diff --git a/src/client/inc/tscLocalMerge.h b/src/client/inc/tscLocalMerge.h
index 19230e34f1f8769229d0f386a8276a6c2395b279..c073f40546c6a5ceaeabeafd3d731fdf211402df 100644
--- a/src/client/inc/tscLocalMerge.h
+++ b/src/client/inc/tscLocalMerge.h
@@ -13,8 +13,8 @@
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
 
-#ifndef TDENGINE_TSCSECONARYMERGE_H
-#define TDENGINE_TSCSECONARYMERGE_H
+#ifndef TDENGINE_TSCLOCALMERGE_H
+#define TDENGINE_TSCLOCALMERGE_H
 
 #ifdef __cplusplus
 extern "C" {
@@ -27,14 +27,7 @@ extern "C" {
 #include "tsclient.h"
 
 #define MAX_NUM_OF_SUBQUERY_RETRY 3
-
-/*
- * @version 0.1
- * @date   2018/01/05
- * @author liaohj
- * management of client-side reducer for metric query
- */
-
+  
 struct SQLFunctionCtx;
 
 typedef struct SLocalDataSource {
@@ -60,7 +53,6 @@ typedef struct SLocalReducer {
   char *                 prevRowOfInput;
   tFilePage *            pResultBuf;
   int32_t                nResultBufSize;
-//  char *                 pBufForInterpo;  // intermediate buffer for interpolation
   tFilePage *            pTempBuffer;
   struct SQLFunctionCtx *pCtx;
   int32_t                rowSize;      // size of each intermediate result.
@@ -81,13 +73,8 @@ typedef struct SLocalReducer {
 } SLocalReducer;
 
 typedef struct SSubqueryState {
-  /*
-   * the number of completed retrieval subquery, once this value equals to numOfVnodes,
-   * all retrieval are completed.Local merge is launched.
-   */
-  int32_t  numOfCompleted;
-  int32_t  numOfTotal;          // number of total sub-queries
-  int32_t  code;                // code from subqueries
+  int32_t  numOfRemain;         // the number of remain unfinished subquery
+  int32_t  numOfTotal;          // the number of total sub-queries
   uint64_t numOfRetrievedRows;  // total number of points in this query
 } SSubqueryState;
 
@@ -128,4 +115,4 @@ int32_t tscDoLocalMerge(SSqlObj *pSql);
 }
 #endif
 
-#endif  // TDENGINE_TSCSECONARYMERGE_H
+#endif  // TDENGINE_TSCLOCALMERGE_H
diff --git a/src/client/inc/tscSubquery.h b/src/client/inc/tscSubquery.h
index 368fe2250a37e3ef226174b80a39e63e0c990fda..82d490376aa8de18814c6cf9a1f3fbfb5be6ce75 100644
--- a/src/client/inc/tscSubquery.h
+++ b/src/client/inc/tscSubquery.h
@@ -26,11 +26,9 @@ extern "C" {
 void tscFetchDatablockFromSubquery(SSqlObj* pSql);
 
 void tscSetupOutputColumnIndex(SSqlObj* pSql);
-int32_t tscLaunchSecondPhaseSubqueries(SSqlObj* pSql);
 void tscJoinQueryCallback(void* param, TAOS_RES* tres, int code);
 
 SJoinSupporter* tscCreateJoinSupporter(SSqlObj* pSql, SSubqueryState* pState, int32_t index);
-void tscDestroyJoinSupporter(SJoinSupporter* pSupporter);
 
 int32_t tscHandleMasterJoinQuery(SSqlObj* pSql);
 
diff --git a/src/client/inc/tscUtil.h b/src/client/inc/tscUtil.h
index 581ce00a62ed4e450d1c4a546e227c0e10580549..d6562f008de5ce8a42969633d53936d19fcc07ef 100644
--- a/src/client/inc/tscUtil.h
+++ b/src/client/inc/tscUtil.h
@@ -64,7 +64,8 @@ typedef struct SJoinSupporter {
   SSubqueryState* pState;
   SSqlObj*        pObj;           // parent SqlObj
   int32_t         subqueryIndex;  // index of sub query
-  int64_t         interval;       // interval time
+  int64_t         intervalTime;   // interval time
+  int64_t         slidingTime;    // sliding time
   SLimitVal       limit;          // limit info
   uint64_t        uid;            // query meter uid
   SArray*         colList;        // previous query information, no need to use this attribute, and the corresponding attribution
diff --git a/src/client/src/tscSubquery.c b/src/client/src/tscSubquery.c
index 4e02325be605a954c9695bb808e063e3b2fc9f68..d25afcf00fd951e5f60d91226e106057114e159a 100644
--- a/src/client/src/tscSubquery.c
+++ b/src/client/src/tscSubquery.c
@@ -12,12 +12,12 @@
  * You should have received a copy of the GNU Affero General Public License
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
+#include "os.h"
 
