
     }
 
     /// Returns the delete opstamp
-    pub fn delete_opstamp(&self) -> Option<Opstamp> {
+    fn delete_opstamp(&self) -> Option<Opstamp> {
         self.delete_opstamp
     }
 
     /// Returns the bitset representing the alive `DocId`s.
-    pub fn alive_bitset(&self) -> Option<&AliveBitSet> {
+    fn alive_bitset(&self) -> Option<&AliveBitSet> {
         self.alive_bitset_opt.as_ref()
     }
 
-    /// Returns true if the `doc` is marked
-    /// as deleted.
-    pub fn is_deleted(&self, doc: DocId) -> bool {
-        self.alive_bitset()
-            .map(|alive_bitset| alive_bitset.is_deleted(doc))
-            .unwrap_or(false)
-    }
-
-    /// Returns an iterator that will iterate over the alive document ids
-    pub fn doc_ids_alive(&self) -> Box<dyn Iterator<Item = DocId> + Send + '_> {
-        if let Some(alive_bitset) = &self.alive_bitset_opt {
-            Box::new(alive_bitset.iter_alive())
-        } else {
-            Box::new(0u32..self.max_doc)
-        }
-    }
-
     /// Summarize total space usage of this segment.
-    pub fn space_usage(&self) -> io::Result<SegmentSpaceUsage> {
+    fn space_usage(&self) -> io::Result<SegmentSpaceUsage> {
         Ok(SegmentSpaceUsage::new(
             self.num_docs(),
             self.termdict_composite.space_usage(self.schema()),
@@ -576,7 +605,7 @@ fn intersect_alive_bitset(
     }
 }
 
-impl fmt::Debug for SegmentReader {
+impl fmt::Debug for TantivySegmentReader {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         write!(f, "SegmentReader({:?})", self.segment_id)
     }

src/indexer/delete_queue.rs

@@ -250,11 +250,15 @@ mod tests {
 
     struct DummyWeight;
     impl Weight for DummyWeight {
-        fn scorer(&self, _reader: &SegmentReader, _boost: Score) -> crate::Result<Box<dyn Scorer>> {
+        fn scorer(
+            &self,
+            _reader: &dyn SegmentReader,
+            _boost: Score,
+        ) -> crate::Result<Box<dyn Scorer>> {
             Err(crate::TantivyError::InternalError("dummy impl".to_owned()))
         }
 
-        fn explain(&self, _reader: &SegmentReader, _doc: DocId) -> crate::Result<Explanation> {
+        fn explain(&self, _reader: &dyn SegmentReader, _doc: DocId) -> crate::Result<Explanation> {
             Err(crate::TantivyError::InternalError("dummy impl".to_owned()))
         }
     }

src/indexer/index_writer.rs

@@ -12,7 +12,9 @@ use super::{AddBatch, AddBatchReceiver, AddBatchSender, PreparedCommit};
 use crate::directory::{DirectoryLock, GarbageCollectionResult, TerminatingWrite};
 use crate::error::TantivyError;
 use crate::fastfield::write_alive_bitset;
-use crate::index::{Index, Segment, SegmentComponent, SegmentId, SegmentMeta, SegmentReader};
+use crate::index::{
+    Index, Segment, SegmentComponent, SegmentId, SegmentMeta, SegmentReader, TantivySegmentReader,
+};
 use crate::indexer::delete_queue::{DeleteCursor, DeleteQueue};
 use crate::indexer::doc_opstamp_mapping::DocToOpstampMapping;
 use crate::indexer::index_writer_status::IndexWriterStatus;
@@ -94,7 +96,7 @@ pub struct IndexWriter<D: Document = TantivyDocument> {
 
 fn compute_deleted_bitset(
     alive_bitset: &mut BitSet,
-    segment_reader: &SegmentReader,
+    segment_reader: &dyn SegmentReader,
     delete_cursor: &mut DeleteCursor,
     doc_opstamps: &DocToOpstampMapping,
     target_opstamp: Opstamp,
@@ -143,7 +145,7 @@ pub fn advance_deletes(
         return Ok(());
     }
 
-    let segment_reader = SegmentReader::open(&segment)?;
+    let segment_reader = TantivySegmentReader::open(&segment)?;
 
     let max_doc = segment_reader.max_doc();
     let mut alive_bitset: BitSet = match segment_entry.alive_bitset() {
@@ -243,7 +245,7 @@ fn apply_deletes(
         .max()
         .expect("Empty DocOpstamp is forbidden");
 
-    let segment_reader = SegmentReader::open(segment)?;
+    let segment_reader = TantivySegmentReader::open(segment)?;
     let doc_to_opstamps = DocToOpstampMapping::WithMap(doc_opstamps);
 
     let max_doc = segment.meta().max_doc();

src/indexer/merger.rs

@@ -1,5 +1,3 @@
-use std::sync::Arc;
-
 use columnar::{
     ColumnType, ColumnarReader, MergeRowOrder, RowAddr, ShuffleMergeOrder, StackMergeOrder,
 };
@@ -12,14 +10,14 @@ use crate::docset::{DocSet, TERMINATED};
 use crate::error::DataCorruption;
 use crate::fastfield::AliveBitSet;
 use crate::fieldnorm::{FieldNormReader, FieldNormReaders, FieldNormsSerializer, FieldNormsWriter};
-use crate::index::{Segment, SegmentComponent, SegmentReader};
+use crate::index::{Segment, SegmentComponent, SegmentReader, TantivySegmentReader};
 use crate::indexer::doc_id_mapping::{MappingType, SegmentDocIdMapping};
 use crate::indexer::SegmentSerializer;
 use crate::postings::{InvertedIndexSerializer, Postings, SegmentPostings};
 use crate::schema::{value_type_to_column_type, Field, FieldType, Schema};
 use crate::store::StoreWriter;
 use crate::termdict::{TermMerger, TermOrdinal};
-use crate::{DocAddress, DocId, InvertedIndexReader};
+use crate::{ArcInvertedIndexReader, DocAddress, DocId};
 
 /// Segment's max doc must be `< MAX_DOC_LIMIT`.
 ///
@@ -27,7 +25,7 @@ use crate::{DocAddress, DocId, InvertedIndexReader};
 pub const MAX_DOC_LIMIT: u32 = 1 << 31;
 
 fn estimate_total_num_tokens_in_single_segment(
-    reader: &SegmentReader,
+    reader: &dyn SegmentReader,
     field: Field,
 ) -> crate::Result<u64> {
     // There are no deletes. We can simply use the exact value saved into the posting list.
@@ -68,7 +66,7 @@ fn estimate_total_num_tokens_in_single_segment(
     Ok((segment_num_tokens as f64 * ratio) as u64)
 }
 
-fn estimate_total_num_tokens(readers: &[SegmentReader], field: Field) -> crate::Result<u64> {
+fn estimate_total_num_tokens(readers: &[TantivySegmentReader], field: Field) -> crate::Result<u64> {
     let mut total_num_tokens: u64 = 0;
     for reader in readers {
         total_num_tokens += estimate_total_num_tokens_in_single_segment(reader, field)?;
@@ -78,7 +76,7 @@ fn estimate_total_num_tokens(readers: &[SegmentReader], field: Field) -> crate::
 
 pub struct IndexMerger {
     schema: Schema,
-    pub(crate) readers: Vec<SegmentReader>,
+    pub(crate) readers: Vec<TantivySegmentReader>,
     max_doc: u32,
 }
 
@@ -170,8 +168,10 @@ impl IndexMerger {
         let mut readers = vec![];
         for (segment, new_alive_bitset_opt) in segments.iter().zip(alive_bitset_opt) {
             if segment.meta().num_docs() > 0 {
-                let reader =
-                    SegmentReader::open_with_custom_alive_set(segment, new_alive_bitset_opt)?;
+                let reader = TantivySegmentReader::open_with_custom_alive_set(
+                    segment,
+                    new_alive_bitset_opt,
+                )?;
                 readers.push(reader);
             }
         }
@@ -204,8 +204,20 @@ impl IndexMerger {
             let fieldnorms_readers: Vec<FieldNormReader> = self
                 .readers
                 .iter()
-                .map(|reader| reader.get_fieldnorms_reader(field))
-                .collect::<Result<_, _>>()?;
+                .map(|reader| {
+                    reader
+                        .fieldnorms_readers()
+                        .get_field(field)?
+                        .ok_or_else(|| {
+                            let field_name = self.schema.get_field_name(field);
+                            let err_msg = format!(
+                                "Field norm not found for field {field_name:?}. Was the field set \
+                                 to record norm during indexing?"
+                            );
+                            crate::TantivyError::SchemaError(err_msg)
+                        })
+                })
+                .collect::<crate::Result<_>>()?;
             for old_doc_addr in doc_id_mapping.iter_old_doc_addrs() {
                 let fieldnorms_reader = &fieldnorms_readers[old_doc_addr.segment_ord as usize];
                 let fieldnorm_id = fieldnorms_reader.fieldnorm_id(old_doc_addr.doc_id);
@@ -262,7 +274,7 @@ impl IndexMerger {
                 }),
         );
 
-        let has_deletes: bool = self.readers.iter().any(SegmentReader::has_deletes);
+        let has_deletes: bool = self.readers.iter().any(|reader| reader.has_deletes());
         let mapping_type = if has_deletes {
             MappingType::StackedWithDeletes
         } else {
@@ -297,7 +309,7 @@ impl IndexMerger {
 
         let mut max_term_ords: Vec<TermOrdinal> = Vec::new();
 
-        let field_readers: Vec<Arc<InvertedIndexReader>> = self
+        let field_readers: Vec<ArcInvertedIndexReader> = self
             .readers
             .iter()
             .map(|reader| reader.inverted_index(indexed_field))
@@ -366,7 +378,7 @@ impl IndexMerger {
             // Let's compute the list of non-empty posting lists
             for (segment_ord, term_info) in merged_terms.current_segment_ords_and_term_infos() {
                 let segment_reader = &self.readers[segment_ord];
-                let inverted_index: &InvertedIndexReader = &field_readers[segment_ord];
+                let inverted_index = field_readers[segment_ord].as_ref();
                 let segment_postings = inverted_index
                     .read_postings_from_terminfo(&term_info, segment_postings_option)?;
                 let alive_bitset_opt = segment_reader.alive_bitset();
@@ -1534,7 +1546,7 @@ mod tests {
         for segment_reader in searcher.segment_readers() {
             let mut term_scorer = term_query
                 .specialized_weight(EnableScoring::enabled_from_searcher(&searcher))?
-                .term_scorer_for_test(segment_reader, 1.0)?
+                .term_scorer_for_test(segment_reader.as_ref(), 1.0)?
                 .unwrap();
             // the difference compared to before is intrinsic to the bm25 formula. no worries
             // there.

