diff --git a/include/libs/stream/tstream.h b/include/libs/stream/tstream.h
index e34b27e9b87f610aaa27c775f37346018342331c..3c171ca5109aa3c0d3b9073b8c741faaf58a506e 100644
--- a/include/libs/stream/tstream.h
+++ b/include/libs/stream/tstream.h
@@ -635,13 +635,15 @@ void         streamMetaInit();
 void         streamMetaCleanup();
 SStreamMeta* streamMetaOpen(const char* path, void* ahandle, FTaskExpand expandFunc, int32_t vgId);
 void         streamMetaClose(SStreamMeta* streamMeta);
+
+// save to b-tree meta store
 int32_t      streamMetaSaveTask(SStreamMeta* pMeta, SStreamTask* pTask);
-int32_t      streamMetaAddDeployedTask(SStreamMeta* pMeta, int64_t ver, SStreamTask* pTask);
-int32_t      streamMetaAddSerializedTask(SStreamMeta* pMeta, int64_t checkpointVer, char* msg, int32_t msgLen);
+int32_t      streamMetaRemoveTask(SStreamMeta* pMeta, int32_t taskId);
+int32_t      streamMetaRegisterTask(SStreamMeta* pMeta, int64_t ver, SStreamTask* pTask);
+int32_t      streamMetaUnregisterTask(SStreamMeta* pMeta, int32_t taskId);
 int32_t      streamMetaGetNumOfTasks(const SStreamMeta* pMeta);   // todo remove it
 SStreamTask* streamMetaAcquireTask(SStreamMeta* pMeta, int32_t taskId);
 void         streamMetaReleaseTask(SStreamMeta* pMeta, SStreamTask* pTask);
-void         streamMetaRemoveTask(SStreamMeta* pMeta, int32_t taskId);
 
 int32_t streamMetaBegin(SStreamMeta* pMeta);
 int32_t streamMetaCommit(SStreamMeta* pMeta);
diff --git a/source/dnode/snode/src/snode.c b/source/dnode/snode/src/snode.c
index 8a7b61135bf5f8d67a5529e2e41814d005cb8737..e8bdf97c70d896ac013200a65022d8fdb30d02f0 100644
--- a/source/dnode/snode/src/snode.c
+++ b/source/dnode/snode/src/snode.c
@@ -160,7 +160,7 @@ int32_t sndProcessTaskDeployReq(SSnode *pSnode, char *msg, int32_t msgLen) {
 
   // 2.save task
   taosWLockLatch(&pSnode->pMeta->lock);
-  code = streamMetaAddDeployedTask(pSnode->pMeta, -1, pTask);
+  code = streamMetaRegisterTask(pSnode->pMeta, -1, pTask);
   if (code < 0) {
     taosWUnLockLatch(&pSnode->pMeta->lock);
     return -1;
@@ -179,7 +179,14 @@ int32_t sndProcessTaskDropReq(SSnode *pSnode, char *msg, int32_t msgLen) {
   SVDropStreamTaskReq *pReq = (SVDropStreamTaskReq *)msg;
   qDebug("snode:%d receive msg to drop stream task:0x%x", pSnode->pMeta->vgId, pReq->taskId);
 
-  streamMetaRemoveTask(pSnode->pMeta, pReq->taskId);
+  SStreamTask* pTask = streamMetaAcquireTask(pSnode->pMeta, pReq->taskId);
+  if (pTask == NULL) {
+    qError("vgId:%d failed to acquire s-task:0x%x when dropping it", pSnode->pMeta->vgId, pReq->taskId);
+    return 0;
+  }
+
+  streamMetaUnregisterTask(pSnode->pMeta, pReq->taskId);
+  streamMetaReleaseTask(pSnode->pMeta, pTask);
   return 0;
 }
 
diff --git a/source/dnode/vnode/src/inc/tq.h b/source/dnode/vnode/src/inc/tq.h
index b77bb54714c09254b61746f807e2e04e26a8d4cc..13b991e0386e8419b542f0be8406fa7cdd20254d 100644
--- a/source/dnode/vnode/src/inc/tq.h
+++ b/source/dnode/vnode/src/inc/tq.h
@@ -172,7 +172,6 @@ int32_t tqStreamTasksStatusCheck(STQ* pTq);
 
 // tq util
 int32_t extractDelDataBlock(const void* pData, int32_t len, int64_t ver, SStreamRefDataBlock** pRefBlock);
-int32_t tqAddInputBlockNLaunchTask(SStreamTask* pTask, SStreamQueueItem* pQueueItem);
 int32_t tqExtractDataForMq(STQ* pTq, STqHandle* pHandle, const SMqPollReq* pRequest, SRpcMsg* pMsg);
 int32_t tqDoSendDataRsp(const SRpcHandleInfo* pRpcHandleInfo, const SMqDataRsp* pRsp, int32_t epoch, int64_t consumerId,
                         int32_t type, int64_t sver, int64_t ever);
diff --git a/source/dnode/vnode/src/tq/tq.c b/source/dnode/vnode/src/tq/tq.c
index 1f6c162b9d162d310315aba8a65cecf02337c0de..a935eaf5f737d22be1ca792955c5ba44398411c3 100644
--- a/source/dnode/vnode/src/tq/tq.c
+++ b/source/dnode/vnode/src/tq/tq.c
@@ -1041,12 +1041,13 @@ int32_t tqProcessTaskDeployReq(STQ* pTq, int64_t sversion, char* msg, int32_t ms
   // 2.save task, use the newest commit version as the initial start version of stream task.
   int32_t taskId = 0;
   taosWLockLatch(&pStreamMeta->lock);
-  code = streamMetaAddDeployedTask(pStreamMeta, sversion, pTask);
+  code = streamMetaRegisterTask(pStreamMeta, sversion, pTask);
 
