Closes #896 - Facet reader related

Bugfix. Acquiring a facet reader on a segment that does not contain any
doc with this facet returns `None`.

.gitignore

@@ -1,4 +1,5 @@
 tantivy.iml
+proptest-regressions
 *.swp
 target
 target/debug

CHANGELOG.md

@@ -1,5 +1,23 @@
+Tantivy 0.13.2
+===================
+Bugfix. Acquiring a facet reader on a segment that does not contain any 
+doc with this facet returns `None`. (#896)
+
+Tantivy 0.13.1
+======================
+Made `Query` and `Collector` `Send + Sync`.
+Updated misc dependency versions.
+
+
 Tantivy 0.13.0
 ======================
+Tantivy 0.13 introduce a change in the index format that will require
+you to reindex your index (BlockWAND information are added in the skiplist). 
+The index size increase is minor as this information is only added for
+full blocks.
+If you have a massive index for which reindexing is not an option, please contact me
+so that we can discuss possible solutions.
+
 - Bugfix in `FuzzyTermQuery` not matching terms by prefix when it should (@Peachball)
 - Relaxed constraints on the custom/tweak score functions. At the segment level, they can be mut, and they are not required to be Sync + Send.
 - `MMapDirectory::open` does not return a `Result` anymore.
@@ -17,6 +35,8 @@ while doc != TERMINATED {
 The change made it possible to greatly simplify a lot of the docset's code.
 - Misc internal optimization and introduction of the `Scorer::for_each_pruning` function. (@fulmicoton)
 - Added an offset option to the Top(.*)Collectors. (@robyoung)
+- Added Block WAND. Performance on TOP-K on term-unions should be greatly increased. (@fulmicoton, and special thanks 
+to the PISA team for answering all my questions!)
 
 Tantivy 0.12.0
 ======================

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "tantivy"
-version = "0.12.0"
+version = "0.13.2"
 authors = ["Paul Masurel <paul.masurel@gmail.com>"]
 license = "MIT"
 categories = ["database-implementations", "data-structures"]
@@ -13,21 +13,21 @@ keywords = ["search", "information", "retrieval"]
 edition = "2018"
 
 [dependencies]
-base64 = "0.12.0"
-byteorder = "1.0"
-crc32fast = "1.2.0"
-once_cell = "1.0"
-regex ={version = "1.3.0", default-features = false, features = ["std"]}
+base64 = "0.12"
+byteorder = "1"
+crc32fast = "1"
+once_cell = "1"
+regex ={version = "1", default-features = false, features = ["std"]}
 tantivy-fst = "0.3"
 memmap = {version = "0.7", optional=true}
-lz4 = {version="1.20", optional=true}
+lz4 = {version="1", optional=true}
 snap = "1"
-atomicwrites = {version="0.2.2", optional=true}
-tempfile = "3.0"
+atomicwrites = {version="0.2", optional=true}
+tempfile = "3"
 log = "0.4"
-serde = {version="1.0", features=["derive"]}
-serde_json = "1.0"
-num_cpus = "1.2"
+serde = {version="1", features=["derive"]}
+serde_json = "1"
+num_cpus = "1"
 fs2={version="0.4", optional=true}
 levenshtein_automata = "0.2"
 notify = {version="4", optional=true}
@@ -35,20 +35,20 @@ uuid = { version = "0.8", features = ["v4", "serde"] }
 crossbeam = "0.7"
 futures = {version = "0.3",  features=["thread-pool"] }
 owning_ref = "0.4"
-stable_deref_trait = "1.0.0"
-rust-stemmers = "1.2"
-downcast-rs = { version="1.0" }
+stable_deref_trait = "1"
+rust-stemmers = "1"
+downcast-rs = "1"
 tantivy-query-grammar = { version="0.13", path="./query-grammar" }
 bitpacking = {version="0.8", default-features = false, features=["bitpacker4x"]}
 census = "0.4"
-fnv = "1.0.6"
+fnv = "1"
 owned-read = "0.4"
 failure = "0.1"
-htmlescape = "0.3.1"
+htmlescape = "0.3"
 fail = "0.4"
 murmurhash32 = "0.2"
 chrono = "0.4"
-smallvec = "1.0"
+smallvec = "1"
 rayon = "1"
 
 [target.'cfg(windows)'.dependencies]
@@ -80,6 +80,7 @@ lz4-compression = ["lz4"]
 failpoints = ["fail/failpoints"]
 unstable = [] # useful for benches.
 wasm-bindgen = ["uuid/wasm-bindgen"]
+scoref64 = [] # scores are f64 instead of f32. was introduced to debug blockwand.
 
 [workspace]
 members = ["query-grammar"]

examples/custom_collector.rs

@@ -14,7 +14,7 @@ use tantivy::fastfield::FastFieldReader;
 use tantivy::query::QueryParser;
 use tantivy::schema::Field;
 use tantivy::schema::{Schema, FAST, INDEXED, TEXT};
-use tantivy::{doc, Index, SegmentReader, TantivyError};
+use tantivy::{doc, Index, Score, SegmentReader, TantivyError};
 
 #[derive(Default)]
 struct Stats {
@@ -114,7 +114,7 @@ struct StatsSegmentCollector {
 impl SegmentCollector for StatsSegmentCollector {
     type Fruit = Option<Stats>;
 
-    fn collect(&mut self, doc: u32, _score: f32) {
+    fn collect(&mut self, doc: u32, _score: Score) {
         let value = self.fast_field_reader.get(doc) as f64;
         self.stats.count += 1;
         self.stats.sum += value;

examples/faceted_search_with_tweaked_score.rs

@@ -56,7 +56,7 @@ fn main() -> tantivy::Result<()> {
         );
         let top_docs_by_custom_score =
             TopDocs::with_limit(2).tweak_score(move |segment_reader: &SegmentReader| {
-                let mut ingredient_reader = segment_reader.facet_reader(ingredient).unwrap();
+                let ingredient_reader = segment_reader.facet_reader(ingredient).unwrap();
                 let facet_dict = ingredient_reader.facet_dict();
 
                 let query_ords: HashSet<u64> = facets

query-grammar/src/occur.rs

@@ -31,22 +31,12 @@ impl Occur {
 
     /// Compose two occur values.
     pub fn compose(left: Occur, right: Occur) -> Occur {
-        match left {
-            Occur::Should => right,
-            Occur::Must => {
-                if right == Occur::MustNot {
-                    Occur::MustNot
-                } else {
-                    Occur::Must
-                }
-            }
-            Occur::MustNot => {
-                if right == Occur::MustNot {
-                    Occur::Must
-                } else {
-                    Occur::MustNot
-                }
-            }
+        match (left, right) {
+            (Occur::Should, _) => right,
+            (Occur::Must, Occur::MustNot) => Occur::MustNot,
+            (Occur::Must, _) => Occur::Must,
+            (Occur::MustNot, Occur::MustNot) => Occur::Must,
+            (Occur::MustNot, _) => Occur::MustNot,
         }
     }
 }
@@ -56,3 +46,27 @@ impl fmt::Display for Occur {
         f.write_char(self.to_char())
     }
 }
+
+#[cfg(test)]
+mod test {
+    use crate::Occur;
+
+    #[test]
+    fn test_Occur_compose() {
+        assert_eq!(Occur::compose(Occur::Should, Occur::Should), Occur::Should);
+        assert_eq!(Occur::compose(Occur::Should, Occur::Must), Occur::Must);
+        assert_eq!(
+            Occur::compose(Occur::Should, Occur::MustNot),
+            Occur::MustNot
+        );
+        assert_eq!(Occur::compose(Occur::Must, Occur::Should), Occur::Must);
+        assert_eq!(Occur::compose(Occur::Must, Occur::Must), Occur::Must);
+        assert_eq!(Occur::compose(Occur::Must, Occur::MustNot), Occur::MustNot);
+        assert_eq!(
+            Occur::compose(Occur::MustNot, Occur::Should),
+            Occur::MustNot
+        );
+        assert_eq!(Occur::compose(Occur::MustNot, Occur::Must), Occur::MustNot);
+        assert_eq!(Occur::compose(Occur::MustNot, Occur::MustNot), Occur::Must);
+    }
+}

query-grammar/src/query_grammar.rs

@@ -180,7 +180,7 @@ fn occur_leaf<'a>() -> impl Parser<&'a str, Output = (Option<Occur>, UserInputAS
     (optional(occur_symbol()), boosted_leaf())
 }
 
-fn positive_float_number<'a>() -> impl Parser<&'a str, Output = f32> {
+fn positive_float_number<'a>() -> impl Parser<&'a str, Output = f64> {
     (many1(digit()), optional((char('.'), many1(digit())))).map(
         |(int_part, decimal_part_opt): (String, Option<(char, String)>)| {
             let mut float_str = int_part;
@@ -188,18 +188,18 @@ fn positive_float_number<'a>() -> impl Parser<&'a str, Output = f32> {
                 float_str.push(chr);
                 float_str.push_str(&decimal_str);
             }
-            float_str.parse::<f32>().unwrap()
+            float_str.parse::<f64>().unwrap()
         },
     )
 }
 
-fn boost<'a>() -> impl Parser<&'a str, Output = f32> {
+fn boost<'a>() -> impl Parser<&'a str, Output = f64> {
     (char('^'), positive_float_number()).map(|(_, boost)| boost)
 }
 
 fn boosted_leaf<'a>() -> impl Parser<&'a str, Output = UserInputAST> {
     (leaf(), optional(boost())).map(|(leaf, boost_opt)| match boost_opt {
-        Some(boost) if (boost - 1.0).abs() > std::f32::EPSILON => {
+        Some(boost) if (boost - 1.0).abs() > std::f64::EPSILON => {
             UserInputAST::Boost(Box::new(leaf), boost)
         }
         _ => leaf,
@@ -282,11 +282,11 @@ mod test {
     use super::*;
     use combine::parser::Parser;
 
-    pub fn nearly_equals(a: f32, b: f32) -> bool {
+    pub fn nearly_equals(a: f64, b: f64) -> bool {
         (a - b).abs() < 0.0005 * (a + b).abs()
     }
 
-    fn assert_nearly_equals(expected: f32, val: f32) {
+    fn assert_nearly_equals(expected: f64, val: f64) {
         assert!(
             nearly_equals(val, expected),
             "Got {}, expected {}.",
@@ -303,7 +303,7 @@ mod test {
 
     #[test]
     fn test_positive_float_number() {
-        fn valid_parse(float_str: &str, expected_val: f32, expected_remaining: &str) {
+        fn valid_parse(float_str: &str, expected_val: f64, expected_remaining: &str) {
             let (val, remaining) = positive_float_number().parse(float_str).unwrap();
             assert_eq!(remaining, expected_remaining);
             assert_nearly_equals(val, expected_val);
@@ -311,9 +311,9 @@ mod test {
         fn error_parse(float_str: &str) {
             assert!(positive_float_number().parse(float_str).is_err());
         }
-        valid_parse("1.0", 1.0f32, "");
-        valid_parse("1", 1.0f32, "");
-        valid_parse("0.234234 aaa", 0.234234f32, " aaa");
+        valid_parse("1.0", 1.0, "");
+        valid_parse("1", 1.0, "");
+        valid_parse("0.234234 aaa", 0.234234f64, " aaa");
         error_parse(".3332");
         error_parse("1.");
         error_parse("-1.");

query-grammar/src/user_input_ast.rs

@@ -87,7 +87,7 @@ impl UserInputBound {
 pub enum UserInputAST {
     Clause(Vec<(Option<Occur>, UserInputAST)>),
     Leaf(Box<UserInputLeaf>),
-    Boost(Box<UserInputAST>, f32),
+    Boost(Box<UserInputAST>, f64),
 }
 
 impl UserInputAST {

src/collector/count_collector.rs

@@ -96,18 +96,18 @@ mod tests {
         }
         {
             let mut count_collector = SegmentCountCollector::default();
-            count_collector.collect(0u32, 1f32);
+            count_collector.collect(0u32, 1.0);
             assert_eq!(count_collector.harvest(), 1);
         }
         {
             let mut count_collector = SegmentCountCollector::default();
-            count_collector.collect(0u32, 1f32);
+            count_collector.collect(0u32, 1.0);
             assert_eq!(count_collector.harvest(), 1);
         }
         {
             let mut count_collector = SegmentCountCollector::default();
-            count_collector.collect(0u32, 1f32);
-            count_collector.collect(1u32, 1f32);
+            count_collector.collect(0u32, 1.0);
+            count_collector.collect(1u32, 1.0);
             assert_eq!(count_collector.harvest(), 2);
         }
     }

src/collector/custom_score_top_collector.rs

@@ -46,7 +46,7 @@ pub trait CustomScorer<TScore>: Sync {
 
 impl<TCustomScorer, TScore> Collector for CustomScoreTopCollector<TCustomScorer, TScore>
 where
-    TCustomScorer: CustomScorer<TScore>,
+    TCustomScorer: CustomScorer<TScore> + Send + Sync,
     TScore: 'static + PartialOrd + Clone + Send + Sync,
 {
     type Fruit = Vec<(TScore, DocAddress)>;

src/collector/mod.rs

@@ -133,7 +133,7 @@ impl<T> Fruit for T where T: Send + downcast_rs::Downcast {}
 /// The collection logic itself is in the `SegmentCollector`.
 ///
 /// Segments are not guaranteed to be visited in any specific order.
-pub trait Collector: Sync {
+pub trait Collector: Sync + Send {
     /// `Fruit` is the type for the result of our collection.
     /// e.g. `usize` for the `Count` collector.
     type Fruit: Fruit;

src/collector/multi_collector.rs

@@ -55,7 +55,7 @@ impl<TCollector: Collector> Collector for CollectorWrapper<TCollector> {
 impl SegmentCollector for Box<dyn BoxableSegmentCollector> {
     type Fruit = Box<dyn Fruit>;
 
-    fn collect(&mut self, doc: u32, score: f32) {
+    fn collect(&mut self, doc: u32, score: Score) {
         self.as_mut().collect(doc, score);
     }
 
@@ -65,7 +65,7 @@ impl SegmentCollector for Box<dyn BoxableSegmentCollector> {
 }
 
 pub trait BoxableSegmentCollector {
-    fn collect(&mut self, doc: u32, score: f32);
+    fn collect(&mut self, doc: u32, score: Score);
     fn harvest_from_box(self: Box<Self>) -> Box<dyn Fruit>;
 }
 
@@ -74,7 +74,7 @@ pub struct SegmentCollectorWrapper<TSegmentCollector: SegmentCollector>(TSegment
 impl<TSegmentCollector: SegmentCollector> BoxableSegmentCollector
     for SegmentCollectorWrapper<TSegmentCollector>
 {
-    fn collect(&mut self, doc: u32, score: f32) {
+    fn collect(&mut self, doc: u32, score: Score) {
         self.0.collect(doc, score);
     }
 

src/collector/tests.rs

@@ -206,7 +206,7 @@ impl Collector for BytesFastFieldTestCollector {
 impl SegmentCollector for BytesFastFieldSegmentCollector {
     type Fruit = Vec<u8>;
 
-    fn collect(&mut self, doc: u32, _score: f32) {
+    fn collect(&mut self, doc: u32, _score: Score) {
         let data = self.reader.get_bytes(doc);
         self.vals.extend(data);
     }

src/collector/top_score_collector.rs

@@ -52,8 +52,8 @@ use std::fmt;
 /// let query = query_parser.parse_query("diary").unwrap();
 /// let top_docs = searcher.search(&query, &TopDocs::with_limit(2)).unwrap();
 ///
-/// assert_eq!(&top_docs[0], &(0.7261542, DocAddress(0, 1)));
-/// assert_eq!(&top_docs[1], &(0.6099695, DocAddress(0, 3)));
+/// assert_eq!(top_docs[0].1, DocAddress(0, 1));
+/// assert_eq!(top_docs[1].1, DocAddress(0, 3));
 /// ```
 pub struct TopDocs(TopCollector<Score>);
 
@@ -139,8 +139,8 @@ impl TopDocs {
     /// let top_docs = searcher.search(&query, &TopDocs::with_limit(2).and_offset(1)).unwrap();
     ///
     /// assert_eq!(top_docs.len(), 2);
-    /// assert_eq!(&top_docs[0], &(0.5204813, DocAddress(0, 4)));
-    /// assert_eq!(&top_docs[1], &(0.4793185, DocAddress(0, 3)));
+    /// assert_eq!(top_docs[0].1, DocAddress(0, 4));
+    /// assert_eq!(top_docs[1].1, DocAddress(0, 3));
     /// ```
     pub fn and_offset(self, offset: usize) -> TopDocs {
         TopDocs(self.0.and_offset(offset))
@@ -303,7 +303,7 @@ impl TopDocs {
     ///                 let popularity: u64 = popularity_reader.get(doc);
     ///                 // Well.. For the sake of the example we use a simple logarithm
     ///                 // function.
-    ///                 let popularity_boost_score = ((2u64 + popularity) as f32).log2();
+    ///                 let popularity_boost_score = ((2u64 + popularity) as Score).log2();
     ///                 popularity_boost_score * original_score
     ///             }
     ///           });
@@ -324,7 +324,7 @@ impl TopDocs {
     where
         TScore: 'static + Send + Sync + Clone + PartialOrd,
         TScoreSegmentTweaker: ScoreSegmentTweaker<TScore> + 'static,
-        TScoreTweaker: ScoreTweaker<TScore, Child = TScoreSegmentTweaker>,
+        TScoreTweaker: ScoreTweaker<TScore, Child = TScoreSegmentTweaker> + Send + Sync,
     {
         TweakedScoreTopCollector::new(score_tweaker, self.0.into_tscore())
     }
@@ -438,7 +438,7 @@ impl TopDocs {
     where
         TScore: 'static + Send + Sync + Clone + PartialOrd,
         TCustomSegmentScorer: CustomSegmentScorer<TScore> + 'static,
-        TCustomScorer: CustomScorer<TScore, Child = TCustomSegmentScorer>,
+        TCustomScorer: CustomScorer<TScore, Child = TCustomSegmentScorer> + Send + Sync,
     {
         CustomScoreTopCollector::new(custom_score, self.0.into_tscore())
     }
@@ -479,7 +479,7 @@ impl Collector for TopDocs {
         let mut heap: BinaryHeap<ComparableDoc<Score, DocId>> = BinaryHeap::with_capacity(heap_len);
 
         if let Some(delete_bitset) = reader.delete_bitset() {
-            let mut threshold = f32::MIN;
+            let mut threshold = Score::MIN;
             weight.for_each_pruning(threshold, reader, &mut |doc, score| {
                 if delete_bitset.is_deleted(doc) {
                     return threshold;
@@ -491,16 +491,16 @@ impl Collector for TopDocs {
                 if heap.len() < heap_len {
                     heap.push(heap_item);
                     if heap.len() == heap_len {
-                        threshold = heap.peek().map(|el| el.feature).unwrap_or(f32::MIN);
+                        threshold = heap.peek().map(|el| el.feature).unwrap_or(Score::MIN);
                     }
                     return threshold;
                 }
                 *heap.peek_mut().unwrap() = heap_item;
-                threshold = heap.peek().map(|el| el.feature).unwrap_or(std::f32::MIN);
+                threshold = heap.peek().map(|el| el.feature).unwrap_or(Score::MIN);
                 threshold
             })?;
         } else {
-            weight.for_each_pruning(f32::MIN, reader, &mut |doc, score| {
+            weight.for_each_pruning(Score::MIN, reader, &mut |doc, score| {
                 let heap_item = ComparableDoc {
                     feature: score,
                     doc,
@@ -509,17 +509,17 @@ impl Collector for TopDocs {
                     heap.push(heap_item);
                     // TODO the threshold is suboptimal for heap.len == heap_len
                     if heap.len() == heap_len {
-                        return heap.peek().map(|el| el.feature).unwrap_or(f32::MIN);
+                        return heap.peek().map(|el| el.feature).unwrap_or(Score::MIN);
                     } else {
-                        return f32::MIN;
+                        return Score::MIN;
                     }
                 }
                 *heap.peek_mut().unwrap() = heap_item;
-                heap.peek().map(|el| el.feature).unwrap_or(std::f32::MIN)
+                heap.peek().map(|el| el.feature).unwrap_or(Score::MIN)
             })?;
         }
 
-        let fruit: Vec<(Score, DocAddress)> = heap
+        let fruit = heap
             .into_sorted_vec()
             .into_iter()
             .map(|cid| (cid.feature, DocAddress(segment_ord, cid.doc)))
@@ -570,6 +570,13 @@ mod tests {
         index
     }
 
+    fn assert_results_equals(results: &[(Score, DocAddress)], expected: &[(Score, DocAddress)]) {
+        for (result, expected) in results.iter().zip(expected.iter()) {
+            assert_eq!(result.1, expected.1);
+            crate::assert_nearly_equals!(result.0, expected.0);
+        }
+    }
+
     #[test]
     fn test_top_collector_not_at_capacity() {
         let index = make_index();
@@ -582,13 +589,13 @@ mod tests {
             .searcher()
             .search(&text_query, &TopDocs::with_limit(4))
             .unwrap();
-        assert_eq!(
-            score_docs,
-            vec![
+        assert_results_equals(
+            &score_docs,
+            &[
                 (0.81221175, DocAddress(0u32, 1)),
                 (0.5376842, DocAddress(0u32, 2)),
-                (0.48527452, DocAddress(0, 0))
-            ]
+                (0.48527452, DocAddress(0, 0)),
+            ],
         );
     }
 
@@ -604,7 +611,7 @@ mod tests {
             .searcher()
             .search(&text_query, &TopDocs::with_limit(4).and_offset(2))
             .unwrap();
-        assert_eq!(score_docs, vec![(0.48527452, DocAddress(0, 0))]);
+        assert_results_equals(&score_docs[..], &[(0.48527452, DocAddress(0, 0))]);
     }
 
     #[test]
@@ -619,12 +626,12 @@ mod tests {
             .searcher()
             .search(&text_query, &TopDocs::with_limit(2))
             .unwrap();
-        assert_eq!(
-            score_docs,
-            vec![
+        assert_results_equals(
+            &score_docs,
+            &[
                 (0.81221175, DocAddress(0u32, 1)),
                 (0.5376842, DocAddress(0u32, 2)),
-            ]
+            ],
         );
     }
 