src/indexer/segment_updater.rs

@@ -710,7 +710,7 @@ mod tests {
     use crate::indexer::segment_updater::merge_filtered_segments;
     use crate::query::QueryParser;
     use crate::schema::*;
-    use crate::{Directory, DocAddress, Index, Segment};
+    use crate::{Directory, DocAddress, Index, Segment, SegmentReader};
 
     #[test]
     fn test_delete_during_merge() -> crate::Result<()> {

src/indexer/segment_writer.rs

@@ -871,7 +871,7 @@ mod tests {
         let searcher = reader.searcher();
         let segment_reader = searcher.segment_reader(0u32);
 
-        fn assert_type(reader: &SegmentReader, field: &str, typ: ColumnType) {
+        fn assert_type(reader: &dyn SegmentReader, field: &str, typ: ColumnType) {
             let cols = reader.fast_fields().dynamic_column_handles(field).unwrap();
             assert_eq!(cols.len(), 1, "{field}");
             assert_eq!(cols[0].column_type(), typ, "{field}");
@@ -890,7 +890,7 @@ mod tests {
         assert_type(segment_reader, "json.my_arr", ColumnType::I64);
         assert_type(segment_reader, "json.my_arr.my_key", ColumnType::Str);
 
-        fn assert_empty(reader: &SegmentReader, field: &str) {
+        fn assert_empty(reader: &dyn SegmentReader, field: &str) {
             let cols = reader.fast_fields().dynamic_column_handles(field).unwrap();
             assert_eq!(cols.len(), 0);
         }

src/lib.rs

@@ -224,8 +224,9 @@ pub use self::docset::{DocSet, COLLECT_BLOCK_BUFFER_LEN, TERMINATED};
 pub use crate::core::{json_utils, Executor, Searcher, SearcherGeneration};
 pub use crate::directory::Directory;
 pub use crate::index::{
-    Index, IndexBuilder, IndexMeta, IndexSettings, InvertedIndexReader, Order, Segment,
-    SegmentMeta, SegmentReader,
+    ArcInvertedIndexReader, ArcSegmentReader, Index, IndexBuilder, IndexMeta, IndexSettings,
+    InvertedIndexReader, Order, Segment, SegmentMeta, SegmentReader, TantivyInvertedIndexReader,
+    TantivySegmentReader,
 };
 pub use crate::indexer::{IndexWriter, SingleSegmentIndexWriter};
 pub use crate::schema::{Document, TantivyDocument, Term};
@@ -377,7 +378,7 @@ pub mod tests {
 
     use common::{BinarySerializable, FixedSize};
     use query_grammar::{UserInputAst, UserInputLeaf, UserInputLiteral};
-    use rand::distributions::{Bernoulli, Uniform};
+    use rand::distr::{Bernoulli, Uniform};
     use rand::rngs::StdRng;
     use rand::{Rng, SeedableRng};
     use time::OffsetDateTime;
@@ -428,7 +429,7 @@ pub mod tests {
     pub fn generate_nonunique_unsorted(max_value: u32, n_elems: usize) -> Vec<u32> {
         let seed: [u8; 32] = [1; 32];
         StdRng::from_seed(seed)
-            .sample_iter(&Uniform::new(0u32, max_value))
+            .sample_iter(&Uniform::new(0u32, max_value).unwrap())
             .take(n_elems)
             .collect::<Vec<u32>>()
     }
@@ -523,11 +524,11 @@ pub mod tests {
         let searcher = index_reader.searcher();
         let reader = searcher.segment_reader(0);
         {
-            let fieldnorm_reader = reader.get_fieldnorms_reader(text_field)?;
+            let fieldnorm_reader = reader.fieldnorms_readers().get_field(text_field)?.unwrap();
             assert_eq!(fieldnorm_reader.fieldnorm(0), 3);
         }
         {
-            let fieldnorm_reader = reader.get_fieldnorms_reader(title_field)?;
+            let fieldnorm_reader = reader.fieldnorms_readers().get_field(title_field)?.unwrap();
             assert_eq!(fieldnorm_reader.fieldnorm_id(0), 0);
         }
         Ok(())
@@ -545,15 +546,18 @@ pub mod tests {
         index_writer.commit()?;
         let reader = index.reader()?;
         let searcher = reader.searcher();
-        let segment_reader: &SegmentReader = searcher.segment_reader(0);
-        let fieldnorms_reader = segment_reader.get_fieldnorms_reader(text_field)?;
+        let segment_reader: &dyn SegmentReader = searcher.segment_reader(0);
+        let fieldnorms_reader = segment_reader
+            .fieldnorms_readers()
+            .get_field(text_field)?
+            .unwrap();
         assert_eq!(fieldnorms_reader.fieldnorm(0), 3);
         assert_eq!(fieldnorms_reader.fieldnorm(1), 0);
         assert_eq!(fieldnorms_reader.fieldnorm(2), 2);
         Ok(())
     }
 
-    fn advance_undeleted(docset: &mut dyn DocSet, reader: &SegmentReader) -> bool {
+    fn advance_undeleted(docset: &mut dyn DocSet, reader: &dyn SegmentReader) -> bool {
         let mut doc = docset.advance();
         while doc != TERMINATED {
             if !reader.is_deleted(doc) {
@@ -1070,7 +1074,7 @@ pub mod tests {
         }
         let reader = index.reader()?;
         let searcher = reader.searcher();
-        let segment_reader: &SegmentReader = searcher.segment_reader(0);
+        let segment_reader: &dyn SegmentReader = searcher.segment_reader(0);
         {
             let fast_field_reader_res = segment_reader.fast_fields().u64("text");
             assert!(fast_field_reader_res.is_err());

src/postings/block_segment_postings.rs

@@ -182,32 +182,6 @@ impl BlockSegmentPostings {
         self.freq_reading_option
     }
 
-    // Resets the block segment postings on another position
-    // in the postings file.
-    //
-    // This is useful for enumerating through a list of terms,
-    // and consuming the associated posting lists while avoiding
-    // reallocating a `BlockSegmentPostings`.
-    //
-    // # Warning
-    //
-    // This does not reset the positions list.
-    pub(crate) fn reset(&mut self, doc_freq: u32, postings_data: OwnedBytes) -> io::Result<()> {
-        let (skip_data_opt, postings_data) =
-            split_into_skips_and_postings(doc_freq, postings_data)?;
-        self.data = postings_data;
-        self.block_max_score_cache = None;
-        self.block_loaded = false;
-        if let Some(skip_data) = skip_data_opt {
-            self.skip_reader.reset(skip_data, doc_freq);
-        } else {
-            self.skip_reader.reset(OwnedBytes::empty(), doc_freq);
-        }
-        self.doc_freq = doc_freq;
-        self.load_block();
-        Ok(())
-    }
-
     /// Returns the overall number of documents in the block postings.
     /// It does not take in account whether documents are deleted or not.
     ///
@@ -521,40 +495,4 @@ mod tests {
         assert_eq!(block_postings.doc(COMPRESSION_BLOCK_SIZE - 1), TERMINATED);
         Ok(())
     }
-
-    #[test]
-    fn test_reset_block_segment_postings() -> crate::Result<()> {
-        let mut schema_builder = Schema::builder();
-        let int_field = schema_builder.add_u64_field("id", INDEXED);
-        let schema = schema_builder.build();
-        let index = Index::create_in_ram(schema);
-        let mut index_writer = index.writer_for_tests()?;
-        // create two postings list, one containing even number,
-        // the other containing odd numbers.
-        for i in 0..6 {
-            let doc = doc!(int_field=> (i % 2) as u64);
-            index_writer.add_document(doc)?;
-        }
-        index_writer.commit()?;
-        let searcher = index.reader()?.searcher();
-        let segment_reader = searcher.segment_reader(0);
-
-        let mut block_segments;
-        {
-            let term = Term::from_field_u64(int_field, 0u64);
-            let inverted_index = segment_reader.inverted_index(int_field)?;
-            let term_info = inverted_index.get_term_info(&term)?.unwrap();
-            block_segments = inverted_index
-                .read_block_postings_from_terminfo(&term_info, IndexRecordOption::Basic)?;
-        }
-        assert_eq!(block_segments.docs(), &[0, 2, 4]);
-        {
-            let term = Term::from_field_u64(int_field, 1u64);
-            let inverted_index = segment_reader.inverted_index(int_field)?;
-            let term_info = inverted_index.get_term_info(&term)?.unwrap();
-            inverted_index.reset_block_postings_from_terminfo(&term_info, &mut block_segments)?;
-        }
-        assert_eq!(block_segments.docs(), &[1, 3, 5]);
-        Ok(())
-    }
 }

src/postings/compression/mod.rs

@@ -397,7 +397,10 @@ mod bench {
         let mut seed: [u8; 32] = [0; 32];
         seed[31] = seed_val;
         let mut rng = StdRng::from_seed(seed);
-        (0u32..).filter(|_| rng.gen_bool(ratio)).take(n).collect()
+        (0u32..)
+            .filter(|_| rng.random_bool(ratio))
+            .take(n)
+            .collect()
     }
 
     pub fn generate_array(n: usize, ratio: f64) -> Vec<u32> {

src/postings/mod.rs

@@ -46,7 +46,7 @@ pub(crate) mod tests {
     use super::{InvertedIndexSerializer, Postings};
     use crate::docset::{DocSet, TERMINATED};
     use crate::fieldnorm::FieldNormReader;
-    use crate::index::{Index, SegmentComponent, SegmentReader};
+    use crate::index::{Index, SegmentComponent, SegmentReader, TantivySegmentReader};
     use crate::indexer::operation::AddOperation;
     use crate::indexer::SegmentWriter;
     use crate::query::Scorer;
@@ -258,9 +258,12 @@ pub(crate) mod tests {
             segment_writer.finalize()?;
         }
         {
-            let segment_reader = SegmentReader::open(&segment)?;
+            let segment_reader = TantivySegmentReader::open(&segment)?;
             {
-                let fieldnorm_reader = segment_reader.get_fieldnorms_reader(text_field)?;
+                let fieldnorm_reader = segment_reader
+                    .fieldnorms_readers()
+                    .get_field(text_field)?
+                    .unwrap();
                 assert_eq!(fieldnorm_reader.fieldnorm(0), 8 + 5);
                 assert_eq!(fieldnorm_reader.fieldnorm(1), 2);
                 for i in 2..1000 {
@@ -604,13 +607,13 @@ mod bench {
             let mut index_writer: IndexWriter = index.writer_for_tests().unwrap();
             for _ in 0..posting_list_size {
                 let mut doc = TantivyDocument::default();
-                if rng.gen_bool(1f64 / 15f64) {
+                if rng.random_bool(1f64 / 15f64) {
                     doc.add_text(text_field, "a");
                 }
-                if rng.gen_bool(1f64 / 10f64) {
+                if rng.random_bool(1f64 / 10f64) {
                     doc.add_text(text_field, "b");
                 }
-                if rng.gen_bool(1f64 / 5f64) {
+                if rng.random_bool(1f64 / 5f64) {
                     doc.add_text(text_field, "c");
                 }
                 doc.add_text(text_field, "d");