 #include "tscSubquery.h"
-#include <qast.h>
-#include <tcompare.h>
-#include <tschemautil.h>
-#include "os.h"
+#include "qast.h"
+#include "tcompare.h"
+#include "tschemautil.h"
 #include "qtsbuf.h"
 #include "tscLog.h"
 #include "tsclient.h"
@@ -169,7 +169,8 @@ SJoinSupporter* tscCreateJoinSupporter(SSqlObj* pSql, SSubqueryState* pState, in
   pSupporter->subqueryIndex = index;
   SQueryInfo* pQueryInfo = tscGetQueryInfoDetail(&pSql->cmd, pSql->cmd.clauseIndex);
   
-  pSupporter->interval = pQueryInfo->intervalTime;
+  pSupporter->intervalTime = pQueryInfo->intervalTime;
+  pSupporter->slidingTime = pQueryInfo->slidingTime;
   pSupporter->limit = pQueryInfo->limit;
 
   STableMetaInfo* pTableMetaInfo = tscGetTableMetaInfoFromCmd(&pSql->cmd, pSql->cmd.clauseIndex, index);
@@ -186,7 +187,7 @@ SJoinSupporter* tscCreateJoinSupporter(SSqlObj* pSql, SSubqueryState* pState, in
   return pSupporter;
 }
 
-void tscDestroyJoinSupporter(SJoinSupporter* pSupporter) {
+static void tscDestroyJoinSupporter(SJoinSupporter* pSupporter) {
   if (pSupporter == NULL) {
     return;
   }
@@ -217,7 +218,7 @@ void tscDestroyJoinSupporter(SJoinSupporter* pSupporter) {
  * primary timestamp column , the secondary query is not necessary
  *
  */
-bool needSecondaryQuery(SQueryInfo* pQueryInfo) {
+static UNUSED_FUNC bool needSecondaryQuery(SQueryInfo* pQueryInfo) {
   size_t numOfCols = taosArrayGetSize(pQueryInfo->colList);
   
   for (int32_t i = 0; i < numOfCols; ++i) {
@@ -233,14 +234,11 @@ bool needSecondaryQuery(SQueryInfo* pQueryInfo) {
 /*
  * launch secondary stage query to fetch the result that contains timestamp in set
  */
-int32_t tscLaunchSecondPhaseSubqueries(SSqlObj* pSql) {
+static int32_t tscLaunchSecondPhaseSubqueries(SSqlObj* pSql) {
   int32_t         numOfSub = 0;
   SJoinSupporter* pSupporter = NULL;
   
-  /*
-   * If the columns are not involved in the final select clause,
-   * the corresponding query will not be issued.
-   */
+  //If the columns are not involved in the final select clause, the corresponding query will not be issued.
   for (int32_t i = 0; i < pSql->numOfSubs; ++i) {
     pSupporter = pSql->pSubs[i]->param;
     if (taosArrayGetSize(pSupporter->exprList) > 0) {
@@ -251,13 +249,12 @@ int32_t tscLaunchSecondPhaseSubqueries(SSqlObj* pSql) {
   assert(numOfSub > 0);
   
   // scan all subquery, if one sub query has only ts, ignore it
-  tscTrace("%p start to launch secondary subquery, total:%d, only:%d needs to query, others are not retrieve in "
-      "select clause", pSql, pSql->numOfSubs, numOfSub);
+  tscTrace("%p start to launch secondary subquery, total:%d, only:%d needs to query", pSql, pSql->numOfSubs, numOfSub);
 
   //the subqueries that do not actually launch the secondary query to virtual node is set as completed.
   SSubqueryState* pState = pSupporter->pState;
   pState->numOfTotal = pSql->numOfSubs;
-  pState->numOfCompleted = (pSql->numOfSubs - numOfSub);
+  pState->numOfRemain = numOfSub;
   
   bool success = true;
   
@@ -301,7 +298,8 @@ int32_t tscLaunchSecondPhaseSubqueries(SSqlObj* pSql) {
     // set the second stage sub query for join process
     TSDB_QUERY_SET_TYPE(pQueryInfo->type, TSDB_QUERY_TYPE_JOIN_SEC_STAGE);
 
-    pQueryInfo->intervalTime = pSupporter->interval;
+    pQueryInfo->intervalTime = pSupporter->intervalTime;
+    pQueryInfo->slidingTime = pSupporter->slidingTime;
     pQueryInfo->groupbyExpr = pSupporter->groupbyExpr;
     
     tscTagCondCopy(&pQueryInfo->tagCond, &pSupporter->tagCond);
@@ -375,6 +373,7 @@ int32_t tscLaunchSecondPhaseSubqueries(SSqlObj* pSql) {
     if (pSql->pSubs[i] == NULL) {
       continue;
     }
+
     tscDoQuery(pSql->pSubs[i]);
   }
 
