diff --git a/source/dnode/vnode/src/inc/vnodeInt.h b/source/dnode/vnode/src/inc/vnodeInt.h
index 5bf0a9b199..a76fc17377 100644
--- a/source/dnode/vnode/src/inc/vnodeInt.h
+++ b/source/dnode/vnode/src/inc/vnodeInt.h
@@ -239,7 +239,7 @@ void    tqClose(STQ*);
 int     tqPushMsg(STQ*, tmsg_t msgType);
 int     tqRegisterPushHandle(STQ* pTq, void* handle, SRpcMsg* pMsg);
 void    tqUnregisterPushHandle(STQ* pTq, void* pHandle);
-int     tqScanWalAsync(STQ* pTq, bool ckPause);
+int     tqScanWalAsync(STQ* pTq);
 int32_t tqStopStreamTasksAsync(STQ* pTq);
 int32_t tqProcessTaskCheckPointSourceReq(STQ* pTq, SRpcMsg* pMsg, SRpcMsg* pRsp);
 int32_t tqProcessTaskCheckpointReadyMsg(STQ* pTq, SRpcMsg* pMsg);
diff --git a/source/dnode/vnode/src/tq/tq.c b/source/dnode/vnode/src/tq/tq.c
index 119edb47bc..fc173eb691 100644
--- a/source/dnode/vnode/src/tq/tq.c
+++ b/source/dnode/vnode/src/tq/tq.c
@@ -920,12 +920,12 @@ static void doStartFillhistoryStep2(SStreamTask* pTask, SStreamTask* pStreamTask
 
     // now the fill-history task starts to scan data from wal files.
     code = streamTaskHandleEvent(pTask->status.pSM, TASK_EVENT_SCANHIST_DONE);
-    if (code == TSDB_CODE_SUCCESS) {
-      code = tqScanWalAsync(pTq, false);
-      if (code) {
-        tqError("vgId:%d failed to start scan wal file, code:%s", vgId, tstrerror(code));
-      }
-    }
+//    if (code == TSDB_CODE_SUCCESS) {
+//      code = tqScanWalAsync(pTq, false);
+//      if (code) {
+//        tqError("vgId:%d failed to start scan wal file, code:%s", vgId, tstrerror(code));
+//      }
+//    }
   }
 }
 
@@ -1122,12 +1122,12 @@ int32_t tqProcessTaskRunReq(STQ* pTq, SRpcMsg* pMsg) {
   }
 
   // let's continue scan data in the wal files
-  if (req.reqType >= 0 || req.reqType == STREAM_EXEC_T_RESUME_TASK) {
-    code = tqScanWalAsync(pTq, false);  // it's ok to failed
-    if (code) {
-      tqError("vgId:%d failed to start scan wal file, code:%s", pTq->pStreamMeta->vgId, tstrerror(code));
-    }
-  }
+//  if (req.reqType >= 0 || req.reqType == STREAM_EXEC_T_RESUME_TASK) {
+//    code = tqScanWalAsync(pTq, false);  // it's ok to failed
+//    if (code) {
+//      tqError("vgId:%d failed to start scan wal file, code:%s", pTq->pStreamMeta->vgId, tstrerror(code));
+//    }
+//  }
 
   return code;
 }
diff --git a/source/dnode/vnode/src/tq/tqPush.c b/source/dnode/vnode/src/tq/tqPush.c
index 2b2667773a..fc83343c99 100644
--- a/source/dnode/vnode/src/tq/tqPush.c
+++ b/source/dnode/vnode/src/tq/tqPush.c
@@ -49,20 +49,6 @@ int32_t tqPushMsg(STQ* pTq, tmsg_t msgType) {
     }
   }
 
-  streamMetaRLock(pTq->pStreamMeta);
-  int32_t numOfTasks = streamMetaGetNumOfTasks(pTq->pStreamMeta);
-  streamMetaRUnLock(pTq->pStreamMeta);
-
-//  tqTrace("vgId:%d handle submit, restore:%d, numOfTasks:%d", TD_VID(pTq->pVnode), pTq->pVnode->restored, numOfTasks);
-
-  // push data for stream processing:
-  // 1. the vnode has already been restored.
-  // 2. the vnode should be the leader.
-  // 3. the stream is not suspended yet.
-  if ((!tsDisableStream) && (numOfTasks > 0)) {
-    code = tqScanWalAsync(pTq, true);
-  }
-
   return code;
 }
 
diff --git a/source/dnode/vnode/src/tq/tqStreamTask.c b/source/dnode/vnode/src/tq/tqStreamTask.c
index 9ea84830f1..33a32617ef 100644
--- a/source/dnode/vnode/src/tq/tqStreamTask.c
+++ b/source/dnode/vnode/src/tq/tqStreamTask.c
@@ -17,22 +17,20 @@
 #include "vnd.h"
 