src/postings/segment_postings.rs

@@ -70,13 +70,13 @@ impl SegmentPostings {
         let mut buffer = Vec::new();
         {
             let mut postings_serializer =
-                PostingsSerializer::new(&mut buffer, 0.0, IndexRecordOption::Basic, None);
+                PostingsSerializer::new(0.0, IndexRecordOption::Basic, None);
             postings_serializer.new_term(docs.len() as u32, false);
             for &doc in docs {
                 postings_serializer.write_doc(doc, 1u32);
             }
             postings_serializer
-                .close_term(docs.len() as u32)
+                .close_term(docs.len() as u32, &mut buffer)
                 .expect("In memory Serialization should never fail.");
         }
         let block_segment_postings = BlockSegmentPostings::open(
@@ -115,7 +115,6 @@ impl SegmentPostings {
             })
             .unwrap_or(0.0);
         let mut postings_serializer = PostingsSerializer::new(
-            &mut buffer,
             average_field_norm,
             IndexRecordOption::WithFreqs,
             fieldnorm_reader,
@@ -125,7 +124,7 @@ impl SegmentPostings {
             postings_serializer.write_doc(doc, tf);
         }
         postings_serializer
-            .close_term(doc_and_tfs.len() as u32)
+            .close_term(doc_and_tfs.len() as u32, &mut buffer)
             .unwrap();
         let block_segment_postings = BlockSegmentPostings::open(
             doc_and_tfs.len() as u32,

src/postings/serializer.rs

@@ -104,10 +104,12 @@ impl InvertedIndexSerializer {
 /// the serialization of a specific field.
 pub struct FieldSerializer<'a> {
     term_dictionary_builder: TermDictionaryBuilder<&'a mut CountingWriter<WritePtr>>,
-    postings_serializer: PostingsSerializer<&'a mut CountingWriter<WritePtr>>,
+    postings_serializer: PostingsSerializer,
     positions_serializer_opt: Option<PositionSerializer<&'a mut CountingWriter<WritePtr>>>,
     current_term_info: TermInfo,
     term_open: bool,
+    postings_write: &'a mut CountingWriter<WritePtr>,
+    postings_start_offset: u64,
 }
 
 impl<'a> FieldSerializer<'a> {
@@ -128,27 +130,30 @@ impl<'a> FieldSerializer<'a> {
             .as_ref()
             .map(|ff_reader| total_num_tokens as Score / ff_reader.num_docs() as Score)
             .unwrap_or(0.0);
-        let postings_serializer = PostingsSerializer::new(
-            postings_write,
-            average_fieldnorm,
-            index_record_option,
-            fieldnorm_reader,
-        );
+        let postings_serializer =
+            PostingsSerializer::new(average_fieldnorm, index_record_option, fieldnorm_reader);
         let positions_serializer_opt = if index_record_option.has_positions() {
             Some(PositionSerializer::new(positions_write))
         } else {
             None
         };
 
+        let postings_start_offset = postings_write.written_bytes();
         Ok(FieldSerializer {
             term_dictionary_builder,
             postings_serializer,
             positions_serializer_opt,
             current_term_info: TermInfo::default(),
             term_open: false,
+            postings_write,
+            postings_start_offset,
         })
     }
 
+    fn postings_offset(&self) -> usize {
+        (self.postings_write.written_bytes() - self.postings_start_offset) as usize
+    }
+
     fn current_term_info(&self) -> TermInfo {
         let positions_start =
             if let Some(positions_serializer) = self.positions_serializer_opt.as_ref() {
@@ -156,7 +161,7 @@ impl<'a> FieldSerializer<'a> {
             } else {
                 0u64
             } as usize;
-        let addr = self.postings_serializer.written_bytes() as usize;
+        let addr = self.postings_offset();
         TermInfo {
             doc_freq: 0,
             postings_range: addr..addr,
@@ -213,21 +218,22 @@ impl<'a> FieldSerializer<'a> {
         crate::fail_point!("FieldSerializer::close_term", |msg: Option<String>| {
             Err(io::Error::new(io::ErrorKind::Other, format!("{msg:?}")))
         });
-        if self.term_open {
-            self.postings_serializer
-                .close_term(self.current_term_info.doc_freq)?;
-            self.current_term_info.postings_range.end =
-                self.postings_serializer.written_bytes() as usize;
 
-            if let Some(positions_serializer) = self.positions_serializer_opt.as_mut() {
-                positions_serializer.close_term()?;
-                self.current_term_info.positions_range.end =
-                    positions_serializer.written_bytes() as usize;
-            }
-            self.term_dictionary_builder
-                .insert_value(&self.current_term_info)?;
-            self.term_open = false;
+        if !self.term_open {
+            return Ok(());
+        };
+
+        self.postings_serializer
+            .close_term(self.current_term_info.doc_freq, self.postings_write)?;
+        self.current_term_info.postings_range.end = self.postings_offset();
+        if let Some(positions_serializer) = self.positions_serializer_opt.as_mut() {
+            positions_serializer.close_term()?;
+            self.current_term_info.positions_range.end =
+                positions_serializer.written_bytes() as usize;
         }
+        self.term_dictionary_builder
+            .insert_value(&self.current_term_info)?;
+        self.term_open = false;
         Ok(())
     }
 
@@ -237,7 +243,7 @@ impl<'a> FieldSerializer<'a> {
         if let Some(positions_serializer) = self.positions_serializer_opt {
             positions_serializer.close()?;
         }
-        self.postings_serializer.close()?;
+        self.postings_write.flush()?;
         self.term_dictionary_builder.finish()?;
         Ok(())
     }
@@ -291,8 +297,7 @@ impl Block {
     }
 }
 
-pub struct PostingsSerializer<W: Write> {
-    output_write: CountingWriter<W>,
+pub struct PostingsSerializer {
     last_doc_id_encoded: u32,
 
     block_encoder: BlockEncoder,
@@ -310,16 +315,13 @@ pub struct PostingsSerializer<W: Write> {
     term_has_freq: bool,
 }
 
-impl<W: Write> PostingsSerializer<W> {
+impl PostingsSerializer {
     pub fn new(
-        write: W,
         avg_fieldnorm: Score,
         mode: IndexRecordOption,
         fieldnorm_reader: Option<FieldNormReader>,
-    ) -> PostingsSerializer<W> {
+    ) -> PostingsSerializer {
         PostingsSerializer {
-            output_write: CountingWriter::wrap(write),
-
             block_encoder: BlockEncoder::new(),
             block: Box::new(Block::new()),
 
@@ -422,11 +424,11 @@ impl<W: Write> PostingsSerializer<W> {
         }
     }
 
-    fn close(mut self) -> io::Result<()> {
-        self.postings_write.flush()
-    }
-
-    pub fn close_term(&mut self, doc_freq: u32) -> io::Result<()> {
+    pub fn close_term(
+        &mut self,
+        doc_freq: u32,
+        output_write: &mut impl std::io::Write,
+    ) -> io::Result<()> {
         if !self.block.is_empty() {
             // we have doc ids waiting to be written
             // this happens when the number of doc ids is
@@ -451,26 +453,16 @@ impl<W: Write> PostingsSerializer<W> {
         }
         if doc_freq >= COMPRESSION_BLOCK_SIZE as u32 {
             let skip_data = self.skip_write.data();
-            VInt(skip_data.len() as u64).serialize(&mut self.output_write)?;
-            self.output_write.write_all(skip_data)?;
+            VInt(skip_data.len() as u64).serialize(output_write)?;
+            output_write.write_all(skip_data)?;
         }
-        self.output_write.write_all(&self.postings_write[..])?;
+        output_write.write_all(&self.postings_write[..])?;
         self.skip_write.clear();
         self.postings_write.clear();
         self.bm25_weight = None;
         Ok(())
     }
 
-    /// Returns the number of bytes written in the postings write object
-    /// at this point.
-    /// When called before writing the postings of a term, this value is used as
-    /// start offset.
-    /// When called after writing the postings of a term, this value is used as a
-    /// end offset.
-    fn written_bytes(&self) -> u64 {
-        self.output_write.written_bytes()
-    }
-
     fn clear(&mut self) {
         self.block.clear();
         self.last_doc_id_encoded = 0;

src/postings/skip.rs

@@ -142,23 +142,6 @@ impl SkipReader {
         skip_reader
     }
 
-    pub fn reset(&mut self, data: OwnedBytes, doc_freq: u32) {
-        self.last_doc_in_block = if doc_freq >= COMPRESSION_BLOCK_SIZE as u32 {
-            0
-        } else {
-            TERMINATED
-        };
-        self.last_doc_in_previous_block = 0u32;
-        self.owned_read = data;
-        self.block_info = BlockInfo::VInt { num_docs: doc_freq };
-        self.byte_offset = 0;
-        self.remaining_docs = doc_freq;
-        self.position_offset = 0u64;
-        if doc_freq >= COMPRESSION_BLOCK_SIZE as u32 {
-            self.read_block_info();
-        }
-    }
-
     // Returns the block max score for this block if available.
     //
     // The block max score is available for all full bitpacked block,

src/query/all_query.rs

@@ -21,7 +21,7 @@ impl Query for AllQuery {
 pub struct AllWeight;
 
 impl Weight for AllWeight {
-    fn scorer(&self, reader: &SegmentReader, boost: Score) -> crate::Result<Box<dyn Scorer>> {
+    fn scorer(&self, reader: &dyn SegmentReader, boost: Score) -> crate::Result<Box<dyn Scorer>> {
         let all_scorer = AllScorer::new(reader.max_doc());
         if boost != 1.0 {
             Ok(Box::new(BoostScorer::new(all_scorer, boost)))
@@ -30,7 +30,7 @@ impl Weight for AllWeight {
         }
     }
 
