fix: repeat compute in case one field aggregation multiple

AUTHORS

@@ -11,3 +11,4 @@ Marty Schoch <marty.schoch@gmail.com>
 Michael Schuett <michaeljs1990@gmail.com>
 Akshay Shekher <akshay.shekher@gmail.com>
 Sergio Rubio <rubiojr@frameos.org>
+Hengfei Yang <hengfei.yang@gmail.com>

search/collector/all.go

@@ -29,13 +29,28 @@ func NewAllCollector() *AllCollector {
 
 func (a *AllCollector) Collect(ctx context.Context, aggs search.Aggregations,
 	searcher search.Collectible) (search.DocumentMatchIterator, error) {
-	return &AllIterator{
+	iter := &AllIterator{
 		ctx:           ctx,
 		neededFields:  aggs.Fields(),
 		bucket:        search.NewBucket("", aggs),
 		searcher:      searcher,
 		searchContext: search.NewSearchContext(searcher.DocumentMatchPoolSize(), 0),
-	}, nil
+	}
+	if len(iter.neededFields) <= 1 {
+		return iter, nil
+	}
+
+	// filter repeat field
+	store := make(map[string]struct{}, len(iter.neededFields))
+	for _, field := range iter.neededFields {
+		store[field] = struct{}{}
+	}
+	iter.neededFields = iter.neededFields[:0]
+	for field := range store {
+		iter.neededFields = append(iter.neededFields, field)
+	}
+
+	return iter, nil
 }
 
 func (a *AllCollector) Size() int {

search/collector/topn.go

@@ -139,6 +139,19 @@ func (hc *TopNCollector) Collect(ctx context.Context, aggs search.Aggregations,
 
 	// add fields needed by aggregations
 	hc.neededFields = append(hc.neededFields, aggs.Fields()...)
+
+	// filter repeat field
+	if len(hc.neededFields) > 1 {
+		store := make(map[string]struct{}, len(hc.neededFields))
+		for _, field := range hc.neededFields {
+			store[field] = struct{}{}
+		}
+		hc.neededFields = hc.neededFields[:0]
+		for field := range store {
+			hc.neededFields = append(hc.neededFields, field)
+		}
+	}
+
 	bucket := search.NewBucket("", aggs)
 
 	var hitNumber int