feat: Make the search algorithm become fully data oriented

Cargo.toml

@@ -21,6 +21,7 @@ serde_derive = "1.0"
 serde_json = { version = "1.0", features = ["preserve_order"] }
 slice-group-by = "0.2"
 unidecode = "0.3"
+rayon = "1.0"
 
 [dependencies.toml]
 git = "https://github.com/Kerollmops/toml-rs.git"

src/rank/criterion/exact.rs

@@ -1,33 +1,40 @@
 use std::cmp::Ordering;
-use std::ops::Deref;
 
-use rocksdb::DB;
 use slice_group_by::GroupBy;
 
-use crate::rank::{match_query_index, Document};
 use crate::rank::criterion::Criterion;
-use crate::database::DatabaseView;
-use crate::Match;
+use crate::rank::RawDocument;
 
 #[inline]
-fn contains_exact(matches: &&[Match]) -> bool {
-    matches.iter().any(|m| m.is_exact)
+fn number_exact_matches(query_index: &[u32], is_exact: &[bool]) -> usize {
+    let mut count = 0;
+    let mut index = 0;
+
+    for group in query_index.linear_group_by(PartialEq::eq) {
+        let len = group.len();
+        count += is_exact[index..index + len].contains(&true) as usize;
+        index += len;
     }
 
-#[inline]
-fn number_exact_matches(matches: &[Match]) -> usize {
-    matches.linear_group_by(match_query_index).filter(contains_exact).count()
+    count
 }
 
 #[derive(Debug, Clone, Copy)]
 pub struct Exact;
 
-impl<D> Criterion<D> for Exact
-where D: Deref<Target=DB>
-{
-    fn evaluate(&self, lhs: &Document, rhs: &Document, _: &DatabaseView<D>) -> Ordering {
-        let lhs = number_exact_matches(&lhs.matches);
-        let rhs = number_exact_matches(&rhs.matches);
+impl Criterion for Exact {
+    fn evaluate(&self, lhs: &RawDocument, rhs: &RawDocument) -> Ordering {
+        let lhs = {
+            let query_index = lhs.query_index();
+            let is_exact = lhs.is_exact();
+            number_exact_matches(query_index, is_exact)
+        };
+
+        let rhs = {
+            let query_index = rhs.query_index();
+            let is_exact = rhs.is_exact();
+            number_exact_matches(query_index, is_exact)
+        };
 
         lhs.cmp(&rhs).reverse()
     }

src/rank/criterion/mod.rs

@@ -4,16 +4,13 @@ mod words_proximity;
 mod sum_of_words_attribute;
 mod sum_of_words_position;
 mod exact;
-mod sort_by;
+// mod sort_by;
 mod document_id;
 
 use std::cmp::Ordering;
-use std::ops::Deref;
-
-use rocksdb::DB;
 
 use crate::database::DatabaseView;
-use crate::rank::Document;
+use crate::rank::RawDocument;
 
 pub use self::{
     sum_of_typos::SumOfTypos,

src/rank/criterion/number_of_words.rs

@@ -1,28 +1,28 @@
 use std::cmp::Ordering;
-use std::ops::Deref;
 
-use rocksdb::DB;
 use slice_group_by::GroupBy;
 
-use crate::rank::{match_query_index, Document};
 use crate::rank::criterion::Criterion;
-use crate::database::DatabaseView;
-use crate::Match;
+use crate::rank::RawDocument;
 
 #[inline]
-fn number_of_query_words(matches: &[Match]) -> usize {
-    matches.linear_group_by(match_query_index).count()
+fn number_of_query_words(query_index: &[u32]) -> usize {
+    query_index.linear_group_by(PartialEq::eq).count()
 }
 
 #[derive(Debug, Clone, Copy)]
 pub struct NumberOfWords;
 
-impl<D> Criterion<D> for NumberOfWords
-where D: Deref<Target=DB>
-{
-    fn evaluate(&self, lhs: &Document, rhs: &Document, _: &DatabaseView<D>) -> Ordering {
-        let lhs = number_of_query_words(&lhs.matches);
-        let rhs = number_of_query_words(&rhs.matches);
+impl Criterion for NumberOfWords {
+    fn evaluate(&self, lhs: &RawDocument, rhs: &RawDocument) -> Ordering {
+        let lhs = {
+            let query_index = lhs.query_index();
+            number_of_query_words(query_index)
+        };
+        let rhs = {
+            let query_index = rhs.query_index();
+            number_of_query_words(query_index)
+        };
 
         lhs.cmp(&rhs).reverse()
     }

src/rank/criterion/sort_by.rs

@@ -7,7 +7,7 @@ use serde::de::DeserializeOwned;
 
 use crate::rank::criterion::Criterion;
 use crate::database::DatabaseView;
-use crate::rank::Document;
+use crate::rank::RawDocument;
 