-    fn explain(&self, reader: &SegmentReader, doc: DocId) -> crate::Result<Explanation> {
+    fn explain(&self, reader: &dyn SegmentReader, doc: DocId) -> crate::Result<Explanation> {
         if doc >= reader.max_doc() {
             return Err(does_not_match(doc));
         }

src/query/automaton_weight.rs

@@ -67,7 +67,7 @@ where
     }
 
     /// Returns the term infos that match the automaton
-    pub fn get_match_term_infos(&self, reader: &SegmentReader) -> crate::Result<Vec<TermInfo>> {
+    pub fn get_match_term_infos(&self, reader: &dyn SegmentReader) -> crate::Result<Vec<TermInfo>> {
         let inverted_index = reader.inverted_index(self.field)?;
         let term_dict = inverted_index.terms();
         let mut term_stream = self.automaton_stream(term_dict)?;
@@ -84,7 +84,7 @@ where
     A: Automaton + Send + Sync + 'static,
     A::State: Clone,
 {
-    fn scorer(&self, reader: &SegmentReader, boost: Score) -> crate::Result<Box<dyn Scorer>> {
+    fn scorer(&self, reader: &dyn SegmentReader, boost: Score) -> crate::Result<Box<dyn Scorer>> {
         let max_doc = reader.max_doc();
         let mut doc_bitset = BitSet::with_max_value(max_doc);
         let inverted_index = reader.inverted_index(self.field)?;
@@ -110,7 +110,7 @@ where
         Ok(Box::new(const_scorer))
     }
 
-    fn explain(&self, reader: &SegmentReader, doc: DocId) -> crate::Result<Explanation> {
+    fn explain(&self, reader: &dyn SegmentReader, doc: DocId) -> crate::Result<Explanation> {
         let mut scorer = self.scorer(reader, 1.0)?;
         if scorer.seek(doc) == doc {
             Ok(Explanation::new("AutomatonScorer", 1.0))

src/query/boolean_query/boolean_weight.rs

@@ -205,7 +205,7 @@ impl<TScoreCombiner: ScoreCombiner> BooleanWeight<TScoreCombiner> {
 
     fn per_occur_scorers(
         &self,
-        reader: &SegmentReader,
+        reader: &dyn SegmentReader,
         boost: Score,
     ) -> crate::Result<HashMap<Occur, Vec<Box<dyn Scorer>>>> {
         let mut per_occur_scorers: HashMap<Occur, Vec<Box<dyn Scorer>>> = HashMap::new();
@@ -221,7 +221,7 @@ impl<TScoreCombiner: ScoreCombiner> BooleanWeight<TScoreCombiner> {
 
     fn complex_scorer<TComplexScoreCombiner: ScoreCombiner>(
         &self,
-        reader: &SegmentReader,
+        reader: &dyn SegmentReader,
         boost: Score,
         score_combiner_fn: impl Fn() -> TComplexScoreCombiner,
     ) -> crate::Result<SpecializedScorer> {
@@ -418,7 +418,7 @@ fn remove_and_count_all_and_empty_scorers(
 }
 
 impl<TScoreCombiner: ScoreCombiner + Sync> Weight for BooleanWeight<TScoreCombiner> {
-    fn scorer(&self, reader: &SegmentReader, boost: Score) -> crate::Result<Box<dyn Scorer>> {
+    fn scorer(&self, reader: &dyn SegmentReader, boost: Score) -> crate::Result<Box<dyn Scorer>> {
         let num_docs = reader.num_docs();
         if self.weights.is_empty() {
             Ok(Box::new(EmptyScorer))
@@ -442,7 +442,7 @@ impl<TScoreCombiner: ScoreCombiner + Sync> Weight for BooleanWeight<TScoreCombin
         }
     }
 
-    fn explain(&self, reader: &SegmentReader, doc: DocId) -> crate::Result<Explanation> {
+    fn explain(&self, reader: &dyn SegmentReader, doc: DocId) -> crate::Result<Explanation> {
         let mut scorer = self.scorer(reader, 1.0)?;
         if scorer.seek(doc) != doc {
             return Err(does_not_match(doc));
@@ -464,7 +464,7 @@ impl<TScoreCombiner: ScoreCombiner + Sync> Weight for BooleanWeight<TScoreCombin
 
     fn for_each(
         &self,
-        reader: &SegmentReader,
+        reader: &dyn SegmentReader,
         callback: &mut dyn FnMut(DocId, Score),
     ) -> crate::Result<()> {
         let scorer = self.complex_scorer(reader, 1.0, &self.score_combiner_fn)?;
@@ -486,7 +486,7 @@ impl<TScoreCombiner: ScoreCombiner + Sync> Weight for BooleanWeight<TScoreCombin
 
     fn for_each_no_score(
         &self,
-        reader: &SegmentReader,
+        reader: &dyn SegmentReader,
         callback: &mut dyn FnMut(&[DocId]),
     ) -> crate::Result<()> {
         let scorer = self.complex_scorer(reader, 1.0, || DoNothingCombiner)?;
@@ -521,7 +521,7 @@ impl<TScoreCombiner: ScoreCombiner + Sync> Weight for BooleanWeight<TScoreCombin
     fn for_each_pruning(
         &self,
         threshold: Score,
-        reader: &SegmentReader,
+        reader: &dyn SegmentReader,
         callback: &mut dyn FnMut(DocId, Score) -> Score,
     ) -> crate::Result<()> {
         let scorer = self.complex_scorer(reader, 1.0, &self.score_combiner_fn)?;

src/query/boost_query.rs

@@ -1,6 +1,6 @@
 use std::fmt;
 
-use crate::docset::COLLECT_BLOCK_BUFFER_LEN;
+use crate::docset::{SeekDangerResult, COLLECT_BLOCK_BUFFER_LEN};
 use crate::fastfield::AliveBitSet;
 use crate::query::{EnableScoring, Explanation, Query, Scorer, Weight};
 use crate::{DocId, DocSet, Score, SegmentReader, Term};
@@ -67,11 +67,11 @@ impl BoostWeight {
 }
 
 impl Weight for BoostWeight {
-    fn scorer(&self, reader: &SegmentReader, boost: Score) -> crate::Result<Box<dyn Scorer>> {
+    fn scorer(&self, reader: &dyn SegmentReader, boost: Score) -> crate::Result<Box<dyn Scorer>> {
         self.weight.scorer(reader, boost * self.boost)
     }
 
-    fn explain(&self, reader: &SegmentReader, doc: u32) -> crate::Result<Explanation> {
+    fn explain(&self, reader: &dyn SegmentReader, doc: u32) -> crate::Result<Explanation> {
         let underlying_explanation = self.weight.explain(reader, doc)?;
         let score = underlying_explanation.value() * self.boost;
         let mut explanation =
@@ -80,7 +80,7 @@ impl Weight for BoostWeight {
         Ok(explanation)
     }
 
-    fn count(&self, reader: &SegmentReader) -> crate::Result<u32> {
+    fn count(&self, reader: &dyn SegmentReader) -> crate::Result<u32> {
         self.weight.count(reader)
     }
 }
@@ -104,8 +104,8 @@ impl<S: Scorer> DocSet for BoostScorer<S> {
     fn seek(&mut self, target: DocId) -> DocId {
         self.underlying.seek(target)
     }
-    fn seek_into_the_danger_zone(&mut self, target: DocId) -> bool {
-        self.underlying.seek_into_the_danger_zone(target)
+    fn seek_danger(&mut self, target: DocId) -> SeekDangerResult {
+        self.underlying.seek_danger(target)
     }
 
     fn fill_buffer(&mut self, buffer: &mut [DocId; COLLECT_BLOCK_BUFFER_LEN]) -> usize {

src/query/const_score_query.rs

@@ -63,12 +63,12 @@ impl ConstWeight {
 }
 
 impl Weight for ConstWeight {
-    fn scorer(&self, reader: &SegmentReader, boost: Score) -> crate::Result<Box<dyn Scorer>> {
+    fn scorer(&self, reader: &dyn SegmentReader, boost: Score) -> crate::Result<Box<dyn Scorer>> {
         let inner_scorer = self.weight.scorer(reader, boost)?;
         Ok(Box::new(ConstScorer::new(inner_scorer, boost * self.score)))
     }
 
-    fn explain(&self, reader: &SegmentReader, doc: u32) -> crate::Result<Explanation> {
+    fn explain(&self, reader: &dyn SegmentReader, doc: u32) -> crate::Result<Explanation> {
         let mut scorer = self.scorer(reader, 1.0)?;
         if scorer.seek(doc) != doc {
             return Err(TantivyError::InvalidArgument(format!(
@@ -81,7 +81,7 @@ impl Weight for ConstWeight {
         Ok(explanation)
     }
 
-    fn count(&self, reader: &SegmentReader) -> crate::Result<u32> {
+    fn count(&self, reader: &dyn SegmentReader) -> crate::Result<u32> {
         self.weight.count(reader)
     }
 }

src/query/disjunction.rs

@@ -1,6 +1,7 @@
 use std::cmp::Ordering;
 use std::collections::BinaryHeap;
 
+use crate::docset::SeekDangerResult;
 use crate::query::score_combiner::DoNothingCombiner;
 use crate::query::{ScoreCombiner, Scorer};
 use crate::{DocId, DocSet, Score, TERMINATED};
@@ -67,10 +68,12 @@ impl<T: Scorer> DocSet for ScorerWrapper<T> {
         self.current_doc = doc_id;
         doc_id
     }
-    fn seek_into_the_danger_zone(&mut self, target: DocId) -> bool {
-        let found = self.scorer.seek_into_the_danger_zone(target);
-        self.current_doc = self.scorer.doc();
-        found
+    fn seek_danger(&mut self, target: DocId) -> SeekDangerResult {
+        let result = self.scorer.seek_danger(target);
+        if result == SeekDangerResult::Found {
+            self.current_doc = target;
+        }
+        result
     }
 
     fn doc(&self) -> DocId {

src/query/empty_query.rs

@@ -26,11 +26,11 @@ impl Query for EmptyQuery {
 /// It is useful for tests and handling edge cases.
 pub struct EmptyWeight;
 impl Weight for EmptyWeight {
-    fn scorer(&self, _reader: &SegmentReader, _boost: Score) -> crate::Result<Box<dyn Scorer>> {
+    fn scorer(&self, _reader: &dyn SegmentReader, _boost: Score) -> crate::Result<Box<dyn Scorer>> {
         Ok(Box::new(EmptyScorer))
     }
 