@@ -405,11 +404,9 @@ void freeJoinSubqueryObj(SSqlObj* pSql) {
 }
 
 static void quitAllSubquery(SSqlObj* pSqlObj, SJoinSupporter* pSupporter) {
-  int32_t numOfTotal = pSupporter->pState->numOfTotal;
-  int32_t finished = atomic_add_fetch_32(&pSupporter->pState->numOfCompleted, 1);
-  
-  pSqlObj->res.code = pSupporter->pState->code;
-  if (finished >= numOfTotal) {
+  assert(pSupporter->pState->numOfRemain > 0);
+
+  if (atomic_sub_fetch_32(&pSupporter->pState->numOfRemain, 1) <= 0) {
     tscError("%p all subquery return and query failed, global code:%d", pSqlObj, pSqlObj->res.code);
     freeJoinSubqueryObj(pSqlObj);
   }
@@ -421,7 +418,7 @@ static void updateQueryTimeRange(SQueryInfo* pQueryInfo, STimeWindow* win) {
   pQueryInfo->window = *win;
 }
 
-static void tSIntersectionAndLaunchSecQuery(SJoinSupporter* pSupporter, SSqlObj* pSql) {
+static UNUSED_FUNC void tSIntersectionAndLaunchSecQuery(SJoinSupporter* pSupporter, SSqlObj* pSql) {
   SSqlObj* pParentSql = pSupporter->pObj;
   SQueryInfo* pParentQueryInfo = tscGetQueryInfoDetail(&pParentSql->cmd, pParentSql->cmd.clauseIndex);
   
@@ -443,22 +440,7 @@ static void tSIntersectionAndLaunchSecQuery(SJoinSupporter* pSupporter, SSqlObj*
 //      return;
 //    }
 //  }
-  
-  int32_t numOfTotal = pSupporter->pState->numOfTotal;
-  int32_t finished = atomic_add_fetch_32(&pSupporter->pState->numOfCompleted, 1);
-  
-  if (finished >= numOfTotal) {
-    assert(finished == numOfTotal);
-    
-    if (pSupporter->pState->code != TSDB_CODE_SUCCESS) {
-      tscTrace("%p sub:%p, numOfSub:%d, quit from further procedure due to other queries failure", pParentSql, pSql,
-               pSupporter->subqueryIndex);
-      freeJoinSubqueryObj(pParentSql);
-      return;
-    }
-    
-    tscTrace("%p all subqueries retrieve ts complete, do ts block intersect", pParentSql);
-    
+
     SJoinSupporter* p1 = pParentSql->pSubs[0]->param;
     SJoinSupporter* p2 = pParentSql->pSubs[1]->param;
     
@@ -471,7 +453,6 @@ static void tSIntersectionAndLaunchSecQuery(SJoinSupporter* pSupporter, SSqlObj*
       updateQueryTimeRange(pParentQueryInfo, &win);
       tscLaunchSecondPhaseSubqueries(pParentSql);
     }
-  }
 }
 
 int32_t tscCompareTidTags(const void* p1, const void* p2) {
@@ -545,11 +526,13 @@ static void issueTSCompQuery(SSqlObj* pSql, SJoinSupporter* pSupporter, SSqlObj*
   tscAddSpecialColumnForSelect(pQueryInfo, 0, TSDB_FUNC_TS_COMP, &index, &colSchema, TSDB_COL_NORMAL);
   
   // set the tags value for ts_comp function
-  SSqlExpr *pExpr = tscSqlExprGet(pQueryInfo, 0);
-  int16_t tagColId = tscGetJoinTagColIdByUid(&pSupporter->tagCond, pTableMetaInfo->pTableMeta->uid);
-  pExpr->param->i64Key = tagColId;
-  pExpr->numOfParams = 1;
-  
+  if (UTIL_TABLE_IS_SUPER_TABLE(pTableMetaInfo)) {
+    SSqlExpr *pExpr = tscSqlExprGet(pQueryInfo, 0);
+    int16_t tagColId = tscGetJoinTagColIdByUid(&pSupporter->tagCond, pTableMetaInfo->pTableMeta->uid);
+    pExpr->param->i64Key = tagColId;
+    pExpr->numOfParams = 1;
+  }
+
   // add the filter tag column
   if (pSupporter->colList != NULL) {
     size_t s = taosArrayGetSize(pSupporter->colList);
@@ -575,7 +558,7 @@ static void issueTSCompQuery(SSqlObj* pSql, SJoinSupporter* pSupporter, SSqlObj*
   tscProcessSql(pSql);
 }
 
-static bool checkForIdenticalTagVal(SQueryInfo* pQueryInfo, SJoinSupporter* p1, void* pSql) {
+static bool checkForDuplicateTagVal(SQueryInfo* pQueryInfo, SJoinSupporter* p1, SSqlObj* pPSqlObj) {
   STableMetaInfo* pTableMetaInfo = tscGetMetaInfo(pQueryInfo, 0);
 
   SSchema* pSchema = tscGetTableTagSchema(pTableMetaInfo->pTableMeta);// todo: tags mismatch, tags not completed
@@ -587,8 +570,8 @@ static bool checkForIdenticalTagVal(SQueryInfo* pQueryInfo, SJoinSupporter* p1,
     STidTags* p = (STidTags*) varDataVal(p1->pIdTagList + i * p1->tagSize);
 
     if (doCompare(prev->tag, p->tag, pColSchema->type, pColSchema->bytes) == 0) {
-      tscError("%p join tags have same value for different table, free all sub SqlObj and quit", pSql);
-      p1->pState->code = TSDB_CODE_QRY_DUP_JOIN_KEY;
+      tscError("%p join tags have same value for different table, free all sub SqlObj and quit", pPSqlObj);
+      pPSqlObj->res.code = TSDB_CODE_QRY_DUP_JOIN_KEY;
       return false;
     }
   }
@@ -596,8 +579,8 @@ static bool checkForIdenticalTagVal(SQueryInfo* pQueryInfo, SJoinSupporter* p1,
   return true;
 }
 
