diff --git a/include/libs/executor/executor.h b/include/libs/executor/executor.h
index 3bef15f3a7..f90c38f341 100644
--- a/include/libs/executor/executor.h
+++ b/include/libs/executor/executor.h
@@ -221,13 +221,9 @@ int32_t qStreamSourceScanParamForHistoryScanStep2(qTaskInfo_t tinfo, SVersionRan
 int32_t qStreamRecoverFinish(qTaskInfo_t tinfo);
 int32_t qRestoreStreamOperatorOption(qTaskInfo_t tinfo);
 bool    qStreamRecoverScanFinished(qTaskInfo_t tinfo);
-bool    qStreamRecoverScanStep1Finished(qTaskInfo_t tinfo);
-bool    qStreamRecoverScanStep2Finished(qTaskInfo_t tinfo);
-int32_t qStreamRecoverSetAllStepFinished(qTaskInfo_t tinfo);
+int32_t qStreamInfoResetTimewindowFilter(qTaskInfo_t tinfo);
 void    resetTaskInfo(qTaskInfo_t tinfo);
 
-void qResetStreamInfoTimeWindow(qTaskInfo_t tinfo);
-
 int32_t qStreamOperatorReleaseState(qTaskInfo_t tInfo);
 int32_t qStreamOperatorReloadState(qTaskInfo_t tInfo);
 
diff --git a/include/libs/stream/tstream.h b/include/libs/stream/tstream.h
index 066f83fbcb..db0509d81d 100644
--- a/include/libs/stream/tstream.h
+++ b/include/libs/stream/tstream.h
@@ -604,15 +604,10 @@ int32_t streamSendCheckRsp(const SStreamMeta* pMeta, const SStreamTaskCheckReq*
 int32_t streamProcessCheckRsp(SStreamTask* pTask, const SStreamTaskCheckRsp* pRsp);
 int32_t streamLaunchFillHistoryTask(SStreamTask* pTask);
 int32_t streamTaskScanHistoryDataComplete(SStreamTask* pTask);
-int32_t streamStartRecoverTask(SStreamTask* pTask, int8_t igUntreated);
+int32_t streamStartScanHistoryAsync(SStreamTask* pTask, int8_t igUntreated);
 bool    streamHistoryTaskSetVerRangeStep2(SStreamTask* pTask, int64_t latestVer);
 
-bool    streamTaskRecoverScanStep1Finished(SStreamTask* pTask);
-bool    streamTaskRecoverScanStep2Finished(SStreamTask* pTask);
-int32_t streamTaskRecoverSetAllStepFinished(SStreamTask* pTask);
-
 // common
-int32_t     streamSetParamForScanHistory(SStreamTask* pTask);
 int32_t     streamRestoreParam(SStreamTask* pTask);
 int32_t     streamSetStatusNormal(SStreamTask* pTask);
 const char* streamGetTaskStatusStr(int32_t status);
@@ -626,7 +621,6 @@ void        streamTaskEnablePause(SStreamTask* pTask);
 // source level
 int32_t streamSetParamForStreamScannerStep1(SStreamTask* pTask, SVersionRange* pVerRange, STimeWindow* pWindow);
 int32_t streamSetParamForStreamScannerStep2(SStreamTask* pTask, SVersionRange* pVerRange, STimeWindow* pWindow);
-int32_t streamBuildSourceRecover1Req(SStreamTask* pTask, SStreamScanHistoryReq* pReq, int8_t igUntreated);
 int32_t streamSourceScanHistoryData(SStreamTask* pTask);
 int32_t streamDispatchScanHistoryFinishMsg(SStreamTask* pTask);
 
diff --git a/source/dnode/vnode/src/tq/tq.c b/source/dnode/vnode/src/tq/tq.c
index 60071645c0..082f0c222d 100644
--- a/source/dnode/vnode/src/tq/tq.c
+++ b/source/dnode/vnode/src/tq/tq.c
@@ -1321,7 +1321,7 @@ int32_t tqProcessTaskScanHistory(STQ* pTq, SRpcMsg* pMsg) {
           "s-task:%s scan-history in stream time window completed, no related fill-history task, reset the time "
           "window:%" PRId64 " - %" PRId64,
           id, pWindow->skey, pWindow->ekey);
-      qResetStreamInfoTimeWindow(pTask->exec.pExecutor);
+      qStreamInfoResetTimewindowFilter(pTask->exec.pExecutor);
     } else {
       // when related fill-history task exists, update the fill-history time window only when the
       // state transfer is completed.
@@ -1592,9 +1592,8 @@ int32_t tqProcessTaskPauseReq(STQ* pTq, int64_t sversion, char* msg, int32_t msg
   SStreamMeta* pMeta = pTq->pStreamMeta;
   SStreamTask* pTask = streamMetaAcquireTask(pMeta, pReq->taskId);
   if (pTask == NULL) {
-    tqError("vgId:%d failed to acquire task:0x%x, it may have been dropped already", pMeta->vgId,
+    tqError("vgId:%d process pause req, failed to acquire task:0x%x, it may have been dropped already", pMeta->vgId,
             pReq->taskId);
-
     // since task is in [STOP|DROPPING] state, it is safe to assume the pause is active
     return TSDB_CODE_SUCCESS;
   }
@@ -1606,9 +1605,8 @@ int32_t tqProcessTaskPauseReq(STQ* pTq, int64_t sversion, char* msg, int32_t msg
   if (pTask->historyTaskId.taskId != 0) {
     pHistoryTask = streamMetaAcquireTask(pMeta, pTask->historyTaskId.taskId);
     if (pHistoryTask == NULL) {
-      tqError("vgId:%d failed to acquire fill-history task:0x%x, it may have been dropped already. Pause success",
+      tqError("vgId:%d process pause req, failed to acquire fill-history task:0x%x, it may have been dropped already",
               pMeta->vgId, pTask->historyTaskId.taskId);
-
       streamMetaReleaseTask(pMeta, pTask);
 