 #define MAX_REPEAT_SCAN_THRESHOLD 3
-#define SCAN_WAL_IDLE_DURATION    500    // idle for 500ms to do next wal scan
+#define SCAN_WAL_IDLE_DURATION    500  // idle for 500ms to do next wal scan
 
 typedef struct SBuildScanWalMsgParam {
   int64_t metaId;
-  int32_t numOfTasks;
-  int8_t  restored;
+//  int8_t  restored;
   SMsgCb  msgCb;
 } SBuildScanWalMsgParam;
 
-static int32_t doScanWalForAllTasks(SStreamMeta* pStreamMeta);
+static int32_t doScanWalForAllTasks(SStreamMeta* pStreamMeta, int32_t* pNumOfTasks);
 static int32_t setWalReaderStartOffset(SStreamTask* pTask, int32_t vgId);
 static bool    handleFillhistoryScanComplete(SStreamTask* pTask, int64_t ver);
 static bool    taskReadyForDataFromWal(SStreamTask* pTask);
 static int32_t doPutDataIntoInputQ(SStreamTask* pTask, int64_t maxVer, int32_t* numOfItems, bool* pSucc);
-static int32_t tqScanWalInFuture(STQ* pTq, int32_t numOfTasks, int32_t idleDuration);
-static int32_t doScanWalAsync(STQ* pTq, bool ckPause);
+static int32_t tqScanWalInFuture(STQ* pTq);
 
 // extract data blocks(submit/delete) from WAL, and add them into the input queue for all the sources tasks.
 int32_t tqScanWal(STQ* pTq) {
@@ -40,44 +38,38 @@ int32_t tqScanWal(STQ* pTq) {
   int32_t      vgId = pMeta->vgId;
   int64_t      st = taosGetTimestampMs();
   int32_t      numOfTasks = 0;
+  int64_t      el = 0;
+  int32_t      code = 0;
 
-  tqDebug("vgId:%d continue to check if data in wal are available, scanCounter:%d", vgId, pMeta->scanInfo.scanCounter);
-
-  // check all tasks
-  int32_t code = doScanWalForAllTasks(pMeta);
-  if (code) {
-    tqError("vgId:%d failed to start all tasks, try next time, code:%s", vgId, tstrerror(code));
+  int32_t old = atomic_val_compare_exchange_32(&pMeta->scanInfo.scanCounter, 0, 1);
+  if (old == 0) {
+    tqDebug("vgId:%d try to scan wal to extract data", vgId);
+  } else {
+    tqDebug("vgId:%d already in wal scan, abort", vgId);
     return code;
   }
 
-  streamMetaWLock(pMeta);
-  int32_t times = (--pMeta->scanInfo.scanCounter);
-  if (times < 0) {
-    tqError("vgId:%d invalid scan counter:%d, reset to 0", vgId, times);
-    times = 0;
-  }
-
-  numOfTasks = taosArrayGetSize(pMeta->pTaskList);
-  streamMetaWUnLock(pMeta);
-
-  int64_t el = (taosGetTimestampMs() - st);
-  tqDebug("vgId:%d scan wal for stream tasks completed, elapsed time:%" PRId64 " ms", vgId, el);
-
-  if (times > 0) {
-    tqDebug("vgId:%d scan wal for stream tasks for %d times in %dms", vgId, times, SCAN_WAL_IDLE_DURATION);
-    code = tqScanWalInFuture(pTq, numOfTasks, SCAN_WAL_IDLE_DURATION);
-    if (code) {
-      tqError("vgId:%d sched scan wal in %dms failed, ignore this failure", vgId, SCAN_WAL_IDLE_DURATION);
-    }
+  // check all tasks
+  code = doScanWalForAllTasks(pMeta, &numOfTasks);
+
+  el = (taosGetTimestampMs() - st);
+  if (code) {
+    tqError("vgId:%d failed to scan wal for all tasks, try next time, elapsed time:%" PRId64 "ms code:%s", vgId, el,
+            tstrerror(code));
+  } else {
+    tqDebug("vgId:%d scan wal for stream tasks completed, elapsed time:%" PRId64 "ms, next scan start in %dms", vgId,
+            el, SCAN_WAL_IDLE_DURATION);
   }
 