 /// An helper struct that permit to sort documents by
 /// some of their stored attributes.

src/rank/criterion/sum_of_typos.rs

@@ -1,24 +1,20 @@
 use std::cmp::Ordering;
-use std::ops::Deref;
 
-use rocksdb::DB;
 use slice_group_by::GroupBy;
 
-use crate::rank::{match_query_index, Document};
 use crate::rank::criterion::Criterion;
-use crate::database::DatabaseView;
-use crate::Match;
+use crate::rank::RawDocument;
 
 #[inline]
-fn sum_matches_typos(matches: &[Match]) -> isize {
+fn sum_matches_typos(query_index: &[u32], distance: &[u8]) -> isize {
     let mut sum_typos = 0;
     let mut number_words = 0;
+    let mut index = 0;
 
-    // note that GroupBy will never return an empty group
-    // so we can do this assumption safely
-    for group in matches.linear_group_by(match_query_index) {
-        sum_typos += unsafe { group.get_unchecked(0).distance as isize };
+    for group in query_index.linear_group_by(PartialEq::eq) {
+        sum_typos += distance[index] as isize;
         number_words += 1;
+        index += group.len();
     }
 
     sum_typos - number_words
@@ -27,78 +23,42 @@ fn sum_matches_typos(matches: &[Match]) -> isize {
 #[derive(Debug, Clone, Copy)]
 pub struct SumOfTypos;
 
-impl<D> Criterion<D> for SumOfTypos
-where D: Deref<Target=DB>
-{
-    fn evaluate(&self, lhs: &Document, rhs: &Document, _: &DatabaseView<D>) -> Ordering {
-        let lhs = sum_matches_typos(&lhs.matches);
-        let rhs = sum_matches_typos(&rhs.matches);
+impl Criterion for SumOfTypos {
+    fn evaluate(&self, lhs: &RawDocument, rhs: &RawDocument) -> Ordering {
+        let lhs = {
+            let query_index = lhs.query_index();
+            let distance = lhs.distance();
+            sum_matches_typos(query_index, distance)
+        };
+
+        let rhs = {
+            let query_index = rhs.query_index();
+            let distance = rhs.distance();
+            sum_matches_typos(query_index, distance)
+        };
 
         lhs.cmp(&rhs)
     }
 }
 
-
 #[cfg(test)]
 mod tests {
     use super::*;
 
-    use crate::{DocumentId, Attribute, WordArea};
-
     // typing: "Geox CEO"
     //
     // doc0: "Geox SpA: CEO and Executive"
     // doc1: "Mt. Gox CEO Resigns From Bitcoin Foundation"
     #[test]
     fn one_typo_reference() {
-        let doc0 = {
-            let matches = vec![
-                Match {
-                    query_index: 0,
-                    distance: 0,
-                    attribute: Attribute::new_faillible(0, 0),
-                    is_exact: false,
-                    word_area: WordArea::new_faillible(0, 6)
-                },
-                Match {
-                    query_index: 1,
-                    distance: 0,
-                    attribute: Attribute::new_faillible(0, 2),
-                    is_exact: false,
-                    word_area: WordArea::new_faillible(0, 6)
-                },
-            ];
-            Document {
-                id: DocumentId(0),
-                matches: matches,
-            }
-        };
+        let query_index0 = &[0, 1];
+        let distance0 = &[0, 0];
 
-        let doc1 = {
-            let matches = vec![
-                Match {
-                    query_index: 0,
-                    distance: 1,
-                    attribute: Attribute::new_faillible(0, 0),
-                    is_exact: false,
-                    word_area: WordArea::new_faillible(0, 6)
-                },
-                Match {
-                    query_index: 1,
-                    distance: 0,
-                    attribute: Attribute::new_faillible(0, 2),
-                    is_exact: false,
-                    word_area: WordArea::new_faillible(0, 6)
-                },
-            ];
-            Document {
-                id: DocumentId(1),
-                matches: matches,
-            }
-        };
+        let query_index1 = &[0, 1];
+        let distance1 = &[1, 0];
 
-        let lhs = sum_matches_typos(&doc0.matches);
-        let rhs = sum_matches_typos(&doc1.matches);
+        let lhs = sum_matches_typos(query_index0, distance0);
+        let rhs = sum_matches_typos(query_index1, distance1);
         assert_eq!(lhs.cmp(&rhs), Ordering::Less);
     }
 