       // since task is in [STOP|DROPPING] state, it is safe to assume the pause is active
@@ -1616,14 +1614,12 @@ int32_t tqProcessTaskPauseReq(STQ* pTq, int64_t sversion, char* msg, int32_t msg
     }
 
     tqDebug("s-task:%s fill-history task handle paused along with related stream task", pHistoryTask->id.idStr);
-    streamTaskPause(pHistoryTask);
-  }
 
-  streamMetaReleaseTask(pMeta, pTask);
-  if (pHistoryTask != NULL) {
+    streamTaskPause(pHistoryTask);
     streamMetaReleaseTask(pMeta, pHistoryTask);
   }
 
+  streamMetaReleaseTask(pMeta, pTask);
   return TSDB_CODE_SUCCESS;
 }
 
@@ -1652,7 +1648,7 @@ int32_t tqProcessTaskResumeImpl(STQ* pTq, SStreamTask* pTask, int64_t sversion,
     }
 
     if (level == TASK_LEVEL__SOURCE && pTask->info.fillHistory && pTask->status.taskStatus == TASK_STATUS__SCAN_HISTORY) {
-      streamStartRecoverTask(pTask, igUntreated);
+      streamStartScanHistoryAsync(pTask, igUntreated);
     } else if (level == TASK_LEVEL__SOURCE && (taosQueueItemSize(pTask->inputQueue->queue) == 0)) {
       tqStartStreamTasks(pTq);
     } else {
diff --git a/source/libs/executor/inc/querytask.h b/source/libs/executor/inc/querytask.h
index cdf37bcc6b..7241b015a0 100644
--- a/source/libs/executor/inc/querytask.h
+++ b/source/libs/executor/inc/querytask.h
@@ -62,8 +62,8 @@ typedef struct {
   SSchemaWrapper*      schema;
   char                 tbName[TSDB_TABLE_NAME_LEN];  // this is the current scan table: todo refactor
   int8_t               recoverStep;
-  bool                 recoverStep1Finished;
-  bool                 recoverStep2Finished;
+//  bool                 recoverStep1Finished;
+//  bool                 recoverStep2Finished;
   int8_t               recoverScanFinished;
   SQueryTableDataCond  tableCond;
   SVersionRange        fillHistoryVer;
diff --git a/source/libs/executor/src/executor.c b/source/libs/executor/src/executor.c
index 5a99c1ea9a..e4ddf9ca6c 100644
--- a/source/libs/executor/src/executor.c
+++ b/source/libs/executor/src/executor.c
@@ -116,17 +116,6 @@ void resetTaskInfo(qTaskInfo_t tinfo) {
   clearStreamBlock(pTaskInfo->pRoot);
 }
 
-void qResetStreamInfoTimeWindow(qTaskInfo_t tinfo) {
-  SExecTaskInfo* pTaskInfo = (SExecTaskInfo*) tinfo;
-  if (pTaskInfo == NULL) {
-    return;
-  }
-
-  qDebug("%s set stream fill-history window:%" PRId64"-%"PRId64, GET_TASKID(pTaskInfo), INT64_MIN, INT64_MAX);
-  pTaskInfo->streamInfo.fillHistoryWindow.skey = INT64_MIN;
-  pTaskInfo->streamInfo.fillHistoryWindow.ekey = INT64_MAX;
-}
-
 static int32_t doSetStreamBlock(SOperatorInfo* pOperator, void* input, size_t numOfBlocks, int32_t type, const char* id) {
   if (pOperator->operatorType != QUERY_NODE_PHYSICAL_PLAN_STREAM_SCAN) {
     if (pOperator->numOfDownstream == 0) {
@@ -341,7 +330,7 @@ qTaskInfo_t qCreateStreamExecTaskInfo(void* msg, SReadHandle* readers, int32_t v
     return NULL;
   }
 
-  qResetStreamInfoTimeWindow(pTaskInfo);
+  qStreamInfoResetTimewindowFilter(pTaskInfo);
   return pTaskInfo;
 }
 