   taskId = pTask->id.taskId;
   int32_t numOfTasks = streamMetaGetNumOfTasks(pStreamMeta);
   if (code < 0) {
     tqError("vgId:%d failed to add s-task:%s, total:%d", vgId, pTask->id.idStr, numOfTasks);
+    tFreeStreamTask(pTask);
     taosWUnLockLatch(&pStreamMeta->lock);
     return -1;
   }
@@ -1136,7 +1137,7 @@ int32_t tqProcessTaskScanHistory(STQ* pTq, SRpcMsg* pMsg) {
                pTask->streamTaskId.taskId, pTask->id.idStr);
 
         pTask->status.taskStatus = TASK_STATUS__DROPPING;
-        tqDebug("s-task:%s scan-history-task set status to be dropping", id);
+        tqDebug("s-task:%s fill-history task set status to be dropping", id);
 
         streamMetaSaveTask(pMeta, pTask);
         streamMetaReleaseTask(pMeta, pTask);
@@ -1166,12 +1167,14 @@ int32_t tqProcessTaskScanHistory(STQ* pTq, SRpcMsg* pMsg) {
     }
 
     if (!streamTaskRecoverScanStep1Finished(pTask)) {
-      tqDebug("s-task:%s level:%d verRange:%" PRId64 " - %" PRId64 " do secondary scan-history-data after halt the related stream task:%s",
-              id, pTask->info.taskLevel, pRange->minVer, pRange->maxVer, id);
+      STimeWindow* pWindow = &pTask->dataRange.window;
+      tqDebug("s-task:%s level:%d verRange:%" PRId64 " - %" PRId64 " window:%" PRId64 "-%" PRId64
+              ", do secondary scan-history data after halt the related stream task:%s",
+              id, pTask->info.taskLevel, pRange->minVer, pRange->maxVer, pWindow->skey, pWindow->ekey, id);
       ASSERT(pTask->status.schedStatus == TASK_SCHED_STATUS__WAITING);
 
       st = taosGetTimestampMs();
-      streamSetParamForStreamScannerStep2(pTask, pRange, &pTask->dataRange.window);
+      streamSetParamForStreamScannerStep2(pTask, pRange, pWindow);
     }
 
     if (!streamTaskRecoverScanStep2Finished(pTask)) {
@@ -1259,6 +1262,7 @@ int32_t tqProcessTaskTransferStateReq(STQ* pTq, SRpcMsg* pMsg) {
   int32_t remain = streamAlignTransferState(pTask);
   if (remain > 0) {
     tqDebug("s-task:%s receive upstream transfer state msg, remain:%d", pTask->id.idStr, remain);
+    streamMetaReleaseTask(pTq->pStreamMeta, pTask);
     return 0;
   }
 
@@ -1466,8 +1470,14 @@ int32_t tqProcessTaskDispatchRsp(STQ* pTq, SRpcMsg* pMsg) {
 int32_t tqProcessTaskDropReq(STQ* pTq, int64_t sversion, char* msg, int32_t msgLen) {
   SVDropStreamTaskReq* pReq = (SVDropStreamTaskReq*)msg;
   tqDebug("vgId:%d receive msg to drop stream task:0x%x", TD_VID(pTq->pVnode), pReq->taskId);
+  SStreamTask* pTask = streamMetaAcquireTask(pTq->pStreamMeta, pReq->taskId);
+  if (pTask == NULL) {
+    tqError("vgId:%d failed to acquire s-task:0x%x when dropping it", pTq->pStreamMeta->vgId, pReq->taskId);
+    return 0;
+  }
 
-  streamMetaRemoveTask(pTq->pStreamMeta, pReq->taskId);
+  streamMetaUnregisterTask(pTq->pStreamMeta, pReq->taskId);
+  streamMetaReleaseTask(pTq->pStreamMeta, pTask);
   return 0;
 }
 
diff --git a/source/dnode/vnode/src/tq/tqRead.c b/source/dnode/vnode/src/tq/tqRead.c
index ba983b1833fa04ca26d6093d07f9f85eafef36ec..675cbe4549d1bf3d0dc916e34bef968951e1363b 100644
--- a/source/dnode/vnode/src/tq/tqRead.c
+++ b/source/dnode/vnode/src/tq/tqRead.c
@@ -336,6 +336,7 @@ int32_t extractMsgFromWal(SWalReader* pReader, void** pItem, const char* id) {
     int32_t len = pReader->pHead->head.bodyLen - sizeof(SMsgHead);
 
     extractDelDataBlock(pBody, len, ver, (SStreamRefDataBlock**)pItem);
+    tqDebug("s-task:%s delete msg extract from WAL, len:%d, ver:%"PRId64, id, len, ver);
   } else {
     ASSERT(0);
   }
diff --git a/source/dnode/vnode/src/tq/tqUtil.c b/source/dnode/vnode/src/tq/tqUtil.c
index 11bfcf7fc528e0426043eb08df00dc395e923a25..c2e4374505a568afc7809f05afe5a99fbc71e440 100644
--- a/source/dnode/vnode/src/tq/tqUtil.c
+++ b/source/dnode/vnode/src/tq/tqUtil.c
@@ -20,21 +20,6 @@
 static int32_t tqSendMetaPollRsp(STqHandle* pHandle, const SRpcMsg* pMsg, const SMqPollReq* pReq,
                                  const SMqMetaRsp* pRsp, int32_t vgId);
 