@@ -640,12 +647,12 @@ mod tests {
             .searcher()
             .search(&text_query, &TopDocs::with_limit(2).and_offset(1))
             .unwrap();
-        assert_eq!(
-            score_docs,
-            vec![
+        assert_results_equals(
+            &score_docs[..],
+            &[
                 (0.5376842, DocAddress(0u32, 2)),
-                (0.48527452, DocAddress(0, 0))
-            ]
+                (0.48527452, DocAddress(0, 0)),
+            ],
         );
     }
 
@@ -706,8 +713,8 @@ mod tests {
         let top_collector = TopDocs::with_limit(4).order_by_u64_field(size);
         let top_docs: Vec<(u64, DocAddress)> = searcher.search(&query, &top_collector).unwrap();
         assert_eq!(
-            top_docs,
-            vec![
+            &top_docs[..],
+            &[
                 (64, DocAddress(0, 1)),
                 (16, DocAddress(0, 2)),
                 (12, DocAddress(0, 0))

src/collector/tweak_score_top_collector.rs

@@ -49,7 +49,7 @@ pub trait ScoreTweaker<TScore>: Sync {
 
 impl<TScoreTweaker, TScore> Collector for TweakedScoreTopCollector<TScoreTweaker, TScore>
 where
-    TScoreTweaker: ScoreTweaker<TScore>,
+    TScoreTweaker: ScoreTweaker<TScore> + Send + Sync,
     TScore: 'static + PartialOrd + Clone + Send + Sync,
 {
     type Fruit = Vec<(TScore, DocAddress)>;

src/common/mod.rs

@@ -10,7 +10,9 @@ pub(crate) use self::bitset::TinySet;
 pub(crate) use self::composite_file::{CompositeFile, CompositeWrite};
 pub use self::counting_writer::CountingWriter;
 pub use self::serialize::{BinarySerializable, FixedSize};
-pub use self::vint::{read_u32_vint, serialize_vint_u32, write_u32_vint, VInt};
+pub use self::vint::{
+    read_u32_vint, read_u32_vint_no_advance, serialize_vint_u32, write_u32_vint, VInt,
+};
 pub use byteorder::LittleEndian as Endianness;
 
 /// Segment's max doc must be `< MAX_DOC_LIMIT`.

src/common/vint.rs

@@ -10,7 +10,7 @@ pub struct VInt(pub u64);
 
 const STOP_BIT: u8 = 128;
 
-pub fn serialize_vint_u32(val: u32) -> (u64, usize) {
+pub fn serialize_vint_u32(val: u32, buf: &mut [u8; 8]) -> &[u8] {
     const START_2: u64 = 1 << 7;
     const START_3: u64 = 1 << 14;
     const START_4: u64 = 1 << 21;
@@ -29,7 +29,7 @@ pub fn serialize_vint_u32(val: u32) -> (u64, usize) {
 
     let val = u64::from(val);
     const STOP_BIT: u64 = 128u64;
-    match val {
+    let (res, num_bytes) = match val {
         0..=STOP_1 => (val | STOP_BIT, 1),
         START_2..=STOP_2 => (
             (val & MASK_1) | ((val & MASK_2) << 1) | (STOP_BIT << (8)),
@@ -56,7 +56,9 @@ pub fn serialize_vint_u32(val: u32) -> (u64, usize) {
                 | (STOP_BIT << (8 * 4)),
             5,
         ),
-    }
+    };
+    LittleEndian::write_u64(&mut buf[..], res);
+    &buf[0..num_bytes]
 }
 
 /// Returns the number of bytes covered by a
@@ -85,23 +87,26 @@ fn vint_len(data: &[u8]) -> usize {
 /// If the buffer does not start by a valid
 /// vint payload
 pub fn read_u32_vint(data: &mut &[u8]) -> u32 {
-    let vlen = vint_len(*data);
+    let (result, vlen) = read_u32_vint_no_advance(*data);
+    *data = &data[vlen..];
+    result
+}
+
+pub fn read_u32_vint_no_advance(data: &[u8]) -> (u32, usize) {
+    let vlen = vint_len(data);
     let mut result = 0u32;
     let mut shift = 0u64;
     for &b in &data[..vlen] {
         result |= u32::from(b & 127u8) << shift;
         shift += 7;
     }
-    *data = &data[vlen..];
-    result
+    (result, vlen)
 }
-
 /// Write a `u32` as a vint payload.
 pub fn write_u32_vint<W: io::Write>(val: u32, writer: &mut W) -> io::Result<()> {
-    let (val, num_bytes) = serialize_vint_u32(val);
-    let mut buffer = [0u8; 8];
-    LittleEndian::write_u64(&mut buffer, val);
-    writer.write_all(&buffer[..num_bytes])
+    let mut buf = [0u8; 8];
+    let data = serialize_vint_u32(val, &mut buf);
+    writer.write_all(&data)
 }
 
 impl VInt {
@@ -172,7 +177,6 @@ mod tests {
     use super::serialize_vint_u32;
     use super::VInt;
     use crate::common::BinarySerializable;
-    use byteorder::{ByteOrder, LittleEndian};
 
     fn aux_test_vint(val: u64) {
         let mut v = [14u8; 10];
@@ -208,12 +212,10 @@ mod tests {
 
     fn aux_test_serialize_vint_u32(val: u32) {
         let mut buffer = [0u8; 10];
-        let mut buffer2 = [0u8; 10];
+        let mut buffer2 = [0u8; 8];
         let len_vint = VInt(val as u64).serialize_into(&mut buffer);
-        let (vint, len) = serialize_vint_u32(val);
-        assert_eq!(len, len_vint, "len wrong for val {}", val);
-        LittleEndian::write_u64(&mut buffer2, vint);
-        assert_eq!(&buffer[..len], &buffer2[..len], "array wrong for {}", val);
+        let res2 = serialize_vint_u32(val, &mut buffer2);
+        assert_eq!(&buffer[..len_vint], res2, "array wrong for {}", val);
     }
 
     #[test]

src/core/segment_reader.rs

@@ -112,8 +112,10 @@ impl SegmentReader {
             return None;
         }
         let term_ords_reader = self.fast_fields().u64s(field)?;
-        let termdict_source = self.termdict_composite.open_read(field)?;
-        let termdict = TermDictionary::from_source(&termdict_source);
+        let termdict = self.termdict_composite
+            .open_read(field)
+            .map(|source| TermDictionary::from_source(&source))
+            .unwrap_or_else(TermDictionary::empty);
         let facet_reader = FacetReader::new(term_ords_reader, termdict);
         Some(facet_reader)
     }
@@ -126,8 +128,8 @@ impl SegmentReader {
     /// They are simply stored as a fast field, serialized in
     /// the `.fieldnorm` file of the segment.
     pub fn get_fieldnorms_reader(&self, field: Field) -> FieldNormReader {
-        if let Some(fieldnorm_source) = self.fieldnorm_readers.get_field(field) {
-            fieldnorm_source
+        if let Some(fieldnorm_reader) = self.fieldnorm_readers.get_field(field) {
+            fieldnorm_reader
         } else {
             let field_name = self.schema.get_field_name(field);
             let err_msg = format!(
@@ -179,7 +181,7 @@ impl SegmentReader {
             Arc::new(FastFieldReaders::load_all(&schema, &fast_fields_composite)?);
 
         let fieldnorm_data = segment.open_read(SegmentComponent::FIELDNORMS)?;
-        let fieldnorm_readers = FieldNormReaders::new(fieldnorm_data)?;
+        let fieldnorm_readers = FieldNormReaders::open(fieldnorm_data)?;
 
         let delete_bitset_opt = if segment.meta().has_deletes() {
             let delete_data = segment.open_read(SegmentComponent::DELETE)?;

src/directory/footer.rs

@@ -183,23 +183,23 @@ impl BinarySerializable for VersionedFooter {
         reader.read_exact(&mut buf[..])?;
         let mut cursor = &buf[..];
         let version = u32::deserialize(&mut cursor)?;
-        if version == 1 {
-            let crc32 = u32::deserialize(&mut cursor)?;
-            let store_compression = String::deserialize(&mut cursor)?;
-            Ok(VersionedFooter::V1 {
-                crc32,
-                store_compression,
-            })
-        } else if version == 2 {
-            let crc32 = u32::deserialize(&mut cursor)?;
-            let store_compression = String::deserialize(&mut cursor)?;
-            Ok(VersionedFooter::V2 {
-                crc32,
-                store_compression,
-            })
-        } else {
-            Ok(VersionedFooter::UnknownVersion)
+        if version != 1 && version != 2 {
+            return Ok(VersionedFooter::UnknownVersion);
         }
+        let crc32 = u32::deserialize(&mut cursor)?;
+        let store_compression = String::deserialize(&mut cursor)?;
+        Ok(if version == 1 {
+            VersionedFooter::V1 {
+                crc32,
+                store_compression,
+            }
+        } else {
+            assert_eq!(version, 2);
+            VersionedFooter::V2 {
+                crc32,
+                store_compression,
+            }
+        })
     }
 }
 

src/directory/watch_event_router.rs

@@ -5,7 +5,7 @@ use std::sync::RwLock;
 use std::sync::Weak;
 
 /// Type alias for callbacks registered when watching files of a `Directory`.
-pub type WatchCallback = Box<dyn Fn() -> () + Sync + Send>;
+pub type WatchCallback = Box<dyn Fn() + Sync + Send>;
 
 /// Helper struct to implement the watch method in `Directory` implementations.
 ///
@@ -32,7 +32,7 @@ impl WatchHandle {
 }
 
 impl WatchCallbackList {
-    /// Suscribes a new callback and returns a handle that controls the lifetime of the callback.
+    /// Subscribes a new callback and returns a handle that controls the lifetime of the callback.
     pub fn subscribe(&self, watch_callback: WatchCallback) -> WatchHandle {
         let watch_callback_arc = Arc::new(watch_callback);
         let watch_callback_weak = Arc::downgrade(&watch_callback_arc);

src/fastfield/delete.rs

@@ -9,6 +9,8 @@ use std::io::Write;
 /// Write a delete `BitSet`
 ///
 /// where `delete_bitset` is the set of deleted `DocId`.
+/// Warning: this function does not call terminate. The caller is in charge of
+/// closing the writer properly.
 pub fn write_delete_bitset(
     delete_bitset: &BitSet,
     max_doc: u32,
@@ -42,6 +44,24 @@ pub struct DeleteBitSet {
 }
 
 impl DeleteBitSet {
+    #[cfg(test)]
+    pub(crate) fn for_test(docs: &[DocId], max_doc: u32) -> DeleteBitSet {
+        use crate::directory::{Directory, RAMDirectory, TerminatingWrite};
+        use std::path::Path;
+        assert!(docs.iter().all(|&doc| doc < max_doc));
+        let mut bitset = BitSet::with_max_value(max_doc);
+        for &doc in docs {
+            bitset.insert(doc);
+        }
+        let mut directory = RAMDirectory::create();
+        let path = Path::new("dummydeletebitset");
+        let mut wrt = directory.open_write(path).unwrap();
+        write_delete_bitset(&bitset, max_doc, &mut wrt).unwrap();
+        wrt.terminate().unwrap();
+        let source = directory.open_read(path).unwrap();
+        Self::open(source)
+    }
+
     /// Opens a delete bitset given its data source.
     pub fn open(data: ReadOnlySource) -> DeleteBitSet {
         let num_deleted: usize = data
@@ -83,42 +103,35 @@ impl HasLen for DeleteBitSet {
 
 #[cfg(test)]
 mod tests {
-    use super::*;
-    use crate::directory::*;
-    use std::path::PathBuf;
+    use super::DeleteBitSet;
+    use crate::common::HasLen;
 
-    fn test_delete_bitset_helper(bitset: &BitSet, max_doc: u32) {
-        let test_path = PathBuf::from("test");
-        let mut directory = RAMDirectory::create();
-        {
-            let mut writer = directory.open_write(&*test_path).unwrap();
-            write_delete_bitset(bitset, max_doc, &mut writer).unwrap();
-            writer.terminate().unwrap();
+    #[test]
+    fn test_delete_bitset_empty() {
+        let delete_bitset = DeleteBitSet::for_test(&[], 10);
+        for doc in 0..10 {
+            assert_eq!(delete_bitset.is_deleted(doc), !delete_bitset.is_alive(doc));
         }
-        let source = directory.open_read(&test_path).unwrap();
-        let delete_bitset = DeleteBitSet::open(source);
-        for doc in 0..max_doc {
-            assert_eq!(bitset.contains(doc), delete_bitset.is_deleted(doc as DocId));
-        }
-        assert_eq!(delete_bitset.len(), bitset.len());
+        assert_eq!(delete_bitset.len(), 0);
     }
 
     #[test]
     fn test_delete_bitset() {
-        {
-            let mut bitset = BitSet::with_max_value(10);
-            bitset.insert(1);
-            bitset.insert(9);
-            test_delete_bitset_helper(&bitset, 10);
-        }
-        {
-            let mut bitset = BitSet::with_max_value(8);
-            bitset.insert(1);
-            bitset.insert(2);
-            bitset.insert(3);
-            bitset.insert(5);
-            bitset.insert(7);
-            test_delete_bitset_helper(&bitset, 8);
+        let delete_bitset = DeleteBitSet::for_test(&[1, 9], 10);
+        assert!(delete_bitset.is_alive(0));
+        assert!(delete_bitset.is_deleted(1));
+        assert!(delete_bitset.is_alive(2));
+        assert!(delete_bitset.is_alive(3));
+        assert!(delete_bitset.is_alive(4));
+        assert!(delete_bitset.is_alive(5));
+        assert!(delete_bitset.is_alive(6));
+        assert!(delete_bitset.is_alive(6));
+        assert!(delete_bitset.is_alive(7));
+        assert!(delete_bitset.is_alive(8));
+        assert!(delete_bitset.is_deleted(9));
+        for doc in 0..10 {
+            assert_eq!(delete_bitset.is_deleted(doc), !delete_bitset.is_alive(doc));
         }
+        assert_eq!(delete_bitset.len(), 2);
     }
 }

src/fastfield/facet_reader.rs

@@ -73,7 +73,52 @@ impl FacetReader {
     }
 
     /// Return the list of facet ordinals associated to a document.
-    pub fn facet_ords(&mut self, doc: DocId, output: &mut Vec<u64>) {
+    pub fn facet_ords(&self, doc: DocId, output: &mut Vec<u64>) {
         self.term_ords.get_vals(doc, output);
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use crate::{Document, schema::{Facet, SchemaBuilder}};
+    use crate::Index;
+
+    #[test]
+    fn test_facet_not_populated_for_all_docs() -> crate::Result<()> {
+        let mut schema_builder = SchemaBuilder::default();
+        let facet_field = schema_builder.add_facet_field("facet");
+        let schema = schema_builder.build();
+        let index = Index::create_in_ram(schema);
+        let mut index_writer = index.writer_with_num_threads(1, 10_000_000)?;
+        index_writer.add_document(doc!(facet_field=>Facet::from_text("/a/b")));
+        index_writer.add_document(Document::default());
+        index_writer.commit()?;
+        let searcher = index.reader()?.searcher();
+        let facet_reader = searcher.segment_reader(0u32).facet_reader(facet_field).unwrap();
+        let mut facet_ords = Vec::new();
+        facet_reader.facet_ords(0u32, &mut facet_ords);
+        assert_eq!(&facet_ords, &[2u64]);
+        facet_reader.facet_ords(1u32, &mut facet_ords);
+        assert!(facet_ords.is_empty());
+        Ok(())
+    }
+    #[test]
+    fn test_facet_not_populated_for_any_docs() -> crate::Result<()> {
+        let mut schema_builder = SchemaBuilder::default();
+        let facet_field = schema_builder.add_facet_field("facet");
+        let schema = schema_builder.build();
+        let index = Index::create_in_ram(schema);
+        let mut index_writer = index.writer_with_num_threads(1, 10_000_000)?;
+        index_writer.add_document(Document::default());
+        index_writer.add_document(Document::default());
+        index_writer.commit()?;
+        let searcher = index.reader()?.searcher();
+        let facet_reader = searcher.segment_reader(0u32).facet_reader(facet_field).unwrap();
+        let mut facet_ords = Vec::new();
+        facet_reader.facet_ords(0u32, &mut facet_ords);
+        assert!(facet_ords.is_empty());
+        facet_reader.facet_ords(1u32, &mut facet_ords);
+        assert!(facet_ords.is_empty());
+        Ok(())
+    }
+}

src/fastfield/writer.rs

@@ -126,6 +126,7 @@ impl FastFieldsWriter {
         for field_writer in &self.single_value_writers {
             field_writer.serialize(serializer)?;
         }
+        
         for field_writer in &self.multi_values_writers {
             let field = field_writer.field();
             field_writer.serialize(serializer, mapping.get(&field))?;

src/fieldnorm/reader.rs

@@ -19,7 +19,7 @@ pub struct FieldNormReaders {
 
 impl FieldNormReaders {
     /// Creates a field norm reader.
-    pub fn new(source: ReadOnlySource) -> crate::Result<FieldNormReaders> {
+    pub fn open(source: ReadOnlySource) -> crate::Result<FieldNormReaders> {
         let data = CompositeFile::open(&source)?;
         Ok(FieldNormReaders {
             data: Arc::new(data),
@@ -103,11 +103,9 @@ impl FieldNormReader {
     pub fn fieldnorm_to_id(fieldnorm: u32) -> u8 {
         fieldnorm_to_id(fieldnorm)
     }
-}
 
-#[cfg(test)]
-impl From<&[u32]> for FieldNormReader {
-    fn from(field_norms: &[u32]) -> FieldNormReader {
+    #[cfg(test)]
+    pub fn for_test(field_norms: &[u32]) -> FieldNormReader {
         let field_norms_id = field_norms
             .iter()
             .cloned()
@@ -119,3 +117,20 @@ impl From<&[u32]> for FieldNormReader {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use crate::fieldnorm::FieldNormReader;
+
+    #[test]
+    fn test_from_fieldnorms_array() {
+        let fieldnorms = &[1, 2, 3, 4, 1_000_000];
+        let fieldnorm_reader = FieldNormReader::for_test(fieldnorms);
+        assert_eq!(fieldnorm_reader.num_docs(), 5);
+        assert_eq!(fieldnorm_reader.fieldnorm(0), 1);
+        assert_eq!(fieldnorm_reader.fieldnorm(1), 2);
+        assert_eq!(fieldnorm_reader.fieldnorm(2), 3);
+        assert_eq!(fieldnorm_reader.fieldnorm(3), 4);
+        assert_eq!(fieldnorm_reader.fieldnorm(4), 983_064);
+    }
+}

src/indexer/index_writer.rs

@@ -536,6 +536,7 @@ impl IndexWriter {
     /// when no documents are remaining.
     ///
     /// Returns the former segment_ready channel.
+    #[allow(unused_must_use)]
     fn recreate_document_channel(&mut self) -> OperationReceiver {
         let (document_sender, document_receiver): (OperationSender, OperationReceiver) =
             channel::bounded(PIPELINE_MAX_SIZE_IN_DOCS);
@@ -575,7 +576,7 @@ impl IndexWriter {
         //
         // This will drop the document queue, and the thread
         // should terminate.
-        mem::replace(self, new_index_writer);
+        *self = new_index_writer;
 
         // Drains the document receiver pipeline :
         // Workers don't need to index the pending documents.

src/indexer/merger.rs

@@ -12,17 +12,18 @@ use crate::fieldnorm::FieldNormsSerializer;
 use crate::fieldnorm::FieldNormsWriter;
 use crate::fieldnorm::{FieldNormReader, FieldNormReaders};
 use crate::indexer::SegmentSerializer;
-use crate::postings::InvertedIndexSerializer;
 use crate::postings::Postings;
+use crate::postings::{InvertedIndexSerializer, SegmentPostings};
 use crate::schema::Cardinality;
 use crate::schema::FieldType;
 use crate::schema::{Field, Schema};
 use crate::store::StoreWriter;
 use crate::termdict::TermMerger;
 use crate::termdict::TermOrdinal;
-use crate::{DocId, SegmentComponent};
+use crate::{DocId, InvertedIndexReader, SegmentComponent};
 use std::cmp;
 use std::collections::HashMap;
+use std::sync::Arc;
 
 fn compute_total_num_tokens(readers: &[SegmentReader], field: Field) -> u64 {
     let mut total_tokens = 0u64;
@@ -497,7 +498,7 @@ impl IndexMerger {
     ) -> crate::Result<Option<TermOrdinalMapping>> {
         let mut positions_buffer: Vec<u32> = Vec::with_capacity(1_000);
         let mut delta_computer = DeltaComputer::new();
-        let field_readers = self
+        let field_readers: Vec<Arc<InvertedIndexReader>> = self
             .readers
             .iter()
             .map(|reader| reader.inverted_index(indexed_field))
@@ -563,47 +564,45 @@ impl IndexMerger {
                          indexed. Have you modified the schema?",
         );
 
+        let mut segment_postings_containing_the_term: Vec<(usize, SegmentPostings)> = vec![];
+
         while merged_terms.advance() {
+            segment_postings_containing_the_term.clear();
             let term_bytes: &[u8] = merged_terms.key();
 
+            let mut total_doc_freq = 0;
+
             // Let's compute the list of non-empty posting lists
-            let segment_postings: Vec<_> = merged_terms
-                .current_kvs()
-                .iter()
-                .flat_map(|heap_item| {
-                    let segment_ord = heap_item.segment_ord;
-                    let term_info = heap_item.streamer.value();
-                    let segment_reader = &self.readers[heap_item.segment_ord];
-                    let inverted_index = segment_reader.inverted_index(indexed_field);
-                    let mut segment_postings = inverted_index
-                        .read_postings_from_terminfo(term_info, segment_postings_option);
-                    let mut doc = segment_postings.doc();
-                    while doc != TERMINATED {
-                        if !segment_reader.is_deleted(doc) {
-                            return Some((segment_ord, segment_postings));
-                        }
-                        doc = segment_postings.advance();
-                    }
-                    None
-                })
-                .collect();
+            for heap_item in merged_terms.current_kvs() {
+                let segment_ord = heap_item.segment_ord;
+                let term_info = heap_item.streamer.value();
+                let segment_reader = &self.readers[heap_item.segment_ord];
+                let inverted_index: &InvertedIndexReader = &*field_readers[segment_ord];
+                let segment_postings =
+                    inverted_index.read_postings_from_terminfo(term_info, segment_postings_option);
+                let delete_bitset_opt = segment_reader.delete_bitset();
+                let doc_freq = if let Some(delete_bitset) = delete_bitset_opt {
+                    segment_postings.doc_freq_given_deletes(delete_bitset)
+                } else {
+                    segment_postings.doc_freq()
+                };
+                if doc_freq > 0u32 {
+                    total_doc_freq += doc_freq;
+                    segment_postings_containing_the_term.push((segment_ord, segment_postings));
+                }
+            }
 
             // At this point, `segment_postings` contains the posting list
-            // of all of the segments containing the given term.
+            // of all of the segments containing the given term (and that are non-empty)
             //
             // These segments are non-empty and advance has already been called.
-            if segment_postings.is_empty() {
+            if total_doc_freq == 0u32 {
+                // All docs that used to contain the term have been deleted. The `term` will be
+                // entirely removed.
                 continue;
             }
-            // If not, the `term` will be entirely removed.
 