-static void getIntersectionOfTagVal(SQueryInfo* pQueryInfo, SSqlObj* pParentSql, SArray** s1, SArray** s2) {
-  tscTrace("%p all subqueries retrieve tags complete, do tags match", pParentSql);
+static void getIntersectionOfTableTuple(SQueryInfo* pQueryInfo, SSqlObj* pParentSql, SArray** s1, SArray** s2) {
+  tscTrace("%p all subqueries retrieve <tid, tags> complete, do tags match", pParentSql);
 
   SJoinSupporter* p1 = pParentSql->pSubs[0]->param;
   SJoinSupporter* p2 = pParentSql->pSubs[1]->param;
@@ -613,7 +596,7 @@ static void getIntersectionOfTagVal(SQueryInfo* pQueryInfo, SSqlObj* pParentSql,
   *s1 = taosArrayInit(p1->num, p1->tagSize);
   *s2 = taosArrayInit(p2->num, p2->tagSize);
 
-  if (!(checkForIdenticalTagVal(pQueryInfo, p1, pParentSql) && checkForIdenticalTagVal(pQueryInfo, p2, pParentSql))) {
+  if (!(checkForDuplicateTagVal(pQueryInfo, p1, pParentSql) && checkForDuplicateTagVal(pQueryInfo, p2, pParentSql))) {
     freeJoinSubqueryObj(pParentSql);
     pParentSql->res.code = TSDB_CODE_QRY_DUP_JOIN_KEY;
     tscQueueAsyncRes(pParentSql);
@@ -642,7 +625,7 @@ static void getIntersectionOfTagVal(SQueryInfo* pQueryInfo, SSqlObj* pParentSql,
   }
 }
 
-static void joinRetrieveCallback(void* param, TAOS_RES* tres, int numOfRows) {
+static void tidTagRetrieveCallback(void* param, TAOS_RES* tres, int32_t numOfRows) {
   SJoinSupporter* pSupporter = (SJoinSupporter*)param;
 
   SSqlObj* pParentSql = pSupporter->pObj;
@@ -652,239 +635,287 @@ static void joinRetrieveCallback(void* param, TAOS_RES* tres, int numOfRows) {
   SSqlRes* pRes = &pSql->res;
 
   SQueryInfo* pQueryInfo = tscGetQueryInfoDetail(pCmd, pCmd->clauseIndex);
+  assert(TSDB_QUERY_HAS_TYPE(pQueryInfo->type, TSDB_QUERY_TYPE_TAG_FILTER_QUERY));
 
-  // response of tag retrieve
-  if (TSDB_QUERY_HAS_TYPE(pQueryInfo->type, TSDB_QUERY_TYPE_TAG_FILTER_QUERY)) {
-    // todo handle error
+  // check for the error code firstly
+  if (taos_errno(pSql) != TSDB_CODE_SUCCESS) {
+    // todo retry if other subqueries are not failed
 
-    if (numOfRows == 0 || pRes->completed) {
-      if (numOfRows > 0) {
-        size_t validLen = pSupporter->tagSize * pRes->numOfRows;
+    assert(numOfRows < 0 && numOfRows == taos_errno(pSql));
+    tscError("%p sub query failed, code:%s, index:%d", pSql, tstrerror(numOfRows), pSupporter->subqueryIndex);
 
-        size_t length = pSupporter->totalLen + validLen;
-        char*  tmp = realloc(pSupporter->pIdTagList, length);
-        assert(tmp != NULL);
-        pSupporter->pIdTagList = tmp;
+    pParentSql->res.code = numOfRows;
+    quitAllSubquery(pParentSql, pSupporter);
 
-        memcpy(pSupporter->pIdTagList + pSupporter->totalLen,pRes->data, validLen);
-        pSupporter->totalLen += validLen;
-        pSupporter->num += pRes->numOfRows;
-      }
+    tscQueueAsyncRes(pParentSql);
+    return;
+  }
 
-      // <tid + tag> tuples have been retrieved to client, try <tid + tag> tuples from the next vnode
-      if (hasMoreVnodesToTry(pSql)) {
-        STableMetaInfo* pTableMetaInfo = tscGetMetaInfo(pQueryInfo, 0);
+  // keep the results in memory
+  if (numOfRows > 0) {
+    size_t validLen = pSupporter->tagSize * pRes->numOfRows;
+    size_t length = pSupporter->totalLen + validLen;
 