+  atomic_store_32(&pMeta->scanInfo.scanCounter, 0);
   return code;
 }
 
 static void doStartScanWal(void* param, void* tmrId) {
-  int32_t vgId = 0;
-  int32_t code = 0;
-
+  int32_t                vgId = 0;
+  int32_t                code = 0;
+  SVnode*                pVnode = NULL;
+  int32_t                numOfTasks = 0;
   SBuildScanWalMsgParam* pParam = (SBuildScanWalMsgParam*)param;
 
   SStreamMeta* pMeta = taosAcquireRef(streamMetaRefPool, pParam->metaId);
@@ -102,71 +94,93 @@ static void doStartScanWal(void* param, void* tmrId) {
 
   vgId = pMeta->vgId;
 
-  tqDebug("vgId:%d create msg to start wal scan, numOfTasks:%d, vnd restored:%d", vgId, pParam->numOfTasks,
-          pParam->restored);
-#if 0
-  // wait for the vnode is freed, and invalid read may occur.
+  if (pMeta->role == NODE_ROLE_FOLLOWER) {
+    tqDebug("vgId:%d not leader, role:%d not scan wal anymore", vgId, pMeta->role);
+
+    code = taosReleaseRef(streamMetaRefPool, pParam->metaId);
+    if (code == TSDB_CODE_SUCCESS) {
+      tqDebug("vgId:%d jump out of scan wal timer since not leader", vgId);
+    } else {
+      tqError("vgId:%d failed to release ref for streamMeta, rid:%" PRId64 " code:%s", vgId, pParam->metaId,
+              tstrerror(code));
+    }
+
+    taosMemFree(pParam);
+    return;
+  }
+
+  if (pMeta->startInfo.startAllTasks) {
+    tqTrace("vgId:%d in restart procedure, not ready to scan wal", vgId);
+    goto _end;
+  }
+
+  streamMetaRLock(pMeta);
+  numOfTasks = taosArrayGetSize(pMeta->pTaskList);
+  streamMetaRUnLock(pMeta);
+
+  if (numOfTasks == 0) {
+    goto _end;
+  }
+
+  tqTrace("vgId:%d create msg to start wal scan, numOfTasks:%d", vgId, numOfTasks);
+
+  // #if 0
+  //  wait for the vnode is freed, and invalid read may occur.
   taosMsleep(10000);
-#endif
+  // #endif
 
   code = streamTaskSchedTask(&pParam->msgCb, vgId, 0, 0, STREAM_EXEC_T_EXTRACT_WAL_DATA);
   if (code) {
     tqError("vgId:%d failed sched task to scan wal, code:%s", vgId, tstrerror(code));
   }
 
+_end:
+  streamTmrStart(doStartScanWal, SCAN_WAL_IDLE_DURATION, pParam, &pMeta->scanInfo.scanTimer, &pMeta->scanInfo.scanTimer,
+                 vgId, "scan-wal");
+
   code = taosReleaseRef(streamMetaRefPool, pParam->metaId);
   if (code) {
     tqError("vgId:%d failed to release ref for streamMeta, rid:%" PRId64 " code:%s", vgId, pParam->metaId,
             tstrerror(code));
   }
-
-  taosMemoryFree(pParam);
 }
 
-int32_t tqScanWalInFuture(STQ* pTq, int32_t numOfTasks, int32_t idleDuration) {
+int32_t tqScanWalAsync(STQ* pTq) {
   SStreamMeta*           pMeta = pTq->pStreamMeta;
   int32_t                code = 0;
   int32_t                vgId = TD_VID(pTq->pVnode);
   tmr_h                  pTimer = NULL;
   SBuildScanWalMsgParam* pParam = NULL;
 