-            // We know that there is at least one document containing
-            // the term, so we add it.
-            let term_doc_freq = segment_postings
-                .iter()
-                .map(|(_, segment_posting)| segment_posting.doc_freq())
-                .sum();
-            let to_term_ord = field_serializer.new_term(term_bytes, term_doc_freq)?;
+            let to_term_ord = field_serializer.new_term(term_bytes, total_doc_freq)?;
 
             if let Some(ref mut term_ord_mapping) = term_ord_mapping_opt {
                 for (segment_ord, from_term_ord) in merged_terms.matching_segments() {
@@ -613,7 +612,9 @@ impl IndexMerger {
 
             // We can now serialize this postings, by pushing each document to the
             // postings serializer.
-            for (segment_ord, mut segment_postings) in segment_postings {
+            for (segment_ord, mut segment_postings) in
+                segment_postings_containing_the_term.drain(..)
+            {
                 let old_to_new_doc_id = &merged_doc_id_map[segment_ord];
 
                 let mut doc = segment_postings.doc();
@@ -686,7 +687,7 @@ impl SerializableSegment for IndexMerger {
         let fieldnorm_data = serializer
             .segment()
             .open_read(SegmentComponent::FIELDNORMS)?;
-        let fieldnorm_readers = FieldNormReaders::new(fieldnorm_data)?;
+        let fieldnorm_readers = FieldNormReaders::open(fieldnorm_data)?;
         let term_ord_mappings =
             self.write_postings(serializer.get_postings_serializer(), fieldnorm_readers)?;
         self.write_fast_fields(serializer.get_fast_field_serializer(), term_ord_mappings)?;
@@ -1558,7 +1559,7 @@ mod tests {
         let searcher = reader.searcher();
         let mut term_scorer = term_query
             .specialized_weight(&searcher, true)
-            .specialized_scorer(searcher.segment_reader(0u32), 1.0f32)?;
+            .specialized_scorer(searcher.segment_reader(0u32), 1.0)?;
         assert_eq!(term_scorer.doc(), 0);
         assert_nearly_equals!(term_scorer.block_max_score(), 0.0079681855);
         assert_nearly_equals!(term_scorer.score(), 0.0079681855);
@@ -1573,7 +1574,7 @@ mod tests {
         for segment_reader in searcher.segment_readers() {
             let mut term_scorer = term_query
                 .specialized_weight(&searcher, true)
-                .specialized_scorer(segment_reader, 1.0f32)?;
+                .specialized_scorer(segment_reader, 1.0)?;
             // the difference compared to before is instrinsic to the bm25 formula. no worries there.
             for doc in segment_reader.doc_ids_alive() {
                 assert_eq!(term_scorer.doc(), doc);
@@ -1597,7 +1598,7 @@ mod tests {
         let segment_reader = searcher.segment_reader(0u32);
         let mut term_scorer = term_query
             .specialized_weight(&searcher, true)
-            .specialized_scorer(segment_reader, 1.0f32)?;
+            .specialized_scorer(segment_reader, 1.0)?;
         // the difference compared to before is instrinsic to the bm25 formula. no worries there.
         for doc in segment_reader.doc_ids_alive() {
             assert_eq!(term_scorer.doc(), doc);

src/indexer/segment_updater.rs

@@ -130,15 +130,14 @@ fn merge(
     // An IndexMerger is like a "view" of our merged segments.
     let merger: IndexMerger = IndexMerger::open(index.schema(), &segments[..])?;
 
-    let merged_segment_id = merged_segment.id();
-
     // ... we just serialize this index merger in our new segment to merge the two segments.
-    let segment_serializer = SegmentSerializer::for_segment(merged_segment)?;
+    let segment_serializer = SegmentSerializer::for_segment(merged_segment.clone())?;
 
     let num_docs = merger.write(segment_serializer)?;
 
-    let segment_meta = index.new_segment_meta(merged_segment_id, num_docs);
+    let merged_segment_id = merged_segment.id();
 
+    let segment_meta = index.new_segment_meta(merged_segment_id, num_docs);
     Ok(SegmentEntry::new(segment_meta, delete_cursor, None))
 }
 

src/indexer/segment_writer.rs

@@ -151,7 +151,7 @@ impl SegmentWriter {
                         if let Some(unordered_term_id) = unordered_term_id_opt {
                             self.fast_field_writers
                                 .get_multivalue_writer(field)
-                                .expect("multified writer for facet missing")
+                                .expect("writer for facet missing")
                                 .add_val(unordered_term_id);
                         }
                     }
@@ -287,7 +287,7 @@ fn write(
     let fieldnorm_data = serializer
         .segment()
         .open_read(SegmentComponent::FIELDNORMS)?;
-    let fieldnorm_readers = FieldNormReaders::new(fieldnorm_data)?;
+    let fieldnorm_readers = FieldNormReaders::open(fieldnorm_data)?;
     let term_ord_map =
         multifield_postings.serialize(serializer.get_postings_serializer(), fieldnorm_readers)?;
     fast_field_writers.serialize(serializer.get_fast_field_serializer(), &term_ord_map)?;

src/lib.rs

@@ -245,11 +245,18 @@ pub type DocId = u32;
 /// with opstamp `n+1`.
 pub type Opstamp = u64;
 
-/// A f32 that represents the relevance of the document to the query
+/// A Score that represents the relevance of the document to the query
 ///
-/// This is modelled internally as a `f32`. The
-/// larger the number, the more relevant the document
-/// to the search
+/// This is modelled internally as a `f64`, because tantivy was compiled with the `scoref64`
+/// feature. The larger the number, the more relevant the document is to the search query.
+#[cfg(feature = "scoref64")]
+pub type Score = f64;
+
+/// A Score that represents the relevance of the document to the query
+///
+/// This is modelled internally as a `f32`. The larger the number, the more relevant
+/// the document to the search query.
+#[cfg(not(feature = "scoref64"))]
 pub type Score = f32;
 
 /// A `SegmentLocalId` identifies a segment.
@@ -282,7 +289,6 @@ pub struct DocAddress(pub SegmentLocalId, pub DocId);
 
 #[cfg(test)]
 mod tests {
-
     use crate::collector::tests::TEST_COLLECTOR_WITH_SCORE;
     use crate::core::SegmentReader;
     use crate::docset::{DocSet, TERMINATED};

src/positions/reader.rs

@@ -78,6 +78,7 @@ impl Positions {
     }
 }
 
+#[derive(Clone)]
 pub struct PositionReader {
     skip_read: OwnedRead,
     position_read: OwnedRead,

src/postings/block_segment_postings.rs

@@ -9,9 +9,9 @@ use crate::query::BM25Weight;
 use crate::schema::IndexRecordOption;
 use crate::{DocId, Score, TERMINATED};
 
-fn max_f32<I: Iterator<Item = f32>>(mut it: I) -> Option<f32> {
+fn max_score<I: Iterator<Item = Score>>(mut it: I) -> Option<Score> {
     if let Some(first) = it.next() {
-        Some(it.fold(first, f32::max))
+        Some(it.fold(first, Score::max))
     } else {
         None
     }
@@ -24,6 +24,7 @@ fn max_f32<I: Iterator<Item = f32>>(mut it: I) -> Option<f32> {
 ///
 /// While it is useful for some very specific high-performance
 /// use cases, you should prefer using `SegmentPostings` for most usage.
+#[derive(Clone)]
 pub struct BlockSegmentPostings {
     pub(crate) doc_decoder: BlockDecoder,
     loaded_offset: usize,
@@ -58,10 +59,14 @@ fn decode_vint_block(
     doc_offset: DocId,
     num_vint_docs: usize,
 ) {
-    doc_decoder.fill(TERMINATED);
-    let num_consumed_bytes = doc_decoder.uncompress_vint_sorted(data, doc_offset, num_vint_docs);
+    let num_consumed_bytes =
+        doc_decoder.uncompress_vint_sorted(data, doc_offset, num_vint_docs, TERMINATED);
     if let Some(freq_decoder) = freq_decoder_opt {
-        freq_decoder.uncompress_vint_unsorted(&data[num_consumed_bytes..], num_vint_docs);
+        freq_decoder.uncompress_vint_unsorted(
+            &data[num_consumed_bytes..],
+            num_vint_docs,
+            TERMINATED,
+        );
     }
 }
 
@@ -124,27 +129,33 @@ impl BlockSegmentPostings {
         fieldnorm_reader: &FieldNormReader,
         bm25_weight: &BM25Weight,
     ) -> Score {
-        let (block_max_score_cache, skip_reader, doc_decoder, freq_decoder) = (
-            &mut self.block_max_score_cache,
-            &self.skip_reader,
-            &self.doc_decoder,
-            &self.freq_decoder,
-        );
-        *block_max_score_cache.get_or_insert_with(|| {
-            skip_reader
-                .block_max_score(bm25_weight)
-                .or_else(|| {
-                    let docs = doc_decoder.output_array();
-                    let freqs = freq_decoder.output_array();
-                    max_f32(docs.iter().cloned().zip(freqs.iter().cloned()).map(
-                        |(doc, term_freq)| {
-                            let fieldnorm_id = fieldnorm_reader.fieldnorm_id(doc);
-                            bm25_weight.score(fieldnorm_id, term_freq)
-                        },
-                    ))
-                })
-                .unwrap_or(0f32)
-        })
+        if let Some(score) = self.block_max_score_cache {
+            return score;
+        }
+        if let Some(skip_reader_max_score) = self.skip_reader.block_max_score(bm25_weight) {
+            // if we are on a full block, the skip reader should have the block max information
+            // for us
+            self.block_max_score_cache = Some(skip_reader_max_score);
+            return skip_reader_max_score;
+        }
+        // this is the last block of the segment posting list.
+        // If it is actually loaded, we can compute block max manually.
+        if self.block_is_loaded() {
+            let docs = self.doc_decoder.output_array().iter().cloned();
+            let freqs = self.freq_decoder.output_array().iter().cloned();
+            let bm25_scores = docs.zip(freqs).map(|(doc, term_freq)| {
+                let fieldnorm_id = fieldnorm_reader.fieldnorm_id(doc);
+                bm25_weight.score(fieldnorm_id, term_freq)
+            });
+            let block_max_score = max_score(bm25_scores).unwrap_or(0.0);
+            self.block_max_score_cache = Some(block_max_score);
+            return block_max_score;
+        }
+        // We do not have access to any good block max value. We return bm25_weight.max_score()
+        // as it is a valid upperbound.
+        //
+        // We do not cache it however, so that it gets computed when once block is loaded.
+        bm25_weight.max_score()
     }
 
     pub(crate) fn freq_reading_option(&self) -> FreqReadingOption {
@@ -164,6 +175,7 @@ impl BlockSegmentPostings {
     pub(crate) fn reset(&mut self, doc_freq: u32, postings_data: ReadOnlySource) {
         let (skip_data_opt, postings_data) = split_into_skips_and_postings(doc_freq, postings_data);
         self.data = ReadOnlySource::new(postings_data);
+        self.block_max_score_cache = None;
         self.loaded_offset = std::usize::MAX;
         if let Some(skip_data) = skip_data_opt {
             self.skip_reader.reset(skip_data, doc_freq);
@@ -242,7 +254,7 @@ impl BlockSegmentPostings {
     /// If all docs are smaller than target, the block loaded may be empty,
     /// or be the last an incomplete VInt block.
     pub fn seek(&mut self, target_doc: DocId) {
-        self.skip_reader.seek(target_doc);
+        self.shallow_seek(target_doc);
         self.load_block();
     }
 
@@ -257,7 +269,9 @@ impl BlockSegmentPostings {
     /// If all docs are smaller than target, the block loaded may be empty,
     /// or be the last an incomplete VInt block.
     pub(crate) fn shallow_seek(&mut self, target_doc: DocId) {
-        self.skip_reader.seek(target_doc);
+        if self.skip_reader.seek(target_doc) {
+            self.block_max_score_cache = None;
+        }
     }
 
     pub(crate) fn block_is_loaded(&self) -> bool {
@@ -265,7 +279,6 @@ impl BlockSegmentPostings {
     }
 
     pub(crate) fn load_block(&mut self) {
-        self.block_max_score_cache = None;
         let offset = self.skip_reader.byte_offset();
         if self.loaded_offset == offset {
             return;
@@ -318,6 +331,7 @@ impl BlockSegmentPostings {
     /// Returns false iff there was no remaining blocks.
     pub fn advance(&mut self) {
         self.skip_reader.advance();
+        self.block_max_score_cache = None;
         self.load_block();
     }
 
@@ -460,21 +474,19 @@ mod tests {
     }
 
     #[test]
-    fn test_block_segment_postings_seek2() {
+    fn test_block_segment_postings_seek() {
         let mut docs = vec![0];
         for i in 0..1300 {
             docs.push((i * i / 100) + i);
         }
         let mut block_postings = build_block_postings(&docs[..]);
         for i in vec![0, 424, 10000] {
-            block_postings.shallow_seek(i);
-            block_postings.load_block();
+            block_postings.seek(i);
             let docs = block_postings.docs();
             assert!(docs[0] <= i);
             assert!(docs.last().cloned().unwrap_or(0u32) >= i);
         }
-        block_postings.shallow_seek(100_000);
-        block_postings.load_block();
+        block_postings.seek(100_000);
         assert_eq!(block_postings.doc(COMPRESSION_BLOCK_SIZE - 1), TERMINATED);
     }
 

src/postings/compression/mod.rs

@@ -1,5 +1,4 @@
 use crate::common::FixedSize;
-use crate::docset::TERMINATED;
 use bitpacking::{BitPacker, BitPacker4x};
 
 pub const COMPRESSION_BLOCK_SIZE: usize = BitPacker4x::BLOCK_LEN;
@@ -53,8 +52,10 @@ impl BlockEncoder {
 /// We ensure that the OutputBuffer is align on 128 bits
 /// in order to run SSE2 linear search on it.
 #[repr(align(128))]
+#[derive(Clone)]
 pub(crate) struct AlignedBuffer(pub [u32; COMPRESSION_BLOCK_SIZE]);
 
+#[derive(Clone)]
 pub struct BlockDecoder {
     bitpacker: BitPacker4x,
     output: AlignedBuffer,
@@ -107,10 +108,6 @@ impl BlockDecoder {
     pub fn output(&self, idx: usize) -> u32 {
         self.output.0[idx]
     }
-
-    pub fn fill(&mut self, val: u32) {
-        self.output.0.iter_mut().for_each(|el| *el = val);
-    }
 }
 
 pub trait VIntEncoder {
@@ -147,11 +144,14 @@ pub trait VIntDecoder {
     /// For instance, if delta encoded are `1, 3, 9`, and the
     /// `offset` is 5, then the output will be:
     /// `5 + 1 = 6, 6 + 3= 9, 9 + 9 = 18`
+    ///
+    /// The value given in `padding` will be used to fill the remaining `128 - num_els` values.
     fn uncompress_vint_sorted(
         &mut self,
         compressed_data: &[u8],
         offset: u32,
         num_els: usize,
+        padding: u32,
     ) -> usize;
 
     /// Uncompress an array of `u32s`, compressed using variable
@@ -159,7 +159,14 @@ pub trait VIntDecoder {
     ///
     /// The method takes a number of int to decompress, and returns
     /// the amount of bytes that were read to decompress them.
-    fn uncompress_vint_unsorted(&mut self, compressed_data: &[u8], num_els: usize) -> usize;
+    ///
+    /// The value given in `padding` will be used to fill the remaining `128 - num_els` values.
+    fn uncompress_vint_unsorted(
+        &mut self,
+        compressed_data: &[u8],
+        num_els: usize,
+        padding: u32,
+    ) -> usize;
 }
 
 impl VIntEncoder for BlockEncoder {
@@ -178,13 +185,21 @@ impl VIntDecoder for BlockDecoder {
         compressed_data: &[u8],
         offset: u32,
         num_els: usize,
+        padding: u32,
     ) -> usize {
         self.output_len = num_els;
+        self.output.0.iter_mut().for_each(|el| *el = padding);
         vint::uncompress_sorted(compressed_data, &mut self.output.0[..num_els], offset)
     }
 
-    fn uncompress_vint_unsorted(&mut self, compressed_data: &[u8], num_els: usize) -> usize {
+    fn uncompress_vint_unsorted(
+        &mut self,
+        compressed_data: &[u8],
+        num_els: usize,
+        padding: u32,
+    ) -> usize {
         self.output_len = num_els;
+        self.output.0.iter_mut().for_each(|el| *el = padding);
         vint::uncompress_unsorted(compressed_data, &mut self.output.0[..num_els])
     }
 }
@@ -193,6 +208,7 @@ impl VIntDecoder for BlockDecoder {
 pub mod tests {
 
     use super::*;
+    use crate::TERMINATED;
 
     #[test]
     fn test_encode_sorted_block() {
@@ -271,18 +287,20 @@ pub mod tests {
     }
     #[test]
     fn test_encode_vint() {
-        {
-            let expected_length = 154;
-            let mut encoder = BlockEncoder::new();
-            let input: Vec<u32> = (0u32..123u32).map(|i| 4 + i * 7 / 2).into_iter().collect();
-            for offset in &[0u32, 1u32, 2u32] {
-                let encoded_data = encoder.compress_vint_sorted(&input, *offset);
-                assert!(encoded_data.len() <= expected_length);
-                let mut decoder = BlockDecoder::default();
-                let consumed_num_bytes =
-                    decoder.uncompress_vint_sorted(&encoded_data, *offset, input.len());
-                assert_eq!(consumed_num_bytes, encoded_data.len());
-                assert_eq!(input, decoder.output_array());
+        const PADDING_VALUE: u32 = 234_234_345u32;
+        let expected_length = 154;
+        let mut encoder = BlockEncoder::new();
+        let input: Vec<u32> = (0u32..123u32).map(|i| 4 + i * 7 / 2).into_iter().collect();
+        for offset in &[0u32, 1u32, 2u32] {
+            let encoded_data = encoder.compress_vint_sorted(&input, *offset);
+            assert!(encoded_data.len() <= expected_length);
+            let mut decoder = BlockDecoder::default();
+            let consumed_num_bytes =
+                decoder.uncompress_vint_sorted(&encoded_data, *offset, input.len(), PADDING_VALUE);
+            assert_eq!(consumed_num_bytes, encoded_data.len());
+            assert_eq!(input, decoder.output_array());
+            for i in input.len()..COMPRESSION_BLOCK_SIZE {
+                assert_eq!(decoder.output(i), PADDING_VALUE);
             }
         }
     }

src/postings/mod.rs

@@ -65,47 +65,42 @@ pub mod tests {
     use std::iter;
 
     #[test]
-    pub fn test_position_write() {
+    pub fn test_position_write() -> crate::Result<()> {
         let mut schema_builder = Schema::builder();
         let text_field = schema_builder.add_text_field("text", TEXT);
         let schema = schema_builder.build();
         let index = Index::create_in_ram(schema);
         let mut segment = index.new_segment();
-        let mut posting_serializer = InvertedIndexSerializer::open(&mut segment).unwrap();
-        {
-            let mut field_serializer = posting_serializer
-                .new_field(text_field, 120 * 4, None)
-                .unwrap();
-            field_serializer.new_term("abc".as_bytes(), 12u32).unwrap();
-            for doc_id in 0u32..120u32 {
-                let delta_positions = vec![1, 2, 3, 2];
-                field_serializer
-                    .write_doc(doc_id, 4, &delta_positions)
-                    .unwrap();
-            }
-            field_serializer.close_term().unwrap();
+        let mut posting_serializer = InvertedIndexSerializer::open(&mut segment)?;
+        let mut field_serializer = posting_serializer.new_field(text_field, 120 * 4, None)?;
+        field_serializer.new_term("abc".as_bytes(), 12u32)?;
+        for doc_id in 0u32..120u32 {
+            let delta_positions = vec![1, 2, 3, 2];
+            field_serializer.write_doc(doc_id, 4, &delta_positions)?;
         }
-        posting_serializer.close().unwrap();
-        let read = segment.open_read(SegmentComponent::POSITIONS).unwrap();
+        field_serializer.close_term()?;
+        posting_serializer.close()?;
+        let read = segment.open_read(SegmentComponent::POSITIONS)?;
         assert!(read.len() <= 140);
+        Ok(())
     }
 
     #[test]
-    pub fn test_skip_positions() {
+    pub fn test_skip_positions() -> crate::Result<()> {
         let mut schema_builder = Schema::builder();
         let title = schema_builder.add_text_field("title", TEXT);
         let schema = schema_builder.build();
         let index = Index::create_in_ram(schema);
-        let mut index_writer = index.writer_with_num_threads(1, 30_000_000).unwrap();
+        let mut index_writer = index.writer_with_num_threads(1, 30_000_000)?;
         index_writer.add_document(doc!(title => r#"abc abc abc"#));
         index_writer.add_document(doc!(title => r#"abc be be be be abc"#));
         for _ in 0..1_000 {
             index_writer.add_document(doc!(title => r#"abc abc abc"#));
         }
         index_writer.add_document(doc!(title => r#"abc be be be be abc"#));
-        index_writer.commit().unwrap();
+        index_writer.commit()?;
 
