Rewrite the phrase query postings lists

This simplified the multiword_rewrite_matches function a little bit.

meilisearch-core/src/bucket_sort.rs

@@ -15,8 +15,9 @@ use levenshtein_automata::DFA;
 use log::debug;
 use meilisearch_tokenizer::{is_cjk, split_query_string};
 use meilisearch_types::{DocIndex, Highlight};
-use sdset::Set;
+use sdset::{Set, SetBuf};
 use slice_group_by::{GroupBy, GroupByMut};
+use itertools::EitherOrBoth;
 
 use crate::automaton::NGRAMS;
 use crate::automaton::{QueryEnhancer, QueryEnhancerBuilder};
@@ -61,7 +62,7 @@ pub fn bucket_sort<'c>(
     let mut raw_documents = Vec::new();
     for raw_matches in bare_matches.linear_group_by_key_mut(|sm| sm.document_id) {
         prefiltered_documents += 1;
-        if let Some(raw_document) = RawDocument::new(raw_matches, &automatons, &arena) {
+        if let Some(raw_document) = RawDocument::new(raw_matches, &automatons, &mut arena) {
             raw_documents.push(raw_document);
         }
     }
@@ -78,7 +79,7 @@ pub fn bucket_sort<'c>(
 
     let criteria = [
         Box::new(Typo) as Box<dyn Criterion>,
-        Box::new(Words) as Box<dyn Criterion>,
+        Box::new(Words),
         Box::new(Proximity),
         Box::new(Attribute),
         Box::new(WordsPosition),
@@ -154,13 +155,11 @@ impl<'a, 'tag> RawDocument<'a, 'tag> {
     fn new<'txn>(
         raw_matches: &'a mut [BareMatch<'tag>],
         automatons: &[QueryWordAutomaton],
-        postings_lists: &SmallArena<'tag, PostingsListView<'txn>>,
+        postings_lists: &mut SmallArena<'tag, PostingsListView<'txn>>,
     ) -> Option<RawDocument<'a, 'tag>>
     {
         raw_matches.sort_unstable_by_key(|m| m.query_index);
 
-        // debug!("{:?} {:?}", raw_matches[0].document_id, raw_matches);
-
         let mut previous_word = None;
         for i in 0..raw_matches.len() {
             let a = &raw_matches[i];
@@ -168,10 +167,17 @@ impl<'a, 'tag> RawDocument<'a, 'tag> {
 
             match auta.phrase_query {
                 Some((0, _)) => {
-                    previous_word = Some(a.query_index);
+                    let b = match raw_matches.get(i + 1) {
-                    let b = raw_matches.get(i + 1)?;
+                        Some(b) => b,
+                        None => {
+                            postings_lists[a.postings_list].rewrite_with(SetBuf::new_unchecked(Vec::new()));
+                            continue;
+                        }
+                    };
+
                     if a.query_index + 1 != b.query_index {
-                        return None;
+                        postings_lists[a.postings_list].rewrite_with(SetBuf::new_unchecked(Vec::new()));
+                        continue
                     }
 
                     let pla = &postings_lists[a.postings_list];
@@ -181,11 +187,31 @@ impl<'a, 'tag> RawDocument<'a, 'tag> {
                         a.attribute.cmp(&b.attribute).then((a.word_index + 1).cmp(&b.word_index))
                     });
 
-                    if !iter.any(|eb| eb.is_both()) { return None }
+                    let mut newa = Vec::new();
+                    let mut newb = Vec::new();
+
+                    for eb in iter {
+                        if let EitherOrBoth::Both(a, b) = eb {
+                            newa.push(*a);
+                            newb.push(*b);
+                        }
+                    }
+
+
+                    if !newa.is_empty() {
+                        previous_word = Some(a.query_index);
+                        postings_lists[a.postings_list].rewrite_with(SetBuf::new_unchecked(newa));
+                        postings_lists[b.postings_list].rewrite_with(SetBuf::new_unchecked(newb));
+
+                    } else {
+                        // TODO use SetBuf::default when merged
+                        postings_lists[a.postings_list].rewrite_with(SetBuf::new_unchecked(Vec::new()));
+                        postings_lists[b.postings_list].rewrite_with(SetBuf::new_unchecked(Vec::new()));
+                    }
                 },
                 Some((1, _)) => {
                     if previous_word.take() != Some(a.query_index - 1) {
-                        return None;
+                        postings_lists[a.postings_list].rewrite_with(SetBuf::new_unchecked(Vec::new()));
                     }
                 },
                 Some((_, _)) => unreachable!(),
@@ -193,6 +219,10 @@ impl<'a, 'tag> RawDocument<'a, 'tag> {
             }
         }
 