@@ -891,8 +880,6 @@ int32_t qStreamSourceScanParamForHistoryScanStep1(qTaskInfo_t tinfo, SVersionRan
   pStreamInfo->fillHistoryVer = *pVerRange;
   pStreamInfo->fillHistoryWindow = *pWindow;
   pStreamInfo->recoverStep = STREAM_RECOVER_STEP__PREPARE1;
-  pStreamInfo->recoverStep1Finished = false;
-  pStreamInfo->recoverStep2Finished = false;
 
   qDebug("%s step 1. set param for stream scanner for scan-history data, verRange:%" PRId64 " - %" PRId64 ", window:%" PRId64
          " - %" PRId64,
@@ -910,8 +897,6 @@ int32_t qStreamSourceScanParamForHistoryScanStep2(qTaskInfo_t tinfo, SVersionRan
   pStreamInfo->fillHistoryVer = *pVerRange;
   pStreamInfo->fillHistoryWindow = *pWindow;
   pStreamInfo->recoverStep = STREAM_RECOVER_STEP__PREPARE2;
-  pStreamInfo->recoverStep1Finished = true;
-  pStreamInfo->recoverStep2Finished = false;
 
   qDebug("%s step 2. set param for stream scanner for scan-history data, verRange:%" PRId64 " - %" PRId64
          ", window:%" PRId64 " - %" PRId64,
@@ -1050,23 +1035,15 @@ bool qStreamRecoverScanFinished(qTaskInfo_t tinfo) {
   return pTaskInfo->streamInfo.recoverScanFinished;
 }
 
-bool qStreamRecoverScanStep1Finished(qTaskInfo_t tinfo) {
+int32_t qStreamInfoResetTimewindowFilter(qTaskInfo_t tinfo) {
   SExecTaskInfo* pTaskInfo = (SExecTaskInfo*)tinfo;
-  return pTaskInfo->streamInfo.recoverStep1Finished;
-}
+  STimeWindow* pWindow = &pTaskInfo->streamInfo.fillHistoryWindow;
 
-bool qStreamRecoverScanStep2Finished(qTaskInfo_t tinfo) {
-  SExecTaskInfo* pTaskInfo = (SExecTaskInfo*)tinfo;
-  return pTaskInfo->streamInfo.recoverStep2Finished;
-}
+  qDebug("%s set remove scan-history filter window:%" PRId64 "-%" PRId64 ", new window:%" PRId64 "-%" PRId64,
+         GET_TASKID(pTaskInfo), pWindow->skey, pWindow->ekey, INT64_MIN, INT64_MAX);
 
-int32_t qStreamRecoverSetAllStepFinished(qTaskInfo_t tinfo) {
-  SExecTaskInfo* pTaskInfo = (SExecTaskInfo*)tinfo;
-  pTaskInfo->streamInfo.recoverStep1Finished = true;
-  pTaskInfo->streamInfo.recoverStep2Finished = true;
-
-  // reset the time window
-  pTaskInfo->streamInfo.fillHistoryWindow.skey = INT64_MIN;
+  pWindow->skey = INT64_MIN;
+  pWindow->ekey = INT64_MAX;
   return 0;
 }
 
diff --git a/source/libs/executor/src/scanoperator.c b/source/libs/executor/src/scanoperator.c
index 7434db61db..738809f588 100644
--- a/source/libs/executor/src/scanoperator.c
+++ b/source/libs/executor/src/scanoperator.c
@@ -1590,38 +1590,51 @@ static void doBlockDataWindowFilter(SSDataBlock* pBlock, int32_t tsIndex, STimeW
 }
 
 // re-build the delete block, ONLY according to the split timestamp
-static void rebuildDeleteBlockData(SSDataBlock* pBlock, int64_t skey, const char* id) {
-  if (skey == INT64_MIN) {
-    return;
-  }
-
+static void rebuildDeleteBlockData(SSDataBlock* pBlock, STimeWindow* pWindow, const char* id) {
   int32_t numOfRows = pBlock->info.rows;
-
-  bool* p = taosMemoryCalloc(numOfRows, sizeof(bool));
-  bool  hasUnqualified = false;
+  bool*   p = taosMemoryCalloc(numOfRows, sizeof(bool));
+  bool    hasUnqualified = false;
+  int64_t skey = pWindow->skey;
+  int64_t ekey = pWindow->ekey;
 
   SColumnInfoData* pSrcStartCol = taosArrayGet(pBlock->pDataBlock, START_TS_COLUMN_INDEX);
   uint64_t*        tsStartCol = (uint64_t*)pSrcStartCol->pData;
   SColumnInfoData* pSrcEndCol = taosArrayGet(pBlock->pDataBlock, END_TS_COLUMN_INDEX);
   uint64_t*        tsEndCol = (uint64_t*)pSrcEndCol->pData;
 
-  for (int32_t i = 0; i < numOfRows; i++) {
-    if (tsStartCol[i] < skey) {
-      tsStartCol[i] = skey;
-    }
+  if (pWindow->skey != INT64_MIN) {
+    for (int32_t i = 0; i < numOfRows; i++) {
+      if (tsStartCol[i] < skey) {
+        tsStartCol[i] = skey;
+      }
 