-        let searcher = index.reader().unwrap().searcher();
+        let searcher = index.reader()?.searcher();
         let inverted_index = searcher.segment_reader(0u32).inverted_index(title);
         let term = Term::from_field_text(title, "abc");
         let mut positions = Vec::new();
@@ -160,6 +155,7 @@ pub mod tests {
             postings.positions(&mut positions);
             assert_eq!(&[0, 5], &positions[..]);
         }
+        Ok(())
     }
 
     #[test]

src/postings/recorder.rs

@@ -75,7 +75,9 @@ pub(crate) trait Recorder: Copy + 'static {
         serializer: &mut FieldSerializer<'_>,
         heap: &MemoryArena,
     ) -> io::Result<()>;
-    /// Returns the number of document containg this term.
+    /// Returns the number of document containing this term.
+    ///
+    /// Returns `None` if not available.
     fn term_doc_freq(&self) -> Option<u32>;
 }
 

src/postings/segment_postings.rs

@@ -10,10 +10,10 @@ use crate::postings::BlockSearcher;
 use crate::postings::Postings;
 
 use crate::schema::IndexRecordOption;
-use crate::DocId;
+use crate::{DocId, TERMINATED};
 
 use crate::directory::ReadOnlySource;
-use crate::fieldnorm::FieldNormReader;
+use crate::fastfield::DeleteBitSet;
 use crate::postings::BlockSegmentPostings;
 
 /// `SegmentPostings` represents the inverted list or postings associated to
@@ -21,6 +21,7 @@ use crate::postings::BlockSegmentPostings;
 ///
 /// As we iterate through the `SegmentPostings`, the frequencies are optionally decoded.
 /// Positions on the other hand, are optionally entirely decoded upfront.
+#[derive(Clone)]
 pub struct SegmentPostings {
     pub(crate) block_cursor: BlockSegmentPostings,
     cur: usize,
@@ -39,6 +40,25 @@ impl SegmentPostings {
         }
     }
 
+    /// Compute the number of non-deleted documents.
+    ///
+    /// This method will clone and scan through the posting lists.
+    /// (this is a rather expensive operation).
+    pub fn doc_freq_given_deletes(&self, delete_bitset: &DeleteBitSet) -> u32 {
+        let mut docset = self.clone();
+        let mut doc_freq = 0;
+        loop {
+            let doc = docset.doc();
+            if doc == TERMINATED {
+                return doc_freq;
+            }
+            if delete_bitset.is_alive(doc) {
+                doc_freq += 1u32;
+            }
+            docset.advance();
+        }
+    }
+
     /// Returns the overall number of documents in the block postings.
     /// It does not take in account whether documents are deleted or not.
     pub fn doc_freq(&self) -> u32 {
@@ -56,7 +76,8 @@ impl SegmentPostings {
     pub fn create_from_docs(docs: &[u32]) -> SegmentPostings {
         let mut buffer = Vec::new();
         {
-            let mut postings_serializer = PostingsSerializer::new(&mut buffer, false, false, None);
+            let mut postings_serializer =
+                PostingsSerializer::new(&mut buffer, 0.0, false, false, None);
             postings_serializer.new_term(docs.len() as u32);
             for &doc in docs {
                 postings_serializer.write_doc(doc, 1u32);
@@ -75,26 +96,48 @@ impl SegmentPostings {
     }
 
     /// Helper functions to create `SegmentPostings` for tests.
+    #[cfg(test)]
     pub fn create_from_docs_and_tfs(
         doc_and_tfs: &[(u32, u32)],
-        fieldnorm_reader: Option<FieldNormReader>,
-    ) -> crate::Result<SegmentPostings> {
-        let mut buffer = Vec::new();
-        let mut postings_serializer =
-            PostingsSerializer::new(&mut buffer, true, false, fieldnorm_reader);
+        fieldnorms: Option<&[u32]>,
+    ) -> SegmentPostings {
+        use crate::fieldnorm::FieldNormReader;
+        use crate::Score;
+        let mut buffer: Vec<u8> = Vec::new();
+        let fieldnorm_reader = fieldnorms.map(FieldNormReader::for_test);
+        let average_field_norm = fieldnorms
+            .map(|fieldnorms| {
+                if fieldnorms.len() == 0 {
+                    return 0.0;
+                }
+                let total_num_tokens: u64 = fieldnorms
+                    .iter()
+                    .map(|&fieldnorm| fieldnorm as u64)
+                    .sum::<u64>();
+                total_num_tokens as Score / fieldnorms.len() as f32
+            })
+            .unwrap_or(0.0);
+        let mut postings_serializer = PostingsSerializer::new(
+            &mut buffer,
+            average_field_norm,
+            true,
+            false,
+            fieldnorm_reader,
+        );
         postings_serializer.new_term(doc_and_tfs.len() as u32);
         for &(doc, tf) in doc_and_tfs {
             postings_serializer.write_doc(doc, tf);
         }
         postings_serializer
-            .close_term(doc_and_tfs.len() as u32)?;
+            .close_term(doc_and_tfs.len() as u32)
+            .unwrap();
         let block_segment_postings = BlockSegmentPostings::from_data(
             doc_and_tfs.len() as u32,
             ReadOnlySource::from(buffer),
             IndexRecordOption::WithFreqs,
             IndexRecordOption::WithFreqs,
         );
-        Ok(SegmentPostings::from_block_postings(block_segment_postings, None))
+        SegmentPostings::from_block_postings(block_segment_postings, None)
     }
 
     /// Reads a Segment postings from an &[u8]
@@ -121,7 +164,7 @@ impl DocSet for SegmentPostings {
     // next needs to be called a first time to point to the correct element.
     #[inline]
     fn advance(&mut self) -> DocId {
-        assert!(self.block_cursor.block_is_loaded());
+        debug_assert!(self.block_cursor.block_is_loaded());
         if self.cur == COMPRESSION_BLOCK_SIZE - 1 {
             self.cur = 0;
             self.block_cursor.advance();
@@ -228,6 +271,7 @@ mod tests {
     use crate::common::HasLen;
 
     use crate::docset::{DocSet, TERMINATED};
+    use crate::fastfield::DeleteBitSet;
     use crate::postings::postings::Postings;
 
     #[test]
@@ -250,4 +294,14 @@ mod tests {
         let postings = SegmentPostings::empty();
         assert_eq!(postings.term_freq(), 1);
     }
+
+    #[test]
+    fn test_doc_freq() {
+        let docs = SegmentPostings::create_from_docs(&[0, 2, 10]);
+        assert_eq!(docs.doc_freq(), 3);
+        let delete_bitset = DeleteBitSet::for_test(&[2], 12);
+        assert_eq!(docs.doc_freq_given_deletes(&delete_bitset), 2);
+        let all_deleted = DeleteBitSet::for_test(&[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11], 12);
+        assert_eq!(docs.doc_freq_given_deletes(&all_deleted), 0);
+    }
 }

src/postings/serializer.rs

@@ -11,7 +11,7 @@ use crate::query::BM25Weight;
 use crate::schema::Schema;
 use crate::schema::{Field, FieldEntry, FieldType};
 use crate::termdict::{TermDictionaryBuilder, TermOrdinal};
-use crate::DocId;
+use crate::{DocId, Score};
 use std::cmp::Ordering;
 use std::io::{self, Write};
 
@@ -97,12 +97,12 @@ impl InvertedIndexSerializer {
         let field_entry: &FieldEntry = self.schema.get_field_entry(field);
         let term_dictionary_write = self.terms_write.for_field(field);
         let postings_write = self.postings_write.for_field(field);
-        total_num_tokens.serialize(postings_write)?;
         let positions_write = self.positions_write.for_field(field);
         let positionsidx_write = self.positionsidx_write.for_field(field);
         let field_type: FieldType = (*field_entry.field_type()).clone();
         FieldSerializer::create(
             &field_type,
+            total_num_tokens,
             term_dictionary_write,
             postings_write,
             positions_write,
@@ -135,12 +135,14 @@ pub struct FieldSerializer<'a> {
 impl<'a> FieldSerializer<'a> {
     fn create(
         field_type: &FieldType,
+        total_num_tokens: u64,
         term_dictionary_write: &'a mut CountingWriter<WritePtr>,
         postings_write: &'a mut CountingWriter<WritePtr>,
         positions_write: &'a mut CountingWriter<WritePtr>,
         positionsidx_write: &'a mut CountingWriter<WritePtr>,
         fieldnorm_reader: Option<FieldNormReader>,
     ) -> io::Result<FieldSerializer<'a>> {
+        total_num_tokens.serialize(postings_write)?;
         let (term_freq_enabled, position_enabled): (bool, bool) = match field_type {
             FieldType::Str(ref text_options) => {
                 if let Some(text_indexing_options) = text_options.get_indexing_options() {
@@ -153,8 +155,13 @@ impl<'a> FieldSerializer<'a> {
             _ => (false, false),
         };
         let term_dictionary_builder = TermDictionaryBuilder::create(term_dictionary_write)?;
+        let average_fieldnorm = fieldnorm_reader
+            .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,
             term_freq_enabled,
             position_enabled,
             fieldnorm_reader,
@@ -197,6 +204,7 @@ impl<'a> FieldSerializer<'a> {
             !self.term_open,
             "Called new_term, while the previous term was not closed."
         );
+
         self.term_open = true;
         self.postings_serializer.clear();
         self.current_term_info = self.current_term_info();
@@ -322,29 +330,18 @@ pub struct PostingsSerializer<W: Write> {
     bm25_weight: Option<BM25Weight>,
 
     num_docs: u32, // Number of docs in the segment
-    avg_fieldnorm: f32, // Average number of term in the field for that segment.
+    avg_fieldnorm: Score, // Average number of term in the field for that segment.
                    // this value is used to compute the block wand information.
 }
 
-fn get_avg_fieldnorm(fieldnorm_reader: &FieldNormReader) -> f32 {
-    let num_docs = fieldnorm_reader.num_docs();
-    let sum_fieldnorm: f32 = (0u32..num_docs)
-        .map(|doc| fieldnorm_reader.fieldnorm(doc) as f32)
-        .sum();
-    sum_fieldnorm / (num_docs as f32)
-}
-
 impl<W: Write> PostingsSerializer<W> {
     pub fn new(
         write: W,
+        avg_fieldnorm: Score,
         termfreq_enabled: bool,
         termfreq_sum_enabled: bool,
         fieldnorm_reader: Option<FieldNormReader>,
     ) -> PostingsSerializer<W> {
-        let avg_fieldnorm: f32 = fieldnorm_reader
-            .as_ref()
-            .map(get_avg_fieldnorm)
-            .unwrap_or(0f32);
         let num_docs = fieldnorm_reader
             .as_ref()
             .map(|fieldnorm_reader| fieldnorm_reader.num_docs())
@@ -403,16 +400,14 @@ impl<W: Write> PostingsSerializer<W> {
                 let sum_freq = self.block.term_freqs().iter().cloned().sum();
                 self.skip_write.write_total_term_freq(sum_freq);
             }
-            let mut blockwand_params_opt = None;
+            let mut blockwand_params = (0u8, 0u32);
             if let Some(bm25_weight) = self.bm25_weight.as_ref() {
                 if let Some(fieldnorm_reader) = self.fieldnorm_reader.as_ref() {
-                    let docs = self.block.doc_ids();
-                    let term_freqs = self.block.term_freqs();
-                    blockwand_params_opt = docs
-                        .iter()
-                        .cloned()
-                        .map(|doc| fieldnorm_reader.fieldnorm_id(doc))
-                        .zip(term_freqs.iter().cloned())
+                    let docs = self.block.doc_ids().iter().cloned();
+                    let term_freqs = self.block.term_freqs().iter().cloned();
+                    let fieldnorms = docs.map(|doc| fieldnorm_reader.fieldnorm_id(doc));
+                    blockwand_params = fieldnorms
+                        .zip(term_freqs)
                         .max_by(
                             |(left_fieldnorm_id, left_term_freq),
                              (right_fieldnorm_id, right_term_freq)| {
@@ -424,10 +419,11 @@ impl<W: Write> PostingsSerializer<W> {
                                     .partial_cmp(&right_score)
                                     .unwrap_or(Ordering::Equal)
                             },
-                        );
+                        )
+                        .unwrap();
                 }
             }
-            let (fieldnorm_id, term_freq) = blockwand_params_opt.unwrap_or((0u8, 0u32));
+            let (fieldnorm_id, term_freq) = blockwand_params;
             self.skip_write.write_blockwand_max(fieldnorm_id, term_freq);
         }
         self.block.clear();

src/postings/skip.rs

@@ -1,4 +1,4 @@
-use crate::common::{BinarySerializable, VInt};
+use crate::common::{read_u32_vint_no_advance, serialize_vint_u32, BinarySerializable, VInt};
 use crate::directory::ReadOnlySource;
 use crate::postings::compression::{compressed_block_size, COMPRESSION_BLOCK_SIZE};
 use crate::query::BM25Weight;
@@ -43,7 +43,9 @@ impl SkipSerializer {
 
     pub fn write_blockwand_max(&mut self, fieldnorm_id: u8, term_freq: u32) {
         self.buffer.push(fieldnorm_id);
-        VInt(term_freq as u64).serialize_into_vec(&mut self.buffer);
+        let mut buf = [0u8; 8];
+        let bytes = serialize_vint_u32(term_freq, &mut buf);
+        self.buffer.extend_from_slice(bytes);
     }
 
     pub fn data(&self) -> &[u8] {
@@ -56,6 +58,7 @@ impl SkipSerializer {
     }
 }
 
+#[derive(Clone)]
 pub(crate) struct SkipReader {
     last_doc_in_block: DocId,
     pub(crate) last_doc_in_previous_block: DocId,
@@ -69,7 +72,7 @@ pub(crate) struct SkipReader {
     position_offset: u64,
 }
 
-#[derive(Clone, Copy, Debug)]
+#[derive(Clone, Eq, PartialEq, Copy, Debug)]
 pub(crate) enum BlockInfo {
     BitPacked {
         doc_num_bits: u8,
@@ -128,6 +131,10 @@ impl SkipReader {
         }
     }
 
+    // Returns the block max score for this block if available.
+    //
+    // The block max score is available for all full bitpacked block,
+    // but no available for the last VInt encoded incomplete block.
     pub fn block_max_score(&self, bm25_weight: &BM25Weight) -> Option<Score> {
         match self.block_info {
             BlockInfo::BitPacked {
@@ -169,9 +176,9 @@ impl SkipReader {
             IndexRecordOption::WithFreqs => {
                 let tf_num_bits = self.owned_read.get(1);
                 let block_wand_fieldnorm_id = self.owned_read.get(2);
-                self.owned_read.advance(3);
-                let block_wand_term_freq =
-                    VInt::deserialize_u64(&mut self.owned_read).unwrap() as u32;
+                let data = &self.owned_read.as_ref()[3..];
+                let (block_wand_term_freq, num_bytes) = read_u32_vint_no_advance(data);
+                self.owned_read.advance(3 + num_bytes);
                 self.block_info = BlockInfo::BitPacked {
                     doc_num_bits,
                     tf_num_bits,
@@ -207,9 +214,15 @@ impl SkipReader {
     ///
     /// If the target is larger than all documents, the skip_reader
     /// then advance to the last Variable In block.
-    pub fn seek(&mut self, target: DocId) {
-        while self.last_doc_in_block() < target {
+    pub fn seek(&mut self, target: DocId) -> bool {
+        if self.last_doc_in_block() >= target {
+            return false;
+        }
+        loop {
             self.advance();
+            if self.last_doc_in_block() >= target {
+                return true;
+            }
         }
     }
 
@@ -225,7 +238,7 @@ impl SkipReader {
                 self.byte_offset += compressed_block_size(doc_num_bits + tf_num_bits);
                 self.position_offset += tf_sum as u64;
             }
-            BlockInfo::VInt { num_docs} => {
+            BlockInfo::VInt { num_docs } => {
                 debug_assert_eq!(num_docs, self.remaining_docs);
                 self.remaining_docs = 0;
                 self.byte_offset = std::usize::MAX;
@@ -236,7 +249,9 @@ impl SkipReader {
             self.read_block_info();
         } else {
             self.last_doc_in_block = TERMINATED;
-            self.block_info = BlockInfo::VInt { num_docs: self.remaining_docs };
+            self.block_info = BlockInfo::VInt {
+                num_docs: self.remaining_docs,
+            };
         }
     }
 }
@@ -269,7 +284,7 @@ mod tests {
             IndexRecordOption::WithFreqs,
         );
         assert_eq!(skip_reader.last_doc_in_block(), 1u32);
-        assert!(matches!(
+        assert_eq!(
             skip_reader.block_info,
             BlockInfo::BitPacked {
                 doc_num_bits: 2u8,
@@ -278,10 +293,10 @@ mod tests {
                 block_wand_fieldnorm_id: 13,
                 block_wand_term_freq: 3
             }
-       ));
+        );
         skip_reader.advance();
         assert_eq!(skip_reader.last_doc_in_block(), 5u32);
-        assert!(matches!(
+        assert_eq!(
             skip_reader.block_info(),
             BlockInfo::BitPacked {
                 doc_num_bits: 5u8,
@@ -290,13 +305,13 @@ mod tests {
                 block_wand_fieldnorm_id: 8,
                 block_wand_term_freq: 2
             }
-       ));
+        );
         skip_reader.advance();
-        assert!(matches!(skip_reader.block_info(), BlockInfo::VInt { num_docs: 3u32 }));
+        assert_eq!(skip_reader.block_info(), BlockInfo::VInt { num_docs: 3u32 });
         skip_reader.advance();
-        assert!(matches!(skip_reader.block_info(), BlockInfo::VInt { num_docs: 0u32 }));
+        assert_eq!(skip_reader.block_info(), BlockInfo::VInt { num_docs: 0u32 });
         skip_reader.advance();
-        assert!(matches!(skip_reader.block_info(), BlockInfo::VInt { num_docs: 0u32 }));
+        assert_eq!(skip_reader.block_info(), BlockInfo::VInt { num_docs: 0u32 });
     }
 
     #[test]
@@ -314,7 +329,7 @@ mod tests {
             IndexRecordOption::Basic,
         );
         assert_eq!(skip_reader.last_doc_in_block(), 1u32);
-        assert!(matches!(
+        assert_eq!(
             skip_reader.block_info(),
             BlockInfo::BitPacked {
                 doc_num_bits: 2u8,
@@ -323,10 +338,10 @@ mod tests {
                 block_wand_fieldnorm_id: 0,
                 block_wand_term_freq: 0
             }
-        ));
+        );
         skip_reader.advance();
         assert_eq!(skip_reader.last_doc_in_block(), 5u32);
-        assert!(matches!(
+        assert_eq!(
             skip_reader.block_info(),
             BlockInfo::BitPacked {
                 doc_num_bits: 5u8,
@@ -335,13 +350,13 @@ mod tests {
                 block_wand_fieldnorm_id: 0,
                 block_wand_term_freq: 0
             }
-        ));
+        );
         skip_reader.advance();
-        assert!(matches!(skip_reader.block_info(), BlockInfo::VInt { num_docs: 3u32 }));
+        assert_eq!(skip_reader.block_info(), BlockInfo::VInt { num_docs: 3u32 });
         skip_reader.advance();
-        assert!(matches!(skip_reader.block_info(), BlockInfo::VInt { num_docs: 0u32 }));
+        assert_eq!(skip_reader.block_info(), BlockInfo::VInt { num_docs: 0u32 });
         skip_reader.advance();
-        assert!(matches!(skip_reader.block_info(), BlockInfo::VInt { num_docs: 0u32 }));
+        assert_eq!(skip_reader.block_info(), BlockInfo::VInt { num_docs: 0u32 });
     }
 
     #[test]
@@ -358,7 +373,7 @@ mod tests {
             IndexRecordOption::Basic,
         );
         assert_eq!(skip_reader.last_doc_in_block(), 1u32);
-        assert!(matches!(
+        assert_eq!(
             skip_reader.block_info(),
             BlockInfo::BitPacked {
                 doc_num_bits: 2u8,
@@ -367,8 +382,8 @@ mod tests {
                 block_wand_fieldnorm_id: 0,
                 block_wand_term_freq: 0
             }
-        ));
+        );
         skip_reader.advance();
-        assert!(matches!(skip_reader.block_info(), BlockInfo::VInt { num_docs: 0u32 }));
+        assert_eq!(skip_reader.block_info(), BlockInfo::VInt { num_docs: 0u32 });
     }
 }

src/query/all_query.rs

@@ -9,7 +9,7 @@ use crate::Score;
 
 /// Query that matches all of the documents.
 ///
-/// All of the document get the score 1f32.
+/// All of the document get the score 1.0.
 #[derive(Clone, Debug)]
 pub struct AllQuery;
 
@@ -23,7 +23,7 @@ impl Query for AllQuery {
 pub struct AllWeight;
 
 impl Weight for AllWeight {
-    fn scorer(&self, reader: &SegmentReader, boost: f32) -> crate::Result<Box<dyn Scorer>> {
+    fn scorer(&self, reader: &SegmentReader, boost: Score) -> crate::Result<Box<dyn Scorer>> {
         let all_scorer = AllScorer {
             doc: 0u32,
             max_doc: reader.max_doc(),
@@ -35,7 +35,7 @@ impl Weight for AllWeight {
         if doc >= reader.max_doc() {
             return Err(does_not_match(doc));
         }
-        Ok(Explanation::new("AllQuery", 1f32))
+        Ok(Explanation::new("AllQuery", 1.0))
     }
 }
 
@@ -66,7 +66,7 @@ impl DocSet for AllScorer {
 
 impl Scorer for AllScorer {
     fn score(&mut self) -> Score {
-        1f32
+        1.0
     }
 }
 