@@ -108,47 +68,14 @@ mod tests {
     // doc1: "bouton"
     #[test]
     fn no_typo() {
-        let doc0 = {
-            let matches = vec![
-                Match {
-                    query_index: 0,
-                    distance: 0,
-                    attribute: Attribute::new_faillible(0, 0),
-                    is_exact: false,
-                    word_area: WordArea::new_faillible(0, 6)
-                },
-                Match {
-                    query_index: 1,
-                    distance: 0,
-                    attribute: Attribute::new_faillible(0, 1),
-                    is_exact: false,
-                    word_area: WordArea::new_faillible(0, 6)
-                },
-            ];
-            Document {
-                id: DocumentId(0),
-                matches: matches,
-            }
-        };
+        let query_index0 = &[0, 1];
+        let distance0 = &[0, 0];
 
-        let doc1 = {
-            let matches = vec![
-                Match {
-                    query_index: 0,
-                    distance: 0,
-                    attribute: Attribute::new_faillible(0, 0),
-                    is_exact: false,
-                    word_area: WordArea::new_faillible(0, 6)
-                },
-            ];
-            Document {
-                id: DocumentId(1),
-                matches: matches,
-            }
-        };
+        let query_index1 = &[0];
+        let distance1 = &[0];
 
-        let lhs = sum_matches_typos(&doc0.matches);
-        let rhs = sum_matches_typos(&doc1.matches);
+        let lhs = sum_matches_typos(query_index0, distance0);
+        let rhs = sum_matches_typos(query_index1, distance1);
         assert_eq!(lhs.cmp(&rhs), Ordering::Less);
     }
 
@@ -158,47 +85,14 @@ mod tests {
     // doc1: "bouton"
     #[test]
     fn one_typo() {
-        let doc0 = {
-            let matches = vec![
-                Match {
-                    query_index: 0,
-                    distance: 0,
-                    attribute: Attribute::new_faillible(0, 0),
-                    is_exact: false,
-                    word_area: WordArea::new_faillible(0, 6)
-                },
-                Match {
-                    query_index: 1,
-                    distance: 1,
-                    attribute: Attribute::new_faillible(0, 1),
-                    is_exact: false,
-                    word_area: WordArea::new_faillible(0, 6)
-                },
-            ];
-            Document {
-                id: DocumentId(0),
-                matches: matches,
-            }
-        };
+        let query_index0 = &[0, 1];
+        let distance0 = &[0, 1];
 
-        let doc1 = {
-            let matches = vec![
-                Match {
-                    query_index: 0,
-                    distance: 0,
-                    attribute: Attribute::new_faillible(0, 0),
-                    is_exact: false,
-                    word_area: WordArea::new_faillible(0, 6)
-                },
-            ];
-            Document {
-                id: DocumentId(1),
-                matches: matches,
-            }
-        };
+        let query_index1 = &[0];
+        let distance1 = &[0];
 
-        let lhs = sum_matches_typos(&doc0.matches);
-        let rhs = sum_matches_typos(&doc1.matches);
+        let lhs = sum_matches_typos(query_index0, distance0);
+        let rhs = sum_matches_typos(query_index1, distance1);
         assert_eq!(lhs.cmp(&rhs), Ordering::Equal);
     }
 }

src/rank/criterion/sum_of_words_attribute.rs

@@ -1,32 +1,39 @@
 use std::cmp::Ordering;
-use std::ops::Deref;
 
-use rocksdb::DB;
 use slice_group_by::GroupBy;
 
-use crate::database::DatabaseView;
-use crate::rank::{match_query_index, Document};
 use crate::rank::criterion::Criterion;
-use crate::Match;
+use crate::rank::RawDocument;
 
 #[inline]
-fn sum_matches_attributes(matches: &[Match]) -> usize {
-    // note that GroupBy will never return an empty group
-    // so we can do this assumption safely
-    matches.linear_group_by(match_query_index).map(|group| {
-        unsafe { group.get_unchecked(0).attribute.attribute() as usize }
-    }).sum()
+fn sum_matches_attributes(query_index: &[u32], attribute: &[u16]) -> usize {
+    let mut sum_attributes = 0;
+    let mut index = 0;
+
+    for group in query_index.linear_group_by(PartialEq::eq) {
+        sum_attributes += attribute[index] as usize;
+        index += group.len();
+    }
+
+    sum_attributes
 }
 