+        if raw_matches.iter().all(|rm| postings_lists[rm.postings_list].is_empty()) {
+            return None
+        }
+
         Some(RawDocument {
             raw_matches,
             processed_matches: Vec::new(),
@@ -231,50 +261,84 @@ pub struct SimpleMatch {
 }
 
 #[derive(Clone)]
-pub struct PostingsListView<'txn> {
+pub enum PostingsListView<'txn> {
-    input: Rc<[u8]>,
+    Original {
-    postings_list: Rc<Cow<'txn, Set<DocIndex>>>,
+        input: Rc<[u8]>,
-    offset: usize,
+        postings_list: Rc<Cow<'txn, Set<DocIndex>>>,
-    len: usize,
+        offset: usize,
+        len: usize,
+    },
+    Rewritten {
+        input: Rc<[u8]>,
+        postings_list: SetBuf<DocIndex>,
+    },
 }
 
 impl fmt::Debug for PostingsListView<'_> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_struct("PostingsListView")
-            .field("input", &std::str::from_utf8(&self.input).unwrap())
+            .field("input", &std::str::from_utf8(&self.input()).unwrap())
             .field("postings_list", &self.as_ref())
             .finish()
     }
 }
 
 impl<'txn> PostingsListView<'txn> {
-    pub fn new(input: Rc<[u8]>, postings_list: Rc<Cow<'txn, Set<DocIndex>>>) -> PostingsListView<'txn> {
+    pub fn original(input: Rc<[u8]>, postings_list: Rc<Cow<'txn, Set<DocIndex>>>) -> PostingsListView<'txn> {
         let len = postings_list.len();
-        PostingsListView { input, postings_list, offset: 0, len }
+        PostingsListView::Original { input, postings_list, offset: 0, len }
+    }
+
+    pub fn rewritten(input: Rc<[u8]>, postings_list: SetBuf<DocIndex>) -> PostingsListView<'txn> {
+        PostingsListView::Rewritten { input, postings_list }
+    }
+
+    pub fn rewrite_with(&mut self, postings_list: SetBuf<DocIndex>) {
+        *self = match self {
+            PostingsListView::Original { input, .. } => {
+                PostingsListView::Rewritten { input: input.clone(), postings_list }
+            },
+            PostingsListView::Rewritten { input, .. } => {
+                PostingsListView::Rewritten { input: input.clone(), postings_list }
+            },
+        };
     }
 
     pub fn len(&self) -> usize {
-        self.len
+        match self {
+            PostingsListView::Original { len, .. } => *len,
+            PostingsListView::Rewritten { postings_list, .. } => postings_list.len(),
+        }
     }
 
     pub fn input(&self) -> &[u8] {
-        &self.input
+        match self {
+            PostingsListView::Original { ref input, .. } => input,
+            PostingsListView::Rewritten { ref input, .. } => input,
+        }
     }
 
-    pub fn range(&self, offset: usize, len: usize) -> PostingsListView<'txn> {
+    pub fn range(&self, range_offset: usize, range_len: usize) -> PostingsListView<'txn> {
-        assert!(offset + len <= self.len);
+        match self {
-        PostingsListView {
+            PostingsListView::Original { input, postings_list, offset, len } => {
-            input: self.input.clone(),
+                assert!(range_offset + range_len <= *len);
-            postings_list: self.postings_list.clone(),
+                PostingsListView::Original {
-            offset: self.offset + offset,
+                    input: input.clone(),
-            len: len,
+                    postings_list: postings_list.clone(),
+                    offset: offset + range_offset,
+                    len: range_len,
+                }
+            },
+            PostingsListView::Rewritten { .. } => {
+                panic!("Cannot create a range on a rewritten postings list view");
+            }
         }
     }
 }
 
 impl AsRef<Set<DocIndex>> for PostingsListView<'_> {
     fn as_ref(&self) -> &Set<DocIndex> {
-        Set::new_unchecked(&self.postings_list[self.offset..self.offset + self.len])
+        self
     }
 }
 
@@ -282,7 +346,12 @@ impl Deref for PostingsListView<'_> {
     type Target = Set<DocIndex>;
 
     fn deref(&self) -> &Set<DocIndex> {
-        Set::new_unchecked(&self.postings_list[self.offset..self.offset + self.len])
+        match *self {
+            PostingsListView::Original { ref postings_list, offset, len, .. } => {
+                Set::new_unchecked(&postings_list[offset..offset + len])
+            },
+            PostingsListView::Rewritten { ref postings_list, .. } => postings_list,
+        }
     }
 }
 