@@ -100,7 +100,7 @@ mod tests {
         let weight = AllQuery.weight(&searcher, false).unwrap();
         {
             let reader = searcher.segment_reader(0);
-            let mut scorer = weight.scorer(reader, 1.0f32).unwrap();
+            let mut scorer = weight.scorer(reader, 1.0).unwrap();
             assert_eq!(scorer.doc(), 0u32);
             assert_eq!(scorer.advance(), 1u32);
             assert_eq!(scorer.doc(), 1u32);
@@ -108,7 +108,7 @@ mod tests {
         }
         {
             let reader = searcher.segment_reader(1);
-            let mut scorer = weight.scorer(reader, 1.0f32).unwrap();
+            let mut scorer = weight.scorer(reader, 1.0).unwrap();
             assert_eq!(scorer.doc(), 0u32);
             assert_eq!(scorer.advance(), TERMINATED);
         }
@@ -122,14 +122,14 @@ mod tests {
         let weight = AllQuery.weight(&searcher, false).unwrap();
         let reader = searcher.segment_reader(0);
         {
-            let mut scorer = weight.scorer(reader, 2.0f32).unwrap();
+            let mut scorer = weight.scorer(reader, 2.0).unwrap();
             assert_eq!(scorer.doc(), 0u32);
-            assert_eq!(scorer.score(), 2.0f32);
+            assert_eq!(scorer.score(), 2.0);
         }
         {
-            let mut scorer = weight.scorer(reader, 1.5f32).unwrap();
+            let mut scorer = weight.scorer(reader, 1.5).unwrap();
             assert_eq!(scorer.doc(), 0u32);
-            assert_eq!(scorer.score(), 1.5f32);
+            assert_eq!(scorer.score(), 1.5);
         }
     }
 }

src/query/automaton_weight.rs

@@ -5,9 +5,9 @@ use crate::query::{BitSetDocSet, Explanation};
 use crate::query::{Scorer, Weight};
 use crate::schema::{Field, IndexRecordOption};
 use crate::termdict::{TermDictionary, TermStreamer};
-use crate::DocId;
 use crate::Result;
 use crate::TantivyError;
+use crate::{DocId, Score};
 use std::sync::Arc;
 use tantivy_fst::Automaton;
 
@@ -40,7 +40,7 @@ impl<A> Weight for AutomatonWeight<A>
 where
     A: Automaton + Send + Sync + 'static,
 {
-    fn scorer(&self, reader: &SegmentReader, boost: f32) -> Result<Box<dyn Scorer>> {
+    fn scorer(&self, reader: &SegmentReader, boost: Score) -> 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);
@@ -67,9 +67,9 @@ where
     }
 
     fn explain(&self, reader: &SegmentReader, doc: DocId) -> Result<Explanation> {
-        let mut scorer = self.scorer(reader, 1.0f32)?;
+        let mut scorer = self.scorer(reader, 1.0)?;
         if scorer.seek(doc) == doc {
-            Ok(Explanation::new("AutomatonScorer", 1.0f32))
+            Ok(Explanation::new("AutomatonScorer", 1.0))
         } else {
             Err(TantivyError::InvalidArgument(
                 "Document does not exist".to_string(),
@@ -144,13 +144,13 @@ mod tests {
         let reader = index.reader().unwrap();
         let searcher = reader.searcher();
         let mut scorer = automaton_weight
-            .scorer(searcher.segment_reader(0u32), 1.0f32)
+            .scorer(searcher.segment_reader(0u32), 1.0)
             .unwrap();
         assert_eq!(scorer.doc(), 0u32);
-        assert_eq!(scorer.score(), 1.0f32);
+        assert_eq!(scorer.score(), 1.0);
         assert_eq!(scorer.advance(), 2u32);
         assert_eq!(scorer.doc(), 2u32);
-        assert_eq!(scorer.score(), 1.0f32);
+        assert_eq!(scorer.score(), 1.0);
         assert_eq!(scorer.advance(), TERMINATED);
     }
 
@@ -162,9 +162,9 @@ mod tests {
         let reader = index.reader().unwrap();
         let searcher = reader.searcher();
         let mut scorer = automaton_weight
-            .scorer(searcher.segment_reader(0u32), 1.32f32)
+            .scorer(searcher.segment_reader(0u32), 1.32)
             .unwrap();
         assert_eq!(scorer.doc(), 0u32);
-        assert_eq!(scorer.score(), 1.32f32);
+        assert_eq!(scorer.score(), 1.32);
     }
 }

src/query/bitset/mod.rs

@@ -61,21 +61,23 @@ impl DocSet for BitSetDocSet {
     }
 
     fn seek(&mut self, target: DocId) -> DocId {
+        if target >= self.docs.max_value() {
+            self.doc = TERMINATED;
+            return TERMINATED;
+        }
         let target_bucket = target / 64u32;
-
-        // Mask for all of the bits greater or equal
-        // to our target document.
         if target_bucket > self.cursor_bucket {
             self.go_to_bucket(target_bucket);
             let greater_filter: TinySet = TinySet::range_greater_or_equal(target);
             self.cursor_tinybitset = self.cursor_tinybitset.intersect(greater_filter);
-            self.advance();
+            self.advance()
+        } else {
+            let mut doc = self.doc();
+            while doc < target {
+                doc = self.advance();
+            }
+            doc
         }
-        let mut doc = self.doc();
-        while doc < target {
-            doc = self.advance();
-        }
-        doc
     }
 
     /// Returns the current document
@@ -114,6 +116,13 @@ mod tests {
         assert_eq!(empty.advance(), TERMINATED)
     }
 
+    #[test]
+    fn test_seek_terminated() {
+        let bitset = BitSet::with_max_value(1000);
+        let mut empty = BitSetDocSet::from(bitset);
+        assert_eq!(empty.seek(TERMINATED), TERMINATED)
+    }
+
     fn test_go_through_sequential(docs: &[DocId]) {
         let mut docset = create_docbitset(docs, 1_000u32);
         for &doc in docs {

src/query/bm25.rs

@@ -6,21 +6,21 @@ use crate::Term;
 use serde::Deserialize;
 use serde::Serialize;
 
-const K1: f32 = 1.2;
-const B: f32 = 0.75;
+const K1: Score = 1.2;
+const B: Score = 0.75;
 
-fn idf(doc_freq: u64, doc_count: u64) -> f32 {
+fn idf(doc_freq: u64, doc_count: u64) -> Score {
     assert!(doc_count >= doc_freq, "{} >= {}", doc_count, doc_freq);
-    let x = ((doc_count - doc_freq) as f32 + 0.5) / (doc_freq as f32 + 0.5);
-    (1f32 + x).ln()
+    let x = ((doc_count - doc_freq) as Score + 0.5) / (doc_freq as Score + 0.5);
+    (1.0 + x).ln()
 }
 
-fn cached_tf_component(fieldnorm: u32, average_fieldnorm: f32) -> f32 {
-    K1 * (1f32 - B + B * fieldnorm as f32 / average_fieldnorm)
+fn cached_tf_component(fieldnorm: u32, average_fieldnorm: Score) -> Score {
+    K1 * (1.0 - B + B * fieldnorm as Score / average_fieldnorm)
 }
 
-fn compute_tf_cache(average_fieldnorm: f32) -> [f32; 256] {
-    let mut cache = [0f32; 256];
+fn compute_tf_cache(average_fieldnorm: Score) -> [Score; 256] {
+    let mut cache: [Score; 256] = [0.0; 256];
     for (fieldnorm_id, cache_mut) in cache.iter_mut().enumerate() {
         let fieldnorm = FieldNormReader::id_to_fieldnorm(fieldnorm_id as u8);
         *cache_mut = cached_tf_component(fieldnorm, average_fieldnorm);
@@ -30,19 +30,20 @@ fn compute_tf_cache(average_fieldnorm: f32) -> [f32; 256] {
 
 #[derive(Clone, PartialEq, Debug, Serialize, Deserialize)]
 pub struct BM25Params {
-    pub idf: f32,
-    pub avg_fieldnorm: f32,
+    pub idf: Score,
+    pub avg_fieldnorm: Score,
 }
 
+#[derive(Clone)]
 pub struct BM25Weight {
     idf_explain: Explanation,
-    weight: f32,
-    cache: [f32; 256],
-    average_fieldnorm: f32,
+    weight: Score,
+    cache: [Score; 256],
+    average_fieldnorm: Score,
 }
 
 impl BM25Weight {
-    pub fn boost_by(&self, boost: f32) -> BM25Weight {
+    pub fn boost_by(&self, boost: Score) -> BM25Weight {
         BM25Weight {
             idf_explain: self.idf_explain.clone(),
             weight: self.weight * boost,
@@ -69,7 +70,7 @@ impl BM25Weight {
             total_num_tokens += inverted_index.total_num_tokens();
             total_num_docs += u64::from(segment_reader.max_doc());
         }
-        let average_fieldnorm = total_num_tokens as f32 / total_num_docs as f32;
+        let average_fieldnorm = total_num_tokens as Score / total_num_docs as Score;
 
         if terms.len() == 1 {
             let term_doc_freq = searcher.doc_freq(&terms[0]);
@@ -81,26 +82,30 @@ impl BM25Weight {
                     let term_doc_freq = searcher.doc_freq(term);
                     idf(term_doc_freq, total_num_docs)
                 })
-                .sum::<f32>();
+                .sum::<Score>();
             let idf_explain = Explanation::new("idf", idf);
             BM25Weight::new(idf_explain, average_fieldnorm)
         }
     }
 
-    pub fn for_one_term(term_doc_freq: u64, total_num_docs: u64, avg_fieldnorm: f32) -> BM25Weight {
+    pub fn for_one_term(
+        term_doc_freq: u64,
+        total_num_docs: u64,
+        avg_fieldnorm: Score,
+    ) -> BM25Weight {
         let idf = idf(term_doc_freq, total_num_docs);
         let mut idf_explain =
             Explanation::new("idf, computed as log(1 + (N - n + 0.5) / (n + 0.5))", idf);
         idf_explain.add_const(
             "n, number of docs containing this term",
-            term_doc_freq as f32,
+            term_doc_freq as Score,
         );
-        idf_explain.add_const("N, total number of docs", total_num_docs as f32);
+        idf_explain.add_const("N, total number of docs", total_num_docs as Score);
         BM25Weight::new(idf_explain, avg_fieldnorm)
     }
 
-    fn new(idf_explain: Explanation, average_fieldnorm: f32) -> BM25Weight {
-        let weight = idf_explain.value() * (1f32 + K1);
+    fn new(idf_explain: Explanation, average_fieldnorm: Score) -> BM25Weight {
+        let weight = idf_explain.value() * (1.0 + K1);
         BM25Weight {
             idf_explain,
             weight,
@@ -119,8 +124,8 @@ impl BM25Weight {
     }
 
     #[inline(always)]
-    pub(crate) fn tf_factor(&self, fieldnorm_id: u8, term_freq: u32) -> f32 {
-        let term_freq = term_freq as f32;
+    pub(crate) fn tf_factor(&self, fieldnorm_id: u8, term_freq: u32) -> Score {
+        let term_freq = term_freq as Score;
         let norm = self.cache[fieldnorm_id as usize];
         term_freq / (term_freq + norm)
     }
@@ -131,7 +136,7 @@ impl BM25Weight {
         let score = self.score(fieldnorm_id, term_freq);
 
         let norm = self.cache[fieldnorm_id as usize];
-        let term_freq = term_freq as f32;
+        let term_freq = term_freq as Score;
         let right_factor = term_freq / (term_freq + norm);
 
         let mut tf_explanation = Explanation::new(
@@ -144,12 +149,12 @@ impl BM25Weight {
         tf_explanation.add_const("b, length normalization parameter", B);
         tf_explanation.add_const(
             "dl, length of field",
-            FieldNormReader::id_to_fieldnorm(fieldnorm_id) as f32,
+            FieldNormReader::id_to_fieldnorm(fieldnorm_id) as Score,
         );
         tf_explanation.add_const("avgdl, average length of field", self.average_fieldnorm);
 
         let mut explanation = Explanation::new("TermQuery, product of...", score);
-        explanation.add_detail(Explanation::new("(K1+1)", K1 + 1f32));
+        explanation.add_detail(Explanation::new("(K1+1)", K1 + 1.0));
         explanation.add_detail(self.idf_explain.clone());
         explanation.add_detail(tf_explanation);
         explanation
@@ -160,10 +165,11 @@ impl BM25Weight {
 mod tests {
 
     use super::idf;
-    use crate::assert_nearly_equals;
+    use crate::{assert_nearly_equals, Score};
 
     #[test]
     fn test_idf() {
-        assert_nearly_equals!(idf(1, 2), std::f32::consts::LN_2);
+        let score: Score = 2.0;
+        assert_nearly_equals!(idf(1, 2), score.ln());
     }
 }

src/query/boolean_query/block_wand.rs

@@ -1,8 +1,21 @@
 use crate::query::term_query::TermScorer;
 use crate::query::Scorer;
 use crate::{DocId, DocSet, Score, TERMINATED};
-use std::ops::DerefMut;
 use std::ops::Deref;
+use std::ops::DerefMut;
+
+fn is_sorted<I: Iterator<Item = DocId>>(mut it: I) -> bool {
+    if let Some(first) = it.next() {
+        let mut prev = first;
+        for doc in it {
+            if doc < prev {
+                return false;
+            }
+            prev = doc;
+        }
+    }
+    true
+}
 
 /// Takes a term_scorers sorted by their current doc() and a threshold and returns
 /// Returns (pivot_len, pivot_ord) defined as follows:
@@ -13,8 +26,11 @@ use std::ops::Deref;
 /// We always have `before_pivot_len` < `pivot_len`.
 ///
 /// None is returned if we establish that no document can exceed the threshold.
-fn find_pivot_doc(term_scorers: &[TermScorerWithMaxScore], threshold: f32) -> Option<(usize, usize, DocId)> {
-    let mut max_score = 0.0f32;
+fn find_pivot_doc(
+    term_scorers: &[TermScorerWithMaxScore],
+    threshold: Score,
+) -> Option<(usize, usize, DocId)> {
+    let mut max_score = 0.0;
     let mut before_pivot_len = 0;
     let mut pivot_doc = TERMINATED;
     while before_pivot_len < term_scorers.len() {
@@ -32,7 +48,8 @@ fn find_pivot_doc(term_scorers: &[TermScorerWithMaxScore], threshold: f32) -> Op
     // Right now i is an ordinal, we want a len.
     let mut pivot_len = before_pivot_len + 1;
     // Some other term_scorer may be positioned on the same document.
-    pivot_len += term_scorers[pivot_len..].iter()
+    pivot_len += term_scorers[pivot_len..]
+        .iter()
         .take_while(|term_scorer| term_scorer.doc() == pivot_doc)
         .count();
     Some((before_pivot_len, pivot_len, pivot_doc))
@@ -40,16 +57,13 @@ fn find_pivot_doc(term_scorers: &[TermScorerWithMaxScore], threshold: f32) -> Op
 
 struct TermScorerWithMaxScore<'a> {
     scorer: &'a mut TermScorer,
-    max_score: f32,
+    max_score: Score,
 }
 
 impl<'a> From<&'a mut TermScorer> for TermScorerWithMaxScore<'a> {
     fn from(scorer: &'a mut TermScorer) -> Self {
         let max_score = scorer.max_score();
-        TermScorerWithMaxScore {
-            scorer,
-            max_score
-        }
+        TermScorerWithMaxScore { scorer, max_score }
     }
 }
 
@@ -61,7 +75,6 @@ impl<'a> Deref for TermScorerWithMaxScore<'a> {
     }
 }
 
-
 impl<'a> DerefMut for TermScorerWithMaxScore<'a> {
     fn deref_mut(&mut self) -> &mut Self::Target {
         self.scorer
@@ -69,7 +82,10 @@ impl<'a> DerefMut for TermScorerWithMaxScore<'a> {
 }
 
 // Before and after calling this method, scorers need to be sorted by their `.doc()`.
-fn block_max_was_too_low_advance_one_scorer(scorers: &mut Vec<TermScorerWithMaxScore>, pivot_len: usize) {
+fn block_max_was_too_low_advance_one_scorer(
+    scorers: &mut Vec<TermScorerWithMaxScore>,
+    pivot_len: usize,
+) {
     let mut scorer_to_seek = pivot_len - 1;
     let mut doc_to_seek_after = scorers[scorer_to_seek].doc();
     for scorer_ord in (0..pivot_len - 1).rev() {
@@ -88,7 +104,6 @@ fn block_max_was_too_low_advance_one_scorer(scorers: &mut Vec<TermScorerWithMaxS
     restore_ordering(scorers, scorer_to_seek);
 }
 
-
 // Given a list of term_scorers and a `ord` and assuming that `term_scorers[ord]` is sorted
 // except term_scorers[ord] that might be in advance compared to its ranks,
 // bubble up term_scorers[ord] in order to restore the ordering.
@@ -100,15 +115,19 @@ fn restore_ordering(term_scorers: &mut Vec<TermScorerWithMaxScore>, ord: usize)
         }
         term_scorers.swap(i, i - 1);
     }
+    debug_assert!(is_sorted(term_scorers.iter().map(|scorer| scorer.doc())));
 }
 
-
 // Attempts to advance all term_scorers between `&term_scorers[0..before_len]` to the pivot.
 // If this works, return true.
 // If this fails (ie: one of the term_scorer does not contain `pivot_doc` and seek goes past the
 // pivot), reorder the term_scorers to ensure the list is still sorted and returns `false`.
 // If a term_scorer reach TERMINATED in the process return false remove the term_scorer and return.
-fn align_scorers(term_scorers: &mut Vec<TermScorerWithMaxScore>, pivot_doc: DocId, before_pivot_len: usize) -> bool {
+fn align_scorers(
+    term_scorers: &mut Vec<TermScorerWithMaxScore>,
+    pivot_doc: DocId,
+    before_pivot_len: usize,
+) -> bool {
     debug_assert_ne!(pivot_doc, TERMINATED);
     for i in (0..before_pivot_len).rev() {
         let new_doc = term_scorers[i].seek(pivot_doc);
@@ -126,16 +145,20 @@ fn align_scorers(term_scorers: &mut Vec<TermScorerWithMaxScore>, pivot_doc: DocI
             return false;
         }
     }
-    return true;
+    true
 }
 
 // Assumes terms_scorers[..pivot_len] are positioned on the same doc (pivot_doc).
 // Advance term_scorers[..pivot_len] and out of these removes the terminated scores.
 // Restores the ordering of term_scorers.
 fn advance_all_scorers_on_pivot(term_scorers: &mut Vec<TermScorerWithMaxScore>, pivot_len: usize) {
+    for term_scorer in &mut term_scorers[..pivot_len] {
+        term_scorer.advance();
+    }
+    // TODO use drain_filter when available.
     let mut i = 0;
-    for _ in 0..pivot_len {
-        if term_scorers[i].advance() == TERMINATED {
+    while i != term_scorers.len() {
+        if term_scorers[i].doc() == TERMINATED {
             term_scorers.swap_remove(i);
         } else {
             i += 1;
@@ -146,17 +169,25 @@ fn advance_all_scorers_on_pivot(term_scorers: &mut Vec<TermScorerWithMaxScore>,
 