-    fn explain(&self, _reader: &SegmentReader, doc: DocId) -> crate::Result<Explanation> {
+    fn explain(&self, _reader: &dyn SegmentReader, doc: DocId) -> crate::Result<Explanation> {
         Err(does_not_match(doc))
     }
 }

src/query/exist_query.rs

@@ -98,7 +98,7 @@ pub struct ExistsWeight {
 }
 
 impl Weight for ExistsWeight {
-    fn scorer(&self, reader: &SegmentReader, boost: Score) -> crate::Result<Box<dyn Scorer>> {
+    fn scorer(&self, reader: &dyn SegmentReader, boost: Score) -> crate::Result<Box<dyn Scorer>> {
         let fast_field_reader = reader.fast_fields();
         let mut column_handles = fast_field_reader.dynamic_column_handles(&self.field_name)?;
         if self.field_type == Type::Json && self.json_subpaths {
@@ -165,7 +165,7 @@ impl Weight for ExistsWeight {
         Ok(Box::new(ConstScorer::new(docset, boost)))
     }
 
-    fn explain(&self, reader: &SegmentReader, doc: DocId) -> crate::Result<Explanation> {
+    fn explain(&self, reader: &dyn SegmentReader, doc: DocId) -> crate::Result<Explanation> {
         let mut scorer = self.scorer(reader, 1.0)?;
         if scorer.seek(doc) != doc {
             return Err(does_not_match(doc));

src/query/intersection.rs

@@ -1,5 +1,5 @@
 use super::size_hint::estimate_intersection;
-use crate::docset::{DocSet, TERMINATED};
+use crate::docset::{DocSet, SeekDangerResult, TERMINATED};
 use crate::query::term_query::TermScorer;
 use crate::query::{EmptyScorer, Scorer};
 use crate::{DocId, Score};
@@ -108,46 +108,63 @@ impl<TDocSet: DocSet, TOtherDocSet: DocSet> DocSet for Intersection<TDocSet, TOt
     #[inline]
     fn advance(&mut self) -> DocId {
         let (left, right) = (&mut self.left, &mut self.right);
-        let mut candidate = left.advance();
-        if candidate == TERMINATED {
-            return TERMINATED;
-        }
 
-        loop {
-            // In the first part we look for a document in the intersection
-            // of the two rarest `DocSet` in the intersection.
+        // Invariant:
+        // - candidate is always <= to the next document in the intersection.
+        // - candidate strictly increases at every occurence of the loop.
+        let mut candidate = 0;
 
-            loop {
-                if right.seek_into_the_danger_zone(candidate) {
-                    break;
-                }
-                let right_doc = right.doc();
-                // TODO: Think about which value would make sense here
-                // It depends on the DocSet implementation, when a seek would outweigh an advance.
-                if right_doc > candidate.wrapping_add(100) {
-                    candidate = left.seek(right_doc);
-                } else {
-                    candidate = left.advance();
-                }
-                if candidate == TERMINATED {
-                    return TERMINATED;
-                }
-            }
+        // Termination: candidate strictly increases.
+        'outer: while candidate < TERMINATED {
+            // As we enter the loop, we should always have candidate < next_doc.
 
-            debug_assert_eq!(left.doc(), right.doc());
-            // test the remaining scorers
-            if self
-                .others
-                .iter_mut()
-                .all(|docset| docset.seek_into_the_danger_zone(candidate))
+            // This step always increases candidate.
+            //
+            // TODO: Think about which value would make sense here
+            // It depends on the DocSet implementation, when a seek would outweigh an advance.
+            candidate = if candidate > left.doc().wrapping_add(100) {
+                left.seek(candidate)
+            } else {
+                left.advance()
+            };
+
+            // Left is positionned on `candidate`.
+            debug_assert_eq!(left.doc(), candidate);
+
+            if let SeekDangerResult::SeekLowerBound(seek_lower_bound) = right.seek_danger(candidate)
             {
-                debug_assert_eq!(candidate, self.left.doc());
-                debug_assert_eq!(candidate, self.right.doc());
-                debug_assert!(self.others.iter().all(|docset| docset.doc() == candidate));
-                return candidate;
+                // The max is technically useless but it makes the invariant
+                // easier to proofread.
+                debug_assert!(seek_lower_bound >= candidate);
+                candidate = seek_lower_bound;
+                continue;
             }
-            candidate = left.advance();
+
+            // Left and right are positionned on `candidate`.
+            debug_assert_eq!(right.doc(), candidate);
+
+            for other in &mut self.others {
+                if let SeekDangerResult::SeekLowerBound(seek_lower_bound) =
+                    other.seek_danger(candidate)
+                {
+                    // One of the scorer does not match, let's restart at the top of the loop.
+                    debug_assert!(seek_lower_bound >= candidate);
+                    candidate = seek_lower_bound;
+                    continue 'outer;
+                }
+            }
+
+            // At this point all scorers are in a valid state, aligned on the next document in the
+            // intersection.
+            debug_assert!(self.others.iter().all(|docset| docset.doc() == candidate));
+            return candidate;
         }
+
+        // We make sure our docset is in a valid state.
+        // In particular, we want .doc() to return TERMINATED.
+        left.seek(TERMINATED);
+
+        TERMINATED
     }
 
     fn seek(&mut self, target: DocId) -> DocId {
@@ -166,13 +183,19 @@ impl<TDocSet: DocSet, TOtherDocSet: DocSet> DocSet for Intersection<TDocSet, TOt
     ///
     /// Some implementations may choose to advance past the target if beneficial for performance.
     /// The return value is `true` if the target is in the docset, and `false` otherwise.
-    fn seek_into_the_danger_zone(&mut self, target: DocId) -> bool {
-        self.left.seek_into_the_danger_zone(target)
-            && self.right.seek_into_the_danger_zone(target)
-            && self
-                .others
-                .iter_mut()
-                .all(|docset| docset.seek_into_the_danger_zone(target))
+    fn seek_danger(&mut self, target: DocId) -> SeekDangerResult {
+        if let SeekDangerResult::SeekLowerBound(new_target) = self.left.seek_danger(target) {
+            return SeekDangerResult::SeekLowerBound(new_target);
+        }
+        if let SeekDangerResult::SeekLowerBound(new_target) = self.right.seek_danger(target) {
+            return SeekDangerResult::SeekLowerBound(new_target);
+        }
+        for docset in &mut self.others {
+            if let SeekDangerResult::SeekLowerBound(new_target) = docset.seek_danger(target) {
+                return SeekDangerResult::SeekLowerBound(new_target);
+            }
+        }
+        SeekDangerResult::Found
     }
 
     #[inline]
@@ -304,6 +327,58 @@ mod tests {
         assert_eq!(intersection.doc(), TERMINATED);
     }
 
+    #[test]
+    fn test_intersection_abc() {
+        let a = VecDocSet::from(vec![2, 3, 6]);
+        let b = VecDocSet::from(vec![1, 3, 5]);
+        let c = VecDocSet::from(vec![1, 3, 5]);
+        let mut intersection = Intersection::new(vec![c, b, a], 10);
+        let mut docs = Vec::new();
+        use crate::DocSet;
+        while intersection.doc() != TERMINATED {
+            docs.push(intersection.doc());
+            intersection.advance();
+        }
+        assert_eq!(&docs, &[3]);
+    }
+
+    #[test]
+    fn test_intersection_termination() {
+        use crate::query::score_combiner::DoNothingCombiner;
+        use crate::query::{BufferedUnionScorer, ConstScorer, VecDocSet};
+
+        let a1 = ConstScorer::new(VecDocSet::from(vec![0u32, 10000]), 1.0);
+        let a2 = ConstScorer::new(VecDocSet::from(vec![0u32, 10000]), 1.0);
+
+        let mut b_scorers = vec![];
+        for _ in 0..2 {
+            // Union matches 0 and 10000.
+            b_scorers.push(ConstScorer::new(VecDocSet::from(vec![0, 10000]), 1.0));
+        }
+        // That's the union of two scores matching 0, and 10_000.
+        let union = BufferedUnionScorer::build(b_scorers, DoNothingCombiner::default, 30000);
+
+        // Mismatching scorer: matches 0 and 20000. We then append more docs at the end to ensure it
+        // is last.
+        let mut m_docs = vec![0, 20000];
+        for i in 30000..30100 {
+            m_docs.push(i);
+        }
+        let m = ConstScorer::new(VecDocSet::from(m_docs), 1.0);
+
+        // Costs: A1=2, A2=2, Union=4, M=102.
+        // Sorted: A1, A2, Union, M.
+        // Left=A1, Right=A2, Others=[Union, M].
+        let mut intersection = crate::query::intersect_scorers(
+            vec![Box::new(a1), Box::new(a2), Box::new(union), Box::new(m)],
+            40000,
+        );
+
+        while intersection.doc() != TERMINATED {
+            intersection.advance();
+        }
+    }
+
     // Strategy to generate sorted and deduplicated vectors of u32 document IDs
     fn sorted_deduped_vec(max_val: u32, max_size: usize) -> impl Strategy<Value = Vec<u32>> {
         prop::collection::vec(0..max_val, 0..max_size).prop_map(|mut vec| {
@@ -335,6 +410,5 @@ mod tests {
             }
             assert_eq!(intersection.doc(), TERMINATED);
         }
-
     }
 }

src/query/phrase_prefix_query/phrase_prefix_scorer.rs

@@ -1,4 +1,4 @@
-use crate::docset::{DocSet, TERMINATED};
+use crate::docset::{DocSet, SeekDangerResult, TERMINATED};
 use crate::fieldnorm::FieldNormReader;
 use crate::postings::Postings;
 use crate::query::bm25::Bm25Weight;
@@ -194,11 +194,16 @@ impl<TPostings: Postings> DocSet for PhrasePrefixScorer<TPostings> {
         self.advance()
     }
 
-    fn seek_into_the_danger_zone(&mut self, target: DocId) -> bool {
-        if self.phrase_scorer.seek_into_the_danger_zone(target) {
-            self.matches_prefix()
+    fn seek_danger(&mut self, target: DocId) -> SeekDangerResult {
+        let seek_res = self.phrase_scorer.seek_danger(target);
+        if seek_res != SeekDangerResult::Found {
+            return seek_res;
+        }
+        // The intersection matched. Now let's see if we match the prefix.
+        if self.matches_prefix() {
+            SeekDangerResult::Found
         } else {
-            false
+            SeekDangerResult::SeekLowerBound(target + 1)
         }
     }
 

src/query/phrase_prefix_query/phrase_prefix_weight.rs

@@ -32,7 +32,7 @@ impl PhrasePrefixWeight {
         }
     }
 
-    fn fieldnorm_reader(&self, reader: &SegmentReader) -> crate::Result<FieldNormReader> {
+    fn fieldnorm_reader(&self, reader: &dyn SegmentReader) -> crate::Result<FieldNormReader> {
         let field = self.phrase_terms[0].1.field();
         if self.similarity_weight_opt.is_some() {
             if let Some(fieldnorm_reader) = reader.fieldnorms_readers().get_field(field)? {
@@ -44,7 +44,7 @@ impl PhrasePrefixWeight {
 
     pub(crate) fn phrase_scorer(
         &self,
-        reader: &SegmentReader,
+        reader: &dyn SegmentReader,
         boost: Score,
     ) -> crate::Result<Option<PhrasePrefixScorer<SegmentPostings>>> {
         let similarity_weight_opt = self
@@ -114,7 +114,7 @@ impl PhrasePrefixWeight {
 }
 
 impl Weight for PhrasePrefixWeight {
-    fn scorer(&self, reader: &SegmentReader, boost: Score) -> crate::Result<Box<dyn Scorer>> {
+    fn scorer(&self, reader: &dyn SegmentReader, boost: Score) -> crate::Result<Box<dyn Scorer>> {
         if let Some(scorer) = self.phrase_scorer(reader, boost)? {
             Ok(Box::new(scorer))
         } else {
@@ -122,7 +122,7 @@ impl Weight for PhrasePrefixWeight {
         }
     }
 