+  // 1. the vnode should be the leader.
+  // 2. the stream isn't disabled
+  if ((pMeta->role == NODE_ROLE_FOLLOWER) || tsDisableStream) {
+    tqInfo("vgId:%d follower node or stream disabled, not scan wal", vgId);
+    return TSDB_CODE_SUCCESS;
+  }
+
   pParam = taosMemoryMalloc(sizeof(SBuildScanWalMsgParam));
   if (pParam == NULL) {
+    tqError("vgId:%d failed to start scan wal, stream not executes, code:%s", vgId, tstrerror(code));
     return terrno;
   }
 
   pParam->metaId = pMeta->rid;
-  pParam->numOfTasks = numOfTasks;
-  pParam->restored = pTq->pVnode->restored;
   pParam->msgCb = pTq->pVnode->msgCb;
 
   code = streamTimerGetInstance(&pTimer);
   if (code) {
-    tqError("vgId:%d failed to get tmr ctrl during sched scan wal", vgId);
+    tqFatal("vgId:%d failed to get tmr ctrl during sched scan wal", vgId);
     taosMemoryFree(pParam);
   } else {
-    streamTmrStart(doStartScanWal, idleDuration, pParam, pTimer, &pMeta->scanInfo.scanTimer, vgId, "scan-wal-fut");
+    // todo: start in 1sec for the first time
+    streamTmrStart(doStartScanWal, 1000, pParam, pTimer, &pMeta->scanInfo.scanTimer, vgId,
+                   "scan-wal");
   }
 
   return code;
 }
 
-int32_t tqScanWalAsync(STQ* pTq, bool ckPause) {
-  SStreamMeta* pMeta = pTq->pStreamMeta;
-  bool         alreadyRestored = pTq->pVnode->restored;
-  int32_t      code = 0;
-
-  // do not launch the stream tasks, if it is a follower or not restored vnode.
-  if (!(vnodeIsRoleLeader(pTq->pVnode) && alreadyRestored)) {
-    return TSDB_CODE_SUCCESS;
-  }
-
-  streamMetaWLock(pMeta);
-  code = doScanWalAsync(pTq, ckPause);
-  streamMetaWUnLock(pMeta);
-  return code;
-}
-
 int32_t tqStopStreamTasksAsync(STQ* pTq) {
   SStreamMeta* pMeta = pTq->pStreamMeta;
   int32_t      vgId = pMeta->vgId;
@@ -347,13 +361,10 @@ int32_t doPutDataIntoInputQ(SStreamTask* pTask, int64_t maxVer, int32_t* numOfIt
   return code;
 }
 
-int32_t doScanWalForAllTasks(SStreamMeta* pStreamMeta) {
+int32_t doScanWalForAllTasks(SStreamMeta* pStreamMeta, int32_t* pNumOfTasks) {
   int32_t vgId = pStreamMeta->vgId;
   SArray* pTaskList = NULL;
-  int32_t numOfTasks = taosArrayGetSize(pStreamMeta->pTaskList);
-  if (numOfTasks == 0) {
-    return TSDB_CODE_SUCCESS;
-  }
+  int32_t numOfTasks = 0;
 
   // clone the task list, to avoid the task update during scan wal files
   streamMetaWLock(pStreamMeta);
@@ -364,10 +375,13 @@ int32_t doScanWalForAllTasks(SStreamMeta* pStreamMeta) {
     return terrno;
   }
 
-  tqDebug("vgId:%d start to check wal to extract new submit block for %d tasks", vgId, numOfTasks);
-
   // update the new task number
   numOfTasks = taosArrayGetSize(pTaskList);
+  if (pNumOfTasks != NULL) {
+    *pNumOfTasks = numOfTasks;
+  }
+
+  tqDebug("vgId:%d start to check wal to extract new submit block for %d tasks", vgId, numOfTasks);
 
   for (int32_t i = 0; i < numOfTasks; ++i) {
     STaskId* pTaskId = taosArrayGet(pTaskList, i);
@@ -426,51 +440,59 @@ int32_t doScanWalForAllTasks(SStreamMeta* pStreamMeta) {
   return TSDB_CODE_SUCCESS;
 }
 