-    if (tsEndCol[i] >= skey) {
-      p[i] = true;
-    } else { // this row should be removed, since it is not in this query time window, which is [skey, INT64_MAX]
-      hasUnqualified = true;
+      if (tsEndCol[i] >= skey) {
+        p[i] = true;
+      } else {  // this row should be removed, since it is not in this query time window, which is [skey, INT64_MAX]
+        hasUnqualified = true;
+      }
+    }
+  } else if (pWindow->ekey != INT64_MAX) {
+    for(int32_t i = 0; i < numOfRows; ++i) {
+      if (tsEndCol[i] > ekey) {
+        tsEndCol[i] = ekey;
+      }
+
+      if (tsStartCol[i] <= ekey) {
+        p[i] = true;
+      } else {
+        hasUnqualified = true;
+      }
     }
   }
 
   if (hasUnqualified) {
     trimDataBlock(pBlock, pBlock->info.rows, p);
+    qDebug("%s re-build delete datablock, start key revised to:%"PRId64", rows:%"PRId64, id, skey, pBlock->info.rows);
+  } else {
+    qDebug("%s not update the delete block", id);
   }
 
-  qDebug("%s re-build delete datablock, start key revised to:%"PRId64", rows:%"PRId64, id, skey, pBlock->info.rows);
   taosMemoryFree(p);
 }
 
@@ -2030,7 +2043,7 @@ FETCH_NEXT_BLOCK:
         }
 
         setBlockGroupIdByUid(pInfo, pDelBlock);
-        rebuildDeleteBlockData(pDelBlock, pStreamInfo->fillHistoryWindow.skey, id);
+        rebuildDeleteBlockData(pDelBlock, &pStreamInfo->fillHistoryWindow, id);
         printDataBlock(pDelBlock, "stream scan delete recv filtered");
         if (pDelBlock->info.rows == 0) {
           if (pInfo->tqReader) {
diff --git a/source/libs/stream/inc/streamInt.h b/source/libs/stream/inc/streamInt.h
index add893c8c7..32d6dc65d9 100644
--- a/source/libs/stream/inc/streamInt.h
+++ b/source/libs/stream/inc/streamInt.h
@@ -62,6 +62,7 @@ SStreamQueueItem* streamMergeQueueItem(SStreamQueueItem* dst, SStreamQueueItem*
 
 int32_t streamAddEndScanHistoryMsg(SStreamTask* pTask, SRpcHandleInfo* pRpcInfo, SStreamScanHistoryFinishReq* pReq);
 int32_t streamNotifyUpstreamContinue(SStreamTask* pTask);
+int32_t streamTaskFillHistoryFinished(SStreamTask* pTask);
 
 extern int32_t streamBackendId;
 extern int32_t streamBackendCfWrapperId;
diff --git a/source/libs/stream/src/streamExec.c b/source/libs/stream/src/streamExec.c
index 4ef7d6084d..d1dff0f2e7 100644
--- a/source/libs/stream/src/streamExec.c
+++ b/source/libs/stream/src/streamExec.c
@@ -163,15 +163,14 @@ static int32_t streamTaskExecImpl(SStreamTask* pTask, SStreamQueueItem* pItem, i
 }
 
 int32_t streamScanExec(SStreamTask* pTask, int32_t batchSz) {
-  int32_t code = 0;
-
   ASSERT(pTask->info.taskLevel == TASK_LEVEL__SOURCE);
-  void* exec = pTask->exec.pExecutor;
+  int32_t code = TSDB_CODE_SUCCESS;
+  void*   exec = pTask->exec.pExecutor;
+  bool    finished = false;
 
   qSetStreamOpOpen(exec);
-  bool finished = false;
 
-  while (1) {
+  while (!finished) {
     if (streamTaskShouldPause(&pTask->status)) {
       double el = (taosGetTimestampMs() - pTask->tsInfo.step1Start) / 1000.0;
       qDebug("s-task:%s paused from the scan-history task, elapsed time:%.2fsec", pTask->id.idStr, el);
@@ -184,44 +183,30 @@ int32_t streamScanExec(SStreamTask* pTask, int32_t batchSz) {
       return -1;
     }
 
-    int32_t batchCnt = 0;
+    int32_t numOfBlocks = 0;
     while (1) {
       if (streamTaskShouldStop(&pTask->status)) {
         taosArrayDestroyEx(pRes, (FDelete)blockDataFreeRes);
         return 0;
       }
 
+      if (streamTaskShouldPause(&pTask->status)) {
+        break;
+      }
+
       SSDataBlock* output = NULL;
       uint64_t     ts = 0;
       if (qExecTask(exec, &output, &ts) < 0) {
         continue;
       }
 
