diff --git a/include/libs/catalog/catalog.h b/include/libs/catalog/catalog.h
index 4e3377a4ce44a1f9632eb8fafe9d4798abc99ace..8db7d34d3e535cf4cfa6d4952ebbbf086a9710cc 100644
--- a/include/libs/catalog/catalog.h
+++ b/include/libs/catalog/catalog.h
@@ -95,7 +95,7 @@ int32_t catalogGetHandle(uint64_t clusterId, SCatalog** catalogHandle);
  */
 void catalogFreeHandle(SCatalog* pCatalog);
 
-int32_t catalogGetDBVgVersion(SCatalog* pCtg, const char* dbFName, int32_t* version, int64_t* dbId);
+int32_t catalogGetDBVgVersion(SCatalog* pCtg, const char* dbFName, int32_t* version, int64_t* dbId, int32_t *tableNum);
 
 /**
  * Get a DB's all vgroup info.
diff --git a/source/libs/catalog/src/catalog.c b/source/libs/catalog/src/catalog.c
index f857ea95c3f297efbed148d3da01fff6fb9bdfea..6127c587ec886f887c6229a9f0c573a930771992 100644
--- a/source/libs/catalog/src/catalog.c
+++ b/source/libs/catalog/src/catalog.c
@@ -965,7 +965,7 @@ int32_t ctgGetVgInfoFromHashValue(SCatalog *pCtg, SDBVgInfo *dbInfo, const SName
   CTG_RET(code);
 }
 
-int32_t ctgStbVersionCompare(const void* key1, const void* key2) {
+int32_t ctgStbVersionSearchCompare(const void* key1, const void* key2) {
   if (*(uint64_t *)key1 < ((SSTableMetaVersion*)key2)->suid) {
     return -1;
   } else if (*(uint64_t *)key1 > ((SSTableMetaVersion*)key2)->suid) {
@@ -975,7 +975,7 @@ int32_t ctgStbVersionCompare(const void* key1, const void* key2) {
   }
 }
 
-int32_t ctgDbVgVersionCompare(const void* key1, const void* key2) {
+int32_t ctgDbVgVersionSearchCompare(const void* key1, const void* key2) {
   if (*(int64_t *)key1 < ((SDbVgVersion*)key2)->dbId) {
     return -1;
   } else if (*(int64_t *)key1 > ((SDbVgVersion*)key2)->dbId) {
@@ -985,6 +985,27 @@ int32_t ctgDbVgVersionCompare(const void* key1, const void* key2) {
   }
 }
 
+int32_t ctgStbVersionSortCompare(const void* key1, const void* key2) {
+  if (((SSTableMetaVersion*)key1)->suid < ((SSTableMetaVersion*)key2)->suid) {
+    return -1;
+  } else if (((SSTableMetaVersion*)key1)->suid > ((SSTableMetaVersion*)key2)->suid) {
+    return 1;
+  } else {
+    return 0;
+  }
+}
+
+int32_t ctgDbVgVersionSortCompare(const void* key1, const void* key2) {
+  if (((SDbVgVersion*)key1)->dbId < ((SDbVgVersion*)key2)->dbId) {
+    return -1;
+  } else if (((SDbVgVersion*)key1)->dbId > ((SDbVgVersion*)key2)->dbId) {
+    return 1;
+  } else {
+    return 0;
+  }
+}
+
+
 int32_t ctgMetaRentInit(SCtgRentMgmt *mgmt, uint32_t rentSec, int8_t type) {
   mgmt->slotRIdx = 0;
   mgmt->slotNum = rentSec / CTG_RENT_SLOT_SECOND;
@@ -1034,7 +1055,7 @@ _return:
   CTG_RET(code);
 }
 
-int32_t ctgMetaRentUpdate(SCtgRentMgmt *mgmt, void *meta, int64_t id, int32_t size, __compar_fn_t compare) {
+int32_t ctgMetaRentUpdate(SCtgRentMgmt *mgmt, void *meta, int64_t id, int32_t size, __compar_fn_t sortCompare, __compar_fn_t searchCompare) {
   int16_t widx = abs(id % mgmt->slotNum);
 
