diff --git a/internal/runner/runner.go b/internal/runner/runner.go
index 948344b11c..6ef7f70c5a 100644
--- a/internal/runner/runner.go
+++ b/internal/runner/runner.go
@@ -32,6 +32,7 @@ import (
 	"github.com/vdaas/vald/internal/log"
 	"github.com/vdaas/vald/internal/log/level"
 	"github.com/vdaas/vald/internal/params"
+	"github.com/vdaas/vald/internal/safety"
 	"github.com/vdaas/vald/internal/timeutil/location"
 	ver "github.com/vdaas/vald/internal/version"
 	"go.uber.org/automaxprocs/maxprocs"
@@ -160,7 +161,9 @@ func Run(ctx context.Context, run Runner, name string) (err error) {
 			}
 		case <-rctx.Done():
 			log.Info("executing daemon pre-stop function")
-			err = run.PreStop(ctx)
+			err = safety.RecoverFunc(func() error {
+				return run.PreStop(ctx)
+			})()
 			if err != nil {
 				log.Error(errors.ErrPreStopFunc(name, err))
 				if _, ok := emap[err.Error()]; !ok {
@@ -170,7 +173,9 @@ func Run(ctx context.Context, run Runner, name string) (err error) {
 			}
 
 			log.Info("executing daemon stop function")
-			err = run.Stop(ctx)
+			err = safety.RecoverFunc(func() error {
+				return run.Stop(ctx)
+			})()
 			if err != nil {
 				log.Error(errors.ErrStopFunc(name, err))
 				if _, ok := emap[err.Error()]; !ok {
@@ -180,7 +185,9 @@ func Run(ctx context.Context, run Runner, name string) (err error) {
 			}
 
 			log.Info("executing daemon post-stop function")
-			err = run.PostStop(ctx)
+			err = safety.RecoverFunc(func() error {
+				return run.PostStop(ctx)
+			})()
 			if err != nil {
 				log.Error(errors.ErrPostStopFunc(name, err))
 				if _, ok := emap[err.Error()]; !ok {
diff --git a/pkg/agent/core/ngt/handler/grpc/handler.go b/pkg/agent/core/ngt/handler/grpc/handler.go
index 806ffcc009..dc2895e26b 100644
--- a/pkg/agent/core/ngt/handler/grpc/handler.go
+++ b/pkg/agent/core/ngt/handler/grpc/handler.go
@@ -421,8 +421,8 @@ func (s *server) IndexInfo(ctx context.Context, _ *payload.Empty) (res *payload.
 		}
 	}()
 	return &payload.Info_Index_Count{
-		Stored:      uint32(len(s.ngt.UUIDs(ctx))),
-		Uncommitted: uint32(len(s.ngt.UncommittedUUIDs())),
+		Stored:      uint32(s.ngt.Len()),
+		Uncommitted: uint32(s.ngt.InsertVCacheLen()),
 		Indexing:    s.ngt.IsIndexing(),
 	}, nil
 }
diff --git a/pkg/agent/core/ngt/service/ngt.go b/pkg/agent/core/ngt/service/ngt.go
index bbf4d81c2d..029e44a397 100644
--- a/pkg/agent/core/ngt/service/ngt.go
+++ b/pkg/agent/core/ngt/service/ngt.go
@@ -69,6 +69,7 @@ type NGT interface {
 type ngt struct {
 	alen     int
 	indexing atomic.Value
+	saveMu   sync.Mutex    // creating or saving index
 	lim      time.Duration // auto indexing time limit
 	dur      time.Duration // auto indexing check duration
 	sdur     time.Duration // auto save index check duration
@@ -234,7 +235,7 @@ func (n *ngt) Start(ctx context.Context) <-chan error {
 			err = nil
 			select {
 			case <-ctx.Done():
-				err = n.CreateAndSaveIndex(ctx, n.dps)
+				err = n.CreateIndex(ctx, n.dps)
 				if err != nil {
 					ech <- err
 					return errors.Wrap(ctx.Err(), err.Error())
@@ -454,6 +455,9 @@ func (n *ngt) CreateIndex(ctx context.Context, poolSize uint32) (err error) {
 		}
 	}()
 
+	n.saveMu.Lock()
+	defer n.saveMu.Unlock()
+
 	if n.indexing.Load().(bool) {
 		return nil
 	}
@@ -558,6 +562,9 @@ func (n *ngt) SaveIndex(ctx context.Context) (err error) {
 		}
 	}()
 
+	n.saveMu.Lock()
+	defer n.saveMu.Unlock()
+
 	if len(n.path) != 0 && !n.inMem {
 		eg, ctx := errgroup.New(ctx)
 		eg.Go(safety.RecoverFunc(func() error {
@@ -594,7 +601,7 @@ func (n *ngt) CreateAndSaveIndex(ctx context.Context, poolSize uint32) (err erro
 	}()
 
 	err = n.CreateIndex(ctx, poolSize)
-	if err != nil {
+	if err != nil && err != errors.ErrUncommittedIndexNotFound {
 		return err
 	}
 	return n.SaveIndex(ctx)
@@ -667,7 +674,7 @@ func (n *ngt) DeleteVCacheLen() uint64 {
 
 func (n *ngt) Close(ctx context.Context) (err error) {
 	if len(n.path) != 0 {
-		err = n.SaveIndex(ctx)
+		err = n.CreateAndSaveIndex(ctx, n.dps)
 	}
 	n.core.Close()
 	return
diff --git a/pkg/agent/sidecar/usecase/sidecar/sidecar.go b/pkg/agent/sidecar/usecase/sidecar/sidecar.go
index dc3c93c933..b133fd1436 100644
--- a/pkg/agent/sidecar/usecase/sidecar/sidecar.go
+++ b/pkg/agent/sidecar/usecase/sidecar/sidecar.go
@@ -134,6 +134,7 @@ func New(cfg *config.Data) (r runner.Runner, err error) {
 	so, err = observer.New(
 		observer.WithErrGroup(eg),
 		observer.WithBackupDuration(cfg.AgentSidecar.AutoBackupDuration),
+		observer.WithPostStopTimeout(cfg.AgentSidecar.PostStopTimeout),
 		observer.WithDir(cfg.AgentSidecar.WatchDir),
 		observer.WithBlobStorage(bs),
 	)