-      if (output == NULL) {
-        if (qStreamRecoverScanFinished(exec)) {
-          finished = true;
-        } else {
-          qSetStreamOpOpen(exec);
-          if (streamTaskShouldPause(&pTask->status)) {
-            SStreamDataBlock* qRes = taosAllocateQitem(sizeof(SStreamDataBlock), DEF_QITEM, 0);
-            if (qRes == NULL) {
-              taosArrayDestroyEx(pRes, (FDelete)blockDataFreeRes);
-              terrno = TSDB_CODE_OUT_OF_MEMORY;
-              return -1;
-            }
-
-            qRes->type = STREAM_INPUT__DATA_BLOCK;
-            qRes->blocks = pRes;
-            code = streamTaskOutputResultBlock(pTask, qRes);
-            if (code == TSDB_CODE_UTIL_QUEUE_OUT_OF_MEMORY) {
-              taosArrayDestroyEx(pRes, (FDelete)blockDataFreeRes);
-              taosFreeQitem(qRes);
-              return code;
-            }
-            return 0;
-          }
-        }
+      if (output == NULL && qStreamRecoverScanFinished(exec)) {
+        finished = true;
         break;
+      } else {
+        if (output == NULL) {
+          ASSERT(0);
+        }
       }
 
       SSDataBlock block = {0};
@@ -229,86 +214,37 @@ int32_t streamScanExec(SStreamTask* pTask, int32_t batchSz) {
       block.info.childId = pTask->info.selfChildId;
       taosArrayPush(pRes, &block);
 
-      batchCnt++;
-
-      qDebug("s-task:%s scan exec numOfBlocks:%d, limit:%d", pTask->id.idStr, batchCnt, batchSz);
-      if (batchCnt >= batchSz) {
+      numOfBlocks++;
+      qDebug("s-task:%s scan exec numOfBlocks:%d, limit:%d", pTask->id.idStr, numOfBlocks, batchSz);
+      if (numOfBlocks >= batchSz) {
         break;
       }
     }
 
-    if (taosArrayGetSize(pRes) == 0) {
-      taosArrayDestroy(pRes);
-
-      if (finished) {
-        qDebug("s-task:%s finish recover exec task ", pTask->id.idStr);
-        break;
-      } else {
-        qDebug("s-task:%s continue recover exec task ", pTask->id.idStr);
-        continue;
+    if (taosArrayGetSize(pRes) > 0) {
+      SStreamDataBlock* qRes = taosAllocateQitem(sizeof(SStreamDataBlock), DEF_QITEM, 0);
+      if (qRes == NULL) {
+        taosArrayDestroyEx(pRes, (FDelete)blockDataFreeRes);
+        terrno = TSDB_CODE_OUT_OF_MEMORY;
+        return -1;
       }
-    }
 
-    SStreamDataBlock* qRes = taosAllocateQitem(sizeof(SStreamDataBlock), DEF_QITEM, 0);
-    if (qRes == NULL) {
-      taosArrayDestroyEx(pRes, (FDelete)blockDataFreeRes);
-      terrno = TSDB_CODE_OUT_OF_MEMORY;
-      return -1;
-    }
+      qRes->type = STREAM_INPUT__DATA_BLOCK;
+      qRes->blocks = pRes;
 
-    qRes->type = STREAM_INPUT__DATA_BLOCK;
-    qRes->blocks = pRes;
-    code = streamTaskOutputResultBlock(pTask, qRes);
-    if (code == TSDB_CODE_UTIL_QUEUE_OUT_OF_MEMORY) {
-      taosArrayDestroyEx(pRes, (FDelete)blockDataFreeRes);
-      taosFreeQitem(qRes);
-      return code;
-    }
-
-    if (finished) {
-      break;
-    }
-  }
-  return 0;
-}
-
-#if 0
-int32_t streamBatchExec(SStreamTask* pTask, int32_t batchLimit) {
-  // fetch all queue item, merge according to batchLimit
-  int32_t numOfItems = taosReadAllQitems(pTask->inputQueue1, pTask->inputQall);
-  if (numOfItems == 0) {
-    qDebug("task: %d, stream task exec over, queue empty", pTask->id.taskId);
-    return 0;
-  }
-  SStreamQueueItem* pMerged = NULL;
-  SStreamQueueItem* pItem = NULL;
-  taosGetQitem(pTask->inputQall, (void**)&pItem);
-  if (pItem == NULL) {
-    if (pMerged != NULL) {
-      // process merged item
+      code = streamTaskOutputResultBlock(pTask, qRes);
+      if (code == TSDB_CODE_UTIL_QUEUE_OUT_OF_MEMORY) {
+        taosArrayDestroyEx(pRes, (FDelete)blockDataFreeRes);
+        taosFreeQitem(qRes);
+        return code;
+      }
     } else {
-      return 0;
+      taosArrayDestroy(pRes);
     }
   }
 
-  // if drop
-  if (pItem->type == STREAM_INPUT__DESTROY) {
-    // set status drop
-    return -1;
-  }
-
-  if (pTask->info.taskLevel == TASK_LEVEL__SINK) {
-    ASSERT(((SStreamQueueItem*)pItem)->type == STREAM_INPUT__DATA_BLOCK);
-    streamTaskOutputResultBlock(pTask, (SStreamDataBlock*)pItem);
-  }
-
-  // exec impl
-
-  // output
-  // try dispatch
   return 0;
 }
-#endif
 
 int32_t updateCheckPointInfo(SStreamTask* pTask) {
   int64_t ckId = 0;
@@ -356,12 +292,12 @@ static void waitForTaskIdle(SStreamTask* pTask, SStreamTask* pStreamTask) {
   }
 }
 