   SCtgRentSlot *slot = &mgmt->slots[widx];
@@ -1048,12 +1069,12 @@ int32_t ctgMetaRentUpdate(SCtgRentMgmt *mgmt, void *meta, int64_t id, int32_t si
 
   if (slot->needSort) {
     qDebug("meta slot before sorte, slot idx:%d, type:%d, size:%d", widx, mgmt->type, (int32_t)taosArrayGetSize(slot->meta));
-    taosArraySort(slot->meta, compare);
+    taosArraySort(slot->meta, sortCompare);
     slot->needSort = false;
     qDebug("meta slot sorted, slot idx:%d, type:%d, size:%d", widx, mgmt->type, (int32_t)taosArrayGetSize(slot->meta));
   }
 
-  void *orig = taosArraySearch(slot->meta, &id, compare, TD_EQ);
+  void *orig = taosArraySearch(slot->meta, &id, searchCompare, TD_EQ);
   if (NULL == orig) {
     qError("meta not found in slot, id:%"PRIx64", slot idx:%d, type:%d, size:%d", id, widx, mgmt->type, (int32_t)taosArrayGetSize(slot->meta));
     CTG_ERR_JRET(TSDB_CODE_CTG_INTERNAL_ERROR);
@@ -1075,7 +1096,7 @@ _return:
   CTG_RET(code);
 }
 
-int32_t ctgMetaRentRemove(SCtgRentMgmt *mgmt, int64_t id, __compar_fn_t compare) {
+int32_t ctgMetaRentRemove(SCtgRentMgmt *mgmt, int64_t id, __compar_fn_t sortCompare, __compar_fn_t searchCompare) {
   int16_t widx = abs(id % mgmt->slotNum);
 
   SCtgRentSlot *slot = &mgmt->slots[widx];
@@ -1088,12 +1109,12 @@ int32_t ctgMetaRentRemove(SCtgRentMgmt *mgmt, int64_t id, __compar_fn_t compare)
   }
 
   if (slot->needSort) {
-    taosArraySort(slot->meta, compare);
+    taosArraySort(slot->meta, sortCompare);
     slot->needSort = false;
     qDebug("meta slot sorted, slot idx:%d, type:%d", widx, mgmt->type);
   }
 
-  int32_t idx = taosArraySearchIdx(slot->meta, &id, compare, TD_EQ);
+  int32_t idx = taosArraySearchIdx(slot->meta, &id, searchCompare, TD_EQ);
   if (idx < 0) {
     qError("meta not found in slot, id:%"PRIx64", slot idx:%d, type:%d", id, widx, mgmt->type);
     CTG_ERR_JRET(TSDB_CODE_CTG_INTERNAL_ERROR);
@@ -1240,7 +1261,7 @@ void ctgRemoveStbRent(SCatalog* pCtg, SCtgTbMetaCache *cache) {
       uint64_t *suid = NULL;
       taosHashGetKey(pIter, (void **)&suid, NULL);
 
-      if (TSDB_CODE_SUCCESS == ctgMetaRentRemove(&pCtg->stbRent, *suid, ctgStbVersionCompare)) {
+      if (TSDB_CODE_SUCCESS == ctgMetaRentRemove(&pCtg->stbRent, *suid, ctgStbVersionSortCompare, ctgStbVersionSearchCompare)) {
         ctgDebug("stb removed from rent, suid:%"PRIx64, *suid);
       }
           
@@ -1264,7 +1285,7 @@ int32_t ctgRemoveDB(SCatalog* pCtg, SCtgDBCache *dbCache, const char* dbFName) {
 
   ctgInfo("db removed from cache, dbFName:%s, dbId:%"PRIx64, dbFName, dbCache->dbId);
 
-  CTG_ERR_RET(ctgMetaRentRemove(&pCtg->dbRent, dbCache->dbId, ctgDbVgVersionCompare));
+  CTG_ERR_RET(ctgMetaRentRemove(&pCtg->dbRent, dbCache->dbId, ctgDbVgVersionSortCompare, ctgDbVgVersionSearchCompare));
   
   ctgDebug("db removed from rent, dbFName:%s, dbId:%"PRIx64, dbFName, dbCache->dbId);
 