-int32_t tqAddInputBlockNLaunchTask(SStreamTask* pTask, SStreamQueueItem* pQueueItem) {
-  int32_t code = tAppendDataToInputQueue(pTask, pQueueItem);
-  if (code < 0) {
-    tqError("s-task:%s failed to put into queue, too many", pTask->id.idStr);
-    return -1;
-  }
-
-  if (streamSchedExec(pTask) < 0) {
-    tqError("stream task:%d failed to be launched, code:%s", pTask->id.taskId, tstrerror(terrno));
-    return -1;
-  }
-
-  return TSDB_CODE_SUCCESS;
-}
-
 int32_t tqInitDataRsp(SMqDataRsp* pRsp, const SMqPollReq* pReq) {
   pRsp->reqOffset = pReq->reqOffset;
 
diff --git a/source/dnode/vnode/src/tsdb/tsdbRead.c b/source/dnode/vnode/src/tsdb/tsdbRead.c
index f4109d5b99108eeeeac63ec55c1222fdc545e1df..2aa21bd86f31e8167d0f5f0fd9406dad9a50d513 100644
--- a/source/dnode/vnode/src/tsdb/tsdbRead.c
+++ b/source/dnode/vnode/src/tsdb/tsdbRead.c
@@ -3179,6 +3179,16 @@ static int32_t doLoadLastBlockSequentially(STsdbReader* pReader) {
 
     // load the last data block of current table
     STableBlockScanInfo* pScanInfo = *(STableBlockScanInfo**)pStatus->pTableIter;
+    if (pScanInfo == NULL) {
+      tsdbError("table Iter is null, invalid pScanInfo, try next table %s", pReader->idStr);
+      bool hasNexTable = moveToNextTable(pUidList, pStatus);
+      if (!hasNexTable) {
+        return TSDB_CODE_SUCCESS;
+      }
+
+      continue;
+    }
+
     if (pReader->pIgnoreTables && taosHashGet(*pReader->pIgnoreTables, &pScanInfo->uid, sizeof(pScanInfo->uid))) {
       // reset the index in last block when handing a new file
       doCleanupTableScanInfo(pScanInfo);
diff --git a/source/libs/executor/src/scanoperator.c b/source/libs/executor/src/scanoperator.c
index 9e5d3a3ab69557eec745809e0d6665437d906567..6c8d9ed59f57320b01474ae0c05af978089217ec 100644
--- a/source/libs/executor/src/scanoperator.c
+++ b/source/libs/executor/src/scanoperator.c
@@ -1774,6 +1774,67 @@ void streamScanOperatorDecode(void* pBuff, int32_t len, SStreamScanInfo* pInfo)
   }
 }
 
+static void doBlockDataWindowFilter(SSDataBlock* pBlock, int32_t tsIndex, STimeWindow* pWindow, const char* id) {
+  if (pWindow->skey != INT64_MIN) {
+    qDebug("%s filter for additional history window, skey:%"PRId64, id, pWindow->skey);
+
+    bool* p = taosMemoryCalloc(pBlock->info.rows, sizeof(bool));
+    bool hasUnqualified = false;
+
+    SColumnInfoData* pCol = taosArrayGet(pBlock->pDataBlock, tsIndex);
+    for(int32_t i = 0; i < pBlock->info.rows; ++i) {
+      int64_t* ts = (int64_t*) colDataGetData(pCol, i);
+      p[i] = (*ts >= pWindow->skey);
+
+      if (!p[i]) {
+        hasUnqualified = true;
+      }
+    }
+
+    if (hasUnqualified) {
+      trimDataBlock(pBlock, pBlock->info.rows, p);
+    }
+
+    taosMemoryFree(p);
+  }
+}
+
+// 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;
+  }
+
+  int32_t numOfRows = pBlock->info.rows;
+
+  bool* p = taosMemoryCalloc(numOfRows, sizeof(bool));
+  bool  hasUnqualified = false;
+
+  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 (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 (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);
+  taosMemoryFree(p);
+}
+
 static SSDataBlock* doStreamScan(SOperatorInfo* pOperator) {
   // NOTE: this operator does never check if current status is done or not
   SExecTaskInfo* pTaskInfo = pOperator->pTaskInfo;
@@ -1800,8 +1861,10 @@ static SSDataBlock* doStreamScan(SOperatorInfo* pOperator) {
     } else {
       pTSInfo->base.cond.startVersion = pStreamInfo->fillHistoryVer.minVer;
       pTSInfo->base.cond.endVersion = pStreamInfo->fillHistoryVer.maxVer;
-      qDebug("stream recover step2, verRange:%" PRId64 " - %" PRId64", %s", pTSInfo->base.cond.startVersion,
-             pTSInfo->base.cond.endVersion, id);
+      pTSInfo->base.cond.twindows = pStreamInfo->fillHistoryWindow;
+      qDebug("stream recover step2, verRange:%" PRId64 " - %" PRId64 ", window:%" PRId64 "-%" PRId64 ", %s",
+             pTSInfo->base.cond.startVersion, pTSInfo->base.cond.endVersion, pTSInfo->base.cond.twindows.skey,
+             pTSInfo->base.cond.twindows.ekey, id);
       pStreamInfo->recoverStep = STREAM_RECOVER_STEP__SCAN2;
     }
 