-static int32_t streamTransferStateToStreamTask(SStreamTask* pTask) {
+static int32_t streamDoTransferStateToStreamTask(SStreamTask* pTask) {
   SStreamMeta* pMeta = pTask->pMeta;
 
   SStreamTask* pStreamTask = streamMetaAcquireTask(pMeta, pTask->streamTaskId.taskId);
   if (pStreamTask == NULL) {
-    // todo: destroy this task here
+    // todo: destroy the fill-history task here
     qError("s-task:%s failed to find related stream task:0x%x, it may have been destroyed or closed", pTask->id.idStr,
            pTask->streamTaskId.taskId);
     return TSDB_CODE_STREAM_TASK_NOT_EXIST;
@@ -402,34 +338,36 @@ static int32_t streamTransferStateToStreamTask(SStreamTask* pTask) {
     qDebug("s-task:%s no need to update time window for non-source task", pStreamTask->id.idStr);
   }
 
-  // expand the query time window for stream scanner
+  // 1. expand the query time window for stream task of WAL scanner
   pTimeWindow->skey = INT64_MIN;
-  qResetStreamInfoTimeWindow(pStreamTask->exec.pExecutor);
+  qStreamInfoResetTimewindowFilter(pStreamTask->exec.pExecutor);
 
-  // transfer the ownership of executor state
+  // 2. transfer the ownership of executor state
   streamTaskReleaseState(pTask);
   streamTaskReloadState(pStreamTask);
 
-  // clear the link between fill-history task and stream task info
+  // 3. clear the link between fill-history task and stream task info
   pStreamTask->historyTaskId.taskId = 0;
+
+  // 4. resume the state of stream task, after this function, the stream task will run immidately. But it can not be
+  // pause, since the pause allowed attribute is not set yet.
   streamTaskResumeFromHalt(pStreamTask);
 
   qDebug("s-task:%s fill-history task set status to be dropping, save the state into disk", pTask->id.idStr);
   int32_t taskId = pTask->id.taskId;
 
-  // free it and remove it from disk meta-store
+  // 5. free it and remove fill-history task from disk meta-store
   streamMetaUnregisterTask(pMeta, taskId);
 
-  // save to disk
+  // 6. save to disk
   taosWLockLatch(&pMeta->lock);
-
   streamMetaSaveTask(pMeta, pStreamTask);
   if (streamMetaCommit(pMeta) < 0) {
     // persist to disk
   }
   taosWUnLockLatch(&pMeta->lock);
 
-  // pause allowed
+  // 7. pause allowed.
   streamTaskEnablePause(pStreamTask);
 
   streamSchedExec(pStreamTask);
@@ -437,6 +375,26 @@ static int32_t streamTransferStateToStreamTask(SStreamTask* pTask) {
   return TSDB_CODE_SUCCESS;
 }
 
+static int32_t streamTransferStateToStreamTask(SStreamTask* pTask) {
+  int32_t code = TSDB_CODE_SUCCESS;
+  if (!pTask->status.transferState) {
+    return code;
+  }
+
+  int32_t level = pTask->info.taskLevel;
+  if (level == TASK_LEVEL__SOURCE) {
+    streamTaskFillHistoryFinished(pTask);
+    streamTaskEndScanWAL(pTask);
+  } else if (level == TASK_LEVEL__AGG) { // do transfer task operator states.
+    code = streamDoTransferStateToStreamTask(pTask);
+    if (code != TSDB_CODE_SUCCESS) {  // todo handle this
+      return code;
+    }
+  }
+
+  return code;
+}
+
 static int32_t extractMsgFromInputQ(SStreamTask* pTask, SStreamQueueItem** pInput, int32_t* numOfBlocks,
                                     const char* id) {
   int32_t retryTimes = 0;
@@ -590,17 +548,16 @@ int32_t streamTaskEndScanWAL(SStreamTask* pTask) {
   double      el = (taosGetTimestampMs() - pTask->tsInfo.step2Start) / 1000.0;
   qDebug("s-task:%s scan-history from WAL stage(step 2) ended, elapsed time:%.2fs", id, el);
 
-  // 3. notify downstream tasks to transfer executor state after handle all history blocks.
-  pTask->status.transferState = true;
-
+  // 1. notify all downstream tasks to transfer executor state after handle all history blocks.
   int32_t code = streamDispatchTransferStateMsg(pTask);
   if (code != TSDB_CODE_SUCCESS) {
     // todo handle error
   }
 
