Minor code fixes (#2252)

- `ScoreBreakdown` map was always getting created, and not being reused.
When recycling the `DocumentMatch`, clear out the score breakdown map
and reuse it when needed.
- Fix dropped error when creating pre-filter searcher.
- Close KNN and Pre-filter Searchers when done.

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: CascadingRadium

search/query/boolean.go

@@ -15,7 +15,6 @@
 package query
 
 import (
-	"bytes"
 	"context"
 	"encoding/json"
 	"fmt"
@@ -203,15 +202,15 @@ func (q *BooleanQuery) Searcher(ctx context.Context, i index.IndexReader, m mapp
 				return false
 			}
 			// Compare document IDs
-			cmp := bytes.Compare(refDoc.IndexInternalID, d.IndexInternalID)
+			cmp := refDoc.IndexInternalID.Compare(d.IndexInternalID)
 			if cmp < 0 {
 				// filterSearcher is behind the current document, Advance() it
 				refDoc, err = filterSearcher.Advance(sctx, d.IndexInternalID)
 				if err != nil || refDoc == nil {
 					return false
 				}
 				// After advance, check if they're now equal
-				return bytes.Equal(refDoc.IndexInternalID, d.IndexInternalID)
+				cmp = refDoc.IndexInternalID.Compare(d.IndexInternalID)
 			}
 			// cmp >= 0: either equal (match) or filterSearcher is ahead (no match)
 			return cmp == 0

search/scorer/scorer_disjunction.go

@@ -88,7 +88,10 @@ func (s *DisjunctionQueryScorer) Score(ctx *search.SearchContext, constituents [
 func (s *DisjunctionQueryScorer) ScoreAndExplBreakdown(ctx *search.SearchContext, constituents []*search.DocumentMatch,
 	matchingIdxs []int, originalPositions []int, countTotal int) *search.DocumentMatch {
 
-	scoreBreakdown := make(map[int]float64)
+	rv := constituents[0]
+	if rv.ScoreBreakdown == nil {
+		rv.ScoreBreakdown = make(map[int]float64, len(constituents))
+	}
 	var childrenExplanations []*search.Explanation
 	if s.options.Explain {
 		// since we want to notify which expl belongs to which matched searcher within the disjunction searcher
@@ -104,7 +107,7 @@ func (s *DisjunctionQueryScorer) ScoreAndExplBreakdown(ctx *search.SearchContext
 			// scorer used in disjunction heap searcher
 			index = matchingIdxs[i]
 		}
-		scoreBreakdown[index] = docMatch.Score
+		rv.ScoreBreakdown[index] = docMatch.Score
 		if s.options.Explain {
 			childrenExplanations[index] = docMatch.Expl
 		}
@@ -113,9 +116,6 @@ func (s *DisjunctionQueryScorer) ScoreAndExplBreakdown(ctx *search.SearchContext
 	if s.options.Explain {
 		explBreakdown = &search.Explanation{Children: childrenExplanations}
 	}
-
-	rv := constituents[0]
-	rv.ScoreBreakdown = scoreBreakdown
 	rv.Expl = explBreakdown
 	rv.FieldTermLocations = search.MergeFieldTermLocations(
 		rv.FieldTermLocations, constituents[1:])

search/search.go

@@ -207,20 +207,29 @@ func (dm *DocumentMatch) Reset() *DocumentMatch {
 	indexInternalID := dm.IndexInternalID
 	// remember the []interface{} used for sort
 	sort := dm.Sort
+	// remember the []string used for decoded sort
+	decodedSort := dm.DecodedSort
 	// remember the FieldTermLocations backing array
 	ftls := dm.FieldTermLocations
 	for i := range ftls { // recycle the ArrayPositions of each location
 		ftls[i].Location.ArrayPositions = ftls[i].Location.ArrayPositions[:0]
 	}
+	// remember the score breakdown map
+	scoreBreakdown := dm.ScoreBreakdown
+	// clear out the score breakdown map
+	clear(scoreBreakdown)
 	// idiom to copy over from empty DocumentMatch (0 allocations)
 	*dm = DocumentMatch{}
 	// reuse the []byte already allocated (and reset len to 0)
 	dm.IndexInternalID = indexInternalID[:0]
 	// reuse the []interface{} already allocated (and reset len to 0)
 	dm.Sort = sort[:0]
-	dm.DecodedSort = dm.DecodedSort[:0]
+	// reuse the []string already allocated (and reset len to 0)
+	dm.DecodedSort = decodedSort[:0]
 	// reuse the FieldTermLocations already allocated (and reset len to 0)
 	dm.FieldTermLocations = ftls[:0]
+	// reuse the score breakdown map already allocated (after clearing it)
+	dm.ScoreBreakdown = scoreBreakdown
 	return dm
 }
 

