cache values to avoid dynamic dispatch inside hot loop

index_alias_impl.go

@@ -571,10 +571,7 @@ func MultiSearch(ctx context.Context, req *SearchRequest, indexes ...Index) (*Se
 
 	// sort all hits with the requested order
 	if len(req.Sort) > 0 {
-		sorter := &multiSearchHitSorter{
-			hits: sr.Hits,
-			sort: req.Sort,
-		}
+		sorter := newMultiSearchHitSorter(req.Sort, sr.Hits)
 		sort.Sort(sorter)
 	}
 
@@ -654,13 +651,24 @@ func (f *indexAliasImplFieldDict) Close() error {
 }
 
 type multiSearchHitSorter struct {
-	hits search.DocumentMatchCollection
-	sort search.SortOrder
+	hits          search.DocumentMatchCollection
+	sort          search.SortOrder
+	cachedScoring []bool
+	cachedDesc    []bool
+}
+
+func newMultiSearchHitSorter(sort search.SortOrder, hits search.DocumentMatchCollection) *multiSearchHitSorter {
+	return &multiSearchHitSorter{
+		sort:          sort,
+		hits:          hits,
+		cachedScoring: sort.CacheIsScore(),
+		cachedDesc:    sort.CacheDescending(),
+	}
 }
 
 func (m *multiSearchHitSorter) Len() int      { return len(m.hits) }
 func (m *multiSearchHitSorter) Swap(i, j int) { m.hits[i], m.hits[j] = m.hits[j], m.hits[i] }
 func (m *multiSearchHitSorter) Less(i, j int) bool {
-	c := m.sort.Compare(m.hits[i], m.hits[j])
+	c := m.sort.Compare(m.cachedScoring, m.cachedDesc, m.hits[i], m.hits[j])
 	return c < 0
 }

search/collectors/collector_heap.go

@@ -28,8 +28,10 @@ type HeapCollector struct {
 	results       search.DocumentMatchCollection
 	facetsBuilder *search.FacetsBuilder
 
-	needDocIds   bool
-	neededFields []string
+	needDocIds    bool
+	neededFields  []string
+	cachedScoring []bool
+	cachedDesc    []bool
 
 	lowestMatchOutsideResults *search.DocumentMatch
 }
@@ -48,6 +50,8 @@ func NewHeapCollector(size int, skip int, sort search.SortOrder) *HeapCollector
 		hc.needDocIds = true
 	}
 	hc.neededFields = sort.RequiredFields()
+	hc.cachedScoring = sort.CacheIsScore()
+	hc.cachedDesc = sort.CacheDescending()
 
 	return hc
 }
@@ -148,7 +152,7 @@ func (hc *HeapCollector) collectSingle(ctx *search.SearchContext, reader index.I
 	// with this one comparision, we can avoid all heap operations if
 	// this hit would have been added and then immediately removed
 	if hc.lowestMatchOutsideResults != nil {
-		cmp := hc.sort.Compare(d, hc.lowestMatchOutsideResults)
+		cmp := hc.sort.Compare(hc.cachedScoring, hc.cachedDesc, d, hc.lowestMatchOutsideResults)
 		if cmp >= 0 {
 			// this hit can't possibly be in the result set, so avoid heap ops
 			ctx.DocumentMatchPool.Put(d)
@@ -162,7 +166,7 @@ func (hc *HeapCollector) collectSingle(ctx *search.SearchContext, reader index.I
 		if hc.lowestMatchOutsideResults == nil {
 			hc.lowestMatchOutsideResults = removed
 		} else {
-			cmp := hc.sort.Compare(removed, hc.lowestMatchOutsideResults)
+			cmp := hc.sort.Compare(hc.cachedScoring, hc.cachedDesc, removed, hc.lowestMatchOutsideResults)
 			if cmp < 0 {
 				tmp := hc.lowestMatchOutsideResults
 				hc.lowestMatchOutsideResults = removed
@@ -239,7 +243,7 @@ func (hc *HeapCollector) Len() int {
 }
 
 func (hc *HeapCollector) Less(i, j int) bool {
-	so := hc.sort.Compare(hc.results[i], hc.results[j])
+	so := hc.sort.Compare(hc.cachedScoring, hc.cachedDesc, hc.results[i], hc.results[j])
 	return -so < 0
 }
 

search/sort.go

@@ -168,11 +168,11 @@ func (so SortOrder) Value(doc *DocumentMatch) {
 
 // Compare will compare two document matches using the specified sort order
 // if both are numbers, we avoid converting back to term
-func (so SortOrder) Compare(i, j *DocumentMatch) int {
+func (so SortOrder) Compare(cachedScoring, cachedDesc []bool, i, j *DocumentMatch) int {
 	// compare the documents on all search sorts until a differences is found
-	for x, soi := range so {
+	for x := range so {
 		c := 0
-		if soi.RequiresScoring() {
+		if cachedScoring[x] {
 			if i.Score < j.Score {
 				c = -1
 			} else if i.Score > j.Score {
@@ -187,7 +187,7 @@ func (so SortOrder) Compare(i, j *DocumentMatch) int {
 		if c == 0 {
 			continue
 		}
-		if soi.Descending() {
+		if cachedDesc[x] {
 			c = -c
 		}
 		return c
@@ -229,6 +229,22 @@ func (so SortOrder) RequiredFields() []string {
 	return rv
 }
 
+func (so SortOrder) CacheIsScore() []bool {
+	var rv []bool
+	for _, soi := range so {
+		rv = append(rv, soi.RequiresScoring())
+	}
+	return rv
+}
+
+func (so SortOrder) CacheDescending() []bool {
+	var rv []bool
+	for _, soi := range so {
+		rv = append(rv, soi.Descending())
+	}
+	return rv
+}
+
 // SortFieldType lets you control some internal sort behavior
 // normally leaving this to the zero-value of SortFieldAuto is fine
 type SortFieldType int