diff --git a/internal/rootcoord/root_coord.go b/internal/rootcoord/root_coord.go
index 13b74c3b43..e1fea8985c 100644
--- a/internal/rootcoord/root_coord.go
+++ b/internal/rootcoord/root_coord.go
@@ -882,6 +882,39 @@ func (c *Core) BuildIndex(ctx context.Context, segID typeutil.UniqueID, field *s
 	return bldID, nil
 }
 
+// RemoveIndex will call drop index service
+func (c *Core) RemoveIndex(ctx context.Context, collName string, indexName string) error {
+	_, indexInfos, err := c.MetaTable.GetIndexByName(collName, indexName)
+	if err != nil {
+		log.Error("GetIndexByName failed,", zap.String("collection name", collName),
+			zap.String("index name", indexName), zap.Error(err))
+		return err
+	}
+	for _, indexInfo := range indexInfos {
+		if err = c.CallDropIndexService(ctx, indexInfo.IndexID); err != nil {
+			log.Error("CallDropIndexService failed,", zap.String("collection name", collName), zap.Error(err))
+			return err
+		}
+	}
+	return nil
+}
+
+// ExpireMetaCache will call invalidate collection meta cache
+func (c *Core) ExpireMetaCache(ctx context.Context, collNames []string, ts typeutil.Timestamp) {
+	for _, collName := range collNames {
+		req := proxypb.InvalidateCollMetaCacheRequest{
+			Base: &commonpb.MsgBase{
+				MsgType:   0, //TODO, msg type
+				MsgID:     0, //TODO, msg id
+				Timestamp: ts,
+				SourceID:  c.session.ServerID,
+			},
+			CollectionName: collName,
+		}
+		c.proxyClientManager.InvalidateCollectionMetaCache(ctx, &req)
+	}
+}
+
 // Register register rootcoord at etcd
 func (c *Core) Register() error {
 	c.session = sessionutil.NewSession(c.ctx, Params.MetaRootPath, Params.EtcdEndpoints)
diff --git a/internal/rootcoord/task.go b/internal/rootcoord/task.go
index 3cb8c90212..e00f4cc3b0 100644
--- a/internal/rootcoord/task.go
+++ b/internal/rootcoord/task.go
@@ -22,7 +22,6 @@ import (
 	"github.com/milvus-io/milvus/internal/proto/etcdpb"
 	"github.com/milvus-io/milvus/internal/proto/internalpb"
 	"github.com/milvus-io/milvus/internal/proto/milvuspb"
-	"github.com/milvus-io/milvus/internal/proto/proxypb"
 	"github.com/milvus-io/milvus/internal/proto/schemapb"
 	"github.com/milvus-io/milvus/internal/util/tsoutil"
 	"github.com/milvus-io/milvus/internal/util/typeutil"
@@ -296,7 +295,10 @@ func (t *DropCollectionReqTask) Execute(ctx context.Context) error {
 		return fmt.Errorf("encodeDdOperation fail, error = %w", err)
 	}
 
-	aliases := t.core.MetaTable.ListAliases(collMeta.ID)
+	// drop all indices
+	if err = t.core.RemoveIndex(ctx, t.Req.CollectionName, ""); err != nil {
+		return err
+	}
 
 	// use lambda function here to guarantee all resources to be released
 	dropCollectionFn := func() error {
@@ -346,36 +348,14 @@ func (t *DropCollectionReqTask) Execute(ctx context.Context) error {
 
 	//notify query service to release collection
 	if err = t.core.CallReleaseCollectionService(t.core.ctx, ts, 0, collMeta.ID); err != nil {
-		log.Error("Failed to CallReleaseCollectionService", zap.String("error", err.Error()))
+		log.Error("Failed to CallReleaseCollectionService", zap.Error(err))
 		return err
 	}
 
-	req := proxypb.InvalidateCollMetaCacheRequest{
-		Base: &commonpb.MsgBase{
-			MsgType:   0, //TODO, msg type
-			MsgID:     0, //TODO, msg id
-			Timestamp: ts,
-			SourceID:  t.core.session.ServerID,
-		},
-		DbName:         t.Req.DbName,
-		CollectionName: t.Req.CollectionName,
-	}
-	// error doesn't matter here
-	t.core.proxyClientManager.InvalidateCollectionMetaCache(ctx, &req)
+	t.core.ExpireMetaCache(ctx, []string{t.Req.CollectionName}, ts)
 
-	for _, alias := range aliases {
-		req = proxypb.InvalidateCollMetaCacheRequest{
-			Base: &commonpb.MsgBase{
-				MsgType:   0, //TODO, msg type
-				MsgID:     0, //TODO, msg id
-				Timestamp: ts,
-				SourceID:  t.core.session.ServerID,
-			},
-			DbName:         t.Req.DbName,
-			CollectionName: alias,
-		}
-		t.core.proxyClientManager.InvalidateCollectionMetaCache(ctx, &req)
-	}
+	aliases := t.core.MetaTable.ListAliases(collMeta.ID)
+	t.core.ExpireMetaCache(ctx, aliases, ts)
 