@@ -1920,6 +1983,7 @@ FETCH_NEXT_BLOCK:
     if (pInfo->pUpdateInfo) {
       pInfo->pUpdateInfo->maxDataVersion = TMAX(pInfo->pUpdateInfo->maxDataVersion, pBlock->info.version);
     }
+
     blockDataUpdateTsWindow(pBlock, 0);
     switch (pBlock->info.type) {
       case STREAM_NORMAL:
@@ -1942,7 +2006,9 @@ FETCH_NEXT_BLOCK:
         } else {
           pDelBlock = pBlock;
         }
+
         setBlockGroupIdByUid(pInfo, pDelBlock);
+        rebuildDeleteBlockData(pDelBlock, pStreamInfo->fillHistoryWindow.skey, id);
         printDataBlock(pDelBlock, "stream scan delete recv filtered");
         if (pDelBlock->info.rows == 0) {
           if (pInfo->tqReader) {
@@ -1950,6 +2016,7 @@ FETCH_NEXT_BLOCK:
           }
           goto FETCH_NEXT_BLOCK;
         }
+
         if (!isIntervalWindow(pInfo) && !isSessionWindow(pInfo) && !isStateWindow(pInfo)) {
           generateDeleteResultBlock(pInfo, pDelBlock, pInfo->pDeleteDataRes);
           pInfo->pDeleteDataRes->info.type = STREAM_DELETE_RESULT;
@@ -2091,39 +2158,15 @@ FETCH_NEXT_BLOCK:
         doCheckUpdate(pInfo, pBlockInfo->window.ekey, pBlock);
         doFilter(pBlock, pOperator->exprSupp.pFilterInfo, NULL);
 
-        {  // do additional time window filter
-          STimeWindow* pWindow = &pStreamInfo->fillHistoryWindow;
-
-          if (pWindow->skey != INT64_MIN) {
-            qDebug("%s filter for additional history window, skey:%"PRId64, id, pWindow->skey);
-
-            bool* p = taosMemoryCalloc(pBlock->info.rows, sizeof(bool));
-            bool hasUnqualified = false;
-
-            SColumnInfoData* pCol = taosArrayGet(pBlock->pDataBlock, pInfo->primaryTsIndex);
-            for(int32_t i = 0; i < pBlock->info.rows; ++i) {
-              int64_t* ts = (int64_t*) colDataGetData(pCol, i);
-              p[i] = (*ts >= pWindow->skey);
-
-              if (!p[i]) {
-                hasUnqualified = true;
-              }
-            }
-
-            if (hasUnqualified) {
-              trimDataBlock(pBlock, pBlock->info.rows, p);
-            }
-
-            taosMemoryFree(p);
-          }
-        }
+        // apply additional time window filter
+        doBlockDataWindowFilter(pBlock, pInfo->primaryTsIndex, &pStreamInfo->fillHistoryWindow, id);
 
         pBlock->info.dataLoad = 1;
         blockDataUpdateTsWindow(pBlock, pInfo->primaryTsIndex);
 
-        qDebug("%s %" PRId64 " rows in datablock, update res:%" PRId64, id, pBlockInfo->rows,
-               pInfo->pUpdateDataRes->info.rows);
-        if (pBlockInfo->rows > 0 || pInfo->pUpdateDataRes->info.rows > 0) {
+        int64_t numOfUpdateRes = pInfo->pUpdateDataRes->info.rows;
+        qDebug("%s %" PRId64 " rows in datablock, update res:%" PRId64, id, pBlockInfo->rows, numOfUpdateRes);
+        if (pBlockInfo->rows > 0 || numOfUpdateRes > 0) {
           break;
         }
       }
diff --git a/source/libs/stream/src/stream.c b/source/libs/stream/src/stream.c
index cae7e10e3e927304c766150468c0c4c84469ef66..fa0561a72216ee7e898b8754faf9e6594b25df22 100644
--- a/source/libs/stream/src/stream.c
+++ b/source/libs/stream/src/stream.c
@@ -65,7 +65,7 @@ static void streamSchedByTimer(void* param, void* tmrId) {
   SStreamTask* pTask = (void*)param;
 
   int8_t status = atomic_load_8(&pTask->triggerStatus);
-  qDebug("s-task:%s in scheduler timer, trigger status:%d", pTask->id.idStr, status);
+  qDebug("s-task:%s in scheduler, trigger status:%d, next:%dms", pTask->id.idStr, status, (int32_t)pTask->triggerParam);
 
   if (streamTaskShouldStop(&pTask->status) || streamTaskShouldPause(&pTask->status)) {
     streamMetaReleaseTask(NULL, pTask);
@@ -74,23 +74,22 @@ static void streamSchedByTimer(void* param, void* tmrId) {
   }
 
   if (status == TASK_TRIGGER_STATUS__ACTIVE) {
-    SStreamTrigger* trigger = taosAllocateQitem(sizeof(SStreamTrigger), DEF_QITEM, 0);
-    if (trigger == NULL) {
+    SStreamTrigger* pTrigger = taosAllocateQitem(sizeof(SStreamTrigger), DEF_QITEM, 0);
+    if (pTrigger == NULL) {
       return;
     }
 