-    fn explain(&self, reader: &SegmentReader, doc: DocId) -> crate::Result<Explanation> {
+    fn explain(&self, reader: &dyn SegmentReader, doc: DocId) -> crate::Result<Explanation> {
         let scorer_opt = self.phrase_scorer(reader, 1.0)?;
         if scorer_opt.is_none() {
             return Err(does_not_match(doc));

src/query/phrase_query/phrase_scorer.rs

@@ -1,6 +1,6 @@
 use std::cmp::Ordering;
 
-use crate::docset::{DocSet, TERMINATED};
+use crate::docset::{DocSet, SeekDangerResult, TERMINATED};
 use crate::fieldnorm::FieldNormReader;
 use crate::postings::Postings;
 use crate::query::bm25::Bm25Weight;
@@ -530,12 +530,18 @@ impl<TPostings: Postings> DocSet for PhraseScorer<TPostings> {
         self.advance()
     }
 
-    fn seek_into_the_danger_zone(&mut self, target: DocId) -> bool {
+    fn seek_danger(&mut self, target: DocId) -> SeekDangerResult {
         debug_assert!(target >= self.doc());
-        if self.intersection_docset.seek_into_the_danger_zone(target) && self.phrase_match() {
-            return true;
+        let seek_res = self.intersection_docset.seek_danger(target);
+        if seek_res != SeekDangerResult::Found {
+            return seek_res;
+        }
+        // The intersection matched. Now let's see if we match the phrase.
+        if self.phrase_match() {
+            SeekDangerResult::Found
+        } else {
+            SeekDangerResult::SeekLowerBound(target + 1)
         }
-        false
     }
 
     fn doc(&self) -> DocId {

src/query/phrase_query/phrase_weight.rs

@@ -29,7 +29,7 @@ impl PhraseWeight {
         }
     }
 
-    fn fieldnorm_reader(&self, reader: &SegmentReader) -> crate::Result<FieldNormReader> {
+    fn fieldnorm_reader(&self, reader: &dyn SegmentReader) -> crate::Result<FieldNormReader> {
         let field = self.phrase_terms[0].1.field();
         if self.similarity_weight_opt.is_some() {
             if let Some(fieldnorm_reader) = reader.fieldnorms_readers().get_field(field)? {
@@ -41,7 +41,7 @@ impl PhraseWeight {
 
     pub(crate) fn phrase_scorer(
         &self,
-        reader: &SegmentReader,
+        reader: &dyn SegmentReader,
         boost: Score,
     ) -> crate::Result<Option<PhraseScorer<SegmentPostings>>> {
         let similarity_weight_opt = self
@@ -74,7 +74,7 @@ impl PhraseWeight {
 }
 
 impl Weight for PhraseWeight {
-    fn scorer(&self, reader: &SegmentReader, boost: Score) -> crate::Result<Box<dyn Scorer>> {
+    fn scorer(&self, reader: &dyn SegmentReader, boost: Score) -> crate::Result<Box<dyn Scorer>> {
         if let Some(scorer) = self.phrase_scorer(reader, boost)? {
             Ok(Box::new(scorer))
         } else {
@@ -82,7 +82,7 @@ impl Weight for PhraseWeight {
         }
     }
 
-    fn explain(&self, reader: &SegmentReader, doc: DocId) -> crate::Result<Explanation> {
+    fn explain(&self, reader: &dyn SegmentReader, doc: DocId) -> crate::Result<Explanation> {
         let scorer_opt = self.phrase_scorer(reader, 1.0)?;
         if scorer_opt.is_none() {
             return Err(does_not_match(doc));

src/query/phrase_query/regex_phrase_weight.rs

@@ -45,7 +45,7 @@ impl RegexPhraseWeight {
         }
     }
 
-    fn fieldnorm_reader(&self, reader: &SegmentReader) -> crate::Result<FieldNormReader> {
+    fn fieldnorm_reader(&self, reader: &dyn SegmentReader) -> crate::Result<FieldNormReader> {
         if self.similarity_weight_opt.is_some() {
             if let Some(fieldnorm_reader) = reader.fieldnorms_readers().get_field(self.field)? {
                 return Ok(fieldnorm_reader);
@@ -56,7 +56,7 @@ impl RegexPhraseWeight {
 
     pub(crate) fn phrase_scorer(
         &self,
-        reader: &SegmentReader,
+        reader: &dyn SegmentReader,
         boost: Score,
     ) -> crate::Result<Option<PhraseScorer<UnionType>>> {
         let similarity_weight_opt = self
@@ -84,7 +84,8 @@ impl RegexPhraseWeight {
                     "Phrase query exceeded max expansions {num_terms}"
                 )));
             }
-            let union = Self::get_union_from_term_infos(&term_infos, reader, &inverted_index)?;
+            let union =
+                Self::get_union_from_term_infos(&term_infos, reader, inverted_index.as_ref())?;
 
             posting_lists.push((offset, union));
         }
@@ -99,7 +100,7 @@ impl RegexPhraseWeight {
 
     /// Add all docs of the term to the docset
     fn add_to_bitset(
-        inverted_index: &InvertedIndexReader,
+        inverted_index: &dyn InvertedIndexReader,
         term_info: &TermInfo,
         doc_bitset: &mut BitSet,
     ) -> crate::Result<()> {
@@ -174,8 +175,8 @@ impl RegexPhraseWeight {
     /// Use Roaring Bitmaps for sparse terms. The full bitvec is main memory consumer currently.
     pub(crate) fn get_union_from_term_infos(
         term_infos: &[TermInfo],
-        reader: &SegmentReader,
-        inverted_index: &InvertedIndexReader,
+        reader: &dyn SegmentReader,
+        inverted_index: &dyn InvertedIndexReader,
     ) -> crate::Result<UnionType> {
         let max_doc = reader.max_doc();
 
@@ -269,7 +270,7 @@ impl RegexPhraseWeight {
 }
 
 impl Weight for RegexPhraseWeight {
-    fn scorer(&self, reader: &SegmentReader, boost: Score) -> crate::Result<Box<dyn Scorer>> {
+    fn scorer(&self, reader: &dyn SegmentReader, boost: Score) -> crate::Result<Box<dyn Scorer>> {
         if let Some(scorer) = self.phrase_scorer(reader, boost)? {
             Ok(Box::new(scorer))
         } else {
@@ -277,7 +278,7 @@ impl Weight for RegexPhraseWeight {
         }
     }
 
-    fn explain(&self, reader: &SegmentReader, doc: DocId) -> crate::Result<Explanation> {
+    fn explain(&self, reader: &dyn SegmentReader, doc: DocId) -> crate::Result<Explanation> {
         let scorer_opt = self.phrase_scorer(reader, 1.0)?;
         if scorer_opt.is_none() {
             return Err(does_not_match(doc));
@@ -311,7 +312,7 @@ mod tests {
         #![proptest_config(ProptestConfig::with_cases(50))]
         #[test]
         fn test_phrase_regex_with_random_strings(mut random_strings in proptest::collection::vec("[c-z ]{0,10}", 1..100), num_occurrences in 1..150_usize) {
-            let mut rng = rand::thread_rng();
+            let mut rng = rand::rng();
 
             // Insert "aaa ccc" the specified number of times into the list
             for _ in 0..num_occurrences {

src/query/query.rs

@@ -146,7 +146,7 @@ pub trait Query: QueryClone + Send + Sync + downcast_rs::Downcast + fmt::Debug {
         let weight = self.weight(EnableScoring::disabled_from_searcher(searcher))?;
         let mut result = 0;
         for reader in searcher.segment_readers() {
-            result += weight.count(reader)? as usize;
+            result += weight.count(reader.as_ref())? as usize;
         }
         Ok(result)
     }

src/query/range_query/range_query.rs

@@ -212,7 +212,7 @@ impl InvertedIndexRangeWeight {
 }
 
 impl Weight for InvertedIndexRangeWeight {
-    fn scorer(&self, reader: &SegmentReader, boost: Score) -> crate::Result<Box<dyn Scorer>> {
+    fn scorer(&self, reader: &dyn SegmentReader, boost: Score) -> crate::Result<Box<dyn Scorer>> {
         let max_doc = reader.max_doc();
         let mut doc_bitset = BitSet::with_max_value(max_doc);
 
@@ -245,7 +245,7 @@ impl Weight for InvertedIndexRangeWeight {
         Ok(Box::new(ConstScorer::new(doc_bitset, boost)))
     }
 
-    fn explain(&self, reader: &SegmentReader, doc: DocId) -> crate::Result<Explanation> {
+    fn explain(&self, reader: &dyn SegmentReader, doc: DocId) -> crate::Result<Explanation> {
         let mut scorer = self.scorer(reader, 1.0)?;
         if scorer.seek(doc) != doc {
             return Err(does_not_match(doc));
@@ -429,7 +429,7 @@ mod tests {
                 docs.push(doc);
             }
 
-            docs.shuffle(&mut rand::thread_rng());
+            docs.shuffle(&mut rand::rng());
             let mut docs_it = docs.into_iter();
             for doc in (&mut docs_it).take(50) {
                 index_writer.add_document(doc)?;
@@ -686,7 +686,7 @@ mod tests {
                 .weight(EnableScoring::disabled_from_schema(&schema))
                 .unwrap();
             let range_scorer = range_weight
-                .scorer(&searcher.segment_readers()[0], 1.0f32)
+                .scorer(searcher.segment_readers()[0].as_ref(), 1.0f32)
                 .unwrap();
             range_scorer
         };

src/query/range_query/range_query_fastfield.rs

@@ -52,7 +52,7 @@ impl FastFieldRangeWeight {
 }
 
 impl Weight for FastFieldRangeWeight {
-    fn scorer(&self, reader: &SegmentReader, boost: Score) -> crate::Result<Box<dyn Scorer>> {
+    fn scorer(&self, reader: &dyn SegmentReader, boost: Score) -> crate::Result<Box<dyn Scorer>> {
         // Check if both bounds are Bound::Unbounded
         if self.bounds.is_unbounded() {
             return Ok(Box::new(AllScorer::new(reader.max_doc())));
@@ -219,7 +219,7 @@ impl Weight for FastFieldRangeWeight {
         }
     }
 