 	// Update DDOperation in etcd
 	return t.core.setDdMsgSendFlag(true)
@@ -566,18 +546,7 @@ func (t *CreatePartitionReqTask) Execute(ctx context.Context) error {
 		return err
 	}
 
-	req := proxypb.InvalidateCollMetaCacheRequest{
-		Base: &commonpb.MsgBase{
-			MsgType:   0, //TODO, msg type
-			MsgID:     0, //TODO, msg id
-			Timestamp: ts,
-			SourceID:  t.core.session.ServerID,
-		},
-		DbName:         t.Req.DbName,
-		CollectionName: t.Req.CollectionName,
-	}
-	// error doesn't matter here
-	t.core.proxyClientManager.InvalidateCollectionMetaCache(ctx, &req)
+	t.core.ExpireMetaCache(ctx, []string{t.Req.CollectionName}, ts)
 
 	// Update DDOperation in etcd
 	return t.core.setDdMsgSendFlag(true)
@@ -662,22 +631,11 @@ func (t *DropPartitionReqTask) Execute(ctx context.Context) error {
 		return err
 	}
 
-	req := proxypb.InvalidateCollMetaCacheRequest{
-		Base: &commonpb.MsgBase{
-			MsgType:   0, //TODO, msg type
-			MsgID:     0, //TODO, msg id
-			Timestamp: ts,
-			SourceID:  t.core.session.ServerID,
-		},
-		DbName:         t.Req.DbName,
-		CollectionName: t.Req.CollectionName,
-	}
-	// error doesn't matter here
-	t.core.proxyClientManager.InvalidateCollectionMetaCache(ctx, &req)
+	t.core.ExpireMetaCache(ctx, []string{t.Req.CollectionName}, ts)
 
 	//notify query service to release partition
 	if err = t.core.CallReleasePartitionService(t.core.ctx, ts, 0, collInfo.ID, []typeutil.UniqueID{partID}); err != nil {
-		log.Error("Failed to CallReleaseCollectionService", zap.String("error", err.Error()))
+		log.Error("Failed to CallReleaseCollectionService", zap.Error(err))
 		return err
 	}
 
@@ -969,22 +927,10 @@ func (t *DropIndexReqTask) Execute(ctx context.Context) error {
 	if t.Type() != commonpb.MsgType_DropIndex {
 		return fmt.Errorf("drop index, msg type = %s", commonpb.MsgType_name[int32(t.Type())])
 	}
-	_, info, err := t.core.MetaTable.GetIndexByName(t.Req.CollectionName, t.Req.IndexName)
-	if err != nil {
-		log.Warn("GetIndexByName failed,", zap.String("collection name", t.Req.CollectionName), zap.String("field name", t.Req.FieldName), zap.String("index name", t.Req.IndexName), zap.Error(err))
+	if err := t.core.RemoveIndex(ctx, t.Req.CollectionName, t.Req.IndexName); err != nil {
 		return err
 	}
-	if len(info) == 0 {
-		return nil
-	}
-	if len(info) != 1 {
-		return fmt.Errorf("len(index) = %d", len(info))
-	}
-	err = t.core.CallDropIndexService(ctx, info[0].IndexID)
-	if err != nil {
-		return err
-	}
-	_, _, err = t.core.MetaTable.DropIndex(t.Req.CollectionName, t.Req.FieldName, t.Req.IndexName)
+	_, _, err := t.core.MetaTable.DropIndex(t.Req.CollectionName, t.Req.FieldName, t.Req.IndexName)
 	return err
 }
 
@@ -1043,17 +989,7 @@ func (t *DropAliasReqTask) Execute(ctx context.Context) error {
 		return fmt.Errorf("meta table drop alias failed, error = %w", err)
 	}
 
-	req := proxypb.InvalidateCollMetaCacheRequest{
-		Base: &commonpb.MsgBase{
-			MsgType:   0, //TODO, msg type
-			MsgID:     0, //TODO, msg id
-			Timestamp: ts,
-			SourceID:  t.core.session.ServerID,
-		},
-		CollectionName: t.Req.Alias,
-	}
-	// error doesn't matter here
-	t.core.proxyClientManager.InvalidateCollectionMetaCache(ctx, &req)
+	t.core.ExpireMetaCache(ctx, []string{t.Req.Alias}, ts)
 
 	return nil
 }
@@ -1084,17 +1020,7 @@ func (t *AlterAliasReqTask) Execute(ctx context.Context) error {
 		return fmt.Errorf("meta table alter alias failed, error = %w", err)
 	}
 
-	req := proxypb.InvalidateCollMetaCacheRequest{
-		Base: &commonpb.MsgBase{
-			MsgType:   0, //TODO, msg type
-			MsgID:     0, //TODO, msg id
-			Timestamp: ts,
-			SourceID:  t.core.session.ServerID,
-		},
-		CollectionName: t.Req.Alias,
-	}
-	// error doesn't matter here
-	t.core.proxyClientManager.InvalidateCollectionMetaCache(ctx, &req)
+	t.core.ExpireMetaCache(ctx, []string{t.Req.Alias}, ts)
 
 	return nil
 }