-    trigger->type = STREAM_INPUT__GET_RES;
-    trigger->pBlock = taosMemoryCalloc(1, sizeof(SSDataBlock));
-    if (trigger->pBlock == NULL) {
-      taosFreeQitem(trigger);
+    pTrigger->type = STREAM_INPUT__GET_RES;
+    pTrigger->pBlock = taosMemoryCalloc(1, sizeof(SSDataBlock));
+    if (pTrigger->pBlock == NULL) {
+      taosFreeQitem(pTrigger);
       return;
     }
 
-    trigger->pBlock->info.type = STREAM_GET_ALL;
     atomic_store_8(&pTask->triggerStatus, TASK_TRIGGER_STATUS__INACTIVE);
-
-    if (tAppendDataToInputQueue(pTask, (SStreamQueueItem*)trigger) < 0) {
-      taosFreeQitem(trigger);
+    pTrigger->pBlock->info.type = STREAM_GET_ALL;
+    if (tAppendDataToInputQueue(pTask, (SStreamQueueItem*)pTrigger) < 0) {
+      taosFreeQitem(pTrigger);
       taosTmrReset(streamSchedByTimer, (int32_t)pTask->triggerParam, pTask, streamEnv.timer, &pTask->schedTimer);
       return;
     }
@@ -102,7 +101,7 @@ static void streamSchedByTimer(void* param, void* tmrId) {
 }
 
 int32_t streamSetupScheduleTrigger(SStreamTask* pTask) {
-  if (pTask->triggerParam != 0) {
+  if (pTask->triggerParam != 0 && pTask->info.fillHistory == 0) {
     int32_t ref = atomic_add_fetch_32(&pTask->refCnt, 1);
     ASSERT(ref == 2 && pTask->schedTimer == NULL);
 
@@ -399,6 +398,7 @@ int32_t tAppendDataToInputQueue(SStreamTask* pTask, SStreamQueueItem* pItem) {
 
   if (type != STREAM_INPUT__GET_RES && type != STREAM_INPUT__CHECKPOINT && pTask->triggerParam != 0) {
     atomic_val_compare_exchange_8(&pTask->triggerStatus, TASK_TRIGGER_STATUS__INACTIVE, TASK_TRIGGER_STATUS__ACTIVE);
+    qDebug("s-task:%s new data arrived, active the trigger, trigerStatus:%d", pTask->id.idStr, pTask->triggerStatus);
   }
 
   return 0;
diff --git a/source/libs/stream/src/streamData.c b/source/libs/stream/src/streamData.c
index 92f1fc47abb8211d652e666fccd6f8e5245d8c5f..bb4b842787a640435f561d6e75074869da8885af 100644
--- a/source/libs/stream/src/streamData.c
+++ b/source/libs/stream/src/streamData.c
@@ -166,6 +166,8 @@ int32_t streamMergeSubmit(SStreamMergedSubmit* pMerged, SStreamDataSubmit* pSubm
 }
 
 SStreamQueueItem* streamMergeQueueItem(SStreamQueueItem* dst, SStreamQueueItem* pElem) {
+  terrno = 0;
+  
   if (dst->type == STREAM_INPUT__DATA_BLOCK && pElem->type == STREAM_INPUT__DATA_BLOCK) {
     SStreamDataBlock* pBlock = (SStreamDataBlock*)dst;
     SStreamDataBlock* pBlockSrc = (SStreamDataBlock*)pElem;
@@ -181,7 +183,10 @@ SStreamQueueItem* streamMergeQueueItem(SStreamQueueItem* dst, SStreamQueueItem*
     return dst;
   } else if (dst->type == STREAM_INPUT__DATA_SUBMIT && pElem->type == STREAM_INPUT__DATA_SUBMIT) {
     SStreamMergedSubmit* pMerged = streamMergedSubmitNew();
-    // todo handle error
+    if (pMerged == NULL) {
+      terrno = TSDB_CODE_OUT_OF_MEMORY;
+      return NULL;
+    }
 
     streamMergeSubmit(pMerged, (SStreamDataSubmit*)dst);
     streamMergeSubmit(pMerged, (SStreamDataSubmit*)pElem);
@@ -189,6 +194,7 @@ SStreamQueueItem* streamMergeQueueItem(SStreamQueueItem* dst, SStreamQueueItem*
     taosFreeQitem(pElem);
     return (SStreamQueueItem*)pMerged;
   } else {
+    qDebug("block type:%d not merged with existed blocks list, type:%d", pElem->type, dst->type);
     return NULL;
   }
 }
diff --git a/source/libs/stream/src/streamExec.c b/source/libs/stream/src/streamExec.c
index e7adcf36dc5b4b2873ecb61390162579d9c922de..af93d95a9fd91b137d5de16c0be338222fb18ea2 100644
--- a/source/libs/stream/src/streamExec.c
+++ b/source/libs/stream/src/streamExec.c
@@ -407,12 +407,14 @@ static int32_t streamTransferStateToStreamTask(SStreamTask* pTask) {
 
   streamTaskResumeFromHalt(pStreamTask);
 
-  pTask->status.taskStatus = TASK_STATUS__DROPPING;
   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
+  streamMetaUnregisterTask(pMeta, taskId);
 