-    fn explain(&self, reader: &SegmentReader, doc: DocId) -> crate::Result<Explanation> {
+    fn explain(&self, reader: &dyn SegmentReader, doc: DocId) -> crate::Result<Explanation> {
         let mut scorer = self.scorer(reader, 1.0)?;
         if scorer.seek(doc) != doc {
             return Err(TantivyError::InvalidArgument(format!(
@@ -236,7 +236,7 @@ impl Weight for FastFieldRangeWeight {
 ///
 /// Convert into fast field value space and search.
 fn search_on_json_numerical_field(
-    reader: &SegmentReader,
+    reader: &dyn SegmentReader,
     field_name: &str,
     typ: Type,
     bounds: BoundsRange<ValueBytes<Vec<u8>>>,
@@ -491,7 +491,7 @@ mod tests {
     use common::DateTime;
     use proptest::prelude::*;
     use rand::rngs::StdRng;
-    use rand::seq::SliceRandom;
+    use rand::seq::IndexedRandom;
     use rand::SeedableRng;
     use time::format_description::well_known::Rfc3339;
     use time::OffsetDateTime;

src/query/reqopt_scorer.rs

@@ -1,6 +1,6 @@
 use std::marker::PhantomData;
 
-use crate::docset::DocSet;
+use crate::docset::{DocSet, SeekDangerResult};
 use crate::query::score_combiner::ScoreCombiner;
 use crate::query::Scorer;
 use crate::{DocId, Score};
@@ -56,9 +56,9 @@ where
         self.req_scorer.seek(target)
     }
 
-    fn seek_into_the_danger_zone(&mut self, target: DocId) -> bool {
+    fn seek_danger(&mut self, target: DocId) -> SeekDangerResult {
         self.score_cache = None;
-        self.req_scorer.seek_into_the_danger_zone(target)
+        self.req_scorer.seek_danger(target)
     }
 
     fn doc(&self) -> DocId {

src/query/term_query/term_scorer.rs

@@ -263,7 +263,9 @@ mod tests {
             let mut block_max_scores_b = vec![];
             let mut docs = vec![];
             {
-                let mut term_scorer = term_weight.term_scorer_for_test(reader, 1.0)?.unwrap();
+                let mut term_scorer = term_weight
+                    .term_scorer_for_test(reader.as_ref(), 1.0)?
+                    .unwrap();
                 while term_scorer.doc() != TERMINATED {
                     let mut score = term_scorer.score();
                     docs.push(term_scorer.doc());
@@ -277,7 +279,9 @@ mod tests {
                 }
             }
             {
-                let mut term_scorer = term_weight.term_scorer_for_test(reader, 1.0)?.unwrap();
+                let mut term_scorer = term_weight
+                    .term_scorer_for_test(reader.as_ref(), 1.0)?
+                    .unwrap();
                 for d in docs {
                     term_scorer.seek_block(d);
                     block_max_scores_b.push(term_scorer.block_max_score());
@@ -304,10 +308,10 @@ mod tests {
         let mut writer: IndexWriter =
             index.writer_with_num_threads(3, 3 * MEMORY_BUDGET_NUM_BYTES_MIN)?;
         use rand::Rng;
-        let mut rng = rand::thread_rng();
+        let mut rng = rand::rng();
         writer.set_merge_policy(Box::new(NoMergePolicy));
         for _ in 0..3_000 {
-            let term_freq = rng.gen_range(1..10000);
+            let term_freq = rng.random_range(1..10000);
             let words: Vec<&str> = std::iter::repeat_n("bbbb", term_freq).collect();
             let text = words.join(" ");
             writer.add_document(doc!(text_field=>text))?;

src/query/term_query/term_weight.rs

@@ -34,11 +34,11 @@ impl TermOrEmptyOrAllScorer {
 }
 
 impl Weight for TermWeight {
-    fn scorer(&self, reader: &SegmentReader, boost: Score) -> crate::Result<Box<dyn Scorer>> {
+    fn scorer(&self, reader: &dyn SegmentReader, boost: Score) -> crate::Result<Box<dyn Scorer>> {
         Ok(self.specialized_scorer(reader, boost)?.into_boxed_scorer())
     }
 
-    fn explain(&self, reader: &SegmentReader, doc: DocId) -> crate::Result<Explanation> {
+    fn explain(&self, reader: &dyn SegmentReader, doc: DocId) -> crate::Result<Explanation> {
         match self.specialized_scorer(reader, 1.0)? {
             TermOrEmptyOrAllScorer::TermScorer(mut term_scorer) => {
                 if term_scorer.doc() > doc || term_scorer.seek(doc) != doc {
@@ -53,7 +53,7 @@ impl Weight for TermWeight {
         }
     }
 
-    fn count(&self, reader: &SegmentReader) -> crate::Result<u32> {
+    fn count(&self, reader: &dyn SegmentReader) -> crate::Result<u32> {
         if let Some(alive_bitset) = reader.alive_bitset() {
             Ok(self.scorer(reader, 1.0)?.count(alive_bitset))
         } else {
@@ -68,7 +68,7 @@ impl Weight for TermWeight {
     /// `DocSet` and push the scored documents to the collector.
     fn for_each(
         &self,
-        reader: &SegmentReader,
+        reader: &dyn SegmentReader,
         callback: &mut dyn FnMut(DocId, Score),
     ) -> crate::Result<()> {
         match self.specialized_scorer(reader, 1.0)? {
@@ -87,7 +87,7 @@ impl Weight for TermWeight {
     /// `DocSet` and push the scored documents to the collector.
     fn for_each_no_score(
         &self,
-        reader: &SegmentReader,
+        reader: &dyn SegmentReader,
         callback: &mut dyn FnMut(&[DocId]),
     ) -> crate::Result<()> {
         match self.specialized_scorer(reader, 1.0)? {
@@ -118,7 +118,7 @@ impl Weight for TermWeight {
     fn for_each_pruning(
         &self,
         threshold: Score,
-        reader: &SegmentReader,
+        reader: &dyn SegmentReader,
         callback: &mut dyn FnMut(DocId, Score) -> Score,
     ) -> crate::Result<()> {
         let specialized_scorer = self.specialized_scorer(reader, 1.0)?;
@@ -166,7 +166,7 @@ impl TermWeight {
     #[cfg(test)]
     pub(crate) fn term_scorer_for_test(
         &self,
-        reader: &SegmentReader,
+        reader: &dyn SegmentReader,
         boost: Score,
     ) -> crate::Result<Option<TermScorer>> {
         let scorer = self.specialized_scorer(reader, boost)?;
@@ -178,7 +178,7 @@ impl TermWeight {
 
     fn specialized_scorer(
         &self,
-        reader: &SegmentReader,
+        reader: &dyn SegmentReader,
         boost: Score,
     ) -> crate::Result<TermOrEmptyOrAllScorer> {
         let field = self.term.field();
@@ -206,7 +206,10 @@ impl TermWeight {
         )))
     }
 
-    fn fieldnorm_reader(&self, segment_reader: &SegmentReader) -> crate::Result<FieldNormReader> {
+    fn fieldnorm_reader(
+        &self,
+        segment_reader: &dyn SegmentReader,
+    ) -> crate::Result<FieldNormReader> {
         if self.scoring_enabled {
             if let Some(field_norm_reader) = segment_reader
                 .fieldnorms_readers()

src/query/union/buffered_union.rs

@@ -1,6 +1,6 @@
 use common::TinySet;
 
-use crate::docset::{DocSet, TERMINATED};
+use crate::docset::{DocSet, SeekDangerResult, TERMINATED};
 use crate::query::score_combiner::{DoNothingCombiner, ScoreCombiner};
 use crate::query::size_hint::estimate_union;
 use crate::query::Scorer;
@@ -225,25 +225,47 @@ where
         }
     }
 
-    fn seek_into_the_danger_zone(&mut self, target: DocId) -> bool {
+    fn seek_danger(&mut self, target: DocId) -> SeekDangerResult {
+        if target >= TERMINATED {
+            return SeekDangerResult::SeekLowerBound(TERMINATED);
+        }
         if self.is_in_horizon(target) {
             // Our value is within the buffered horizon and the docset may already have been
             // processed and removed, so we need to use seek, which uses the regular advance.
-            self.seek(target) == target
-        } else {
-            // The docsets are not in the buffered range, so we can use seek_into_the_danger_zone
-            // of the underlying docsets
-            let is_hit = self
-                .docsets
-                .iter_mut()
-                .any(|docset| docset.seek_into_the_danger_zone(target));
+            let seek_doc = self.seek(target);
+            if seek_doc == target {
+                return SeekDangerResult::Found;
+            } else {
+                return SeekDangerResult::SeekLowerBound(seek_doc);
+            };
+        }
 
-            // The API requires the DocSet to be in a valid state when `seek_into_the_danger_zone`
-            // returns true.
-            if is_hit {
-                self.seek(target);
+        // The docsets are not in the buffered range, so we can use seek_into_the_danger_zone
+        // of the underlying docsets
+        let mut is_hit = false;
+        let mut min_new_target = TERMINATED;
+
+        for docset in self.docsets.iter_mut() {
+            match docset.seek_danger(target) {
+                SeekDangerResult::Found => {
+                    is_hit = true;
+                    break;
+                }
+                SeekDangerResult::SeekLowerBound(new_target) => {
+                    min_new_target = min_new_target.min(new_target);
+                }
             }
-            is_hit
+        }
+
+        // The API requires the DocSet to be in a valid state when `seek_into_the_danger_zone`
+        // returns Found.
+        if is_hit {
+            // The doc is found. Let's make sure we position the union on the target
+            // to bring it back to a valid state.
+            self.seek(target);
+            SeekDangerResult::Found
+        } else {
+            SeekDangerResult::SeekLowerBound(min_new_target)
         }
     }
 

src/query/union/mod.rs

@@ -14,7 +14,7 @@ mod tests {
     use common::BitSet;
 
     use super::{SimpleUnion, *};
-    use crate::docset::{DocSet, TERMINATED};
+    use crate::docset::{DocSet, SeekDangerResult, TERMINATED};
     use crate::postings::tests::test_skip_against_unoptimized;
     use crate::query::score_combiner::DoNothingCombiner;
     use crate::query::union::bitset_union::BitSetPostingUnion;
@@ -254,6 +254,27 @@ mod tests {
             vec![1, 2, 3, 7, 8, 9, 99, 100, 101, 500, 20000],
         );
     }
+
+    #[test]
+    fn test_buffered_union_seek_into_danger_zone_terminated() {
+        let scorer1 = ConstScorer::new(VecDocSet::from(vec![1, 2]), 1.0);
+        let scorer2 = ConstScorer::new(VecDocSet::from(vec![2, 3]), 1.0);
+
+        let mut union_scorer =
+            BufferedUnionScorer::build(vec![scorer1, scorer2], DoNothingCombiner::default, 100);
+
+        // Advance to end
+        while union_scorer.doc() != TERMINATED {
+            union_scorer.advance();
+        }
+
+        assert_eq!(union_scorer.doc(), TERMINATED);
+
+        assert_eq!(
+            union_scorer.seek_danger(TERMINATED),
+            SeekDangerResult::SeekLowerBound(TERMINATED)
+        );
+    }
 }
 