-        int32_t totalVgroups = pTableMetaInfo->vgroupList->numOfVgroups;
-        pTableMetaInfo->vgroupIndex += 1;
-        assert(pTableMetaInfo->vgroupIndex < totalVgroups);
+    // todo handle memory error
+    char* tmp = realloc(pSupporter->pIdTagList, length);
+    if (tmp == NULL) {
+      tscError("%p failed to malloc memory", pSql);
 
-        tscTrace("%p tid_tag from vgroup index:%d completed, try next vgroup:%d. total vgroups:%d. current numOfRes:%d",
-                 pSql, pTableMetaInfo->vgroupIndex - 1, pTableMetaInfo->vgroupIndex, totalVgroups,
-                 pSupporter->num);
+      pParentSql->res.code = TAOS_SYSTEM_ERROR(errno);
+      quitAllSubquery(pParentSql, pSupporter);
 
-        pCmd->command = TSDB_SQL_SELECT;
-        tscResetForNextRetrieve(&pSql->res);
+      tscQueueAsyncRes(pParentSql);
+      return;
+    }
 
-        // set the callback function
-        pSql->fp = tscJoinQueryCallback;
-        tscProcessSql(pSql);
-        return;
-      }
+    pSupporter->pIdTagList = tmp;
 
-      int32_t numOfTotal = pSupporter->pState->numOfTotal;
-      int32_t finished = atomic_add_fetch_32(&pSupporter->pState->numOfCompleted, 1);
-      if (finished < numOfTotal) {
-        return;
-      }
+    memcpy(pSupporter->pIdTagList + pSupporter->totalLen, pRes->data, validLen);
+    pSupporter->totalLen += validLen;
+    pSupporter->num += pRes->numOfRows;
 
-      // all subquery are returned, start to compare the tags
-      assert(finished == numOfTotal);
+    // query not completed, continue to retrieve tid + tag tuples
+    if (!pRes->completed) {
+      taos_fetch_rows_a(tres, tidTagRetrieveCallback, param);
+      return;
+    }
+  }
 
-      SArray *s1 = NULL, *s2 = NULL;
-      getIntersectionOfTagVal(pQueryInfo, pParentSql, &s1, &s2);
+  // data in current vnode has all returned to client, try next vnode if exits
+  // <tid + tag> tuples have been retrieved to client, try <tid + tag> tuples from the next vnode
+  if (hasMoreVnodesToTry(pSql)) {
+    STableMetaInfo* pTableMetaInfo = tscGetMetaInfo(pQueryInfo, 0);
 
-      if (taosArrayGetSize(s1) == 0 || taosArrayGetSize(s2) == 0) {  // no results,return.
-        tscTrace("%p free all sub SqlObj and quit", pParentSql);
-        freeJoinSubqueryObj(pParentSql);
-        return;
-      } else {
-        SSqlCmd* pSubCmd1 = &pParentSql->pSubs[0]->cmd;
-        SSqlCmd* pSubCmd2 = &pParentSql->pSubs[1]->cmd;
+    int32_t totalVgroups = pTableMetaInfo->vgroupList->numOfVgroups;
+    pTableMetaInfo->vgroupIndex += 1;
+    assert(pTableMetaInfo->vgroupIndex < totalVgroups);
 
-        SQueryInfo*     pQueryInfo1 = tscGetQueryInfoDetail(pSubCmd1, 0);
-        STableMetaInfo* pTableMetaInfo1 = tscGetMetaInfo(pQueryInfo1, 0);
-        tscBuildVgroupTableInfo(pParentSql, pTableMetaInfo1, s1);
+    tscTrace("%p tid_tag from vgroup index:%d completed, try next vgroup:%d. total vgroups:%d. current numOfRes:%d",
+             pSql, pTableMetaInfo->vgroupIndex - 1, pTableMetaInfo->vgroupIndex, totalVgroups, pSupporter->num);
 
-        SQueryInfo*     pQueryInfo2 = tscGetQueryInfoDetail(pSubCmd2, 0);
-        STableMetaInfo* pTableMetaInfo2 = tscGetMetaInfo(pQueryInfo2, 0);
-        tscBuildVgroupTableInfo(pParentSql, pTableMetaInfo2, s2);
+    pCmd->command = TSDB_SQL_SELECT;
+    tscResetForNextRetrieve(&pSql->res);
 
-        pSupporter->pState->numOfCompleted = 0;
-        pSupporter->pState->code = 0;
-        pSupporter->pState->numOfTotal = 2;
+    // set the callback function
+    pSql->fp = tscJoinQueryCallback;
+    tscProcessSql(pSql);
+    return;
+  }
 
-        for (int32_t m = 0; m < pParentSql->numOfSubs; ++m) {
-          SSqlObj* psub = pParentSql->pSubs[m];
-          issueTSCompQuery(psub, psub->param, pParentSql);
-        }
-      }
+  // no data exists in next vnode, mark the <tid, tags> query completed
+  // only when there is no subquery exits any more, proceeds to get the intersect of the <tid, tags> tuple sets.
+  if (atomic_sub_fetch_32(&pSupporter->pState->numOfRemain, 1) > 0) {
+    return;
+  }
 