   // save to disk
   taosWLockLatch(&pMeta->lock);
-  streamMetaSaveTask(pMeta, pTask);
   streamMetaSaveTask(pMeta, pStreamTask);
   if (streamMetaCommit(pMeta) < 0) {
     // persist to disk
@@ -464,7 +466,12 @@ static int32_t extractMsgFromInputQ(SStreamTask* pTask, SStreamQueueItem** pInpu
       // todo we need to sort the data block, instead of just appending into the array list.
       void* newRet = streamMergeQueueItem(*pInput, qItem);
       if (newRet == NULL) {
-        qError("s-task:%s failed to merge blocks from inputQ, numOfBlocks:%d", id, *numOfBlocks);
+        if (terrno == 0) {
+          qDebug("s-task:%s failed to merge blocks from inputQ, numOfBlocks:%d", id, *numOfBlocks);
+        } else {
+          qDebug("s-task:%s failed to merge blocks from inputQ, numOfBlocks:%d, code:%s", id, *numOfBlocks,
+              tstrerror(terrno));
+        }
         streamQueueProcessFail(pTask->inputQueue);
         return TSDB_CODE_SUCCESS;
       }
@@ -492,6 +499,10 @@ int32_t streamExecForAll(SStreamTask* pTask) {
   while (1) {
     int32_t batchSize = 0;
     SStreamQueueItem* pInput = NULL;
+    if (streamTaskShouldStop(&pTask->status)) {
+      qDebug("s-task:%s stream task stopped, abort", id);
+      break;
+    }
 
     // merge multiple input data if possible in the input queue.
     qDebug("s-task:%s start to extract data block from inputQ", id);
diff --git a/source/libs/stream/src/streamMeta.c b/source/libs/stream/src/streamMeta.c
index 0ef9807f8a17e3ddd688c0f8782171dd6d05a539..758530f4fbcc9c240bbc5d0ec3f4482d16abde4c 100644
--- a/source/libs/stream/src/streamMeta.c
+++ b/source/libs/stream/src/streamMeta.c
@@ -217,6 +217,7 @@ int32_t streamMetaSaveTask(SStreamMeta* pMeta, SStreamTask* pTask) {
   tEncoderClear(&encoder);
 
   if (tdbTbUpsert(pMeta->pTaskDb, &pTask->id.taskId, sizeof(int32_t), buf, len, pMeta->txn) < 0) {
+    qError("s-task:%s save to disk failed, code:%s", pTask->id.idStr, tstrerror(terrno));
     return -1;
   }
 
@@ -224,8 +225,19 @@ int32_t streamMetaSaveTask(SStreamMeta* pMeta, SStreamTask* pTask) {
   return 0;
 }
 
+int32_t streamMetaRemoveTask(SStreamMeta* pMeta, int32_t taskId) {
+  int32_t code = tdbTbDelete(pMeta->pTaskDb, &taskId, sizeof(taskId), pMeta->txn);
+  if (code != 0) {
+    qError("vgId:%d failed to remove task:0x%x from metastore, code:%s", pMeta->vgId, taskId, tstrerror(terrno));
+  } else {
+    qDebug("vgId:%d remove task:0x%x from metastore", pMeta->vgId, taskId);
+  }
+
+  return code;
+}
+
 // add to the ready tasks hash map, not the restored tasks hash map
-int32_t streamMetaAddDeployedTask(SStreamMeta* pMeta, int64_t ver, SStreamTask* pTask) {
+int32_t streamMetaRegisterTask(SStreamMeta* pMeta, int64_t ver, SStreamTask* pTask) {
   void* p = taosHashGet(pMeta->pTasks, &pTask->id.taskId, sizeof(pTask->id.taskId));
   if (p == NULL) {
     if (pMeta->expandFunc(pMeta->ahandle, pTask, ver) < 0) {
@@ -233,6 +245,8 @@ int32_t streamMetaAddDeployedTask(SStreamMeta* pMeta, int64_t ver, SStreamTask*
       return -1;
     }
 
+    taosArrayPush(pMeta->pTaskList, &pTask->id.taskId);
+
     if (streamMetaSaveTask(pMeta, pTask) < 0) {
       tFreeStreamTask(pTask);
       return -1;
@@ -242,7 +256,6 @@ int32_t streamMetaAddDeployedTask(SStreamMeta* pMeta, int64_t ver, SStreamTask*
       tFreeStreamTask(pTask);
       return -1;
     }
-    taosArrayPush(pMeta->pTaskList, &pTask->id.taskId);
   } else {
     return 0;
   }
@@ -281,6 +294,7 @@ void streamMetaReleaseTask(SStreamMeta* pMeta, SStreamTask* pTask) {
     qTrace("s-task:%s release task, ref:%d", pTask->id.idStr, ref);
   } else if (ref == 0) {
     ASSERT(streamTaskShouldStop(&pTask->status));
+    qTrace("s-task:%s all refs are gone, free it", pTask->id.idStr);
     tFreeStreamTask(pTask);
   } else if (ref < 0) {
     qError("task ref is invalid, ref:%d, %s", ref, pTask->id.idStr);
@@ -297,7 +311,7 @@ static void doRemoveIdFromList(SStreamMeta* pMeta, int32_t num, int32_t taskId)
   }
 }
 
-void streamMetaRemoveTask(SStreamMeta* pMeta, int32_t taskId) {
+int32_t streamMetaUnregisterTask(SStreamMeta* pMeta, int32_t taskId) {
   SStreamTask* pTask = NULL;
 