 pub fn block_wand(
     mut scorers: Vec<TermScorer>,
-    mut threshold: f32,
+    mut threshold: Score,
     callback: &mut dyn FnMut(u32, Score) -> Score,
 ) {
-    let mut scorers: Vec<TermScorerWithMaxScore> = scorers.iter_mut().map(TermScorerWithMaxScore::from).collect();
+    let mut scorers: Vec<TermScorerWithMaxScore> = scorers
+        .iter_mut()
+        .map(TermScorerWithMaxScore::from)
+        .collect();
     scorers.sort_by_key(|scorer| scorer.doc());
     loop {
         // At this point we need to ensure that the scorers are sorted!
-        if let Some((before_pivot_len, pivot_len, pivot_doc)) = find_pivot_doc(&scorers[..], threshold) {
+        debug_assert!(is_sorted(scorers.iter().map(|scorer| scorer.doc())));
+        if let Some((before_pivot_len, pivot_len, pivot_doc)) =
+            find_pivot_doc(&scorers[..], threshold)
+        {
             debug_assert_ne!(pivot_doc, TERMINATED);
             debug_assert!(before_pivot_len < pivot_len);
-            let block_max_score_upperbound: Score =  scorers[..pivot_len].iter_mut()
+
+            let block_max_score_upperbound: Score = scorers[..pivot_len]
+                .iter_mut()
                 .map(|scorer| {
                     scorer.shallow_seek(pivot_doc);
                     scorer.block_max_score()
@@ -168,7 +199,7 @@ pub fn block_wand(
             //
             // `block_segment_postings.load_block()` need to be called separately.
             if block_max_score_upperbound <= threshold {
-                // Block max condition was not reached.
+                // Block max condition was not reached
                 // We could get away by simply advancing the scorers to DocId + 1 but it would
                 // be inefficient. The optimization requires proper explanation and was
                 // isolated in a different function.
@@ -198,9 +229,204 @@ pub fn block_wand(
             }
             // let's advance all of the scorers that are currently positioned on the pivot.
             advance_all_scorers_on_pivot(&mut scorers, pivot_len);
-
         } else {
             return;
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use crate::query::score_combiner::SumCombiner;
+    use crate::query::term_query::TermScorer;
+    use crate::query::Union;
+    use crate::query::{BM25Weight, Scorer};
+    use crate::{DocId, DocSet, Score, TERMINATED};
+    use proptest::prelude::*;
+    use std::cmp::Ordering;
+    use std::collections::BinaryHeap;
+    use std::iter;
+
+    struct Float(Score);
+    impl Eq for Float {}
+    impl PartialEq for Float {
+        fn eq(&self, other: &Self) -> bool {
+            self.cmp(&other) == Ordering::Equal
+        }
+    }
+    impl PartialOrd for Float {
+        fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+            Some(self.cmp(other))
+        }
+    }
+    impl Ord for Float {
+        fn cmp(&self, other: &Self) -> Ordering {
+            other.0.partial_cmp(&self.0).unwrap_or(Ordering::Equal)
+        }
+    }
+
+    fn nearly_equals(left: Score, right: Score) -> bool {
+        (left - right).abs() < 0.000001 * (left + right).abs()
+    }
+
+    fn compute_checkpoints_for_each_pruning(
+        term_scorers: Vec<TermScorer>,
+        n: usize,
+    ) -> Vec<(DocId, Score)> {
+        let mut heap: BinaryHeap<Float> = BinaryHeap::with_capacity(n);
+        let mut checkpoints: Vec<(DocId, Score)> = Vec::new();
+        let mut limit: Score = 0.0;
+        super::block_wand(term_scorers, Score::MIN, &mut |doc, score| {
+            heap.push(Float(score));
+            if heap.len() > n {
+                heap.pop().unwrap();
+            }
+            if heap.len() == n {
+                limit = heap.peek().unwrap().0;
+            }
+            if !nearly_equals(score, limit) {
+                checkpoints.push((doc, score));
+            }
+            return limit;
+        });
+        checkpoints
+    }
+
+    fn compute_checkpoints_manual(term_scorers: Vec<TermScorer>, n: usize) -> Vec<(DocId, Score)> {
+        let mut heap: BinaryHeap<Float> = BinaryHeap::with_capacity(n);
+        let mut checkpoints: Vec<(DocId, Score)> = Vec::new();
+        let mut scorer: Union<TermScorer, SumCombiner> = Union::from(term_scorers);
+
+        let mut limit = Score::MIN;
+        loop {
+            if scorer.doc() == TERMINATED {
+                break;
+            }
+            let doc = scorer.doc();
+            let score = scorer.score();
+            if score > limit {
+                heap.push(Float(score));
+                if heap.len() > n {
+                    heap.pop().unwrap();
+                }
+                if heap.len() == n {
+                    limit = heap.peek().unwrap().0;
+                }
+                if !nearly_equals(score, limit) {
+                    checkpoints.push((doc, score));
+                }
+            }
+            scorer.advance();
+        }
+        checkpoints
+    }
+
+    const MAX_TERM_FREQ: u32 = 100u32;
+
+    fn posting_list(max_doc: u32) -> BoxedStrategy<Vec<(DocId, u32)>> {
+        (1..max_doc + 1)
+            .prop_flat_map(move |doc_freq| {
+                (
+                    proptest::bits::bitset::sampled(doc_freq as usize, 0..max_doc as usize),
+                    proptest::collection::vec(1u32..MAX_TERM_FREQ, doc_freq as usize),
+                )
+            })
+            .prop_map(|(docset, term_freqs)| {
+                docset
+                    .iter()
+                    .map(|doc| doc as u32)
+                    .zip(term_freqs.iter().cloned())
+                    .collect::<Vec<_>>()
+            })
+            .boxed()
+    }
+
+    fn gen_term_scorers(num_scorers: usize) -> BoxedStrategy<(Vec<Vec<(DocId, u32)>>, Vec<u32>)> {
+        (1u32..100u32)
+            .prop_flat_map(move |max_doc: u32| {
+                (
+                    proptest::collection::vec(posting_list(max_doc), num_scorers),
+                    proptest::collection::vec(2u32..10u32 * MAX_TERM_FREQ, max_doc as usize),
+                )
+            })
+            .boxed()
+    }
+
+    fn test_block_wand_aux(posting_lists: &[Vec<(DocId, u32)>], fieldnorms: &[u32]) {
+        // We virtually repeat all docs 64 times in order to emulate blocks of 2 documents
+        // and surface blogs more easily.
+        const REPEAT: usize = 64;
+        let fieldnorms_expanded = fieldnorms
+            .iter()
+            .cloned()
+            .flat_map(|fieldnorm| iter::repeat(fieldnorm).take(REPEAT))
+            .collect::<Vec<u32>>();
+
+        let postings_lists_expanded: Vec<Vec<(DocId, u32)>> = posting_lists
+            .iter()
+            .map(|posting_list| {
+                posting_list
+                    .into_iter()
+                    .cloned()
+                    .flat_map(|(doc, term_freq)| {
+                        (0 as u32..REPEAT as u32).map(move |offset| {
+                            (
+                                doc * (REPEAT as u32) + offset,
+                                if offset == 0 { term_freq } else { 1 },
+                            )
+                        })
+                    })
+                    .collect::<Vec<(DocId, u32)>>()
+            })
+            .collect::<Vec<_>>();
+
+        let total_fieldnorms: u64 = fieldnorms_expanded
+            .iter()
+            .cloned()
+            .map(|fieldnorm| fieldnorm as u64)
+            .sum();
+        let average_fieldnorm = (total_fieldnorms as Score) / (fieldnorms_expanded.len() as Score);
+        let max_doc = fieldnorms_expanded.len();
+
+        let term_scorers: Vec<TermScorer> = postings_lists_expanded
+            .iter()
+            .map(|postings| {
+                let bm25_weight = BM25Weight::for_one_term(
+                    postings.len() as u64,
+                    max_doc as u64,
+                    average_fieldnorm,
+                );
+                TermScorer::create_for_test(postings, &fieldnorms_expanded[..], bm25_weight)
+            })
+            .collect();
+        for top_k in 1..4 {
+            let checkpoints_for_each_pruning =
+                compute_checkpoints_for_each_pruning(term_scorers.clone(), top_k);
+            let checkpoints_manual = compute_checkpoints_manual(term_scorers.clone(), top_k);
+            assert_eq!(checkpoints_for_each_pruning.len(), checkpoints_manual.len());
+            for (&(left_doc, left_score), &(right_doc, right_score)) in checkpoints_for_each_pruning
+                .iter()
+                .zip(checkpoints_manual.iter())
+            {
+                assert_eq!(left_doc, right_doc);
+                assert!(nearly_equals(left_score, right_score));
+            }
+        }
+    }
+
+    proptest! {
+        #![proptest_config(ProptestConfig::with_cases(500))]
+        #[test]
+        fn test_block_wand_two_term_scorers((posting_lists, fieldnorms) in gen_term_scorers(2)) {
+            test_block_wand_aux(&posting_lists[..], &fieldnorms[..]);
+        }
+    }
+
+    proptest! {
+        #![proptest_config(ProptestConfig::with_cases(500))]
+        #[test]
+        fn test_block_wand_three_term_scorers((posting_lists, fieldnorms) in gen_term_scorers(3)) {
+            test_block_wand_aux(&posting_lists[..], &fieldnorms[..]);
+        }
+    }
+}

src/query/boolean_query/boolean_weight.rs

@@ -78,7 +78,7 @@ impl BooleanWeight {
     fn per_occur_scorers(
         &self,
         reader: &SegmentReader,
-        boost: f32,
+        boost: Score,
     ) -> crate::Result<HashMap<Occur, Vec<Box<dyn Scorer>>>> {
         let mut per_occur_scorers: HashMap<Occur, Vec<Box<dyn Scorer>>> = HashMap::new();
         for &(ref occur, ref subweight) in &self.weights {
@@ -94,7 +94,7 @@ impl BooleanWeight {
     fn complex_scorer<TScoreCombiner: ScoreCombiner>(
         &self,
         reader: &SegmentReader,
-        boost: f32,
+        boost: Score,
     ) -> crate::Result<SpecializedScorer> {
         let mut per_occur_scorers = self.per_occur_scorers(reader, boost)?;
 
@@ -147,7 +147,7 @@ impl BooleanWeight {
 }
 
 impl Weight for BooleanWeight {
-    fn scorer(&self, reader: &SegmentReader, boost: f32) -> crate::Result<Box<dyn Scorer>> {
+    fn scorer(&self, reader: &SegmentReader, boost: Score) -> crate::Result<Box<dyn Scorer>> {
         if self.weights.is_empty() {
             Ok(Box::new(EmptyScorer))
         } else if self.weights.len() == 1 {
@@ -169,12 +169,12 @@ impl Weight for BooleanWeight {
     }
 
     fn explain(&self, reader: &SegmentReader, doc: DocId) -> crate::Result<Explanation> {
-        let mut scorer = self.scorer(reader, 1.0f32)?;
+        let mut scorer = self.scorer(reader, 1.0)?;
         if scorer.seek(doc) != doc {
             return Err(does_not_match(doc));
         }
         if !self.scoring_enabled {
-            return Ok(Explanation::new("BooleanQuery with no scoring", 1f32));
+            return Ok(Explanation::new("BooleanQuery with no scoring", 1.0));
         }
 
         let mut explanation = Explanation::new("BooleanClause. Sum of ...", scorer.score());
@@ -193,7 +193,7 @@ impl Weight for BooleanWeight {
         reader: &SegmentReader,
         callback: &mut dyn FnMut(DocId, Score),
     ) -> crate::Result<()> {
-        let scorer = self.complex_scorer::<SumWithCoordsCombiner>(reader, 1.0f32)?;
+        let scorer = self.complex_scorer::<SumWithCoordsCombiner>(reader, 1.0)?;
         match scorer {
             SpecializedScorer::TermUnion(term_scorers) => {
                 let mut union_scorer =
@@ -219,11 +219,11 @@ impl Weight for BooleanWeight {
     /// important optimization (e.g. BlockWAND for union).
     fn for_each_pruning(
         &self,
-        threshold: f32,
+        threshold: Score,
         reader: &SegmentReader,
         callback: &mut dyn FnMut(DocId, Score) -> Score,
     ) -> crate::Result<()> {
-        let scorer = self.complex_scorer::<SumWithCoordsCombiner>(reader, 1.0f32)?;
+        let scorer = self.complex_scorer::<SumWithCoordsCombiner>(reader, 1.0)?;
         match scorer {
             SpecializedScorer::TermUnion(term_scorers) => {
                 super::block_wand(term_scorers, threshold, callback);

src/query/boolean_query/mod.rs

@@ -61,9 +61,7 @@ mod tests {
         let query = query_parser.parse_query("+a").unwrap();
         let searcher = index.reader().unwrap().searcher();
         let weight = query.weight(&searcher, true).unwrap();
-        let scorer = weight
-            .scorer(searcher.segment_reader(0u32), 1.0f32)
-            .unwrap();
+        let scorer = weight.scorer(searcher.segment_reader(0u32), 1.0).unwrap();
         assert!(scorer.is::<TermScorer>());
     }
 
@@ -75,17 +73,13 @@ mod tests {
         {
             let query = query_parser.parse_query("+a +b +c").unwrap();
             let weight = query.weight(&searcher, true).unwrap();
-            let scorer = weight
-                .scorer(searcher.segment_reader(0u32), 1.0f32)
-                .unwrap();
+            let scorer = weight.scorer(searcher.segment_reader(0u32), 1.0).unwrap();
             assert!(scorer.is::<Intersection<TermScorer>>());
         }
         {
             let query = query_parser.parse_query("+a +(b c)").unwrap();
             let weight = query.weight(&searcher, true).unwrap();
-            let scorer = weight
-                .scorer(searcher.segment_reader(0u32), 1.0f32)
-                .unwrap();
+            let scorer = weight.scorer(searcher.segment_reader(0u32), 1.0).unwrap();
             assert!(scorer.is::<Intersection<Box<dyn Scorer>>>());
         }
     }
@@ -98,9 +92,7 @@ mod tests {
         {
             let query = query_parser.parse_query("+a b").unwrap();
             let weight = query.weight(&searcher, true).unwrap();
-            let scorer = weight
-                .scorer(searcher.segment_reader(0u32), 1.0f32)
-                .unwrap();
+            let scorer = weight.scorer(searcher.segment_reader(0u32), 1.0).unwrap();
             assert!(scorer.is::<RequiredOptionalScorer<
                 Box<dyn Scorer>,
                 Box<dyn Scorer>,
@@ -110,9 +102,7 @@ mod tests {
         {
             let query = query_parser.parse_query("+a b").unwrap();
             let weight = query.weight(&searcher, false).unwrap();
-            let scorer = weight
-                .scorer(searcher.segment_reader(0u32), 1.0f32)
-                .unwrap();
+            let scorer = weight.scorer(searcher.segment_reader(0u32), 1.0).unwrap();
             assert!(scorer.is::<TermScorer>());
         }
     }
@@ -255,17 +245,17 @@ mod tests {
         let boolean_weight = boolean_query.weight(&searcher, true).unwrap();
         {
             let mut boolean_scorer = boolean_weight
-                .scorer(searcher.segment_reader(0u32), 1.0f32)
+                .scorer(searcher.segment_reader(0u32), 1.0)
                 .unwrap();
             assert_eq!(boolean_scorer.doc(), 0u32);
-            assert_nearly_equals!(boolean_scorer.score(), 0.84163445f32);
+            assert_nearly_equals!(boolean_scorer.score(), 0.84163445);
         }
         {
             let mut boolean_scorer = boolean_weight
-                .scorer(searcher.segment_reader(0u32), 2.0f32)
+                .scorer(searcher.segment_reader(0u32), 2.0)
                 .unwrap();
             assert_eq!(boolean_scorer.doc(), 0u32);
-            assert_nearly_equals!(boolean_scorer.score(), 1.6832689f32);
+            assert_nearly_equals!(boolean_scorer.score(), 1.6832689);
         }
     }
 
@@ -295,170 +285,9 @@ mod tests {
                 (Occur::Must, make_term_query("a")),
                 (Occur::Must, make_term_query("b")),
             ]);
-            assert_eq!(score_docs(&boolean_query), vec![0.977973, 0.84699446]);
+            let scores = score_docs(&boolean_query);
+            assert_nearly_equals!(scores[0], 0.977973);
+            assert_nearly_equals!(scores[1], 0.84699446);
         }
     }
-
-    // motivated by #554
-    #[test]
-    fn test_bm25_several_fields() {
-        let mut schema_builder = Schema::builder();
-        let title = schema_builder.add_text_field("title", TEXT);
-        let text = schema_builder.add_text_field("text", TEXT);
-        let schema = schema_builder.build();
-        let index = Index::create_in_ram(schema);
-
-        let mut index_writer = index.writer_with_num_threads(1, 3_000_000).unwrap();
-        index_writer.add_document(doc!(
-            // tf = 1 0
-            title =>  "Законы притяжения   Оксана Кулакова",
-            // tf = 1 0
-            text => "Законы притяжения Оксана Кулакова]  \n\nТема: Сексуальное искусство, Женственность\nТип товара: Запись вебинара (аудио)\nПродолжительность: 1,5 часа\n\nСсылка на вебинар:\n  ",
-        ));
-        index_writer.add_document(doc!(
-            // tf = 1 0
-            title => "Любимые русские пироги (Оксана Путан)",
-            // tf = 2 0
-            text => "http://i95.fastpic.ru/big/2017/0628/9a/615b9c8504d94a3893d7f496ac53539a.jpg \n\nОт издателя\nОксана Путан   профессиональный повар, автор кулинарных книг и известный кулинарный блогер. Ее рецепты отличаются практичностью, доступностью и пользуются огромной популярностью в русскоязычном интернете. Это третья книга автора о самом вкусном и ароматном   настоящих русских пирогах и выпечке!\nДаже новички на кухне легко готовят по ее рецептам. Оксана описывает процесс приготовления настолько подробно и понятно, что вам остается только наслаждаться готовкой и не тратить время на лишние усилия. Готовьте легко и просто!\n\nhttps://www.ozon.ru/context/detail/id/139872462/"
-        ));
-        index_writer.add_document(doc!(
-            // tf = 1 1
-            title =>  "PDF Мастер Класс \"Морячок\" (Оксана Лифенко)",
-            // tf = 0 0
-            text => "https://i.ibb.co/pzvHrDN/I3d U T6 Gg TM.jpg\nhttps://i.ibb.co/NFrb6v6/N0ls Z9nwjb U.jpg\nВ описание входит штаны, кофта, берет, матросский воротник. Описание продается в формате PDF, состоит из 12 страниц формата А4 и может быть напечатано на любом принтере.\nОписание предназначено для кукол BJD RealPuki от FairyLand, но может подойти и другим подобным куклам. Также вы можете вязать этот наряд из обычной пряжи, и он подойдет для куколок побольше.\nhttps://vk.com/market 95724412?w=product 95724412_2212"
-        ));
-        for _ in 0..1_000 {
-            index_writer.add_document(doc!(
-                title =>  "a b d e f g",
-                text => "maitre corbeau sur un arbre perche tenait dans son bec un fromage Maitre rnard par lodeur alleche lui tint a peu pres ce langage."
-            ));
-        }
-        index_writer.commit().unwrap();
-        let reader = index.reader().unwrap();
-        let searcher = reader.searcher();
-        let query_parser = QueryParser::for_index(&index, vec![title, text]);
-        let query = query_parser.parse_query("Оксана Лифенко").unwrap();
-        let weight = query.weight(&searcher, true).unwrap();
-        let mut scorer = weight
-            .scorer(searcher.segment_reader(0u32), 1.0f32)
-            .unwrap();
-        scorer.advance();
-
-        let explanation = query.explain(&searcher, DocAddress(0u32, 0u32)).unwrap();
-        assert_eq!(
-            explanation.to_pretty_json(),
-            r#"{
-  "value": 12.997711,
-  "description": "BooleanClause. Sum of ...",
-  "details": [
-    {
-      "value": 12.997711,
-      "description": "BooleanClause. Sum of ...",
-      "details": [
-        {
-          "value": 6.551476,
-          "description": "TermQuery, product of...",
-          "details": [
-            {
-              "value": 2.2,
-              "description": "(K1+1)"
-            },
-            {
-              "value": 5.658984,
-              "description": "idf, computed as log(1 + (N - n + 0.5) / (n + 0.5))",
-              "details": [
-                {
-                  "value": 3.0,
-                  "description": "n, number of docs containing this term"
-                },
-                {
-                  "value": 1003.0,
-                  "description": "N, total number of docs"
-                }
-              ]
-            },
-            {
-              "value": 0.5262329,
-              "description": "freq / (freq + k1 * (1 - b + b * dl / avgdl))",
-              "details": [
-                {
-                  "value": 1.0,
-                  "description": "freq, occurrences of term within document"
-                },
-                {
-                  "value": 1.2,
-                  "description": "k1, term saturation parameter"
-                },
-                {
-                  "value": 0.75,
-                  "description": "b, length normalization parameter"
-                },
-                {
-                  "value": 4.0,
-                  "description": "dl, length of field"
-                },
-                {
-                  "value": 5.997009,
-                  "description": "avgdl, average length of field"
-                }
-              ]
-            }
-          ]
-        },
-        {
-          "value": 6.446235,
-          "description": "TermQuery, product of...",
-          "details": [
-            {
-              "value": 2.2,
-              "description": "(K1+1)"
-            },
-            {
-              "value": 5.9954567,
-              "description": "idf, computed as log(1 + (N - n + 0.5) / (n + 0.5))",
-              "details": [
-                {
-                  "value": 2.0,
-                  "description": "n, number of docs containing this term"
-                },
-                {
-                  "value": 1003.0,
-                  "description": "N, total number of docs"
-                }
-              ]
-            },
-            {
-              "value": 0.4887212,
-              "description": "freq / (freq + k1 * (1 - b + b * dl / avgdl))",
-              "details": [
-                {
-                  "value": 1.0,
-                  "description": "freq, occurrences of term within document"
-                },
-                {
-                  "value": 1.2,
-                  "description": "k1, term saturation parameter"
-                },
-                {
-                  "value": 0.75,
-                  "description": "b, length normalization parameter"
-                },
-                {
-                  "value": 20.0,
-                  "description": "dl, length of field"
-                },
-                {
-                  "value": 24.123629,
-                  "description": "avgdl, average length of field"
-                }
-              ]
-            }
-          ]
-        }
-      ]
-    }
-  ]
-}"#
-        );
-    }
 }

src/query/boost_query.rs

@@ -1,7 +1,7 @@
 use crate::fastfield::DeleteBitSet;
 use crate::query::explanation::does_not_match;
 use crate::query::{Explanation, Query, Scorer, Weight};
-use crate::{DocId, DocSet, Searcher, SegmentReader, Term};
+use crate::{DocId, DocSet, Score, Searcher, SegmentReader, Term};
 use std::collections::BTreeSet;
 use std::fmt;
 
@@ -12,12 +12,12 @@ use std::fmt;
 /// factor.
 pub struct BoostQuery {
     query: Box<dyn Query>,
-    boost: f32,
+    boost: Score,
 }
 
 impl BoostQuery {
     /// Builds a boost query.
-    pub fn new(query: Box<dyn Query>, boost: f32) -> BoostQuery {
+    pub fn new(query: Box<dyn Query>, boost: Score) -> BoostQuery {
         BoostQuery { query, boost }
     }
 }
@@ -55,22 +55,22 @@ impl Query for BoostQuery {
 
 pub(crate) struct BoostWeight {
     weight: Box<dyn Weight>,
-    boost: f32,
+    boost: Score,
 }
 
 impl BoostWeight {
-    pub fn new(weight: Box<dyn Weight>, boost: f32) -> Self {
+    pub fn new(weight: Box<dyn Weight>, boost: Score) -> Self {
         BoostWeight { weight, boost }
     }
 }
 
 impl Weight for BoostWeight {
-    fn scorer(&self, reader: &SegmentReader, boost: f32) -> crate::Result<Box<dyn Scorer>> {
+    fn scorer(&self, reader: &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> {
-        let mut scorer = self.scorer(reader, 1.0f32)?;
+        let mut scorer = self.scorer(reader, 1.0)?;
         if scorer.seek(doc) != doc {
             return Err(does_not_match(doc));
         }
@@ -88,11 +88,11 @@ impl Weight for BoostWeight {
 
 pub(crate) struct BoostScorer<S: Scorer> {
     underlying: S,
-    boost: f32,
+    boost: Score,
 }
 
 impl<S: Scorer> BoostScorer<S> {
-    pub fn new(underlying: S, boost: f32) -> BoostScorer<S> {
+    pub fn new(underlying: S, boost: Score) -> BoostScorer<S> {
         BoostScorer { underlying, boost }
     }
 }
@@ -128,7 +128,7 @@ impl<S: Scorer> DocSet for BoostScorer<S> {
 }
 
 impl<S: Scorer> Scorer for BoostScorer<S> {
-    fn score(&mut self) -> f32 {
+    fn score(&mut self) -> Score {
         self.underlying.score() * self.boost
     }
 }

src/query/empty_query.rs

@@ -34,7 +34,7 @@ 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: f32) -> crate::Result<Box<dyn Scorer>> {
+    fn scorer(&self, _reader: &SegmentReader, _boost: Score) -> crate::Result<Box<dyn Scorer>> {
         Ok(Box::new(EmptyScorer))
     }
 