-int32_t doScanWalAsync(STQ* pTq, bool ckPause) {
-  SStreamMeta* pMeta = pTq->pStreamMeta;
-  bool         alreadyRestored = pTq->pVnode->restored;
-  int32_t      vgId = pMeta->vgId;
-  int32_t      numOfTasks = taosArrayGetSize(pMeta->pTaskList);
-
-  if (numOfTasks == 0) {
-    tqDebug("vgId:%d no stream tasks existed to run", vgId);
-    return 0;
-  }
-
-  if (pMeta->startInfo.startAllTasks) {
-    tqTrace("vgId:%d in restart procedure, not scan wal", vgId);
-    return 0;
-  }
-
-  pMeta->scanInfo.scanCounter += 1;
-  if (pMeta->scanInfo.scanCounter > MAX_REPEAT_SCAN_THRESHOLD) {
-    pMeta->scanInfo.scanCounter = MAX_REPEAT_SCAN_THRESHOLD;
-  }
-
-  if (pMeta->scanInfo.scanCounter > 1) {
-    tqDebug("vgId:%d wal read task has been launched, remain scan times:%d", vgId, pMeta->scanInfo.scanCounter);
-    return 0;
-  }
-
-  int32_t numOfPauseTasks = pMeta->numOfPausedTasks;
-  if (ckPause && numOfTasks == numOfPauseTasks) {
-    tqDebug("vgId:%d ignore all submit, all streams had been paused, reset the walScanCounter", vgId);
-
-    // reset the counter value, since we do not launch the scan wal operation.
-    pMeta->scanInfo.scanCounter = 0;
-    return 0;
-  }
-
-  tqDebug("vgId:%d create msg to start wal scan to launch stream tasks, numOfTasks:%d, vnd restored:%d", vgId,
-          numOfTasks, alreadyRestored);
-
-  return streamTaskSchedTask(&pTq->pVnode->msgCb, vgId, 0, 0, STREAM_EXEC_T_EXTRACT_WAL_DATA);
-}
+// int32_t doScanWalAsync(STQ* pTq) {
+//   SStreamMeta* pMeta = pTq->pStreamMeta;
+//   bool         alreadyRestored = pTq->pVnode->restored;
+//   int32_t      vgId = pMeta->vgId;
+//   int32_t      code = 0;
+//   int32_t      numOfTasks = taosArrayGetSize(pMeta->pTaskList);
+//
+//   //  if (numOfTasks == 0) {
+////    tqDebug("vgId:%d no stream tasks existed to run", vgId);
+////    return 0;
+////  }
+//
+////  if (pMeta->startInfo.startAllTasks) {
+////    tqTrace("vgId:%d in restart procedure, not scan wal", vgId);
+////    return 0;
+////  }
+//
+////  pMeta->scanInfo.scanCounter += 1;
+////  if (pMeta->scanInfo.scanCounter > MAX_REPEAT_SCAN_THRESHOLD) {
+////    pMeta->scanInfo.scanCounter = MAX_REPEAT_SCAN_THRESHOLD;
+////  }
+//
+////  if (pMeta->scanInfo.scanCounter > 1) {
+////    tqDebug("vgId:%d wal read task has been launched, remain scan times:%d", vgId, pMeta->scanInfo.scanCounter);
+////    return 0;
+////  }
+//
+////  int32_t numOfPauseTasks = pMeta->numOfPausedTasks;
+////  if (ckPause && numOfTasks == numOfPauseTasks) {
+////    tqDebug("vgId:%d ignore all submit, all streams had been paused, reset the walScanCounter", vgId);
+////
+////     reset the counter value, since we do not launch the scan wal operation.
+////    pMeta->scanInfo.scanCounter = 0;
+////    return 0;
+////  }
+//
+////  tqDebug("vgId:%d create msg to start wal scan to launch stream tasks, numOfTasks:%d, vnd restored:%d", vgId,
+////          numOfTasks, alreadyRestored);
+////
+////  code = streamTaskSchedTask(&pTq->pVnode->msgCb, vgId, 0, 0, STREAM_EXEC_T_EXTRACT_WAL_DATA);
+////  if (code) {
+////    tqError("vgId:%d failed create msg to scan data in wal, retry in %dms", vgId, SCAN_WAL_IDLE_DURATION);
+////  }
+//
+//  code = tqScanWalInFuture(pTq, numOfTasks, SCAN_WAL_IDLE_DURATION);
+//  if (code) {
+//    tqError("vgId:%d sched scan wal in %dms failed, ignore this failure", vgId, SCAN_WAL_IDLE_DURATION);
+//  }
+//}
 