 #[derive(Debug, Clone, Copy)]
 pub struct SumOfWordsAttribute;
 
-impl<D> Criterion<D> for SumOfWordsAttribute
-where D: Deref<Target=DB>
-{
-    fn evaluate(&self, lhs: &Document, rhs: &Document, _: &DatabaseView<D>) -> Ordering {
-        let lhs = sum_matches_attributes(&lhs.matches);
-        let rhs = sum_matches_attributes(&rhs.matches);
+impl Criterion for SumOfWordsAttribute {
+    fn evaluate(&self, lhs: &RawDocument, rhs: &RawDocument) -> Ordering {
+        let lhs = {
+            let query_index = lhs.query_index();
+            let attribute = lhs.attribute();
+            sum_matches_attributes(query_index, attribute)
+        };
+
+        let rhs = {
+            let query_index = rhs.query_index();
+            let attribute = rhs.attribute();
+            sum_matches_attributes(query_index, attribute)
+        };
 
         lhs.cmp(&rhs)
     }

src/rank/criterion/sum_of_words_position.rs

@@ -1,32 +1,39 @@
 use std::cmp::Ordering;
-use std::ops::Deref;
 
-use rocksdb::DB;
 use slice_group_by::GroupBy;
 
-use crate::database::DatabaseView;
-use crate::rank::{match_query_index, Document};
 use crate::rank::criterion::Criterion;
-use crate::Match;
+use crate::rank::RawDocument;
 
 #[inline]
-fn sum_matches_attribute_index(matches: &[Match]) -> usize {
-    // note that GroupBy will never return an empty group
-    // so we can do this assumption safely
-    matches.linear_group_by(match_query_index).map(|group| {
-        unsafe { group.get_unchecked(0).attribute.word_index() as usize }
-    }).sum()
+fn sum_matches_attribute_index(query_index: &[u32], word_index: &[u32]) -> usize {
+    let mut sum_word_index = 0;
+    let mut index = 0;
+
+    for group in query_index.linear_group_by(PartialEq::eq) {
+        sum_word_index += word_index[index] as usize;
+        index += group.len();
+    }
+
+    sum_word_index
 }
 
 #[derive(Debug, Clone, Copy)]
 pub struct SumOfWordsPosition;
 
-impl<D> Criterion<D> for SumOfWordsPosition
-where D: Deref<Target=DB>
-{
-    fn evaluate(&self, lhs: &Document, rhs: &Document, _: &DatabaseView<D>) -> Ordering {
-        let lhs = sum_matches_attribute_index(&lhs.matches);
-        let rhs = sum_matches_attribute_index(&rhs.matches);
+impl Criterion for SumOfWordsPosition {
+    fn evaluate(&self, lhs: &RawDocument, rhs: &RawDocument) -> Ordering {
+        let lhs = {
+            let query_index = lhs.query_index();
+            let word_index = lhs.word_index();
+            sum_matches_attribute_index(query_index, word_index)
+        };
+
+        let rhs = {
+            let query_index = rhs.query_index();
+            let word_index = rhs.word_index();
+            sum_matches_attribute_index(query_index, word_index)
+        };
 
         lhs.cmp(&rhs)
     }

src/rank/criterion/words_proximity.rs

@@ -1,16 +1,17 @@
 use std::cmp::{self, Ordering};
-use std::ops::Deref;
 
-use rocksdb::DB;
 use slice_group_by::GroupBy;
 
-use crate::rank::{match_query_index, Document};
 use crate::rank::criterion::Criterion;
-use crate::database::DatabaseView;
-use crate::Match;
+use crate::rank::RawDocument;
 
 const MAX_DISTANCE: u32 = 8;
 
+#[inline]
+fn clone_tuple<T: Clone, U: Clone>((a, b): (&T, &U)) -> (T, U) {
+    (a.clone(), b.clone())
+}
+
 fn index_proximity(lhs: u32, rhs: u32) -> u32 {
     if lhs < rhs {
         cmp::min(rhs - lhs, MAX_DISTANCE)
@@ -19,30 +20,48 @@ fn index_proximity(lhs: u32, rhs: u32) -> u32 {
     }
 }
 
-fn attribute_proximity(lhs: &Match, rhs: &Match) -> u32 {
-    if lhs.attribute.attribute() != rhs.attribute.attribute() { return MAX_DISTANCE }
-    index_proximity(lhs.attribute.word_index(), rhs.attribute.word_index())
+fn attribute_proximity((lattr, lwi): (u16, u32), (rattr, rwi): (u16, u32)) -> u32 {
+    if lattr != rattr { return MAX_DISTANCE }
+    index_proximity(lwi, rwi)
 }
 