search/searcher/search_knn.go

@@ -84,7 +84,7 @@ func (s *KNNSearcher) VectorOptimize(ctx context.Context, octx index.VectorOptim
 
 func (s *KNNSearcher) Advance(ctx *search.SearchContext, ID index.IndexInternalID) (
 	*search.DocumentMatch, error) {
-	knnMatch, err := s.vectorReader.Next(s.vd.Reset())
+	knnMatch, err := s.vectorReader.Advance(ID, s.vd.Reset())
 	if err != nil {
 		return nil, err
 	}

search_knn.go

@@ -381,7 +381,7 @@ func addSortAndFieldsToKNNHits(req *SearchRequest, knnHits []*search.DocumentMat
 	return nil
 }
 
-func (i *indexImpl) runKnnCollector(ctx context.Context, req *SearchRequest, reader index.IndexReader, preSearch bool) ([]*search.DocumentMatch, error) {
+func (i *indexImpl) runKnnCollector(ctx context.Context, req *SearchRequest, reader index.IndexReader, preSearch bool) (knnHits []*search.DocumentMatch, err error) {
 	// Maps the index of a KNN query in the request to its pre-filter result:
 	// - If the KNN query is **not filtered**, the value will be `nil`.
 	// - If the KNN query **is filtered**, the value will be an eligible document selector
@@ -401,21 +401,33 @@ func (i *indexImpl) runKnnCollector(ctx context.Context, req *SearchRequest, rea
 			continue
 		}
 		// Applies to all supported types of queries.
-		filterSearcher, _ := filterQ.Searcher(ctx, reader, i.m, search.SearcherOptions{
+		filterSearcher, err := filterQ.Searcher(ctx, reader, i.m, search.SearcherOptions{
 			Score: "none", // just want eligible hits --> don't compute scores if not needed
 		})
+		if err != nil {
+			return nil, err
+		}
 		// Using the index doc count to determine collector size since we do not
 		// have an estimate of the number of eligible docs in the index yet.
 		indexDocCount, err := i.DocCount()
 		if err != nil {
+			// close the searcher before returning
+			filterSearcher.Close()
 			return nil, err
 		}
 		filterColl := collector.NewEligibleCollector(int(indexDocCount))
 		err = filterColl.Collect(ctx, filterSearcher, reader)
 		if err != nil {
+			// close the searcher before returning
+			filterSearcher.Close()
 			return nil, err
 		}
 		knnFilterResults[idx] = filterColl.EligibleSelector()
+		// Close the filter searcher, as we are done with it.
+		err = filterSearcher.Close()
+		if err != nil {
+			return nil, err
+		}
 	}
 
 	// Add the filter hits when creating the kNN query
@@ -429,12 +441,17 @@ func (i *indexImpl) runKnnCollector(ctx context.Context, req *SearchRequest, rea
 	if err != nil {
 		return nil, err
 	}
+	defer func() {
+		if serr := knnSearcher.Close(); err == nil && serr != nil {
+			err = serr
+		}
+	}()
 	knnCollector := collector.NewKNNCollector(kArray, sumOfK)
 	err = knnCollector.Collect(ctx, knnSearcher, reader)
 	if err != nil {
 		return nil, err
 	}
-	knnHits := knnCollector.Results()
+	knnHits = knnCollector.Results()
 	if !preSearch {
 		knnHits = finalizeKNNResults(req, knnHits)
 	}