 void streamMetaFreeTQDuringScanWalError(STQ* pTq) {
   SBuildScanWalMsgParam* p = taosMemoryCalloc(1, sizeof(SBuildScanWalMsgParam));
   p->metaId = pTq->pStreamMeta->rid;
-  p->numOfTasks = 0;
 
   doStartScanWal(p, 0);
 }
\ No newline at end of file
diff --git a/source/dnode/vnode/src/tq/tqUtil.c b/source/dnode/vnode/src/tq/tqUtil.c
index 197a45cdb9..6f001981fb 100644
--- a/source/dnode/vnode/src/tq/tqUtil.c
+++ b/source/dnode/vnode/src/tq/tqUtil.c
@@ -47,6 +47,10 @@ END:
 void tqUpdateNodeStage(STQ* pTq, bool isLeader) {
   SSyncState state = syncGetState(pTq->pVnode->sync);
   streamMetaUpdateStageRole(pTq->pStreamMeta, state.term, isLeader);
+
+  if (isLeader) {
+    tqScanWalAsync(pTq);
+  }
 }
 
 static int32_t tqInitTaosxRsp(SMqDataRsp* pRsp, STqOffsetVal pOffset) {
diff --git a/source/dnode/vnode/src/tqCommon/tqCommon.c b/source/dnode/vnode/src/tqCommon/tqCommon.c
index 77632d328e..7fc2881881 100644
--- a/source/dnode/vnode/src/tqCommon/tqCommon.c
+++ b/source/dnode/vnode/src/tqCommon/tqCommon.c
@@ -938,10 +938,10 @@ int32_t tqStartTaskCompleteCallback(SStreamMeta* pMeta) {
 
   streamMetaWUnLock(pMeta);
 
-  if (scanWal && (vgId != SNODE_HANDLE)) {
-    tqDebug("vgId:%d start scan wal for executing tasks", vgId);
-    code = tqScanWalAsync(pMeta->ahandle, true);
-  }
+//  if (scanWal && (vgId != SNODE_HANDLE)) {
+//    tqDebug("vgId:%d start scan wal for executing tasks", vgId);
+//    code = tqScanWalAsync(pMeta->ahandle, true);
+//  }
 
   return code;
 }
@@ -1170,7 +1170,7 @@ static int32_t tqProcessTaskResumeImpl(void* handle, SStreamTask* pTask, int64_t
       pTask->hTaskInfo.operatorOpen = false;
       code = streamStartScanHistoryAsync(pTask, igUntreated);
     } else if (level == TASK_LEVEL__SOURCE && (streamQueueGetNumOfItems(pTask->inputq.queue) == 0)) {
-      code = tqScanWalAsync((STQ*)handle, false);
+//      code = tqScanWalAsync((STQ*)handle, false);
     } else {
       code = streamTrySchedExec(pTask);
     }
diff --git a/source/libs/stream/src/streamHb.c b/source/libs/stream/src/streamHb.c
index 7c157bb05e..36a6488709 100644
--- a/source/libs/stream/src/streamHb.c
+++ b/source/libs/stream/src/streamHb.c
@@ -341,7 +341,7 @@ void streamMetaHbToMnode(void* param, void* tmrId) {
     if (code == TSDB_CODE_SUCCESS) {
       stInfo("vgId:%d role:%d not leader not send hb to mnode", vgId, role);
     } else {
-      stError("vgId:%d role:%d not leader not send hb to mnodefailed to release the meta rid:%" PRId64, vgId, role, rid);
+      stError("vgId:%d role:%d not leader not send hb to mnode, failed to release meta rid:%" PRId64, vgId, role, rid);
     }
 //    taosMemoryFree(param);
     return;
diff --git a/source/libs/stream/src/streamMeta.c b/source/libs/stream/src/streamMeta.c
index ddd0201460..733bae1097 100644
--- a/source/libs/stream/src/streamMeta.c
+++ b/source/libs/stream/src/streamMeta.c
@@ -1320,7 +1320,7 @@ void streamMetaUpdateStageRole(SStreamMeta* pMeta, int64_t stage, bool isLeader)
 
   // mark the sign to send msg before close all tasks
   // 1. for leader vnode, always send msg before closing
-  // 2. for follower vnode, if it's is changed from leader, also sending msg before closing.
+  // 2. for follower vnode, if it's changed from leader, also sending msg before closing.
   if (pMeta->role == NODE_ROLE_LEADER) {
     pMeta->sendMsgBeforeClosing = true;
   }