-fn min_proximity(lhs: &[Match], rhs: &[Match]) -> u32 {
+fn min_proximity((lattr, lwi): (&[u16], &[u32]), (rattr, rwi): (&[u16], &[u32])) -> u32 {
     let mut min_prox = u32::max_value();
-    for a in lhs {
-        for b in rhs {
+    for a in lattr.iter().zip(lwi) {
+        for b in rattr.iter().zip(rwi) {
+            let a = clone_tuple(a);
+            let b = clone_tuple(b);
             min_prox = cmp::min(min_prox, attribute_proximity(a, b));
         }
     }
     min_prox
 }
 
-fn matches_proximity(matches: &[Match]) -> u32 {
+fn matches_proximity(query_index: &[u32], attribute: &[u16], word_index: &[u32]) -> u32 {
     let mut proximity = 0;
-    let mut iter = matches.linear_group_by(match_query_index);
 
-    // iterate over groups by windows of size 2
-    let mut last = iter.next();
+    let mut index = 0;
+    let mut iter = query_index.linear_group_by(PartialEq::eq);
+    let mut last = iter.next().map(|group| {
+        let len = group.len();
+
+        let rattr = &attribute[index..index + len];
+        let rwi = &word_index[index..index + len];
+        index += len;
+
+        (rattr, rwi)
+    });
+
     while let (Some(lhs), Some(rhs)) = (last, iter.next()) {
+        let len = rhs.len();
+
+        let rattr = &attribute[index..index + len];
+        let rwi = &word_index[index..index + len];
+        let rhs = (rattr, rwi);
+
         proximity += min_proximity(lhs, rhs);
         last = Some(rhs);
+        index += len;
     }
 
     proximity
@@ -51,18 +70,26 @@ fn matches_proximity(matches: &[Match]) -> u32 {
 #[derive(Debug, Clone, Copy)]
 pub struct WordsProximity;
 
-impl<D> Criterion<D> for WordsProximity
-where D: Deref<Target=DB>
-{
-    fn evaluate(&self, lhs: &Document, rhs: &Document, _: &DatabaseView<D>) -> Ordering {
-        let lhs = matches_proximity(&lhs.matches);
-        let rhs = matches_proximity(&rhs.matches);
+impl Criterion for WordsProximity {
+    fn evaluate(&self, lhs: &RawDocument, rhs: &RawDocument) -> Ordering {
+        let lhs = {
+            let query_index = lhs.query_index();
+            let attribute = lhs.attribute();
+            let word_index = lhs.word_index();
+            matches_proximity(query_index, attribute, word_index)
+        };
+
+        let rhs = {
+            let query_index = rhs.query_index();
+            let attribute = rhs.attribute();
+            let word_index = rhs.word_index();
+            matches_proximity(query_index, attribute, word_index)
+        };
 
         lhs.cmp(&rhs)
     }
 }
 
-
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -80,18 +107,14 @@ mod tests {
         // { id: 2, attr: 2, attr_index: 0 }
         // { id: 3, attr: 3, attr_index: 1 }
 
-        let matches = &[
-            Match { query_index: 0, attribute: Attribute::new_faillible(0, 0), ..Match::zero() },
-            Match { query_index: 1, attribute: Attribute::new_faillible(1, 0), ..Match::zero() },
-            Match { query_index: 2, attribute: Attribute::new_faillible(1, 1), ..Match::zero() },
-            Match { query_index: 2, attribute: Attribute::new_faillible(2, 0), ..Match::zero() },
-            Match { query_index: 3, attribute: Attribute::new_faillible(3, 1), ..Match::zero() },
-        ];
+        let query_index = &[0, 1, 2, 2, 3];
+        let attribute = &[0, 1, 1, 2, 3];
+        let word_index = &[0, 0, 1, 0, 1];
 
         //   soup -> of = 8
         // + of -> the  = 1
         // + the -> day = 8 (not 1)
-        assert_eq!(matches_proximity(matches), 17);
+        assert_eq!(matches_proximity(query_index, attribute, word_index), 17);
     }
 
     #[test]
@@ -106,19 +129,14 @@ mod tests {
         // { id: 3, attr: 0, attr_index: 1 }
         // { id: 3, attr: 1, attr_index: 3 }
 