   // pre-delete operation
@@ -309,7 +323,7 @@ void streamMetaRemoveTask(SStreamMeta* pMeta, int32_t taskId) {
   } else {
     qDebug("vgId:%d failed to find the task:0x%x, it may be dropped already", pMeta->vgId, taskId);
     taosWUnLockLatch(&pMeta->lock);
-    return;
+    return 0;
   }
   taosWUnLockLatch(&pMeta->lock);
 
@@ -339,27 +353,26 @@ void streamMetaRemoveTask(SStreamMeta* pMeta, int32_t taskId) {
   ppTask = (SStreamTask**)taosHashGet(pMeta->pTasks, &taskId, sizeof(int32_t));
   if (ppTask) {
     taosHashRemove(pMeta->pTasks, &taskId, sizeof(int32_t));
-    tdbTbDelete(pMeta->pTaskDb, &taskId, sizeof(int32_t), pMeta->txn);
-
     atomic_store_8(&pTask->status.taskStatus, TASK_STATUS__DROPPING);
+
     ASSERT(pTask->status.timerActive == 0);
 
     int32_t num = taosArrayGetSize(pMeta->pTaskList);
-    qDebug("s-task:%s set the drop task flag, remain running s-task:%d", pTask->id.idStr, num - 1);
     doRemoveIdFromList(pMeta, num, pTask->id.taskId);
 
     // remove the ref by timer
     if (pTask->triggerParam != 0) {
       taosTmrStop(pTask->schedTimer);
-      streamMetaReleaseTask(pMeta, pTask);
     }
 
+    streamMetaRemoveTask(pMeta, taskId);
     streamMetaReleaseTask(pMeta, pTask);
   } else {
     qDebug("vgId:%d failed to find the task:0x%x, it may have been dropped already", pMeta->vgId, taskId);
   }
 
   taosWUnLockLatch(&pMeta->lock);
+  return 0;
 }
 
 int32_t streamMetaBegin(SStreamMeta* pMeta) {
@@ -404,7 +417,9 @@ int32_t streamMetaAbort(SStreamMeta* pMeta) {
 
 int32_t streamLoadTasks(SStreamMeta* pMeta, int64_t ver) {
   TBC* pCur = NULL;
+
   if (tdbTbcOpen(pMeta->pTaskDb, &pCur, NULL) < 0) {
+    qError("vgId:%d failed to open stream meta, code:%s", pMeta->vgId, tstrerror(terrno));
     return -1;
   }
 
@@ -413,6 +428,7 @@ int32_t streamLoadTasks(SStreamMeta* pMeta, int64_t ver) {
   void*    pVal = NULL;
   int32_t  vLen = 0;
   SDecoder decoder;
+  SArray*  pRecycleList = taosArrayInit(4, sizeof(int32_t));
 
   tdbTbcMoveToFirst(pCur);
 
@@ -422,6 +438,7 @@ int32_t streamLoadTasks(SStreamMeta* pMeta, int64_t ver) {
       tdbFree(pKey);
       tdbFree(pVal);
       tdbTbcClose(pCur);
+      taosArrayDestroy(pRecycleList);
       return -1;
     }
 
@@ -429,16 +446,29 @@ int32_t streamLoadTasks(SStreamMeta* pMeta, int64_t ver) {
     tDecodeStreamTask(&decoder, pTask);
     tDecoderClear(&decoder);
 
-    // remove duplicate
+    if (pTask->status.taskStatus == TASK_STATUS__DROPPING) {
+      int32_t taskId = pTask->id.taskId;
+      tFreeStreamTask(pTask);
+
+      taosArrayPush(pRecycleList, &taskId);
+
+      int32_t total = taosArrayGetSize(pRecycleList);
+      qDebug("s-task:0x%x is already dropped, add into recycle list, total:%d", taskId, total);
+      continue;
+    }
+
+    // do duplicate task check.
     void* p = taosHashGet(pMeta->pTasks, &pTask->id.taskId, sizeof(pTask->id.taskId));
     if (p == NULL) {
       if (pMeta->expandFunc(pMeta->ahandle, pTask, pTask->chkInfo.version) < 0) {
         tdbFree(pKey);
         tdbFree(pVal);
         tdbTbcClose(pCur);
-        taosMemoryFree(pTask);
+        tFreeStreamTask(pTask);
+        taosArrayDestroy(pRecycleList);
         return -1;
       }
+
       taosArrayPush(pMeta->pTaskList, &pTask->id.taskId);
     } else {
       tdbFree(pKey);
@@ -452,7 +482,8 @@ int32_t streamLoadTasks(SStreamMeta* pMeta, int64_t ver) {
       tdbFree(pKey);
       tdbFree(pVal);
       tdbTbcClose(pCur);
-      taosMemoryFree(pTask);
+      tFreeStreamTask(pTask);
+      taosArrayDestroy(pRecycleList);
       return -1;
     }
 
@@ -462,8 +493,18 @@ int32_t streamLoadTasks(SStreamMeta* pMeta, int64_t ver) {
   tdbFree(pKey);
   tdbFree(pVal);
   if (tdbTbcClose(pCur) < 0) {
+    taosArrayDestroy(pRecycleList);
     return -1;
   }
 