-    } else {
-      if (numOfRows < 0) {  // error
-        pSupporter->pState->code = numOfRows;
-        quitAllSubquery(pParentSql, pSupporter);
+  SArray *s1 = NULL, *s2 = NULL;
+  getIntersectionOfTableTuple(pQueryInfo, pParentSql, &s1, &s2);
+  if (taosArrayGetSize(s1) == 0 || taosArrayGetSize(s2) == 0) {  // no results,return.
+    tscTrace("%p free all sub SqlObj and quit", pParentSql);
+    freeJoinSubqueryObj(pParentSql);
+    return;
+  }
 
-        pParentSql->res.code = numOfRows;
-        tscQueueAsyncRes(pParentSql);
-        return;
-      }
+  // proceed to for ts_comp query
+  SSqlCmd* pSubCmd1 = &pParentSql->pSubs[0]->cmd;
+  SSqlCmd* pSubCmd2 = &pParentSql->pSubs[1]->cmd;
 
-      size_t length = pSupporter->totalLen + pRes->rspLen;
-      assert(length > 0);
+  SQueryInfo*     pQueryInfo1 = tscGetQueryInfoDetail(pSubCmd1, 0);
+  STableMetaInfo* pTableMetaInfo1 = tscGetMetaInfo(pQueryInfo1, 0);
+  tscBuildVgroupTableInfo(pParentSql, pTableMetaInfo1, s1);
 
-      char* tmp = realloc(pSupporter->pIdTagList, length);
-      assert(tmp != NULL);
+  SQueryInfo*     pQueryInfo2 = tscGetQueryInfoDetail(pSubCmd2, 0);
+  STableMetaInfo* pTableMetaInfo2 = tscGetMetaInfo(pQueryInfo2, 0);
+  tscBuildVgroupTableInfo(pParentSql, pTableMetaInfo2, s2);
 
-      pSupporter->pIdTagList = tmp;
+  pSupporter->pState->numOfTotal = 2;
+  pSupporter->pState->numOfRemain = pSupporter->pState->numOfTotal;
 
-      memcpy(pSupporter->pIdTagList, pRes->data, pRes->rspLen);
-      pSupporter->totalLen += pRes->rspLen;
-      pSupporter->num += pRes->numOfRows;
+  for (int32_t m = 0; m < pParentSql->numOfSubs; ++m) {
+    SSqlObj* sub = pParentSql->pSubs[m];
+    issueTSCompQuery(sub, sub->param, pParentSql);
+  }
+}
 
-      // continue retrieve data from vnode
-      taos_fetch_rows_a(tres, joinRetrieveCallback, param);
-    }
+static void tsCompRetrieveCallback(void* param, TAOS_RES* tres, int32_t numOfRows) {
+  SJoinSupporter* pSupporter = (SJoinSupporter*)param;
 
+  SSqlObj* pParentSql = pSupporter->pObj;
+
+  SSqlObj* pSql = (SSqlObj*)tres;
+  SSqlCmd* pCmd = &pSql->cmd;
+  SSqlRes* pRes = &pSql->res;
+
+  SQueryInfo* pQueryInfo = tscGetQueryInfoDetail(pCmd, pCmd->clauseIndex);
+  assert(!TSDB_QUERY_HAS_TYPE(pQueryInfo->type, TSDB_QUERY_TYPE_JOIN_SEC_STAGE));
+
+  // check for the error code firstly
+  if (taos_errno(pSql) != TSDB_CODE_SUCCESS) {
+    // todo retry if other subqueries are not failed yet 
+    assert(numOfRows < 0 && numOfRows == taos_errno(pSql));
+    tscError("%p sub query failed, code:%s, index:%d", pSql, tstrerror(numOfRows), pSupporter->subqueryIndex);
+
+    pParentSql->res.code = numOfRows;
+    quitAllSubquery(pParentSql, pSupporter);
+
+    tscQueueAsyncRes(pParentSql);
     return;
   }
 
-  if (!TSDB_QUERY_HAS_TYPE(pQueryInfo->type, TSDB_QUERY_TYPE_JOIN_SEC_STAGE)) {
-    if (numOfRows < 0) {
-      tscError("%p sub query failed, code:%s, index:%d", pSql, tstrerror(numOfRows), pSupporter->subqueryIndex);
-      pSupporter->pState->code = numOfRows;
-      quitAllSubquery(pParentSql, pSupporter);
+  if (numOfRows > 0) {  // write the compressed timestamp to disk file
+    fwrite(pRes->data, pRes->numOfRows, 1, pSupporter->f);
+    fclose(pSupporter->f);
+    pSupporter->f = NULL;
+
+    STSBuf* pBuf = tsBufCreateFromFile(pSupporter->path, true);
+    if (pBuf == NULL) {  // in error process, close the fd
+      tscError("%p invalid ts comp file from vnode, abort subquery, file size:%d", pSql, numOfRows);
+
+      pParentSql->res.code = TAOS_SYSTEM_ERROR(errno);
+      tscQueueAsyncRes(pParentSql);
+
       return;
     }
 