-        let matches = &[
-            Match { query_index: 0, attribute: Attribute::new_faillible(0, 0), ..Match::zero() },
-            Match { query_index: 0, attribute: Attribute::new_faillible(1, 0), ..Match::zero() },
-            Match { query_index: 1, attribute: Attribute::new_faillible(1, 1), ..Match::zero() },
-            Match { query_index: 2, attribute: Attribute::new_faillible(1, 2), ..Match::zero() },
-            Match { query_index: 3, attribute: Attribute::new_faillible(0, 1), ..Match::zero() },
-            Match { query_index: 3, attribute: Attribute::new_faillible(1, 3), ..Match::zero() },
-        ];
+        let query_index = &[0, 0, 1, 2, 3, 3];
+        let attribute = &[0, 1, 1, 1, 0, 1];
+        let word_index = &[0, 0, 1, 2, 1, 3];
 
         //   soup -> of = 1
         // + of -> the  = 1
         // + the -> day = 1
-        assert_eq!(matches_proximity(matches), 3);
+        assert_eq!(matches_proximity(query_index, attribute, word_index), 3);
     }
 }
 

src/rank/mod.rs

@@ -2,32 +2,182 @@ pub mod criterion;
 mod query_builder;
 mod distinct_map;
 
+use std::sync::Arc;
+
+use slice_group_by::GroupBy;
+use rayon::slice::ParallelSliceMut;
+
 use crate::{Match, DocumentId};
 
 pub use self::query_builder::{FilterFunc, QueryBuilder, DistinctQueryBuilder};
 
-#[inline]
-fn match_query_index(a: &Match, b: &Match) -> bool {
-    a.query_index == b.query_index
-}
-
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub struct Document {
     pub id: DocumentId,
     pub matches: Vec<Match>,
 }
 
 impl Document {
-    pub fn new(doc: DocumentId, match_: Match) -> Self {
-        unsafe { Self::from_sorted_matches(doc, vec![match_]) }
+    pub fn from_raw(raw: &RawDocument) -> Document {
+        let len = raw.matches.range.len();
+        let mut matches = Vec::with_capacity(len);
+
+        let query_index = raw.query_index();
+        let distance = raw.distance();
+        let attribute = raw.attribute();
+        let word_index = raw.word_index();
+        let is_exact = raw.is_exact();
+        let char_index = raw.char_index();
+        let char_length = raw.char_length();
+
+        for i in 0..len {
+            let match_ = Match {
+                query_index: query_index[i],
+                distance: distance[i],
+                attribute: attribute[i],
+                word_index: word_index[i],
+                is_exact: is_exact[i],
+                char_index: char_index[i],
+                char_length: char_length[i],
+            };
+            matches.push(match_);
         }
 
-    pub fn from_matches(doc: DocumentId, mut matches: Vec<Match>) -> Self {
-        matches.sort_unstable();
-        unsafe { Self::from_sorted_matches(doc, matches) }
+        Document { id: raw.id, matches }
+    }
 }
 