+  if (taosArrayGetSize(pRecycleList) > 0) {
+    for(int32_t i = 0; i < taosArrayGetSize(pRecycleList); ++i) {
+      int32_t taskId = *(int32_t*) taosArrayGet(pRecycleList, i);
+      streamMetaRemoveTask(pMeta, taskId);
+    }
+  }
+
+  qDebug("vgId:%d load %d task from disk", pMeta->vgId, (int32_t) taosArrayGetSize(pMeta->pTaskList));
+  taosArrayDestroy(pRecycleList);
   return 0;
 }
diff --git a/source/libs/stream/src/streamRecover.c b/source/libs/stream/src/streamRecover.c
index 1c9e2672d19ccaaf1ae76ddd8aa7c87b690031e6..dffa28e769a6082d48afcea35a23db0175b41844 100644
--- a/source/libs/stream/src/streamRecover.c
+++ b/source/libs/stream/src/streamRecover.c
@@ -765,7 +765,13 @@ void streamTaskSetRangeStreamCalc(SStreamTask* pTask) {
   } else {
     SHistDataRange* pRange = &pTask->dataRange;
 
-    int64_t ekey = pRange->window.ekey + 1;
+    int64_t ekey = 0;
+    if (pRange->window.ekey < INT64_MAX) {
+      ekey = pRange->window.ekey + 1;
+    } else {
+      ekey = pRange->window.ekey;
+    }
+
     int64_t ver = pRange->range.minVer;
 
     pRange->window.skey = ekey;
diff --git a/source/libs/stream/src/streamTask.c b/source/libs/stream/src/streamTask.c
index 863c4ce0252e3b08aea5ba79b7ae4b2e624cdc13..1eb8d119168d23b96a851e0946e968c4e1b1fef8 100644
--- a/source/libs/stream/src/streamTask.c
+++ b/source/libs/stream/src/streamTask.c
@@ -211,7 +211,7 @@ static void freeItem(void* p) {
 }
 
 void tFreeStreamTask(SStreamTask* pTask) {
-  qDebug("free s-task:%s", pTask->id.idStr);
+  qDebug("free s-task:%s, %p", pTask->id.idStr, pTask);
 
   int32_t status = atomic_load_8((int8_t*)&(pTask->status.taskStatus));
   if (pTask->inputQueue) {
diff --git a/tests/script/tsim/stream/basic3.sim b/tests/script/tsim/stream/basic3.sim
index 2df33541b461b1f2fe1c772cb80550e421fe56aa..f18061a6df012b5093beef6c8f1588a61b69f5b8 100644
--- a/tests/script/tsim/stream/basic3.sim
+++ b/tests/script/tsim/stream/basic3.sim
@@ -1,11 +1,9 @@
 system sh/stop_dnodes.sh
 system sh/deploy.sh -n dnode1 -i 1
-system sh/cfg.sh -n dnode1 -c debugflag -v 131
 system sh/cfg.sh -n dnode1 -c keepColumnName -v 1
 system sh/exec.sh -n dnode1 -s start
 
-sleep 5000
-
+sleep 1000
 sql connect
 
 print ========== interval\session\state window
@@ -32,7 +30,6 @@ sql create stream streamd6 into streamt6 as select ca, _wstart,_wend, count(*),
 
 
 sql alter local 'keepColumnName' '1'
-
 sql CREATE STABLE `meters_test_data` (`ts` TIMESTAMP, `close` FLOAT, `parttime` TIMESTAMP, `parttime_str` VARCHAR(32)) TAGS (`id` VARCHAR(32));
 
 sql_error create stream realtime_meters fill_history 1 into realtime_meters as select last(parttime),first(close),last(close) from meters_test_data partition by tbname state_window(parttime_str);
@@ -58,17 +55,13 @@ sql_error create stream streamd11 into streamd11 as select _wstart, _wend, count
 sql alter local 'keepColumnName' '0'
 
 sql create stream realtime_meters fill_history 1 into realtime_meters as select last(parttime),first(close),last(close) from meters_test_data partition by tbname state_window(parttime_str);
-
 sql desc realtime_meters;
-
 if $rows == 0 then
   return -1
 endi
 
-sql create stream streamd7 into streamt7 as select  _wstart, _wend, count(*), first(ca), last(ca) from t1 interval(10s);
-
+sql create stream streamd7 into streamt7 as select  _wstart t1, _wend t2, count(*), first(ca), last(ca) from t1 interval(10s);
 sql desc streamt7;
-
 if $rows == 0 then
   return -1
 endi
@@ -76,12 +69,11 @@ endi
 sql create stream streamd71 into streamt71 as select _wstart, _wend, count(*) as ca, first(ca), last(ca) as c2 from t1 interval(10s);
 
 sql desc streamt71;
-
 if $rows == 0 then
   return -1
 endi
 
-sleep 3000
+sleep 1000
 
 sql drop stream if exists streamd1;
 sql drop stream if exists streamd2;
@@ -93,23 +85,19 @@ sql drop stream if exists streamd6;
 sql create stream streamd10 into streamd10 as select _wstart, _wend, count(*), first(ca), last(cb) as c2 from t1 interval(10s);
 
 sql desc streamd10;
-
 if $rows == 0 then
   return -1
 endi
 
 sql_error create stream streamd11 into streamd11 as select _wstart, _wend, count(*), last(ca), last(ca) from t1 interval(10s);
 
-
 sql create stream streamd12 into streamd12 as select _wstart, _wend, count(*), last(ca), last(cb) as c2 from t1 interval(10s);
-
 sql desc streamd12;
 
 if $rows == 0 then
   return -1
 endi
 
-
 _OVER:
 system sh/exec.sh -n dnode1 -s stop -x SIGINT
 print =============== check