-  // the last execution of fill-history task, in order to transfer task operator states.
-  code = streamTransferStateToStreamTask(pTask);
-  if (code != TSDB_CODE_SUCCESS) {  // todo handle this
+  // 2. do transfer stream task operator states.
+  pTask->status.transferState = true;
+  code = streamDoTransferStateToStreamTask(pTask);
+  if (code != TSDB_CODE_SUCCESS) { // todo handle error
     return code;
   }
 
@@ -624,9 +581,11 @@ int32_t streamTryExec(SStreamTask* pTask) {
     // todo the task should be commit here
     if (taosQueueEmpty(pTask->inputQueue->queue)) {
       // fill-history WAL scan has completed
-      if (pTask->info.taskLevel == TASK_LEVEL__SOURCE && pTask->status.transferState == true) {
-        streamTaskRecoverSetAllStepFinished(pTask);
-        streamTaskEndScanWAL(pTask);
+      if (pTask->status.transferState) {
+        code = streamTransferStateToStreamTask(pTask);
+        if (code != TSDB_CODE_SUCCESS) {
+          return code;
+        }
       } else {
         atomic_store_8(&pTask->status.schedStatus, TASK_SCHED_STATUS__INACTIVE);
         qDebug("s-task:%s exec completed, status:%s, sched-status:%d", id, streamGetTaskStatusStr(pTask->status.taskStatus),
diff --git a/source/libs/stream/src/streamRecover.c b/source/libs/stream/src/streamRecover.c
index df45ff2759..bd2d67e14a 100644
--- a/source/libs/stream/src/streamRecover.c
+++ b/source/libs/stream/src/streamRecover.c
@@ -17,23 +17,30 @@
 #include "ttimer.h"
 #include "wal.h"
 
-static void launchFillHistoryTask(SStreamTask* pTask);
-static void streamTaskSetRangeStreamCalc(SStreamTask* pTask);
+typedef struct SStreamTaskRetryInfo {
+  SStreamMeta* pMeta;
+  int32_t taskId;
+} SStreamTaskRetryInfo;
 
-static void streamTaskSetForReady(SStreamTask* pTask, int32_t numOfReqs) {
+static int32_t streamSetParamForScanHistory(SStreamTask* pTask);
+static void    launchFillHistoryTask(SStreamTask* pTask);
+static void    streamTaskSetRangeStreamCalc(SStreamTask* pTask);
+static int32_t initScanHistoryReq(SStreamTask* pTask, SStreamScanHistoryReq* pReq, int8_t igUntreated);
+
+static void streamTaskSetReady(SStreamTask* pTask, int32_t numOfReqs) {
   ASSERT(pTask->status.downstreamReady == 0);
   pTask->status.downstreamReady = 1;
-  int64_t el = (taosGetTimestampMs() - pTask->tsInfo.init);
 
+  int64_t el = (taosGetTimestampMs() - pTask->tsInfo.init);
   qDebug("s-task:%s all %d downstream ready, init completed, elapsed time:%dms, task status:%s",
          pTask->id.idStr, numOfReqs, (int32_t) el, streamGetTaskStatusStr(pTask->status.taskStatus));
 }
 
-int32_t streamStartRecoverTask(SStreamTask* pTask, int8_t igUntreated) {
+int32_t streamStartScanHistoryAsync(SStreamTask* pTask, int8_t igUntreated) {
   SStreamScanHistoryReq req;
-  streamBuildSourceRecover1Req(pTask, &req, igUntreated);
-  int32_t len = sizeof(SStreamScanHistoryReq);
+  initScanHistoryReq(pTask, &req, igUntreated);
 
+  int32_t len = sizeof(SStreamScanHistoryReq);
   void* serializedReq = rpcMallocCont(len);
   if (serializedReq == NULL) {
     return -1;
@@ -65,9 +72,9 @@ static int32_t doLaunchScanHistoryTask(SStreamTask* pTask) {
   if (pTask->info.fillHistory) {
     streamSetParamForScanHistory(pTask);
   }
-  streamSetParamForStreamScannerStep1(pTask, pRange, &pTask->dataRange.window);
 
-  int32_t code = streamStartRecoverTask(pTask, 0);
+  streamSetParamForStreamScannerStep1(pTask, pRange, &pTask->dataRange.window);
+  int32_t code = streamStartScanHistoryAsync(pTask, 0);
   return code;
 }
 
@@ -142,7 +149,7 @@ int32_t streamTaskDoCheckDownstreamTasks(SStreamTask* pTask) {
   } else {
     qDebug("s-task:%s (vgId:%d) set downstream ready, since no downstream", pTask->id.idStr, pTask->info.nodeId);
 
-    streamTaskSetForReady(pTask, 0);
+    streamTaskSetReady(pTask, 0);
     streamTaskSetRangeStreamCalc(pTask);
     streamTaskLaunchScanHistory(pTask);
 
@@ -188,7 +195,7 @@ int32_t streamTaskCheckStatus(SStreamTask* pTask) {
 }
 
 static void doProcessDownstreamReadyRsp(SStreamTask* pTask, int32_t numOfReqs) {
-  streamTaskSetForReady(pTask, numOfReqs);
+  streamTaskSetReady(pTask, numOfReqs);
   const char* id = pTask->id.idStr;
 
   int8_t      status = pTask->status.taskStatus;
@@ -319,7 +326,7 @@ int32_t streamSetParamForStreamScannerStep2(SStreamTask* pTask, SVersionRange *p
   return qStreamSourceScanParamForHistoryScanStep2(pTask->exec.pExecutor, pVerRange, pWindow);
 }
 