-    pub unsafe fn from_sorted_matches(id: DocumentId, matches: Vec<Match>) -> Self {
-        Self { id, matches }
+#[derive(Clone)]
+pub struct RawDocument {
+    pub id: DocumentId,
+    pub matches: SharedMatches,
+}
+
+impl RawDocument {
+    fn new(id: DocumentId, range: Range, matches: Arc<Matches>) -> RawDocument {
+        RawDocument { id, matches: SharedMatches { range, matches } }
+    }
+
+    pub fn query_index(&self) -> &[u32] {
+        let r = self.matches.range;
+        // it is safe because construction/modifications
+        // can only be done in this module
+        unsafe { &self.matches.matches.query_index.get_unchecked(r.start..r.end) }
+    }
+
+    pub fn distance(&self) -> &[u8] {
+        let r = self.matches.range;
+        // it is safe because construction/modifications
+        // can only be done in this module
+        unsafe { &self.matches.matches.distance.get_unchecked(r.start..r.end) }
+    }
+
+    pub fn attribute(&self) -> &[u16] {
+        let r = self.matches.range;
+        // it is safe because construction/modifications
+        // can only be done in this module
+        unsafe { &self.matches.matches.attribute.get_unchecked(r.start..r.end) }
+    }
+
+    pub fn word_index(&self) -> &[u32] {
+        let r = self.matches.range;
+        // it is safe because construction/modifications
+        // can only be done in this module
+        unsafe { &self.matches.matches.word_index.get_unchecked(r.start..r.end) }
+    }
+
+    pub fn is_exact(&self) -> &[bool] {
+        let r = self.matches.range;
+        // it is safe because construction/modifications
+        // can only be done in this module
+        unsafe { &self.matches.matches.is_exact.get_unchecked(r.start..r.end) }
+    }
+
+    pub fn char_index(&self) -> &[u32] {
+        let r = self.matches.range;
+        // it is safe because construction/modifications
+        // can only be done in this module
+        unsafe { &self.matches.matches.char_index.get_unchecked(r.start..r.end) }
+    }
+
+    pub fn char_length(&self) -> &[u16] {
+        let r = self.matches.range;
+        // it is safe because construction/modifications
+        // can only be done in this module
+        unsafe { &self.matches.matches.char_length.get_unchecked(r.start..r.end) }
+    }
+}
+
+pub fn raw_documents_from_matches(mut matches: Vec<(DocumentId, Match)>) -> Vec<RawDocument> {
+    let mut docs_ranges = Vec::<(DocumentId, Range)>::new();
+    let mut matches2 = Matches::with_capacity(matches.len());
+
+    matches.par_sort_unstable();
+
+    for group in matches.linear_group_by(|(a, _), (b, _)| a == b) {
+        let id = group[0].0;
+        let start = docs_ranges.last().map(|(_, r)| r.end).unwrap_or(0);
+        let end = start + group.len();
+        docs_ranges.push((id, Range { start, end }));
+
+        matches2.extend_from_slice(group);
+    }
+
+    let matches = Arc::new(matches2);
+    docs_ranges.into_iter().map(|(i, r)| RawDocument::new(i, r, matches.clone())).collect()
+}
+
+#[derive(Debug, Copy, Clone)]
+struct Range {
+    start: usize,
+    end: usize,
+}
+
+impl Range {
+    fn len(self) -> usize {
+        self.end - self.start
+    }
+}
+
+#[derive(Clone)]
+pub struct SharedMatches {
+    range: Range,
+    matches: Arc<Matches>,
+}
+
+#[derive(Clone)]
+struct Matches {
+    query_index: Vec<u32>,
+    distance: Vec<u8>,
+    attribute: Vec<u16>,
+    word_index: Vec<u32>,
+    is_exact: Vec<bool>,
+    char_index: Vec<u32>,
+    char_length: Vec<u16>,
+}
+
+impl Matches {
+    fn with_capacity(cap: usize) -> Matches {
+        Matches {
+            query_index: Vec::with_capacity(cap),
+            distance: Vec::with_capacity(cap),
+            attribute: Vec::with_capacity(cap),
+            word_index: Vec::with_capacity(cap),
+            is_exact: Vec::with_capacity(cap),
+            char_index: Vec::with_capacity(cap),
+            char_length: Vec::with_capacity(cap),
+        }
+    }
+
+    fn extend_from_slice(&mut self, matches: &[(DocumentId, Match)]) {
+        for (_, match_) in matches {
+            self.query_index.push(match_.query_index);
+            self.distance.push(match_.distance);
+            self.attribute.push(match_.attribute);
+            self.word_index.push(match_.word_index);
+            self.is_exact.push(match_.is_exact);
+            self.char_index.push(match_.char_index);
+            self.char_length.push(match_.char_length);
+        }
     }
 }

src/rank/query_builder.rs

@@ -4,7 +4,9 @@ use std::error::Error;
 use std::hash::Hash;
 use std::rc::Rc;
 
+use rayon::slice::ParallelSliceMut;
 use slice_group_by::GroupByMut;
+use elapsed::measure_time;
 use hashbrown::HashMap;
 use fst::Streamer;
 use rocksdb::DB;
@@ -15,7 +17,7 @@ use crate::rank::distinct_map::{DistinctMap, BufferedDistinctMap};
 use crate::rank::criterion::Criteria;
 use crate::database::DatabaseView;
 use crate::{Match, DocumentId};
-use crate::rank::Document;
+use crate::rank::{raw_documents_from_matches, RawDocument, Document};
 
 fn split_whitespace_automatons(query: &str) -> Vec<DfaExt> {
     let has_end_whitespace = query.chars().last().map_or(false, char::is_whitespace);
@@ -81,7 +83,7 @@ where D: Deref<Target=DB>,
         }
     }
 
-    fn query_all(&self, query: &str) -> Vec<Document> {
+    fn query_all(&self, query: &str) -> Vec<RawDocument> {
         let automatons = split_whitespace_automatons(query);
 
         let mut stream = {
@@ -94,7 +96,7 @@ where D: Deref<Target=DB>,
         };
 
         let mut number_matches = 0;
-        let mut matches = HashMap::new();
+        let mut matches = Vec::new();
 
         while let Some((input, indexed_values)) = stream.next() {
             for iv in indexed_values {
@@ -105,7 +107,6 @@ where D: Deref<Target=DB>,
                 let doc_indexes = &self.view.index().positive.indexes();
                 let doc_indexes = &doc_indexes[iv.value as usize];
 
