diff --git a/source/dnode/vnode/src/tq/tq.c b/source/dnode/vnode/src/tq/tq.c
index a5a3175652..bcf665ddfb 100644
--- a/source/dnode/vnode/src/tq/tq.c
+++ b/source/dnode/vnode/src/tq/tq.c
@@ -1149,12 +1149,10 @@ int32_t tqProcessTaskScanHistory(STQ* pTq, SRpcMsg* pMsg) {
     // 1. get the related stream task
     pStreamTask = streamMetaAcquireTask(pMeta, pTask->streamTaskId.streamId, pTask->streamTaskId.taskId);
     if (pStreamTask == NULL) {
-      // todo delete this task, if the related stream task is dropped
-      qError("failed to find s-task:0x%"PRIx64", it may have been destroyed, drop fill-history task:%s",
+      tqError("failed to find s-task:0x%"PRIx64", it may have been destroyed, drop related fill-history task:%s",
              pTask->streamTaskId.taskId, pTask->id.idStr);
 
       tqDebug("s-task:%s fill-history task set status to be dropping", id);
-
       streamBuildAndSendDropTaskMsg(pTask->pMsgCb, pMeta->vgId, &pTask->id);
 
       atomic_store_32(&pTask->status.inScanHistorySentinel, 0);
@@ -1163,68 +1161,6 @@ int32_t tqProcessTaskScanHistory(STQ* pTq, SRpcMsg* pMsg) {
     }
 
     ASSERT(pStreamTask->info.taskLevel == TASK_LEVEL__SOURCE);
-#if 0
-    // 2. it cannot be paused, when the stream task in TASK_STATUS__SCAN_HISTORY status. Let's wait for the
-    // stream task get ready for scan history data
-    while (streamTaskGetStatus(pStreamTask, NULL) == TASK_STATUS__SCAN_HISTORY) {
-      tqDebug(
-          "s-task:%s level:%d related stream task:%s(status:%s) not ready for halt, wait for it and recheck in 100ms",
-          id, pTask->info.taskLevel, pStreamTask->id.idStr, streamGetTaskStatusStr(pStreamTask->status.taskStatus));
-      taosMsleep(100);
-    }
-
-    // now we can stop the stream task execution
-    int64_t nextProcessedVer = 0;
-
-    while (1) {
-      taosThreadMutexLock(&pStreamTask->lock);
-      int8_t status = pStreamTask->status.taskStatus;
-      if (status == TASK_STATUS__DROPPING || status == TASK_STATUS__STOP) {
-        // return; do nothing
-      }
-
-      if (status == TASK_STATUS__HALT) {
-//        tqDebug("s-task:%s level:%d sched-status:%d is halt by fill-history task:%s", pStreamTask->id.idStr,
-//                pStreamTask->info.taskLevel, pStreamTask->status.schedStatus, id);
-//        latestVer = walReaderGetCurrentVer(pStreamTask->exec.pWalReader);
-//
-//        taosThreadMutexUnlock(&pStreamTask->lock);
-//        break;
-      }
-
-      if (pStreamTask->status.taskStatus == TASK_STATUS__CK) {
-        qDebug("s-task:%s status:%s during generating checkpoint, wait for 1sec and retry set status:halt",
-               pStreamTask->id.idStr, streamGetTaskStatusStr(TASK_STATUS__CK));
-        taosThreadMutexUnlock(&pStreamTask->lock);
-        taosMsleep(1000);
-        continue;
-      }
-
-      // upgrade to halt status
-      if (status == TASK_STATUS__PAUSE) {
-        qDebug("s-task:%s upgrade status to %s from %s", pStreamTask->id.idStr, streamGetTaskStatusStr(TASK_STATUS__HALT),
-               streamGetTaskStatusStr(TASK_STATUS__PAUSE));
-      } else {
-        qDebug("s-task:%s halt task, prev status:%s", pStreamTask->id.idStr, streamGetTaskStatusStr(status));
-      }
-
-      pStreamTask->status.keepTaskStatus = status;
-      pStreamTask->status.taskStatus = TASK_STATUS__HALT;
-
-      // wal scan not start yet, reset it to be the start position
-      nextProcessedVer = walReaderGetCurrentVer(pStreamTask->exec.pWalReader);
-      if (nextProcessedVer == -1) {
-        nextProcessedVer = pStreamTask->dataRange.range.maxVer + 1;
-      }
-
-      tqDebug("s-task:%s level:%d nextProcessedVer:%" PRId64 ", sched-status:%d is halt by fill-history task:%s",
-              pStreamTask->id.idStr, pStreamTask->info.taskLevel, nextProcessedVer, pStreamTask->status.schedStatus,
-              id);
-
-      taosThreadMutexUnlock(&pStreamTask->lock);
-      break;
-    }
-#endif
 
     streamTaskHandleEvent(pStreamTask->status.pSM, TASK_EVENT_HALT);
     int64_t nextProcessedVer = pStreamTask->hTaskInfo.haltVer;
diff --git a/source/dnode/vnode/src/tq/tqStreamTask.c b/source/dnode/vnode/src/tq/tqStreamTask.c
index 1f1dd61c3c..1672c8e609 100644
--- a/source/dnode/vnode/src/tq/tqStreamTask.c
+++ b/source/dnode/vnode/src/tq/tqStreamTask.c
@@ -446,6 +446,7 @@ int32_t doScanWalForAllTasks(SStreamMeta* pStreamMeta, bool* pScanIdle) {
     int64_t maxVer = (pTask->info.fillHistory == 1) ? pTask->dataRange.range.maxVer : INT64_MAX;
 