@@ -335,7 +404,7 @@ fn fetch_matches<'txn, 'tag>(
 
                 let input = Rc::from(input);
                 let postings_list = Rc::new(postings_list);
-                let postings_list_view = PostingsListView::new(input, postings_list);
+                let postings_list_view = PostingsListView::original(input, postings_list);
 
                 let mut offset = 0;
                 for group in postings_list_view.linear_group_by_key(|di| di.document_id) {

meilisearch-core/src/criterion2.rs

@@ -52,38 +52,9 @@ fn prepare_query_distances<'a, 'tag, 'txn>(
     for document in documents {
         if !document.processed_distances.is_empty() { continue }
 
-        // debug!("{:?}", document.raw_matches[0].document_id);
-
         let mut processed = Vec::new();
-        let mut raw_matches = document.raw_matches.iter().peekable();
+        for m in document.raw_matches.iter() {
-        while let Some(m) = raw_matches.next() {
+            if postings_lists[m.postings_list].is_empty() { continue }
-
-            // let automaton = &automatons[m.query_index as usize];
-
-            // debug!("{:?} {:?}", m, automaton);
-            // debug!("{:?}", &postings_lists[m.postings_list]);
-
-            // match automaton.phrase_query {
-            //     Some((0, len)) => {
-            //         match raw_matches.peek() {
-            //             Some(BareMatch { query_index, .. }) => {
-            //                 if *query_index != m.query_index + 1 {
-            //                     raw_matches.next();
-            //                     continue
-            //                 }
-            //             },
-            //             None => continue,
-            //         }
-            //     },
-            //     Some((_, _)) => continue,
-            //     None => (),
-            // }
-
-            // FIXME we really need to take splitted words into account
-            //       those must be seen at the same level as the non-splitteds
-            // if automatons[m.query_index as usize].phrase_query.is_some() {
-            //     continue
-            // }
 
             let range = query_enhancer.replacement(m.query_index as u32);
             let new_len = cmp::max(range.end as usize, processed.len());
@@ -99,8 +70,6 @@ fn prepare_query_distances<'a, 'tag, 'txn>(
             }
         }
 
-        // debug!("{:?}", processed);
-
         document.processed_distances = processed;
     }
 }
@@ -444,54 +413,11 @@ impl Criterion for StableDocId {
 }
 
 pub fn multiword_rewrite_matches(
-    simple_matches: &mut [SimpleMatch],
+    matches: &mut [SimpleMatch],
     query_enhancer: &QueryEnhancer,
     automatons: &[QueryWordAutomaton],
 ) -> SetBuf<SimpleMatch>
 {
-    let mut matches = Vec::with_capacity(simple_matches.len());
-
-    // let before_sort = Instant::now();
-    // we sort the matches by word index to make them rewritable
-    simple_matches.sort_unstable_by_key(|m| (m.attribute, m.query_index, m.word_index));
-    // debug!("sorting dirty matches took {:.02?}", before_sort.elapsed());
-
-    for same_attribute in simple_matches.linear_group_by_key(|m| m.attribute) {
-        let iter = same_attribute.linear_group_by_key(|m| m.query_index);
-        let mut iter = iter.peekable();
-
-        while let Some(same_query_index) = iter.next() {
-            let query_index = same_query_index[0].query_index;
-
-            // TODO we need to support phrase query of longer length
-            if let Some((i, len)) = automatons[query_index as usize].phrase_query {
-                if i != 0 { continue }
-
-                // is the next query_index group the required one
-                if iter.peek().map_or(false, |g| g[0].query_index == query_index + 1) {
-                    if let Some(next) = iter.next() {
-                        for ma in same_query_index {
-                            for mb in next {
-                                if ma.word_index == mb.word_index + 1 {
-                                    matches.push(*ma);
-                                    matches.push(*mb);
-                                }
-                            }
-                        }
-                    }
-                }
-            } else {
-                matches.extend_from_slice(same_query_index);
-            }
-        }
-    }
-
-    // let is_phrase_query = automatons[match_.query_index as usize].phrase_query_len.is_some();
-    // let next_query_index = match_.query_index + 1;
-    // if is_phrase_query && iter.remainder().iter().find(|m| m.query_index == next_query_index).is_none() {
-    //     continue
-    // }
-
     matches.sort_unstable_by_key(|m| (m.attribute, m.word_index));
 
     let mut padded_matches = Vec::with_capacity(matches.len());