diff --git a/internal/rootcoord/import_manager.go b/internal/rootcoord/import_manager.go
index e8c05e342c..f9857d4274 100644
--- a/internal/rootcoord/import_manager.go
+++ b/internal/rootcoord/import_manager.go
@@ -154,7 +154,7 @@ func (m *importManager) flipTaskStateLoop(wg *sync.WaitGroup) {
 			log.Info("import manager context done, exit check flipTaskStateLoop")
 			return
 		case <-flipPersistedTicker.C:
-			log.Debug("start trying to flip ImportPersisted task")
+			// log.Debug("start trying to flip ImportPersisted task")
 			if err := m.loadAndFlipPersistedTasks(m.ctx); err != nil {
 				log.Error("failed to flip ImportPersisted task", zap.Error(err))
 			}
@@ -786,7 +786,7 @@ func (m *importManager) getTaskState(tID int64) *milvuspb.GetImportStateResponse
 // other in-progress tasks as failed, when `load2Mem` is set to `true`.
 // loadFromTaskStore instead returns a list of all import tasks if `load2Mem` is set to `false`.
 func (m *importManager) loadFromTaskStore(load2Mem bool) ([]*datapb.ImportTaskInfo, error) {
-	log.Info("import manager starts loading from Etcd")
+	// log.Info("import manager starts loading from Etcd")
 	_, v, err := m.taskStore.LoadWithPrefix(Params.RootCoordCfg.ImportTaskSubPath)
 	if err != nil {
 		log.Error("import manager failed to load from Etcd", zap.Error(err))
diff --git a/internal/rootcoord/root_coord.go b/internal/rootcoord/root_coord.go
index 9389b6d110..89a864b1ab 100644
--- a/internal/rootcoord/root_coord.go
+++ b/internal/rootcoord/root_coord.go
@@ -1765,7 +1765,7 @@ func (c *Core) ReportImport(ctx context.Context, ir *rootcoordpb.ImportResult) (
 
 	// If setting ImportState_ImportCompleted, simply update the state and return directly.
 	if ir.GetState() == commonpb.ImportState_ImportCompleted {
-		log.Warn("this should not be called!")
+		log.Warn("ReportImport() should not be called when import task is completed!")
 	}
 	// Upon receiving ReportImport request, update the related task's state in task store.
 	ti, err := c.importManager.updateTaskInfo(ir)
@@ -1782,14 +1782,16 @@ func (c *Core) ReportImport(ctx context.Context, ir *rootcoordpb.ImportResult) (
 		log.Info("an import task has failed, marking DataNode available and resending import task",
 			zap.Int64("task ID", ir.GetTaskId()))
 		resendTaskFunc()
-	} else if ir.GetState() != commonpb.ImportState_ImportPersisted {
-		log.Warn("unexpected import task state reported, return immediately (this should not happen)",
-			zap.Any("task ID", ir.GetTaskId()),
-			zap.Any("import state", ir.GetState()))
+	} else if ir.GetState() == commonpb.ImportState_ImportCompleted {
+		// When a DataNode completes importing, remove this DataNode from the busy node list and send out import tasks again.
+		log.Info("an import task has completed, marking DataNode available and resending import task",
+			zap.Int64("task ID", ir.GetTaskId()))
 		resendTaskFunc()
-	} else {
+	} else if ir.GetState() == commonpb.ImportState_ImportPersisted {
 		// Here ir.GetState() == commonpb.ImportState_ImportPersisted
 		// Seal these import segments, so they can be auto-flushed later.
+		log.Info("an import task turns to persisted state, flush segments to be sealed",
+			zap.Any("task ID", ir.GetTaskId()), zap.Any("segments", ir.GetSegments()))
 		if err := c.broker.Flush(ctx, ti.GetCollectionId(), ir.GetSegments()); err != nil {
 			log.Error("failed to call Flush on bulk insert segments",
 				zap.Int64("task ID", ir.GetTaskId()))
diff --git a/internal/rootcoord/root_coord_test.go b/internal/rootcoord/root_coord_test.go
index b95ace38ca..38b924bb02 100644
--- a/internal/rootcoord/root_coord_test.go
+++ b/internal/rootcoord/root_coord_test.go
@@ -1184,24 +1184,7 @@ func TestCore_ReportImport(t *testing.T) {
 		assert.NotEqual(t, commonpb.ErrorCode_Success, resp.GetErrorCode())
 	})
 
-	t.Run("report import started state", func(t *testing.T) {
-		ctx := context.Background()
-		c := newTestCore(withHealthyCode())
-		c.importManager = newImportManager(ctx, mockKv, idAlloc, callImportServiceFn, callMarkSegmentsDropped, callGetSegmentStates, nil, nil)
-		c.importManager.loadFromTaskStore(true)
-		c.importManager.sendOutTasks(ctx)
-		resp, err := c.ReportImport(ctx, &rootcoordpb.ImportResult{
-			TaskId: 100,
-			State:  commonpb.ImportState_ImportStarted,
-		})
-		assert.NoError(t, err)
-		assert.Equal(t, commonpb.ErrorCode_Success, resp.GetErrorCode())
-		// Change the state back.
-		err = c.importManager.setImportTaskState(100, commonpb.ImportState_ImportPending)
-		assert.NoError(t, err)
-	})
-
-	t.Run("report persisted import", func(t *testing.T) {
+	testFunc := func(state commonpb.ImportState) {
 		ctx := context.Background()
 		c := newTestCore(
 			withHealthyCode(),
@@ -1216,13 +1199,29 @@ func TestCore_ReportImport(t *testing.T) {
 
 		resp, err := c.ReportImport(ctx, &rootcoordpb.ImportResult{
 			TaskId: 100,
-			State:  commonpb.ImportState_ImportPersisted,
+			State:  state,
 		})
 		assert.NoError(t, err)
 		assert.Equal(t, commonpb.ErrorCode_Success, resp.GetErrorCode())
 		// Change the state back.
 		err = c.importManager.setImportTaskState(100, commonpb.ImportState_ImportPending)
 		assert.NoError(t, err)
+	}
+
+	t.Run("report import started state", func(t *testing.T) {
+		testFunc(commonpb.ImportState_ImportStarted)
+	})
+
+	t.Run("report import persisted state", func(t *testing.T) {
+		testFunc(commonpb.ImportState_ImportPersisted)
+	})
+
+	t.Run("report import completed state", func(t *testing.T) {
+		testFunc(commonpb.ImportState_ImportCompleted)
+	})
+
+	t.Run("report import failed state", func(t *testing.T) {
+		testFunc(commonpb.ImportState_ImportFailed)
 	})
 }