-int32_t streamBuildSourceRecover1Req(SStreamTask* pTask, SStreamScanHistoryReq* pReq, int8_t igUntreated) {
+int32_t initScanHistoryReq(SStreamTask* pTask, SStreamScanHistoryReq* pReq, int8_t igUntreated) {
   pReq->msgHead.vgId = pTask->info.nodeId;
   pReq->streamId = pTask->id.streamId;
   pReq->taskId = pTask->id.taskId;
@@ -524,11 +531,6 @@ static void doCheckDownstreamStatus(SStreamTask* pTask, SStreamTask* pHTask) {
   streamTaskDoCheckDownstreamTasks(pHTask);
 }
 
-typedef struct SStreamTaskRetryInfo {
-  SStreamMeta* pMeta;
-  int32_t taskId;
-} SStreamTaskRetryInfo;
-
 static void tryLaunchHistoryTask(void* param, void* tmrId) {
   SStreamTaskRetryInfo* pInfo = param;
   SStreamMeta*          pMeta = pInfo->pMeta;
@@ -638,7 +640,7 @@ int32_t streamTaskScanHistoryDataComplete(SStreamTask* pTask) {
     }
   }
 
-  // dispatch recover finish req to all related downstream task
+  // dispatch scan-history finish req to all related downstream task
   code = streamDispatchScanHistoryFinishMsg(pTask);
   if (code < 0) {
     return -1;
@@ -647,19 +649,9 @@ int32_t streamTaskScanHistoryDataComplete(SStreamTask* pTask) {
   return 0;
 }
 
-bool streamTaskRecoverScanStep1Finished(SStreamTask* pTask) {
+int32_t streamTaskFillHistoryFinished(SStreamTask* pTask) {
   void* exec = pTask->exec.pExecutor;
-  return qStreamRecoverScanStep1Finished(exec);
-}
-
-bool streamTaskRecoverScanStep2Finished(SStreamTask* pTask) {
-  void* exec = pTask->exec.pExecutor;
-  return qStreamRecoverScanStep2Finished(exec);
-}
-
-int32_t streamTaskRecoverSetAllStepFinished(SStreamTask* pTask) {
-  void* exec = pTask->exec.pExecutor;
-  return qStreamRecoverSetAllStepFinished(exec);
+  return qStreamInfoResetTimewindowFilter(exec);
 }
 
 bool streamHistoryTaskSetVerRangeStep2(SStreamTask* pTask, int64_t latestVer) {
@@ -669,7 +661,7 @@ bool streamHistoryTaskSetVerRangeStep2(SStreamTask* pTask, int64_t latestVer) {
   int64_t nextStartVer = pRange->maxVer + 1;
   if (nextStartVer > latestVer - 1) {
     // no input data yet. no need to execute the secondardy scan while stream task halt
-    streamTaskRecoverSetAllStepFinished(pTask);
+    streamTaskFillHistoryFinished(pTask);
     qDebug(
         "s-task:%s no need to perform secondary scan-history data(step 2), since no data ingest during step1 scan, "
         "related stream task currentVer:%" PRId64,
@@ -684,7 +676,6 @@ bool streamHistoryTaskSetVerRangeStep2(SStreamTask* pTask, int64_t latestVer) {
   }
 }
 
-
 int32_t tEncodeStreamTaskCheckReq(SEncoder* pEncoder, const SStreamTaskCheckReq* pReq) {
   if (tStartEncode(pEncoder) < 0) return -1;
   if (tEncodeI64(pEncoder, pReq->reqId) < 0) return -1;
@@ -857,7 +848,7 @@ void streamTaskPause(SStreamTask* pTask) {
     taosMsleep(100);
   }
 
-  // todo: use the lock of the task.
+  // todo: use the task lock, stead of meta lock
   taosWLockLatch(&pMeta->lock);
 
   status = pTask->status.taskStatus;
@@ -871,6 +862,12 @@ void streamTaskPause(SStreamTask* pTask) {
   atomic_store_8(&pTask->status.taskStatus, TASK_STATUS__PAUSE);
   taosWUnLockLatch(&pMeta->lock);
 
+  // in case of fill-history task, stop the tsdb file scan operation.
+  if (pTask->info.fillHistory == 1) {
+    void* pExecutor = pTask->exec.pExecutor;
+    qKillTask(pExecutor, TSDB_CODE_SUCCESS);
+  }
+
   int64_t el = taosGetTimestampMs() - st;
   qDebug("vgId:%d s-task:%s set pause flag, prev:%s, elapsed time:%dms", pMeta->vgId, pTask->id.idStr,
          streamGetTaskStatusStr(pTask->status.keepTaskStatus), (int32_t)el);