Add nil check in reduce and add collection rwmutex when release segments (#17698)

Signed-off-by: bigsheeper <yihao.dai@zilliz.com>

internal/querynode/impl.go

@@ -349,7 +349,17 @@ func (node *QueryNode) ReleaseSegments(ctx context.Context, in *queryPb.ReleaseS
 		return status, nil
 	}
 
-	// collection lock is not needed since we guarantee not query/search will be dispatch from leader
+	collection, err := node.metaReplica.getCollectionByID(in.CollectionID)
+	if err != nil {
+		status := &commonpb.Status{
+			ErrorCode: commonpb.ErrorCode_UnexpectedError,
+			Reason:    fmt.Sprintf("cannot find collection %d when ReleaseSegments", in.CollectionID),
+		}
+		return status, nil
+	}
+
+	collection.Lock()
+	defer collection.Unlock()
 	for _, id := range in.SegmentIDs {
 		switch in.GetScope() {
 		case queryPb.DataScope_Streaming:

internal/querynode/impl_test.go

@@ -444,6 +444,24 @@ func TestImpl_ReleaseSegments(t *testing.T) {
 		assert.NoError(t, err)
 		assert.Equal(t, commonpb.ErrorCode_Success, status.ErrorCode)
 	})
+
+	wg.Add(1)
+	t.Run("test no collection", func(t *testing.T) {
+		defer wg.Done()
+		node, err := genSimpleQueryNode(ctx)
+		assert.NoError(t, err)
+		err = node.metaReplica.removeCollection(defaultCollectionID)
+		assert.NoError(t, err)
+
+		req := &queryPb.ReleaseSegmentsRequest{
+			Base:         genCommonMsgBase(commonpb.MsgType_ReleaseSegments),
+			CollectionID: defaultCollectionID,
+		}
+
+		status, err := node.ReleaseSegments(ctx, req)
+		assert.NoError(t, err)
+		assert.Equal(t, commonpb.ErrorCode_UnexpectedError, status.ErrorCode)
+	})
 	wg.Wait()
 }
 

internal/querynode/reduce.go

@@ -92,6 +92,9 @@ func reduceSearchResultsAndFillData(plan *SearchPlan, searchResults []*SearchRes
 
 	cSearchResults := make([]C.CSearchResult, 0)
 	for _, res := range searchResults {
+		if res == nil {
+			return nil, fmt.Errorf("nil searchResult detected when reduceSearchResultsAndFillData")
+		}
 		cSearchResults = append(cSearchResults, res.cSearchResult)
 	}
 	cSearchResultPtr := (*C.CSearchResult)(&cSearchResults[0])

internal/querynode/reduce_test.go

@@ -104,8 +104,20 @@ func TestReduce_AllFunc(t *testing.T) {
 	deleteCollection(collection)
 }
 
-func TestReduce_nilPlan(t *testing.T) {
-	plan := &SearchPlan{}
-	_, err := reduceSearchResultsAndFillData(plan, nil, 1, nil, nil)
-	assert.Error(t, err)
+func TestReduce_Invalid(t *testing.T) {
+	t.Run("nil plan", func(t *testing.T) {
+		plan := &SearchPlan{}
+		_, err := reduceSearchResultsAndFillData(plan, nil, 1, nil, nil)
+		assert.Error(t, err)
+	})
+
+	t.Run("nil search result", func(t *testing.T) {
+		collection := newCollection(defaultCollectionID, genTestCollectionSchema())
+		searchReq, err := genSearchPlanAndRequests(collection, IndexHNSW, 10)
+		assert.NoError(t, err)
+		searchResults := make([]*SearchResult, 0)
+		searchResults = append(searchResults, nil)
+		_, err = reduceSearchResultsAndFillData(searchReq.plan, searchResults, 1, []int32{10}, []int32{10})
+		assert.Error(t, err)
+	})
 }

internal/querynode/search.go

@@ -20,6 +20,7 @@ import (
 	"fmt"
 	"sync"
 
+	"github.com/milvus-io/milvus/internal/log"
 	"github.com/milvus-io/milvus/internal/metrics"
 	"github.com/milvus-io/milvus/internal/util/timerecord"
 )
@@ -39,6 +40,7 @@ func searchOnSegments(replica ReplicaInterface, segType segmentType, searchReq *
 			defer wg.Done()
 			seg, err := replica.getSegmentByID(segID, segType)
 			if err != nil {
+				log.Error(err.Error()) // should not happen but still ignore it since the result is still correct
 				return
 			}
 			// record search time