-    if (numOfRows > 0) { // write the compressed timestamp to disk file
-      fwrite(pRes->data, pRes->numOfRows, 1, pSupporter->f);
-      fclose(pSupporter->f);
-      pSupporter->f = NULL;
-
-      STSBuf* pBuf = tsBufCreateFromFile(pSupporter->path, true);
-      if (pBuf == NULL) {  // in error process, close the fd
-        tscError("%p invalid ts comp file from vnode, abort subquery, file size:%d", pSql, numOfRows);
+    if (pSupporter->pTSBuf == NULL) {
+      tscTrace("%p create tmp file for ts block:%s, size:%d bytes", pSql, pBuf->path, numOfRows);
+      pSupporter->pTSBuf = pBuf;
+    } else {
+      assert(pQueryInfo->numOfTables == 1);  // for subquery, only one
+      STableMetaInfo* pTableMetaInfo = tscGetMetaInfo(pQueryInfo, 0);
 
-        pSupporter->pState->code = TSDB_CODE_TSC_APP_ERROR;  // todo set the informative code
-        quitAllSubquery(pParentSql, pSupporter);
-        return;
-      }
+      tsBufMerge(pSupporter->pTSBuf, pBuf, pTableMetaInfo->vgroupIndex);
+      tsBufDestory(pBuf);
+    }
 
-      if (pSupporter->pTSBuf == NULL) {
-        tscTrace("%p create tmp file for ts block:%s, size:%d bytes", pSql, pBuf->path, numOfRows);
-        pSupporter->pTSBuf = pBuf;
-      } else {
-        assert(pQueryInfo->numOfTables == 1);  // for subquery, only one
-        STableMetaInfo* pTableMetaInfo = tscGetMetaInfo(pQueryInfo, 0);
+    // continue to retrieve ts-comp data from vnode
+    if (!pRes->completed) {
+      getTmpfilePath("ts-join", pSupporter->path);
+      pSupporter->f = fopen(pSupporter->path, "w");
+      pRes->row = pRes->numOfRows;
 
-        tsBufMerge(pSupporter->pTSBuf, pBuf, pTableMetaInfo->vgroupIndex);
-        tsBufDestory(pBuf);
-      }
+      taos_fetch_rows_a(tres, tsCompRetrieveCallback, param);
+      return;
     }
+  }
 
-    if (pRes->completed) {
-      if (hasMoreVnodesToTry(pSql)) {
-        STableMetaInfo* pTableMetaInfo = tscGetMetaInfo(pQueryInfo, 0);
+  if (hasMoreVnodesToTry(pSql)) {
+    STableMetaInfo* pTableMetaInfo = tscGetMetaInfo(pQueryInfo, 0);
 
-        int32_t totalVgroups = pTableMetaInfo->vgroupList->numOfVgroups;
-        pTableMetaInfo->vgroupIndex += 1;
-        assert(pTableMetaInfo->vgroupIndex < totalVgroups);
+    int32_t totalVgroups = pTableMetaInfo->vgroupList->numOfVgroups;
+    pTableMetaInfo->vgroupIndex += 1;
+    assert(pTableMetaInfo->vgroupIndex < totalVgroups);
 
-        tscTrace("%p results from vgroup index:%d completed, try next vgroup:%d. total vgroups:%d. current numOfRes:%d",
-                 pSql, pTableMetaInfo->vgroupIndex - 1, pTableMetaInfo->vgroupIndex, totalVgroups,
-                 pRes->numOfClauseTotal);
+    tscTrace("%p results from vgroup index:%d completed, try next vgroup:%d. total vgroups:%d. current numOfRes:%d",
+             pSql, pTableMetaInfo->vgroupIndex - 1, pTableMetaInfo->vgroupIndex, totalVgroups,
+             pRes->numOfClauseTotal);
 
-        pCmd->command = TSDB_SQL_SELECT;
-        tscResetForNextRetrieve(&pSql->res);
+    pCmd->command = TSDB_SQL_SELECT;
+    tscResetForNextRetrieve(&pSql->res);
 
-        assert(pSupporter->f == NULL);
-        getTmpfilePath("ts-join", pSupporter->path);
-        pSupporter->f = fopen(pSupporter->path, "w");
-        pRes->row = pRes->numOfRows;
+    assert(pSupporter->f == NULL);
+    getTmpfilePath("ts-join", pSupporter->path);
+    
+    // TODO check for failure
+    pSupporter->f = fopen(pSupporter->path, "w");
+    pRes->row = pRes->numOfRows;
 
-        // set the callback function
-        pSql->fp = tscJoinQueryCallback;
-        tscProcessSql(pSql);
-        return;
-      } else {
-        tSIntersectionAndLaunchSecQuery(pSupporter, pSql);
-      }
+    // set the callback function
+    pSql->fp = tscJoinQueryCallback;
+    tscProcessSql(pSql);
+    return;
+  }
 
-    } else {  // open a new file to save the incoming result
-      getTmpfilePath("ts-join", pSupporter->path);
-      pSupporter->f = fopen(pSupporter->path, "w");
-      pRes->row = pRes->numOfRows;
+  if (atomic_sub_fetch_32(&pSupporter->pState->numOfRemain, 1) > 0) {
+    return;
+  }
 