@@ -64,7 +64,7 @@ impl DocSet for EmptyScorer {
 
 impl Scorer for EmptyScorer {
     fn score(&mut self) -> Score {
-        0f32
+        0.0
     }
 }
 

src/query/explanation.rs

@@ -1,4 +1,4 @@
-use crate::{DocId, TantivyError};
+use crate::{DocId, Score, TantivyError};
 use serde::Serialize;
 use std::fmt;
 
@@ -13,7 +13,7 @@ pub(crate) fn does_not_match(doc: DocId) -> TantivyError {
 /// representation of this tree when debugging a given score.
 #[derive(Clone, Serialize)]
 pub struct Explanation {
-    value: f32,
+    value: Score,
     description: String,
     #[serde(skip_serializing_if = "Vec::is_empty")]
     details: Vec<Explanation>,
@@ -27,7 +27,7 @@ impl fmt::Debug for Explanation {
 
 impl Explanation {
     /// Creates a new explanation object.
-    pub fn new<T: ToString>(description: T, value: f32) -> Explanation {
+    pub fn new<T: ToString>(description: T, value: Score) -> Explanation {
         Explanation {
             value,
             description: description.to_string(),
@@ -36,7 +36,7 @@ impl Explanation {
     }
 
     /// Returns the value associated to the current node.
-    pub fn value(&self) -> f32 {
+    pub fn value(&self) -> Score {
         self.value
     }
 
@@ -48,7 +48,7 @@ impl Explanation {
     }
 
     /// Shortcut for `self.details.push(Explanation::new(name, value));`
-    pub fn add_const<T: ToString>(&mut self, name: T, value: f32) {
+    pub fn add_const<T: ToString>(&mut self, name: T, value: Score) {
         self.details.push(Explanation::new(name, value));
     }
 

src/query/fuzzy_query.rs

@@ -199,7 +199,7 @@ mod test {
                 .unwrap();
             assert_eq!(top_docs.len(), 1, "Expected only 1 document");
             let (score, _) = top_docs[0];
-            assert_nearly_equals!(1f32, score);
+            assert_nearly_equals!(1.0, score);
         }
 
         // fails because non-prefix Levenshtein distance is more than 1 (add 'a' and 'n')
@@ -223,7 +223,7 @@ mod test {
                 .unwrap();
             assert_eq!(top_docs.len(), 1, "Expected only 1 document");
             let (score, _) = top_docs[0];
-            assert_nearly_equals!(1f32, score);
+            assert_nearly_equals!(1.0, score);
         }
     }
 }

src/query/phrase_query/mod.rs

@@ -79,7 +79,7 @@ pub mod tests {
             .collect();
         let phrase_query = PhraseQuery::new(terms);
         let phrase_weight = phrase_query.phrase_weight(&searcher, false)?;
-        let mut phrase_scorer = phrase_weight.scorer(searcher.segment_reader(0), 1.0f32)?;
+        let mut phrase_scorer = phrase_weight.scorer(searcher.segment_reader(0), 1.0)?;
         assert_eq!(phrase_scorer.doc(), 1);
         assert_eq!(phrase_scorer.advance(), TERMINATED);
         Ok(())

src/query/phrase_query/phrase_scorer.rs

@@ -3,7 +3,7 @@ use crate::fieldnorm::FieldNormReader;
 use crate::postings::Postings;
 use crate::query::bm25::BM25Weight;
 use crate::query::{Intersection, Scorer};
-use crate::DocId;
+use crate::{DocId, Score};
 use std::cmp::Ordering;
 
 struct PostingsWithOffset<TPostings> {
@@ -257,7 +257,7 @@ impl<TPostings: Postings> DocSet for PhraseScorer<TPostings> {
 }
 
 impl<TPostings: Postings> Scorer for PhraseScorer<TPostings> {
-    fn score(&mut self) -> f32 {
+    fn score(&mut self) -> Score {
         let doc = self.doc();
         let fieldnorm_id = self.fieldnorm_reader.fieldnorm_id(doc);
         self.similarity_weight

src/query/phrase_query/phrase_weight.rs

@@ -9,8 +9,8 @@ use crate::query::Weight;
 use crate::query::{EmptyScorer, Explanation};
 use crate::schema::IndexRecordOption;
 use crate::schema::Term;
-use crate::Result;
 use crate::{DocId, DocSet};
+use crate::{Result, Score};
 
 pub struct PhraseWeight {
     phrase_terms: Vec<(usize, Term)>,
@@ -40,7 +40,7 @@ impl PhraseWeight {
     fn phrase_scorer(
         &self,
         reader: &SegmentReader,
-        boost: f32,
+        boost: Score,
     ) -> Result<Option<PhraseScorer<SegmentPostings>>> {
         let similarity_weight = self.similarity_weight.boost_by(boost);
         let fieldnorm_reader = self.fieldnorm_reader(reader);
@@ -85,7 +85,7 @@ impl PhraseWeight {
 }
 
 impl Weight for PhraseWeight {
-    fn scorer(&self, reader: &SegmentReader, boost: f32) -> Result<Box<dyn Scorer>> {
+    fn scorer(&self, reader: &SegmentReader, boost: Score) -> Result<Box<dyn Scorer>> {
         if let Some(scorer) = self.phrase_scorer(reader, boost)? {
             Ok(Box::new(scorer))
         } else {
@@ -94,7 +94,7 @@ impl Weight for PhraseWeight {
     }
 
     fn explain(&self, reader: &SegmentReader, doc: DocId) -> Result<Explanation> {
-        let scorer_opt = self.phrase_scorer(reader, 1.0f32)?;
+        let scorer_opt = self.phrase_scorer(reader, 1.0)?;
         if scorer_opt.is_none() {
             return Err(does_not_match(doc));
         }
@@ -130,7 +130,7 @@ mod tests {
         ]);
         let phrase_weight = phrase_query.phrase_weight(&searcher, true).unwrap();
         let mut phrase_scorer = phrase_weight
-            .phrase_scorer(searcher.segment_reader(0u32), 1.0f32)
+            .phrase_scorer(searcher.segment_reader(0u32), 1.0)
             .unwrap()
             .unwrap();
         assert_eq!(phrase_scorer.doc(), 1);

src/query/query.rs

@@ -40,7 +40,7 @@ use std::fmt;
 ///
 /// When implementing a new type of `Query`, it is normal to implement a
 /// dedicated `Query`, `Weight` and `Scorer`.
-pub trait Query: QueryClone + downcast_rs::Downcast + fmt::Debug {
+pub trait Query: QueryClone + Send + Sync + downcast_rs::Downcast + fmt::Debug {
     /// Create the weight associated to a query.
     ///
     /// If scoring is not required, setting `scoring_enabled` to `false`

src/query/query_parser/logical_ast.rs

@@ -2,6 +2,7 @@ use crate::query::Occur;
 use crate::schema::Field;
 use crate::schema::Term;
 use crate::schema::Type;
+use crate::Score;
 use std::fmt;
 use std::ops::Bound;
 
@@ -21,12 +22,12 @@ pub enum LogicalLiteral {
 pub enum LogicalAST {
     Clause(Vec<(Occur, LogicalAST)>),
     Leaf(Box<LogicalLiteral>),
-    Boost(Box<LogicalAST>, f32),
+    Boost(Box<LogicalAST>, Score),
 }
 
 impl LogicalAST {
-    pub fn boost(self, boost: f32) -> LogicalAST {
-        if (boost - 1.0f32).abs() < std::f32::EPSILON {
+    pub fn boost(self, boost: Score) -> LogicalAST {
+        if (boost - 1.0).abs() < Score::EPSILON {
             self
         } else {
             LogicalAST::Boost(Box::new(self), boost)

src/query/query_parser/query_parser.rs

@@ -12,6 +12,7 @@ use crate::schema::{Facet, IndexRecordOption};
 use crate::schema::{Field, Schema};
 use crate::schema::{FieldType, Term};
 use crate::tokenizer::TokenizerManager;
+use crate::Score;
 use std::borrow::Cow;
 use std::collections::HashMap;
 use std::num::{ParseFloatError, ParseIntError};
@@ -172,7 +173,7 @@ pub struct QueryParser {
     default_fields: Vec<Field>,
     conjunction_by_default: bool,
     tokenizer_manager: TokenizerManager,
-    boost: HashMap<Field, f32>,
+    boost: HashMap<Field, Score>,
 }
 
 fn all_negative(ast: &LogicalAST) -> bool {
@@ -228,7 +229,7 @@ impl QueryParser {
     /// If the query defines a query boost through the query language (e.g: `country:France^3.0`),
     /// the two boosts (the one defined in the query, and the one defined in the `QueryParser`)
     /// are multiplied together.
-    pub fn set_field_boost(&mut self, field: Field, boost: f32) {
+    pub fn set_field_boost(&mut self, field: Field, boost: Score) {
         self.boost.insert(field, boost);
     }
 
@@ -440,14 +441,14 @@ impl QueryParser {
             }
             UserInputAST::Boost(ast, boost) => {
                 let ast = self.compute_logical_ast_with_occur(*ast)?;
-                Ok(ast.boost(boost))
+                Ok(ast.boost(boost as Score))
             }
             UserInputAST::Leaf(leaf) => self.compute_logical_ast_from_leaf(*leaf),
         }
     }
 
-    fn field_boost(&self, field: Field) -> f32 {
-        self.boost.get(&field).cloned().unwrap_or(1.0f32)
+    fn field_boost(&self, field: Field) -> Score {
+        self.boost.get(&field).cloned().unwrap_or(1.0)
     }
 
     fn compute_logical_ast_from_leaf(
@@ -658,7 +659,7 @@ mod test {
         let mut query_parser = make_query_parser();
         let schema = make_schema();
         let text_field = schema.get_field("text").unwrap();
-        query_parser.set_field_boost(text_field, 2.0f32);
+        query_parser.set_field_boost(text_field, 2.0);
         let query = query_parser.parse_query("text:hello").unwrap();
         assert_eq!(
             format!("{:?}", query),
@@ -671,7 +672,7 @@ mod test {
         let mut query_parser = make_query_parser();
         let schema = make_schema();
         let title_field = schema.get_field("title").unwrap();
-        query_parser.set_field_boost(title_field, 2.0f32);
+        query_parser.set_field_boost(title_field, 2.0);
         let query = query_parser.parse_query("title:[A TO B]").unwrap();
         assert_eq!(
             format!("{:?}", query),
@@ -684,7 +685,7 @@ mod test {
         let mut query_parser = make_query_parser();
         let schema = make_schema();
         let text_field = schema.get_field("text").unwrap();
-        query_parser.set_field_boost(text_field, 2.0f32);
+        query_parser.set_field_boost(text_field, 2.0);
         let query = query_parser.parse_query("text:hello^2").unwrap();
         assert_eq!(
             format!("{:?}", query),

src/query/range_query.rs

@@ -9,8 +9,8 @@ use crate::query::{Query, Scorer, Weight};
 use crate::schema::Type;
 use crate::schema::{Field, IndexRecordOption, Term};
 use crate::termdict::{TermDictionary, TermStreamer};
-use crate::DocId;
 use crate::Result;
+use crate::{DocId, Score};
 use std::collections::Bound;
 use std::ops::Range;
 
@@ -289,7 +289,7 @@ impl RangeWeight {
 }
 
 impl Weight for RangeWeight {
-    fn scorer(&self, reader: &SegmentReader, boost: f32) -> Result<Box<dyn Scorer>> {
+    fn scorer(&self, reader: &SegmentReader, boost: Score) -> Result<Box<dyn Scorer>> {
         let max_doc = reader.max_doc();
         let mut doc_bitset = BitSet::with_max_value(max_doc);
 
@@ -316,11 +316,11 @@ impl Weight for RangeWeight {
     }
 
     fn explain(&self, reader: &SegmentReader, doc: DocId) -> Result<Explanation> {
-        let mut scorer = self.scorer(reader, 1.0f32)?;
+        let mut scorer = self.scorer(reader, 1.0)?;
         if scorer.seek(doc) != doc {
             return Err(does_not_match(doc));
         }
-        Ok(Explanation::new("RangeQuery", 1.0f32))
+        Ok(Explanation::new("RangeQuery", 1.0))
     }
 }
 
@@ -328,8 +328,9 @@ impl Weight for RangeWeight {
 mod tests {
 
     use super::RangeQuery;
-    use crate::collector::Count;
-    use crate::schema::{Document, Field, Schema, INDEXED};
+    use crate::collector::{Count, TopDocs};
+    use crate::query::QueryParser;
+    use crate::schema::{Document, Field, Schema, INDEXED, TEXT};
     use crate::Index;
     use std::collections::Bound;
 
@@ -476,4 +477,28 @@ mod tests {
             91
         );
     }
+
+    #[test]
+    fn test_bug_reproduce_range_query() -> crate::Result<()> {
+        let mut schema_builder = Schema::builder();
+        schema_builder.add_text_field("title", TEXT);
+        schema_builder.add_i64_field("year", INDEXED);
+        let schema = schema_builder.build();
+        let index = Index::create_in_ram(schema.clone());
+        let mut index_writer = index.writer_with_num_threads(1, 10_000_000)?;
+        let title = schema.get_field("title").unwrap();
+        let year = schema.get_field("year").unwrap();
+        index_writer.add_document(doc!(
+          title => "hemoglobin blood",
+          year => 1990 as i64
+        ));
+        index_writer.commit()?;
+        let reader = index.reader()?;
+        let searcher = reader.searcher();
+        let query_parser = QueryParser::for_index(&index, vec![title]);
+        let query = query_parser.parse_query("hemoglobin AND year:[1970 TO 1990]")?;
+        let top_docs = searcher.search(&query, &TopDocs::with_limit(10))?;
+        assert_eq!(top_docs.len(), 1);
+        Ok(())
+    }
 }

src/query/regex_query.rs

@@ -129,7 +129,7 @@ mod test {
                 .unwrap();
             assert_eq!(scored_docs.len(), 1, "Expected only 1 document");
             let (score, _) = scored_docs[0];
-            assert_nearly_equals!(1f32, score);
+            assert_nearly_equals!(1.0, score);
         }
         let top_docs = searcher
             .search(&query_matching_zero, &TopDocs::with_limit(2))

src/query/reqopt_scorer.rs

@@ -112,47 +112,47 @@ mod tests {
     fn test_reqopt_scorer() {
         let mut reqoptscorer: RequiredOptionalScorer<_, _, SumCombiner> =
             RequiredOptionalScorer::new(
-                ConstScorer::new(VecDocSet::from(vec![1, 3, 7, 8, 9, 10, 13, 15]), 1.0f32),
-                ConstScorer::new(VecDocSet::from(vec![1, 2, 7, 11, 12, 15]), 1.0f32),
+                ConstScorer::new(VecDocSet::from(vec![1, 3, 7, 8, 9, 10, 13, 15]), 1.0),
+                ConstScorer::new(VecDocSet::from(vec![1, 2, 7, 11, 12, 15]), 1.0),
             );
         {
             assert_eq!(reqoptscorer.doc(), 1);
-            assert_eq!(reqoptscorer.score(), 2f32);
+            assert_eq!(reqoptscorer.score(), 2.0);
         }
         {
             assert_eq!(reqoptscorer.advance(), 3);
             assert_eq!(reqoptscorer.doc(), 3);
-            assert_eq!(reqoptscorer.score(), 1f32);
+            assert_eq!(reqoptscorer.score(), 1.0);
         }
         {
             assert_eq!(reqoptscorer.advance(), 7);
             assert_eq!(reqoptscorer.doc(), 7);
-            assert_eq!(reqoptscorer.score(), 2f32);
+            assert_eq!(reqoptscorer.score(), 2.0);
         }
         {
             assert_eq!(reqoptscorer.advance(), 8);
             assert_eq!(reqoptscorer.doc(), 8);
-            assert_eq!(reqoptscorer.score(), 1f32);
+            assert_eq!(reqoptscorer.score(), 1.0);
         }
         {
             assert_eq!(reqoptscorer.advance(), 9);
             assert_eq!(reqoptscorer.doc(), 9);
-            assert_eq!(reqoptscorer.score(), 1f32);
+            assert_eq!(reqoptscorer.score(), 1.0);
         }
         {
             assert_eq!(reqoptscorer.advance(), 10);
             assert_eq!(reqoptscorer.doc(), 10);
-            assert_eq!(reqoptscorer.score(), 1f32);
+            assert_eq!(reqoptscorer.score(), 1.0);
         }
         {
             assert_eq!(reqoptscorer.advance(), 13);
             assert_eq!(reqoptscorer.doc(), 13);
-            assert_eq!(reqoptscorer.score(), 1f32);
+            assert_eq!(reqoptscorer.score(), 1.0);
         }
         {
             assert_eq!(reqoptscorer.advance(), 15);
             assert_eq!(reqoptscorer.doc(), 15);
-            assert_eq!(reqoptscorer.score(), 2f32);
+            assert_eq!(reqoptscorer.score(), 2.0);
         }
         assert_eq!(reqoptscorer.advance(), TERMINATED);
     }

src/query/score_combiner.rs

@@ -31,7 +31,7 @@ impl ScoreCombiner for DoNothingCombiner {
     fn clear(&mut self) {}
 
     fn score(&self) -> Score {
-        1f32
+        1.0
     }
 }
 
@@ -47,7 +47,7 @@ impl ScoreCombiner for SumCombiner {
     }
 
     fn clear(&mut self) {
-        self.score = 0f32;
+        self.score = 0.0;
     }
 
     fn score(&self) -> Score {
@@ -70,7 +70,7 @@ impl ScoreCombiner for SumWithCoordsCombiner {
     }
 
     fn clear(&mut self) {
-        self.score = 0f32;
+        self.score = 0.0;
         self.num_fields = 0;
     }
 

src/query/scorer.rs

@@ -35,14 +35,14 @@ pub struct ConstScorer<TDocSet: DocSet> {
 
 impl<TDocSet: DocSet> ConstScorer<TDocSet> {
     /// Creates a new `ConstScorer`.
-    pub fn new(docset: TDocSet, score: f32) -> ConstScorer<TDocSet> {
+    pub fn new(docset: TDocSet, score: Score) -> ConstScorer<TDocSet> {
         ConstScorer { docset, score }
     }
 }
 
 impl<TDocSet: DocSet> From<TDocSet> for ConstScorer<TDocSet> {
     fn from(docset: TDocSet) -> Self {
-        ConstScorer::new(docset, 1.0f32)
+        ConstScorer::new(docset, 1.0)
     }
 }
 

src/query/term_query/mod.rs

@@ -15,7 +15,7 @@ mod tests {
     use crate::postings::compression::COMPRESSION_BLOCK_SIZE;
     use crate::query::{Query, QueryParser, Scorer, TermQuery};
     use crate::schema::{Field, IndexRecordOption, Schema, STRING, TEXT};
-    use crate::{Term, Index, TERMINATED};
+    use crate::{Index, Term, TERMINATED};
 
     #[test]
     pub fn test_term_query_no_freq() {
@@ -37,9 +37,9 @@ mod tests {
         );
         let term_weight = term_query.weight(&searcher, true).unwrap();
         let segment_reader = searcher.segment_reader(0);
-        let mut term_scorer = term_weight.scorer(segment_reader, 1.0f32).unwrap();
+        let mut term_scorer = term_weight.scorer(segment_reader, 1.0).unwrap();
         assert_eq!(term_scorer.doc(), 0);
-        assert_eq!(term_scorer.score(), 0.28768212);
+        assert_nearly_equals!(term_scorer.score(), 0.28768212);
     }
 
     #[test]
@@ -64,7 +64,7 @@ mod tests {
         );
         let term_weight = term_query.weight(&searcher, true)?;
         let segment_reader = searcher.segment_reader(0);
-        let mut term_scorer = term_weight.scorer(segment_reader, 1.0f32)?;
+        let mut term_scorer = term_weight.scorer(segment_reader, 1.0)?;
         for i in 0u32..COMPRESSION_BLOCK_SIZE as u32 {
             assert_eq!(term_scorer.doc(), i);
             if i == COMPRESSION_BLOCK_SIZE as u32 - 1u32 {
@@ -161,7 +161,7 @@ mod tests {
         let term_query = TermQuery::new(term_a, IndexRecordOption::Basic);
         let searcher = index.reader()?.searcher();
         let term_weight = term_query.weight(&searcher, false)?;
-        let mut term_scorer = term_weight.scorer(searcher.segment_reader(0u32), 1.0f32)?;
+        let mut term_scorer = term_weight.scorer(searcher.segment_reader(0u32), 1.0)?;
         assert_eq!(term_scorer.doc(), 0u32);
         term_scorer.seek(1u32);
         assert_eq!(term_scorer.doc(), 1u32);

src/query/term_query/term_scorer.rs

@@ -8,6 +8,7 @@ use crate::postings::SegmentPostings;
 use crate::postings::{FreqReadingOption, Postings};
 use crate::query::bm25::BM25Weight;
 
+#[derive(Clone)]
 pub struct TermScorer {
     postings: SegmentPostings,
     fieldnorm_reader: FieldNormReader,
@@ -28,34 +29,28 @@ impl TermScorer {
     }
 
     pub(crate) fn shallow_seek(&mut self, target_doc: DocId) {
-        self.postings.block_cursor.shallow_seek(target_doc)
+        self.postings.block_cursor.shallow_seek(target_doc);
     }
 