 #[cfg(all(test, feature = "unstable"))]

src/query/vec_docset.rs

@@ -17,6 +17,9 @@ pub struct VecDocSet {
 
 impl From<Vec<DocId>> for VecDocSet {
     fn from(doc_ids: Vec<DocId>) -> VecDocSet {
+        // We do not use `slice::is_sorted`, as we want to check for doc ids to be strictly
+        // sorted.
+        assert!(doc_ids.windows(2).all(|w| w[0] < w[1]));
         VecDocSet { doc_ids, cursor: 0 }
     }
 }

src/query/weight.rs

@@ -69,13 +69,13 @@ pub trait Weight: Send + Sync + 'static {
     /// `boost` is a multiplier to apply to the score.
     ///
     /// See [`Query`](crate::query::Query).
-    fn scorer(&self, reader: &SegmentReader, boost: Score) -> crate::Result<Box<dyn Scorer>>;
+    fn scorer(&self, reader: &dyn SegmentReader, boost: Score) -> crate::Result<Box<dyn Scorer>>;
 
     /// Returns an [`Explanation`] for the given document.
-    fn explain(&self, reader: &SegmentReader, doc: DocId) -> crate::Result<Explanation>;
+    fn explain(&self, reader: &dyn SegmentReader, doc: DocId) -> crate::Result<Explanation>;
 
     /// Returns the number documents within the given [`SegmentReader`].
-    fn count(&self, reader: &SegmentReader) -> crate::Result<u32> {
+    fn count(&self, reader: &dyn SegmentReader) -> crate::Result<u32> {
         let mut scorer = self.scorer(reader, 1.0)?;
         if let Some(alive_bitset) = reader.alive_bitset() {
             Ok(scorer.count(alive_bitset))
@@ -88,7 +88,7 @@ pub trait Weight: Send + Sync + 'static {
     /// `DocSet` and push the scored documents to the collector.
     fn for_each(
         &self,
-        reader: &SegmentReader,
+        reader: &dyn SegmentReader,
         callback: &mut dyn FnMut(DocId, Score),
     ) -> crate::Result<()> {
         let mut scorer = self.scorer(reader, 1.0)?;
@@ -100,7 +100,7 @@ pub trait Weight: Send + Sync + 'static {
     /// `DocSet` and push the scored documents to the collector.
     fn for_each_no_score(
         &self,
-        reader: &SegmentReader,
+        reader: &dyn SegmentReader,
         callback: &mut dyn FnMut(&[DocId]),
     ) -> crate::Result<()> {
         let mut docset = self.scorer(reader, 1.0)?;
@@ -123,7 +123,7 @@ pub trait Weight: Send + Sync + 'static {
     fn for_each_pruning(
         &self,
         threshold: Score,
-        reader: &SegmentReader,
+        reader: &dyn SegmentReader,
         callback: &mut dyn FnMut(DocId, Score) -> Score,
     ) -> crate::Result<()> {
         let mut scorer = self.scorer(reader, 1.0)?;

src/reader/mod.rs

@@ -10,7 +10,7 @@ use self::warming::WarmingState;
 use crate::core::searcher::{SearcherGeneration, SearcherInner};
 use crate::directory::{Directory, WatchCallback, WatchHandle, META_LOCK};
 use crate::store::DOCSTORE_CACHE_CAPACITY;
-use crate::{Index, Inventory, Searcher, SegmentReader, TrackedObject};
+use crate::{ArcSegmentReader, Index, Inventory, Searcher, TantivySegmentReader, TrackedObject};
 
 /// Defines when a new version of the index should be reloaded.
 ///
@@ -189,19 +189,22 @@ impl InnerIndexReader {
     ///
     /// This function acquires a lock to prevent GC from removing files
     /// as we are opening our index.
-    fn open_segment_readers(index: &Index) -> crate::Result<Vec<SegmentReader>> {
+    fn open_segment_readers(index: &Index) -> crate::Result<Vec<ArcSegmentReader>> {
         // Prevents segment files from getting deleted while we are in the process of opening them
         let _meta_lock = index.directory().acquire_lock(&META_LOCK)?;
         let searchable_segments = index.searchable_segments()?;
         let segment_readers = searchable_segments
             .iter()
-            .map(SegmentReader::open)
+            .map(|segment| {
+                TantivySegmentReader::open(segment)
+                    .map(|reader| Arc::new(reader) as ArcSegmentReader)
+            })
             .collect::<crate::Result<_>>()?;
         Ok(segment_readers)
     }
 
     fn track_segment_readers_in_inventory(
-        segment_readers: &[SegmentReader],
+        segment_readers: &[ArcSegmentReader],
         searcher_generation_counter: &Arc<AtomicU64>,
         searcher_generation_inventory: &Inventory<SearcherGeneration>,
     ) -> TrackedObject<SearcherGeneration> {

src/schema/field_entry.rs

@@ -210,8 +210,11 @@ mod tests {
         index_writer.add_document(doc!(text=>"abc"))?;
         index_writer.commit()?;
         let searcher = index.reader()?.searcher();
-        let err = searcher.segment_reader(0u32).get_fieldnorms_reader(text);
-        assert!(matches!(err, Err(crate::TantivyError::SchemaError(_))));
+        let fieldnorm_opt = searcher
+            .segment_reader(0u32)
+            .fieldnorms_readers()
+            .get_field(text)?;
+        assert!(fieldnorm_opt.is_none());
         Ok(())
     }
 }

src/store/mod.rs

@@ -26,7 +26,7 @@
 //! and should rely on either
 //!
 //! - at the segment level, the [`SegmentReader`'s `doc`
-//!   method](../struct.SegmentReader.html#method.doc)
+//!   method](../trait.SegmentReader.html#method.doc)
 //! - at the index level, the [`Searcher::doc()`](crate::Searcher::doc) method
 
 mod compressors;

src/termdict/fst_termdict/merger.rs

@@ -95,7 +95,7 @@ impl<'a> TermMerger<'a> {
 #[cfg(all(test, feature = "unstable"))]
 mod bench {
     use rand::distributions::Alphanumeric;
-    use rand::{thread_rng, Rng};
+    use rand::{rng, Rng};
     use test::{self, Bencher};
 
     use super::TermMerger;
@@ -117,9 +117,9 @@ mod bench {
         let buffer: Vec<u8> = {
             let mut terms = vec![];
             for _i in 0..num_terms {
-                let rand_string: String = thread_rng()
+                let rand_string: String = rng()
                     .sample_iter(&Alphanumeric)
-                    .take(thread_rng().gen_range(30..42))
+                    .take(rng().random_range(30..42))
                     .map(char::from)
                     .collect();
                 terms.push(rand_string);

sstable/Cargo.toml

@@ -25,7 +25,7 @@ zstd-compression = ["zstd"]
 proptest = "1"
 criterion = { version = "0.5", default-features = false }
 names = "0.14"
-rand = "0.8"
+rand = "0.9"
 
 [[bench]]
 name = "stream_bench"

sstable/benches/stream_bench.rs

@@ -10,9 +10,9 @@ use tantivy_sstable::{Dictionary, MonotonicU64SSTable};
 const CHARSET: &[u8] = b"abcdefghij";
 
 fn generate_key(rng: &mut impl Rng) -> String {
-    let len = rng.gen_range(3..12);
+    let len = rng.random_range(3..12);
     std::iter::from_fn(|| {
-        let idx = rng.gen_range(0..CHARSET.len());
+        let idx = rng.random_range(0..CHARSET.len());
         Some(CHARSET[idx] as char)
     })
     .take(len)

stacker/Cargo.toml

@@ -23,12 +23,12 @@ name = "hashmap"
 path = "example/hashmap.rs"
 
 [dev-dependencies]
-rand = "0.8.5"
+rand = "0.9"
 zipf = "7.0.0"
 rustc-hash = "2.1.0"
 proptest = "1.2.0"
 binggan = { version = "0.14.0" }
-rand_distr = "0.4.3"
+rand_distr = "0.5"
 
 [features]
 compare_hash_only = ["ahash"] # Compare hash only, not the key in the Hashmap

stacker/benches/bench.rs

@@ -90,10 +90,10 @@ fn bench_vint() {
             }
             // benchmark zipfs distribution numbers
             {
-                use rand::distributions::Distribution;
+                use rand::distr::Distribution;
                 use rand::rngs::StdRng;
                 let mut rng = StdRng::from_seed([3u8; 32]);
-                let zipf = zipf::ZipfDistribution::new(10_000, 1.03).unwrap();
+                let zipf = rand_distr::Zipf::new(10_000.0f64, 1.03).unwrap();
                 let numbers: Vec<[u8; 8]> = (0..num_numbers)
                     .map(|_| zipf.sample(&mut rng).to_le_bytes())
                     .collect();

stacker/fuzz_test/Cargo.toml

@@ -7,8 +7,8 @@ edition = "2021"
 
 [dependencies]
 ahash = "0.8.7"
-rand = "0.8.5"
-rand_distr = "0.4.3"
+rand = "0.9"
+rand_distr = "0.5"
 tantivy-stacker = { version = "0.2.0", path = ".." }
 
 [workspace]

stacker/fuzz_test/src/main.rs

@@ -14,7 +14,7 @@ fn test_with_seed(seed: u64) {
     let mut hash_map = AHashMap::new();
     let mut arena_hashmap = ArenaHashMap::default();
     let mut rng = StdRng::seed_from_u64(seed);
-    let key_count = rng.gen_range(1_000..=1_000_000);
+    let key_count = rng.random_range(1_000..=1_000_000);
     let exp = Exp::new(0.05).unwrap();
 
     for _ in 0..key_count {