     taosThreadMutexLock(&pTask->lock);
+    tqDebug("s-task:%s lock", pTask->id.idStr);
 
     char* p = NULL;
     ETaskStatus status = streamTaskGetStatus(pTask, &p);
diff --git a/source/libs/stream/src/streamDispatch.c b/source/libs/stream/src/streamDispatch.c
index cd8bbacb98..14129522d6 100644
--- a/source/libs/stream/src/streamDispatch.c
+++ b/source/libs/stream/src/streamDispatch.c
@@ -1004,6 +1004,8 @@ int32_t streamAddEndScanHistoryMsg(SStreamTask* pTask, SRpcHandleInfo* pRpcInfo,
   info.msg.info = *pRpcInfo;
 
   taosThreadMutexLock(&pTask->lock);
+  stDebug("s-task:%s lock", pTask->id.idStr);
+
   if (pTask->pRspMsgList == NULL) {
     pTask->pRspMsgList = taosArrayInit(4, sizeof(SStreamContinueExecInfo));
   }
diff --git a/source/libs/stream/src/streamTaskSm.c b/source/libs/stream/src/streamTaskSm.c
index 205994b7cc..71521bd8f2 100644
--- a/source/libs/stream/src/streamTaskSm.c
+++ b/source/libs/stream/src/streamTaskSm.c
@@ -201,6 +201,7 @@ static int32_t doHandleEvent(SStreamTaskSM* pSM, EStreamTaskEvent event, STaskSt
   if (pTrans->attachEvent.event != 0) {
     attachEvent(pTask, &pTrans->attachEvent);
     taosThreadMutexUnlock(&pTask->lock);
+    stDebug("s-task:%s unlock1", pTask->id.idStr);
 
     while (1) {
       // wait for the task to be here
@@ -224,6 +225,7 @@ static int32_t doHandleEvent(SStreamTaskSM* pSM, EStreamTaskEvent event, STaskSt
     pSM->pActiveTrans = pTrans;
     pSM->startTs = taosGetTimestampMs();
     taosThreadMutexUnlock(&pTask->lock);
+    stDebug("s-task:%s unlock2", pTask->id.idStr);
 
     int32_t code = pTrans->pAction(pTask);
     // todo handle error code;
@@ -242,6 +244,8 @@ int32_t streamTaskHandleEvent(SStreamTaskSM* pSM, EStreamTaskEvent event) {
 
   while (1) {
     taosThreadMutexLock(&pTask->lock);
+    stDebug("s-task:%s lock", pTask->id.idStr);
+
     if (pSM->pActiveTrans != NULL && pSM->pActiveTrans->autoInvokeEndFn) {
       taosThreadMutexUnlock(&pTask->lock);
       taosMsleep(100);
@@ -282,6 +286,8 @@ int32_t streamTaskOnHandleEventSuccess(SStreamTaskSM* pSM, EStreamTaskEvent even
 
   // do update the task status
   taosThreadMutexLock(&pTask->lock);
+  stDebug("s-task:%s lock", pTask->id.idStr);
+
   STaskStateTrans* pTrans = pSM->pActiveTrans;
 
   if (pTrans == NULL) {
@@ -292,6 +298,7 @@ int32_t streamTaskOnHandleEventSuccess(SStreamTaskSM* pSM, EStreamTaskEvent even
             StreamTaskEventList[event].name, pSM->current.name, StreamTaskEventList[pSM->prev.evt].name);
 
     taosThreadMutexUnlock(&pTask->lock);
+    stDebug("s-task:%s unlockx", pTask->id.idStr);
     return TSDB_CODE_INVALID_PARA;
   }
 
@@ -299,6 +306,7 @@ int32_t streamTaskOnHandleEventSuccess(SStreamTaskSM* pSM, EStreamTaskEvent even
     stWarn("s-task:%s handle event:%s failed, current status:%s, active trans evt:%s", pTask->id.idStr,
            StreamTaskEventList[event].name, pSM->current.name, StreamTaskEventList[pTrans->event].name);
     taosThreadMutexUnlock(&pTask->lock);
+    stDebug("s-task:%s unlocky", pTask->id.idStr);
     return TSDB_CODE_INVALID_PARA;
   }
 
@@ -328,6 +336,7 @@ int32_t streamTaskOnHandleEventSuccess(SStreamTaskSM* pSM, EStreamTaskEvent even
       pSM->pActiveTrans = pNextTrans;
       pSM->startTs = taosGetTimestampMs();
       taosThreadMutexUnlock(&pTask->lock);
+      stDebug("s-task:%s unlockf", pTask->id.idStr);
 
       int32_t code = pNextTrans->pAction(pSM->pTask);
       if (pNextTrans->autoInvokeEndFn) {
@@ -338,6 +347,7 @@ int32_t streamTaskOnHandleEventSuccess(SStreamTaskSM* pSM, EStreamTaskEvent even
     }
   } else {
     taosThreadMutexUnlock(&pTask->lock);
+    stDebug("s-task:%s unlockz", pTask->id.idStr);
 
     int64_t el = (taosGetTimestampMs() - pSM->startTs);
     stDebug("s-task:%s handle event:%s completed, elapsed time:%" PRId64 "ms state:%s -> %s", pTask->id.idStr,