-
     #[cfg(test)]
     pub fn create_for_test(
         doc_and_tfs: &[(DocId, u32)],
-        fieldnorm_vals: &[u32],
+        fieldnorms: &[u32],
         similarity_weight: BM25Weight,
-    ) -> crate::Result<TermScorer> {
+    ) -> TermScorer {
         assert!(!doc_and_tfs.is_empty());
-        assert!(doc_and_tfs.len() <= fieldnorm_vals.len());
-
-        let doc_freq = doc_and_tfs.len();
-        let max_doc = doc_and_tfs.last().unwrap().0 + 1;
-        let mut fieldnorms: Vec<u32> = std::iter::repeat(1).take(max_doc as usize).collect();
-
-        for i in 0..doc_freq {
-            let doc = doc_and_tfs[i].0;
-            let fieldnorm = fieldnorm_vals[i];
-            fieldnorms[doc as usize] = fieldnorm;
-        }
-        let fieldnorm_reader = FieldNormReader::from(&fieldnorms[..]);
-
+        assert!(
+            doc_and_tfs
+                .iter()
+                .map(|(doc, _tf)| *doc)
+                .max()
+                .unwrap_or(0u32)
+                < fieldnorms.len() as u32
+        );
         let segment_postings =
-            SegmentPostings::create_from_docs_and_tfs(doc_and_tfs, Some(fieldnorm_reader.clone()))?;
-
-        Ok(TermScorer::new(segment_postings, fieldnorm_reader, similarity_weight))
+            SegmentPostings::create_from_docs_and_tfs(doc_and_tfs, Some(fieldnorms));
+        let fieldnorm_reader = FieldNormReader::for_test(fieldnorms);
+        TermScorer::new(segment_postings, fieldnorm_reader, similarity_weight)
     }
 
     /// See `FreqReadingOption`.
@@ -86,10 +81,6 @@ impl TermScorer {
         self.postings.term_freq()
     }
 
-    pub fn doc_freq(&self) -> usize {
-        self.postings.doc_freq() as usize
-    }
-
     pub fn fieldnorm_id(&self) -> u8 {
         self.fieldnorm_reader.fieldnorm_id(self.doc())
     }
@@ -100,7 +91,7 @@ impl TermScorer {
         self.similarity_weight.explain(fieldnorm_id, term_freq)
     }
 
-    pub fn max_score(&self) -> f32 {
+    pub fn max_score(&self) -> Score {
         self.similarity_weight.max_score()
     }
 
@@ -137,48 +128,53 @@ impl Scorer for TermScorer {
 
 #[cfg(test)]
 mod tests {
-    use crate::assert_nearly_equals;
+    use crate::merge_policy::NoMergePolicy;
     use crate::postings::compression::COMPRESSION_BLOCK_SIZE;
     use crate::query::term_query::TermScorer;
-    use crate::query::{BM25Weight, Scorer};
+    use crate::query::{BM25Weight, Scorer, TermQuery};
+    use crate::schema::{IndexRecordOption, Schema, TEXT};
+    use crate::Score;
+    use crate::{assert_nearly_equals, Index, Searcher, SegmentId, Term};
     use crate::{DocId, DocSet, TERMINATED};
+    use futures::executor::block_on;
     use proptest::prelude::*;
 
     #[test]
     fn test_term_scorer_max_score() -> crate::Result<()> {
-        let bm25_weight = BM25Weight::for_one_term(3, 6, 10f32);
-        let mut term_scorer =
-            TermScorer::create_for_test(&[(2, 3), (3, 12), (7, 8)], &[10, 12, 100], bm25_weight)?;
+        let bm25_weight = BM25Weight::for_one_term(3, 6, 10.0);
+        let mut term_scorer = TermScorer::create_for_test(
+            &[(2, 3), (3, 12), (7, 8)],
+            &[0, 0, 10, 12, 0, 0, 0, 100],
+            bm25_weight,
+        );
         let max_scorer = term_scorer.max_score();
-        assert_eq!(max_scorer, 1.3990127f32);
+        crate::assert_nearly_equals!(max_scorer, 1.3990127);
         assert_eq!(term_scorer.doc(), 2);
         assert_eq!(term_scorer.term_freq(), 3);
-        assert_nearly_equals!(term_scorer.block_max_score(), 1.3676447f32);
-        assert_nearly_equals!(term_scorer.score(), 1.0892314f32);
+        assert_nearly_equals!(term_scorer.block_max_score(), 1.3676447);
+        assert_nearly_equals!(term_scorer.score(), 1.0892314);
         assert_eq!(term_scorer.advance(), 3);
         assert_eq!(term_scorer.doc(), 3);
         assert_eq!(term_scorer.term_freq(), 12);
-        assert_nearly_equals!(term_scorer.score(), 1.3676447f32);
+        assert_nearly_equals!(term_scorer.score(), 1.3676447);
         assert_eq!(term_scorer.advance(), 7);
         assert_eq!(term_scorer.doc(), 7);
         assert_eq!(term_scorer.term_freq(), 8);
-        assert_nearly_equals!(term_scorer.score(), 0.72015285f32);
+        assert_nearly_equals!(term_scorer.score(), 0.72015285);
         assert_eq!(term_scorer.advance(), TERMINATED);
         Ok(())
     }
 
-
     #[test]
     fn test_term_scorer_shallow_advance() -> crate::Result<()> {
-        let bm25_weight = BM25Weight::for_one_term(300, 1024, 10f32);
+        let bm25_weight = BM25Weight::for_one_term(300, 1024, 10.0);
         let mut doc_and_tfs = vec![];
         for i in 0u32..300u32 {
             let doc = i * 10;
             doc_and_tfs.push((doc, 1u32 + doc % 3u32));
         }
-        let fieldnorms: Vec<u32> = std::iter::repeat(10u32).take(1024).collect();
-        let mut term_scorer =
-            TermScorer::create_for_test(&doc_and_tfs, &fieldnorms, bm25_weight)?;
+        let fieldnorms: Vec<u32> = std::iter::repeat(10u32).take(3_000).collect();
+        let mut term_scorer = TermScorer::create_for_test(&doc_and_tfs, &fieldnorms, bm25_weight);
         assert_eq!(term_scorer.doc(), 0u32);
         term_scorer.shallow_seek(1289);
         assert_eq!(term_scorer.doc(), 0u32);
@@ -205,7 +201,7 @@ mod tests {
          let average_fieldnorm = fieldnorms
              .iter()
              .cloned()
-             .sum::<u32>() as f32 / term_doc_freq as f32;
+             .sum::<u32>() as Score / term_doc_freq as Score;
              // Average fieldnorm is over the entire index,
              // not necessarily the docs that are in the posting list.
              // For this reason we multiply by 1.1 to make a realistic value.
@@ -214,12 +210,12 @@ mod tests {
             average_fieldnorm);
 
          let mut term_scorer =
-              TermScorer::create_for_test(&doc_tfs[..], &fieldnorms[..], bm25_weight).unwrap();
+              TermScorer::create_for_test(&doc_tfs[..], &fieldnorms[..], bm25_weight);
 
          let docs: Vec<DocId> = (0..term_doc_freq).map(|doc| doc as DocId).collect();
          for block in docs.chunks(COMPRESSION_BLOCK_SIZE) {
-             let block_max_score = term_scorer.block_max_score();
-             let mut block_max_score_computed = 0.0f32;
+             let block_max_score: Score = term_scorer.block_max_score();
+             let mut block_max_score_computed: Score = 0.0;
              for &doc in block {
                 assert_eq!(term_scorer.doc(), doc);
                 block_max_score_computed = block_max_score_computed.max(term_scorer.score());
@@ -229,4 +225,113 @@ mod tests {
          }
         }
     }
+
+    #[test]
+    fn test_block_wand() {
+        let mut doc_tfs: Vec<(u32, u32)> = vec![];
+        for doc in 0u32..128u32 {
+            doc_tfs.push((doc, 1u32));
+        }
+        for doc in 128u32..256u32 {
+            doc_tfs.push((doc, if doc == 200 { 2u32 } else { 1u32 }));
+        }
+        doc_tfs.push((256, 1u32));
+        doc_tfs.push((257, 3u32));
+        doc_tfs.push((258, 1u32));
+
+        let fieldnorms: Vec<u32> = std::iter::repeat(20u32).take(300).collect();
+        let bm25_weight = BM25Weight::for_one_term(10, 129, 20.0);
+        let mut docs = TermScorer::create_for_test(&doc_tfs[..], &fieldnorms[..], bm25_weight);
+        assert_nearly_equals!(docs.block_max_score(), 2.5161593);
+        docs.shallow_seek(135);
+        assert_nearly_equals!(docs.block_max_score(), 3.4597192);
+        docs.shallow_seek(256);
+        // the block is not loaded yet.
+        assert_nearly_equals!(docs.block_max_score(), 5.2971773);
+        assert_eq!(256, docs.seek(256));
+        assert_nearly_equals!(docs.block_max_score(), 3.9539647);
+    }
+
+    fn test_block_wand_aux(term_query: &TermQuery, searcher: &Searcher) -> crate::Result<()> {
+        let term_weight = term_query.specialized_weight(&searcher, true);
+        for reader in searcher.segment_readers() {
+            let mut block_max_scores = vec![];
+            let mut block_max_scores_b = vec![];
+            let mut docs = vec![];
+            {
+                let mut term_scorer = term_weight.specialized_scorer(reader, 1.0)?;
+                while term_scorer.doc() != TERMINATED {
+                    let mut score = term_scorer.score();
+                    docs.push(term_scorer.doc());
+                    for _ in 0..128 {
+                        score = score.max(term_scorer.score());
+                        if term_scorer.advance() == TERMINATED {
+                            break;
+                        }
+                    }
+                    block_max_scores.push(score);
+                }
+            }
+            {
+                let mut term_scorer = term_weight.specialized_scorer(reader, 1.0)?;
+                for d in docs {
+                    term_scorer.shallow_seek(d);
+                    block_max_scores_b.push(term_scorer.block_max_score());
+                }
+            }
+            for (l, r) in block_max_scores
+                .iter()
+                .cloned()
+                .zip(block_max_scores_b.iter().cloned())
+            {
+                assert_nearly_equals!(l, r);
+            }
+        }
+        Ok(())
+    }
+
+    #[ignore]
+    #[test]
+    fn test_block_wand_long_test() -> crate::Result<()> {
+        let mut schema_builder = Schema::builder();
+        let text_field = schema_builder.add_text_field("text", TEXT);
+        let schema = schema_builder.build();
+        let index = Index::create_in_ram(schema);
+        let mut writer = index.writer_with_num_threads(3, 30_000_000)?;
+        use rand::Rng;
+        let mut rng = rand::thread_rng();
+        writer.set_merge_policy(Box::new(NoMergePolicy));
+        for _ in 0..3_000 {
+            let term_freq = rng.gen_range(1, 10000);
+            let words: Vec<&str> = std::iter::repeat("bbbb").take(term_freq).collect();
+            let text = words.join(" ");
+            writer.add_document(doc!(text_field=>text));
+        }
+        writer.commit()?;
+        let term_query = TermQuery::new(
+            Term::from_field_text(text_field, &"bbbb"),
+            IndexRecordOption::WithFreqs,
+        );
+        let segment_ids: Vec<SegmentId>;
+        let reader = index.reader()?;
+        {
+            let searcher = reader.searcher();
+            segment_ids = searcher
+                .segment_readers()
+                .iter()
+                .map(|segment| segment.segment_id())
+                .collect();
+            test_block_wand_aux(&term_query, &searcher)?;
+        }
+        {
+            let _ = block_on(writer.merge(&segment_ids[..]));
+        }
+        {
+            reader.reload()?;
+            let searcher = reader.searcher();
+            assert_eq!(searcher.segment_readers().len(), 1);
+            test_block_wand_aux(&term_query, &searcher)?;
+        }
+        Ok(())
+    }
 }

src/query/term_query/term_weight.rs

@@ -19,13 +19,13 @@ pub struct TermWeight {
 }
 
 impl Weight for TermWeight {
-    fn scorer(&self, reader: &SegmentReader, boost: f32) -> Result<Box<dyn Scorer>> {
+    fn scorer(&self, reader: &SegmentReader, boost: Score) -> Result<Box<dyn Scorer>> {
         let term_scorer = self.specialized_scorer(reader, boost)?;
         Ok(Box::new(term_scorer))
     }
 
     fn explain(&self, reader: &SegmentReader, doc: DocId) -> Result<Explanation> {
-        let mut scorer = self.specialized_scorer(reader, 1.0f32)?;
+        let mut scorer = self.specialized_scorer(reader, 1.0)?;
         if scorer.seek(doc) != doc {
             return Err(does_not_match(doc));
         }
@@ -34,7 +34,7 @@ impl Weight for TermWeight {
 
     fn count(&self, reader: &SegmentReader) -> Result<u32> {
         if let Some(delete_bitset) = reader.delete_bitset() {
-            Ok(self.scorer(reader, 1.0f32)?.count(delete_bitset))
+            Ok(self.scorer(reader, 1.0)?.count(delete_bitset))
         } else {
             let field = self.term.field();
             Ok(reader
@@ -52,7 +52,7 @@ impl Weight for TermWeight {
         reader: &SegmentReader,
         callback: &mut dyn FnMut(DocId, Score),
     ) -> crate::Result<()> {
-        let mut scorer = self.specialized_scorer(reader, 1.0f32)?;
+        let mut scorer = self.specialized_scorer(reader, 1.0)?;
         for_each_scorer(&mut scorer, callback);
         Ok(())
     }
@@ -69,11 +69,11 @@ impl Weight for TermWeight {
     /// important optimization (e.g. BlockWAND for union).
     fn for_each_pruning(
         &self,
-        threshold: f32,
+        threshold: Score,
         reader: &SegmentReader,
         callback: &mut dyn FnMut(DocId, Score) -> Score,
     ) -> crate::Result<()> {
-        let mut scorer = self.scorer(reader, 1.0f32)?;
+        let mut scorer = self.scorer(reader, 1.0)?;
         for_each_pruning_scorer(&mut scorer, threshold, callback);
         Ok(())
     }
@@ -92,7 +92,11 @@ impl TermWeight {
         }
     }
 
-    pub fn specialized_scorer(&self, reader: &SegmentReader, boost: f32) -> Result<TermScorer> {
+    pub(crate) fn specialized_scorer(
+        &self,
+        reader: &SegmentReader,
+        boost: Score,
+    ) -> Result<TermScorer> {
         let field = self.term.field();
         let inverted_index = reader.inverted_index(field);
         let fieldnorm_reader = reader.get_fieldnorms_reader(field);

src/query/union.rs

@@ -55,7 +55,7 @@ where
             cursor: HORIZON_NUM_TINYBITSETS,
             offset: 0,
             doc: 0,
-            score: 0f32,
+            score: 0.0,
         };
         if union.refill() {
             union.advance();
@@ -274,7 +274,7 @@ mod tests {
                 vals.iter()
                     .cloned()
                     .map(VecDocSet::from)
-                    .map(|docset| ConstScorer::new(docset, 1.0f32))
+                    .map(|docset| ConstScorer::new(docset, 1.0))
                     .collect::<Vec<ConstScorer<VecDocSet>>>(),
             )
         };
@@ -321,7 +321,7 @@ mod tests {
                     .iter()
                     .map(|docs| docs.clone())
                     .map(VecDocSet::from)
-                    .map(|docset| ConstScorer::new(docset, 1.0f32))
+                    .map(|docset| ConstScorer::new(docset, 1.0))
                     .collect::<Vec<_>>(),
             ));
             res

src/query/weight.rs

@@ -28,7 +28,7 @@ pub(crate) fn for_each_scorer<TScorer: Scorer + ?Sized>(
 /// important optimization (e.g. BlockWAND for union).
 pub(crate) fn for_each_pruning_scorer<TScorer: Scorer + ?Sized>(
     scorer: &mut TScorer,
-    mut threshold: f32,
+    mut threshold: Score,
     callback: &mut dyn FnMut(DocId, Score) -> Score,
 ) {
     let mut doc = scorer.doc();
@@ -51,14 +51,14 @@ pub trait Weight: Send + Sync + 'static {
     /// `boost` is a multiplier to apply to the score.
     ///
     /// See [`Query`](./trait.Query.html).
-    fn scorer(&self, reader: &SegmentReader, boost: f32) -> crate::Result<Box<dyn Scorer>>;
+    fn scorer(&self, reader: &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>;
 
     /// Returns the number documents within the given `SegmentReader`.
     fn count(&self, reader: &SegmentReader) -> crate::Result<u32> {
-        let mut scorer = self.scorer(reader, 1.0f32)?;
+        let mut scorer = self.scorer(reader, 1.0)?;
         if let Some(delete_bitset) = reader.delete_bitset() {
             Ok(scorer.count(delete_bitset))
         } else {
@@ -73,7 +73,7 @@ pub trait Weight: Send + Sync + 'static {
         reader: &SegmentReader,
         callback: &mut dyn FnMut(DocId, Score),
     ) -> crate::Result<()> {
-        let mut scorer = self.scorer(reader, 1.0f32)?;
+        let mut scorer = self.scorer(reader, 1.0)?;
         for_each_scorer(scorer.as_mut(), callback);
         Ok(())
     }
@@ -90,11 +90,11 @@ pub trait Weight: Send + Sync + 'static {
     /// important optimization (e.g. BlockWAND for union).
     fn for_each_pruning(
         &self,
-        threshold: f32,
+        threshold: Score,
         reader: &SegmentReader,
         callback: &mut dyn FnMut(DocId, Score) -> Score,
     ) -> crate::Result<()> {
-        let mut scorer = self.scorer(reader, 1.0f32)?;
+        let mut scorer = self.scorer(reader, 1.0)?;
         for_each_pruning_scorer(scorer.as_mut(), threshold, callback);
         Ok(())
     }

src/snippet/mod.rs

@@ -2,8 +2,8 @@ use crate::query::Query;
 use crate::schema::Field;
 use crate::schema::Value;
 use crate::tokenizer::{TextAnalyzer, Token};
-use crate::Document;
 use crate::Searcher;
+use crate::{Document, Score};
 use htmlescape::encode_minimal;
 use std::cmp::Ordering;
 use std::collections::BTreeMap;
@@ -30,7 +30,7 @@ impl HighlightSection {
 
 #[derive(Debug)]
 pub struct FragmentCandidate {
-    score: f32,
+    score: Score,
     start_offset: usize,
     stop_offset: usize,
     num_chars: usize,
@@ -58,7 +58,7 @@ impl FragmentCandidate {
     /// taking the token and terms, the token is added to the fragment.
     /// if the token is one of the terms, the score
     /// and highlighted fields are updated in the fragment.
-    fn try_add_token(&mut self, token: &Token, terms: &BTreeMap<String, f32>) {
+    fn try_add_token(&mut self, token: &Token, terms: &BTreeMap<String, Score>) {
         self.stop_offset = token.offset_to;
 
         if let Some(&score) = terms.get(&token.text.to_lowercase()) {
@@ -142,7 +142,7 @@ impl Snippet {
 fn search_fragments<'a>(
     tokenizer: &TextAnalyzer,
     text: &'a str,
-    terms: &BTreeMap<String, f32>,
+    terms: &BTreeMap<String, Score>,
     max_num_chars: usize,
 ) -> Vec<FragmentCandidate> {
     let mut token_stream = tokenizer.token_stream(text);
@@ -248,7 +248,7 @@ fn select_best_fragment_combination(fragments: &[FragmentCandidate], text: &str)
 /// # }
 /// ```
 pub struct SnippetGenerator {
-    terms_text: BTreeMap<String, f32>,
+    terms_text: BTreeMap<String, Score>,
     tokenizer: TextAnalyzer,
     field: Field,
     max_num_chars: usize,
@@ -263,12 +263,12 @@ impl SnippetGenerator {
     ) -> crate::Result<SnippetGenerator> {
         let mut terms = BTreeSet::new();
         query.query_terms(&mut terms);
-        let terms_text: BTreeMap<String, f32> = terms
+        let terms_text: BTreeMap<String, Score> = terms
             .into_iter()
             .filter(|term| term.field() == field)
             .flat_map(|term| {
                 let doc_freq = searcher.doc_freq(&term);
-                let score = 1f32 / (1f32 + doc_freq as f32);
+                let score = 1.0 / (1.0 + doc_freq as Score);
                 if doc_freq > 0 {
                     Some((term.text().to_string(), score))
                 } else {
@@ -291,7 +291,7 @@ impl SnippetGenerator {
     }
 
     #[cfg(test)]
-    pub fn terms_text(&self) -> &BTreeMap<String, f32> {
+    pub fn terms_text(&self) -> &BTreeMap<String, Score> {
         &self.terms_text
     }
 
@@ -373,8 +373,8 @@ Survey in 2016, 2017, and 2018."#;
     fn test_snippet_scored_fragment() {
         {
             let terms = btreemap! {
-                String::from("rust") =>1.0f32,
-                String::from("language") => 0.9f32
+                String::from("rust") =>1.0,
+                String::from("language") => 0.9
             };
             let fragments = search_fragments(&From::from(SimpleTokenizer), TEST_TEXT, &terms, 20);
             {
@@ -387,8 +387,8 @@ Survey in 2016, 2017, and 2018."#;
         }
         {
             let terms = btreemap! {
-                String::from("rust") =>0.9f32,
-                String::from("language") => 1.0f32
+                String::from("rust") =>0.9,
+                String::from("language") => 1.0
             };
             let fragments = search_fragments(&From::from(SimpleTokenizer), TEST_TEXT, &terms, 20);
             //assert_eq!(fragments.len(), 7);
@@ -525,7 +525,7 @@ Survey in 2016, 2017, and 2018."#;
             let snippet_generator =
                 SnippetGenerator::create(&searcher, &*query, text_field).unwrap();
             assert_eq!(
-                &btreemap!("a".to_string() => 0.25f32),
+                &btreemap!("a".to_string() => 0.25),
                 snippet_generator.terms_text()
             );
         }
@@ -534,7 +534,7 @@ Survey in 2016, 2017, and 2018."#;
             let snippet_generator =
                 SnippetGenerator::create(&searcher, &*query, text_field).unwrap();
             assert_eq!(
-                &btreemap!("a".to_string() => 0.25f32, "b".to_string() => 0.5),
+                &btreemap!("a".to_string() => 0.25, "b".to_string() => 0.5),
                 snippet_generator.terms_text()
             );
         }
@@ -543,7 +543,7 @@ Survey in 2016, 2017, and 2018."#;
             let snippet_generator =
                 SnippetGenerator::create(&searcher, &*query, text_field).unwrap();
             assert_eq!(
-                &btreemap!("a".to_string() => 0.25f32, "b".to_string() => 0.5),
+                &btreemap!("a".to_string() => 0.25, "b".to_string() => 0.5),
                 snippet_generator.terms_text()
             );
         }