@@ -1372,7 +1393,7 @@ int32_t ctgUpdateDBVgInfo(SCatalog* pCtg, const char* dbFName, uint64_t dbId, SD
   dbCache = NULL;
 
   strncpy(vgVersion.dbFName, dbFName, sizeof(vgVersion.dbFName));
-  CTG_ERR_RET(ctgMetaRentUpdate(&pCtg->dbRent, &vgVersion, vgVersion.dbId, sizeof(SDbVgVersion), ctgDbVgVersionCompare));
+  CTG_ERR_RET(ctgMetaRentUpdate(&pCtg->dbRent, &vgVersion, vgVersion.dbId, sizeof(SDbVgVersion), ctgDbVgVersionSortCompare, ctgDbVgVersionSearchCompare));
   
   CTG_RET(code);
 }
@@ -1405,7 +1426,7 @@ int32_t ctgUpdateTblMeta(SCatalog *pCtg, SCtgDBCache *dbCache, char *dbFName, ui
 
         ctgDebug("stb removed from stbCache, dbFName:%s, stb:%s, suid:%"PRIx64, dbFName, tbName, orig->suid);
         
-        ctgMetaRentRemove(&pCtg->stbRent, orig->suid, ctgStbVersionCompare);
+        ctgMetaRentRemove(&pCtg->stbRent, orig->suid, ctgStbVersionSortCompare, ctgStbVersionSearchCompare);
       }
 
       origSuid = orig->suid;
@@ -1932,7 +1953,7 @@ int32_t ctgActRemoveStb(SCtgMetaAction *action) {
   
   ctgInfo("stb removed from cache, dbFName:%s, stbName:%s, suid:%"PRIx64, msg->dbFName, msg->stbName, msg->suid);
 
-  CTG_ERR_JRET(ctgMetaRentRemove(&msg->pCtg->stbRent, msg->suid, ctgStbVersionCompare));
+  CTG_ERR_JRET(ctgMetaRentRemove(&msg->pCtg->stbRent, msg->suid, ctgStbVersionSortCompare, ctgStbVersionSearchCompare));
   
   ctgDebug("stb removed from rent, dbFName:%s, stbName:%s, suid:%"PRIx64, msg->dbFName, msg->stbName, msg->suid);
   
@@ -2171,7 +2192,7 @@ void catalogFreeHandle(SCatalog* pCtg) {
   ctgInfo("handle freed, culsterId:%"PRIx64, clusterId);
 }
 
-int32_t catalogGetDBVgVersion(SCatalog* pCtg, const char* dbFName, int32_t* version, int64_t* dbId) {
+int32_t catalogGetDBVgVersion(SCatalog* pCtg, const char* dbFName, int32_t* version, int64_t* dbId, int32_t *tableNum) {
   CTG_API_ENTER();
 
   if (NULL == pCtg || NULL == dbFName || NULL == version || NULL == dbId) {
@@ -2202,6 +2223,7 @@ int32_t catalogGetDBVgVersion(SCatalog* pCtg, const char* dbFName, int32_t* vers
 
   *version = dbCache->vgInfo->vgVersion;
   *dbId = dbCache->dbId;
+  *tableNum = dbCache->vgInfo->numOfTable;
 
   ctgReleaseVgInfo(dbCache);
   ctgReleaseDBCache(pCtg, dbCache);
diff --git a/source/libs/parser/src/astTranslate.c b/source/libs/parser/src/astTranslate.c
index be5cf62a3c620c62a04defb029cae3af9e21a58f..b9d9835c887328bbc0aec93e372e87634dc2dab8 100644
--- a/source/libs/parser/src/astTranslate.c
+++ b/source/libs/parser/src/astTranslate.c
@@ -863,6 +863,8 @@ static int32_t translateUseDatabase(STranslateContext* pCxt, SUseDatabaseStmt* p
   SUseDbReq usedbReq = {0};
   tNameExtractFullName(&name, usedbReq.db);
 