-                number_matches += doc_indexes.len();
                 for doc_index in doc_indexes {
                     let match_ = Match {
                         query_index: iv.index as u32,
@@ -116,15 +117,18 @@ where D: Deref<Target=DB>,
                         char_index: doc_index.char_index,
                         char_length: doc_index.char_length,
                     };
-                    matches.entry(doc_index.document_id).or_insert_with(Vec::new).push(match_);
+                    matches.push((doc_index.document_id, match_));
                 }
             }
         }
 
-        info!("{} total documents to classify", matches.len());
-        info!("{} total matches to classify", number_matches);
+        let total_matches = matches.len();
+        let raw_documents = raw_documents_from_matches(matches);
 
-        matches.into_iter().map(|(i, m)| Document::from_matches(i, m)).collect()
+        info!("{} total documents to classify", raw_documents.len());
+        info!("{} total matches to classify", total_matches);
+
+        raw_documents
     }
 }
 
@@ -140,7 +144,7 @@ where D: Deref<Target=DB>,
             return builder.query(query, range);
         }
 
-        let (elapsed, mut documents) = elapsed::measure_time(|| self.query_all(query));
+        let (elapsed, mut documents) = measure_time(|| self.query_all(query));
         info!("query_all took {}", elapsed);
 
         let mut groups = vec![documents.as_mut_slice()];
@@ -177,12 +181,9 @@ where D: Deref<Target=DB>,
             }
         }
 
-        // `drain` removes the documents efficiently using `ptr::copy`
-        // TODO it could be more efficient to have a custom iterator
         let offset = cmp::min(documents.len(), range.start);
-        documents.drain(0..offset);
-        documents.truncate(range.len());
-        documents
+        let iter = documents.into_iter().skip(offset).take(range.len());
+        iter.map(|d| Document::from_raw(&d)).collect()
     }
 }
 
@@ -215,7 +216,9 @@ where D: Deref<Target=DB>,
       K: Hash + Eq,
 {
     pub fn query(self, query: &str, range: Range<usize>) -> Vec<Document> {
-        let mut documents = self.inner.query_all(query);
+        let (elapsed, mut documents) = measure_time(|| self.inner.query_all(query));
+        info!("query_all took {}", elapsed);
+
         let mut groups = vec![documents.as_mut_slice()];
         let mut key_cache = HashMap::new();
         let view = &self.inner.view;
@@ -227,12 +230,14 @@ where D: Deref<Target=DB>,
         let mut distinct_map = DistinctMap::new(self.size);
         let mut distinct_raw_offset = 0;
 
-        'criteria: for criterion in self.inner.criteria.as_ref() {
+        'criteria: for (ci, criterion) in self.inner.criteria.as_ref().iter().enumerate() {
             let tmp_groups = mem::replace(&mut groups, Vec::new());
             let mut buf_distinct = BufferedDistinctMap::new(&mut distinct_map);
             let mut documents_seen = 0;
 
             for group in tmp_groups {
+                info!("criterion {}, documents group of size {}", ci, group.len());
+
                 // if this group does not overlap with the requested range,
                 // push it without sorting and splitting it
                 if documents_seen + group.len() < distinct_raw_offset {
@@ -241,9 +246,12 @@ where D: Deref<Target=DB>,
                     continue;
                 }
 
-                group.sort_unstable_by(|a, b| criterion.evaluate(a, b, view));
+                let (elapsed, _) = measure_time(|| {
+                    group.par_sort_unstable_by(|a, b| criterion.evaluate(a, b));
+                });
+                info!("criterion {} sort took {}", ci, elapsed);
 
-                for group in group.binary_group_by_mut(|a, b| criterion.eq(a, b, view)) {
+                for group in group.binary_group_by_mut(|a, b| criterion.eq(a, b)) {
                     // we must compute the real distinguished len of this sub-group
                     for document in group.iter() {
                         let filter_accepted = match &self.inner.filter {
@@ -302,7 +310,7 @@ where D: Deref<Target=DB>,
                 };
 
                 if distinct_accepted && seen.len() > range.start {
-                    out_documents.push(document);
+                    out_documents.push(Document::from_raw(&document));
                     if out_documents.len() == range.len() { break }
                 }
             }