add mixed AND OR test, fix buffered_union

src/docset.rs

@@ -53,14 +53,16 @@ pub trait DocSet: Send {
 
     /// Seeks to the target if possible and returns true if the target is in the DocSet.
     ///
-    /// DocSets that already have an efficient `seek` method don't need to implement `seek_exact`.
-    /// All wrapper DocSets should forward `seek_exact` to the underlying DocSet.
+    /// DocSets that already have an efficient `seek` method don't need to implement
+    /// `seek_into_the_danger_zone`. All wrapper DocSets should forward
+    /// `seek_into_the_danger_zone` to the underlying DocSet.
     ///
     /// ## API Behaviour
-    /// If `seek_exact` is returning true, a call to `doc()` has to return target.
-    /// If `seek_exact` is returning false, a call to `doc()` may return any doc between
-    /// the last doc that matched and target or a doc that is a valid next hit after target.
-    /// The DocSet is considered to be in an invalid state until `seek_exact` returns true again.
+    /// If `seek_into_the_danger_zone` is returning true, a call to `doc()` has to return target.
+    /// If `seek_into_the_danger_zone` is returning false, a call to `doc()` may return any doc
+    /// between the last doc that matched and target or a doc that is a valid next hit after
+    /// target. The DocSet is considered to be in an invalid state until
+    /// `seek_into_the_danger_zone` returns true again.
     ///
     /// `target` needs to be equal or larger than `doc` when in a valid state.
     ///

src/query/mod.rs

@@ -70,9 +70,81 @@ pub use self::weight::Weight;
 
 #[cfg(test)]
 mod tests {
+    use crate::collector::TopDocs;
+    use crate::query::phrase_query::tests::create_index;
     use crate::query::QueryParser;
     use crate::schema::{Schema, TEXT};
-    use crate::{Index, Term};
+    use crate::{DocAddress, Index, Term};
+
+    #[test]
+    pub fn test_mixed_intersection_and_union() -> crate::Result<()> {
+        let index = create_index(&["a b", "a c", "a b c", "b"])?;
+        let schema = index.schema();
+        let text_field = schema.get_field("text").unwrap();
+        let searcher = index.reader()?.searcher();
+
+        let do_search = |term: &str| {
+            let query = QueryParser::for_index(&index, vec![text_field])
+                .parse_query(term)
+                .unwrap();
+            let top_docs: Vec<(f32, DocAddress)> =
+                searcher.search(&query, &TopDocs::with_limit(10)).unwrap();
+
+            top_docs.iter().map(|el| el.1.doc_id).collect::<Vec<_>>()
+        };
+
+        assert_eq!(do_search("a AND b"), vec![0, 2]);
+        assert_eq!(do_search("(a OR b) AND C"), vec![2, 1]);
+        // The intersection code has special code for more than 2 intersections
+        // left, right + others
+        // The will place the union in the "others" insersection to that seek_into_the_danger_zone
+        // is called
+        assert_eq!(
+            do_search("(a OR b) AND (c OR a) AND (b OR c)"),
+            vec![2, 1, 0]
+        );
+
+        Ok(())
+    }
+
+    #[test]
+    pub fn test_mixed_intersection_and_union_with_skip() -> crate::Result<()> {
+        // Test 4096 skip in BufferedUnionScorer
+        let mut data: Vec<&str> = Vec::new();
+        data.push("a b");
+        let zz_data = vec!["z z"; 5000];
+        data.extend_from_slice(&zz_data);
+        data.extend_from_slice(&["a c"]);
+        data.extend_from_slice(&zz_data);
+        data.extend_from_slice(&["a b c", "b"]);
+        let index = create_index(&data)?;
+        let schema = index.schema();
+        let text_field = schema.get_field("text").unwrap();
+        let searcher = index.reader()?.searcher();
+
+        let do_search = |term: &str| {
+            let query = QueryParser::for_index(&index, vec![text_field])
+                .parse_query(term)
+                .unwrap();
+            let top_docs: Vec<(f32, DocAddress)> =
+                searcher.search(&query, &TopDocs::with_limit(10)).unwrap();
+
+            top_docs.iter().map(|el| el.1.doc_id).collect::<Vec<_>>()
+        };
+
+        assert_eq!(do_search("a AND b"), vec![0, 10002]);
+        assert_eq!(do_search("(a OR b) AND C"), vec![10002, 5001]);
+        // The intersection code has special code for more than 2 intersections
+        // left, right + others
+        // The will place the union in the "others" insersection to that seek_into_the_danger_zone
+        // is called
+        assert_eq!(
+            do_search("(a OR b) AND (c OR a) AND (b OR c)"),
+            vec![10002, 5001, 0]
+        );
+
+        Ok(())
+    }
 
     #[test]
     fn test_query_terms() {

src/query/union/buffered_union.rs

@@ -15,7 +15,7 @@ const HORIZON: u32 = 64u32 * 64u32;
 // This function is similar except that it does is not unstable, and
 // it does not keep the original vector ordering.
 //
-// Also, it does not "yield" any elements.
+// Elements are dropped and not yielded.
 fn unordered_drain_filter<T, P>(v: &mut Vec<T>, mut predicate: P)
 where P: FnMut(&mut T) -> bool {
     let mut i = 0;
@@ -141,6 +141,11 @@ impl<TScorer: Scorer, TScoreCombiner: ScoreCombiner> BufferedUnionScorer<TScorer
         }
         false
     }
+
+    fn is_in_horizon(&self, target: DocId) -> bool {
+        let gap = target - self.offset;
+        gap < HORIZON
+    }
 }
 
 impl<TScorer, TScoreCombiner> DocSet for BufferedUnionScorer<TScorer, TScoreCombiner>
@@ -216,15 +221,25 @@ where
     }
 
     fn seek_into_the_danger_zone(&mut self, target: DocId) -> bool {
-        let is_hit = self
-            .docsets
-            .iter_mut()
-            .all(|docset| docset.seek_into_the_danger_zone(target));
-        // The API requires the DocSet to be in a valid state when `seek_exact` returns true.
-        if is_hit {
-            self.seek(target);
+        if self.is_in_horizon(target) {
+            // Our value is within the buffered horizon and the docset may already have been
+            // processed and removed, so we need to use seek, which uses the regular advance.
+            self.seek(target) == target
+        } else {
+            // The docsets are not in the buffered range, so we can use seek_into_the_danger_zone
+            // of the underlying docsets
+            let is_hit = self
+                .docsets
+                .iter_mut()
+                .any(|docset| docset.seek_into_the_danger_zone(target));
+
+            // The API requires the DocSet to be in a valid state when `seek_into_the_danger_zone`
+            // returns true.
+            if is_hit {
+                self.seek(target);
+            }
+            is_hit
         }
-        is_hit
     }
 
     fn doc(&self) -> DocId {