+  catalogGetDBVgVersion(pCxt->pParseCxt->pCatalog, usedbReq.db, &usedbReq.vgVersion, &usedbReq.dbId, &usedbReq.numOfTable);
+
   pCxt->pCmdMsg = malloc(sizeof(SCmdMsgInfo));
   if (NULL== pCxt->pCmdMsg) {
     return TSDB_CODE_OUT_OF_MEMORY;
diff --git a/source/libs/scheduler/inc/schedulerInt.h b/source/libs/scheduler/inc/schedulerInt.h
index 2af10a0e2d37b7f8bb55319b125c0ab66b11af7a..12c4f824ac3416b8b024d2d20fbca8ef63d4c87d 100644
--- a/source/libs/scheduler/inc/schedulerInt.h
+++ b/source/libs/scheduler/inc/schedulerInt.h
@@ -79,9 +79,10 @@ typedef struct SSchCallbackParam {
 
 typedef struct SSchFlowControl {
   SRWLatch  lock;
+  bool      sorted;
   int32_t   tableNumSum;
   uint32_t  execTaskNum;
-  SArray   *taskList;      // Element is SQueryTask*
+  SArray   *taskList;      // Element is SSchTask*
 } SSchFlowControl;
 
 typedef struct SSchLevel {
@@ -207,6 +208,7 @@ int32_t schCheckIncTaskFlowQuota(SSchJob *pJob, SSchTask *pTask, bool *enough);
 int32_t schLaunchTasksInFlowCtrlList(SSchJob *pJob, SSchTask *pTask);
 int32_t schLaunchTaskImpl(SSchJob *pJob, SSchTask *pTask);
 int32_t schFetchFromRemote(SSchJob *pJob);
+int32_t schProcessOnTaskFailure(SSchJob *pJob, SSchTask *pTask, int32_t errCode);
 
 
 #ifdef __cplusplus
diff --git a/source/libs/scheduler/src/schFlowCtrl.c b/source/libs/scheduler/src/schFlowCtrl.c
index 1dc99354a15fafa634fc58b2ab513d94a85f5e22..9fba6523b6bbfcb165d5e6acff3b53fc73620fd8 100644
--- a/source/libs/scheduler/src/schFlowCtrl.c
+++ b/source/libs/scheduler/src/schFlowCtrl.c
@@ -165,6 +165,7 @@ int32_t schCheckIncTaskFlowQuota(SSchJob *pJob, SSchTask *pTask, bool *enough) {
     }
 
     *enough = false;
+    ctrl->sorted = false;
     
     break;
   } while (true);
@@ -179,31 +180,89 @@ _return:
   SCH_RET(code);
 }
 
-int32_t schLaunchTasksInFlowCtrlListImpl(SSchJob *pJob, SSchFlowControl *ctrl) {
-  do {
-    SCH_LOCK(SCH_WRITE, &ctrl->lock);
-    
-    if (NULL == ctrl->taskList || taosArrayGetSize(ctrl->taskList) <= 0) {
-      SCH_UNLOCK(SCH_WRITE, &ctrl->lock);
-      return TSDB_CODE_SUCCESS;
-    }
+int32_t schTaskTableNumCompare(const void* key1, const void* key2) {
+  SSchTask *pTask1 = *(SSchTask **)key1;
+  SSchTask *pTask2 = *(SSchTask **)key2;
+  
+  if (pTask1->plan->execNodeStat.tableNum < pTask2->plan->execNodeStat.tableNum) {
+    return 1;
+  } else if (pTask1->plan->execNodeStat.tableNum > pTask2->plan->execNodeStat.tableNum) {
+    return -1;
+  } else {
+    return 0;
+  }
+}
 
-    SSchTask *pTask = *(SSchTask **)taosArrayPop(ctrl->taskList);
-    
+
+int32_t schLaunchTasksInFlowCtrlListImpl(SSchJob *pJob, SSchFlowControl *ctrl) {
+  SCH_LOCK(SCH_WRITE, &ctrl->lock);
+  
+  if (NULL == ctrl->taskList || taosArrayGetSize(ctrl->taskList) <= 0) {
     SCH_UNLOCK(SCH_WRITE, &ctrl->lock);
+    return TSDB_CODE_SUCCESS;
+  }
 
