diff --git a/internal/rootcoord/broker.go b/internal/rootcoord/broker.go
index c1fa30d0ac..8701a5c6f2 100644
--- a/internal/rootcoord/broker.go
+++ b/internal/rootcoord/broker.go
@@ -58,9 +58,7 @@ type Broker interface {
 	GcConfirm(ctx context.Context, collectionID, partitionID UniqueID) bool
 
 	DropCollectionIndex(ctx context.Context, collID UniqueID, partIDs []UniqueID) error
-	GetSegmentIndexState(ctx context.Context, collID UniqueID, indexName string, segIDs []UniqueID) ([]*indexpb.SegmentIndexState, error)
-	DescribeIndex(ctx context.Context, colID UniqueID) (*indexpb.DescribeIndexResponse, error)
-
+	// notify observer to clean their meta cache
 	BroadcastAlteredCollection(ctx context.Context, req *milvuspb.AlterCollectionRequest) error
 }
 
@@ -270,12 +268,6 @@ func (b *ServerBroker) BroadcastAlteredCollection(ctx context.Context, req *milv
 	return nil
 }
 
-func (b *ServerBroker) DescribeIndex(ctx context.Context, colID UniqueID) (*indexpb.DescribeIndexResponse, error) {
-	return b.s.dataCoord.DescribeIndex(ctx, &indexpb.DescribeIndexRequest{
-		CollectionID: colID,
-	})
-}
-
 func (b *ServerBroker) GcConfirm(ctx context.Context, collectionID, partitionID UniqueID) bool {
 	log := log.Ctx(ctx).With(zap.Int64("collection", collectionID), zap.Int64("partition", partitionID))
 
diff --git a/internal/rootcoord/mock_test.go b/internal/rootcoord/mock_test.go
index f17ff9d1e2..fe0940928d 100644
--- a/internal/rootcoord/mock_test.go
+++ b/internal/rootcoord/mock_test.go
@@ -899,7 +899,6 @@ type mockBroker struct {
 	FlushFunc             func(ctx context.Context, cID int64, segIDs []int64) error
 
 	DropCollectionIndexFunc  func(ctx context.Context, collID UniqueID, partIDs []UniqueID) error
-	DescribeIndexFunc        func(ctx context.Context, colID UniqueID) (*indexpb.DescribeIndexResponse, error)
 	GetSegmentIndexStateFunc func(ctx context.Context, collID UniqueID, indexName string, segIDs []UniqueID) ([]*indexpb.SegmentIndexState, error)
 
 	BroadcastAlteredCollectionFunc func(ctx context.Context, req *milvuspb.AlterCollectionRequest) error
@@ -935,10 +934,6 @@ func (b mockBroker) DropCollectionIndex(ctx context.Context, collID UniqueID, pa
 	return b.DropCollectionIndexFunc(ctx, collID, partIDs)
 }
 
-func (b mockBroker) DescribeIndex(ctx context.Context, colID UniqueID) (*indexpb.DescribeIndexResponse, error) {
-	return b.DescribeIndexFunc(ctx, colID)
-}
-
 func (b mockBroker) GetSegmentIndexState(ctx context.Context, collID UniqueID, indexName string, segIDs []UniqueID) ([]*indexpb.SegmentIndexState, error) {
 	return b.GetSegmentIndexStateFunc(ctx, collID, indexName, segIDs)
 }