-    bool enough = false;  
-    SCH_ERR_RET(schCheckIncTaskFlowQuota(pJob, pTask, &enough));
+  int32_t remainNum = schMgmt.cfg.maxNodeTableNum - ctrl->tableNumSum;
+  int32_t taskNum = taosArrayGetSize(ctrl->taskList);
+  int32_t code = 0;
+  SSchTask *pTask = NULL;
+  
+  if (taskNum > 1 && !ctrl->sorted) {
+    taosArraySort(ctrl->taskList, schTaskTableNumCompare); // desc order
+  }
+
+  for (int32_t i = 0; i < taskNum; ++i) {
+    pTask = *(SSchTask **)taosArrayGet(ctrl->taskList, i);
+    SEp *ep = SCH_GET_CUR_EP(&pTask->plan->execNode);
+
+    if (pTask->plan->execNodeStat.tableNum > remainNum && ctrl->execTaskNum > 0) {
+      SCH_TASK_DLOG("task NOT to launch, fqdn:%s, port:%d, tableNum:%d, remainNum:%d, remainExecTaskNum:%d", 
+         ep->fqdn, ep->port, pTask->plan->execNodeStat.tableNum, ctrl->tableNumSum, ctrl->execTaskNum);
 
-    if (enough) {
-      SCH_ERR_RET(schLaunchTaskImpl(pJob, pTask));
       continue;
     }
+    
+    ctrl->tableNumSum += pTask->plan->execNodeStat.tableNum;
+    ++ctrl->execTaskNum;
+
+    taosArrayRemove(ctrl->taskList, i);
+    
+    SCH_TASK_DLOG("task to launch, fqdn:%s, port:%d, tableNum:%d, remainNum:%d, remainExecTaskNum:%d", 
+       ep->fqdn, ep->port, pTask->plan->execNodeStat.tableNum, ctrl->tableNumSum, ctrl->execTaskNum);
+    
+    SCH_ERR_JRET(schLaunchTaskImpl(pJob, pTask));
+    
+    remainNum -= pTask->plan->execNodeStat.tableNum;
+    if (remainNum <= 0) {
+      SCH_TASK_DLOG("no more task to launch, fqdn:%s, port:%d, remainNum:%d, remainExecTaskNum:%d", 
+         ep->fqdn, ep->port, ctrl->tableNumSum, ctrl->execTaskNum);
+    
+      break;
+    }
 
-    break;
-  } while (true);
+    if (i < (taskNum - 1)) {
+      SSchTask *pLastTask = *(SSchTask **)taosArrayGetLast(ctrl->taskList);
+      if (remainNum < pLastTask->plan->execNodeStat.tableNum) {
+        SCH_TASK_DLOG("no more task to launch, fqdn:%s, port:%d, remainNum:%d, remainExecTaskNum:%d, smallestInList:%d", 
+           ep->fqdn, ep->port, ctrl->tableNumSum, ctrl->execTaskNum, pLastTask->plan->execNodeStat.tableNum);
+      
+        break;
+      }
+    }
 
-  return TSDB_CODE_SUCCESS;
+    --i;
+    --taskNum;
+  }
+  
+_return:
+
+  SCH_UNLOCK(SCH_WRITE, &ctrl->lock);
+
+  if (code) {
+    code = schProcessOnTaskFailure(pJob, pTask, code);
+  }
+  
+  SCH_RET(code);
 }
 
 
diff --git a/source/libs/scheduler/src/scheduler.c b/source/libs/scheduler/src/scheduler.c
index 32cac59b810837c6fe59dca12c043e3b523a6b82..fe886dfcdbe8f4f3f35f74d4406efcb48982e003 100644
--- a/source/libs/scheduler/src/scheduler.c
+++ b/source/libs/scheduler/src/scheduler.c
@@ -608,6 +608,7 @@ int32_t schHandleTaskRetry(SSchJob *pJob, SSchTask *pTask) {
 
   if (SCH_TASK_NEED_FLOW_CTRL(pJob, pTask)) {
     SCH_ERR_RET(schDecTaskFlowQuota(pJob, pTask));
+    SCH_ERR_RET(schLaunchTasksInFlowCtrlList(pJob, pTask));
   }
 
   if (SCH_IS_DATA_SRC_TASK(pTask)) {