-      taos_fetch_rows_a(tres, joinRetrieveCallback, param);
-    }
-  } else {  // secondary stage retrieve, driven by taos_fetch_row or other functions
-    if (numOfRows < 0) {
-      pSupporter->pState->code = numOfRows;
-      tscError("%p retrieve failed, code:%s, index:%d", pSql, tstrerror(numOfRows), pSupporter->subqueryIndex);
-    }
+  tscTrace("%p all subquery retrieve ts complete, do ts block intersect", pParentSql);
 
-    if (numOfRows >= 0) {
-      pRes->numOfTotal += pRes->numOfRows;
-    }
+  // proceeds to launched secondary query to retrieve final data
+  SJoinSupporter* p1 = pParentSql->pSubs[0]->param;
+  SJoinSupporter* p2 = pParentSql->pSubs[1]->param;
 
-    if (tscNonOrderedProjectionQueryOnSTable(pQueryInfo, 0) && numOfRows == 0) {
-      STableMetaInfo* pTableMetaInfo = tscGetMetaInfo(pQueryInfo, 0);
-      assert(pQueryInfo->numOfTables == 1);
+  STimeWindow win = TSWINDOW_INITIALIZER;
+  int64_t num = doTSBlockIntersect(pParentSql, p1, p2, &win);
+  if (num <= 0) {  // no result during ts intersect
+    tscTrace("%p no results generated in ts intersection, free all sub SqlObj and quit", pParentSql);
+    freeJoinSubqueryObj(pParentSql);
+    
+    return;
+  }
+
+  // launch the query the retrieve actual results from vnode along with the filtered timestamp
+  SQueryInfo* pPQueryInfo = tscGetQueryInfoDetail(&pParentSql->cmd, pParentSql->cmd.clauseIndex);
+  updateQueryTimeRange(pPQueryInfo, &win);
+  tscLaunchSecondPhaseSubqueries(pParentSql);
+}
 
-      // for projection query, need to try next vnode if current vnode is exhausted
-      if ((++pTableMetaInfo->vgroupIndex) < pTableMetaInfo->vgroupList->numOfVgroups) {
-        pSupporter->pState->numOfCompleted = 0;
-        pSupporter->pState->numOfTotal = 1;
+static void joinRetrieveFinalResCallback(void* param, TAOS_RES* tres, int numOfRows) {
+  SJoinSupporter* pSupporter = (SJoinSupporter*)param;
 
-        pSql->cmd.command = TSDB_SQL_SELECT;
-        pSql->fp = tscJoinQueryCallback;
-        tscProcessSql(pSql);
+  SSqlObj* pParentSql = pSupporter->pObj;
+  SSubqueryState* pState = pSupporter->pState;
 
-        return;
-      }
-    }
+  SSqlObj* pSql = (SSqlObj*)tres;
+  SSqlCmd* pCmd = &pSql->cmd;
+  SSqlRes* pRes = &pSql->res;
 
-    int32_t numOfTotal = pSupporter->pState->numOfTotal;
-    int32_t finished = atomic_add_fetch_32(&pSupporter->pState->numOfCompleted, 1);
+  SQueryInfo* pQueryInfo = tscGetQueryInfoDetail(pCmd, pCmd->clauseIndex);
 
-    if (finished >= numOfTotal) {
-      assert(finished == numOfTotal);
-      tscTrace("%p all %d secondary subquery retrieves completed, global code:%d", tres, numOfTotal,
-               pParentSql->res.code);
+  // TODO put to async res?
+  if (taos_errno(pSql) != TSDB_CODE_SUCCESS) {
+    assert(numOfRows == taos_errno(pSql));
 
-      if (pSupporter->pState->code != TSDB_CODE_SUCCESS) {
-        pParentSql->res.code = pSupporter->pState->code;
-        freeJoinSubqueryObj(pParentSql);
-        pParentSql->res.completed = true;
-      }
+    pParentSql->res.code = numOfRows;
+    tscError("%p retrieve failed, index:%d, code:%s", pSql, pSupporter->subqueryIndex, tstrerror(numOfRows));
+  }
 
-      // update the records for each subquery in parent sql object.
-      for (int32_t i = 0; i < pParentSql->numOfSubs; ++i) {
-        if (pParentSql->pSubs[i] == NULL) {
-          continue;
-        }
+  if (numOfRows >= 0) {
+    pRes->numOfTotal += pRes->numOfRows;
+  }
 
-        SSqlRes* pRes1 = &pParentSql->pSubs[i]->res;
-        pRes1->numOfClauseTotal += pRes1->numOfRows;
-      }
+  if (tscNonOrderedProjectionQueryOnSTable(pQueryInfo, 0) && numOfRows == 0) {
+    STableMetaInfo* pTableMetaInfo = tscGetMetaInfo(pQueryInfo, 0);
+    assert(pQueryInfo->numOfTables == 1);
 
-      // data has retrieved to client, build the join results
-      tscBuildResFromSubqueries(pParentSql);
-    } else {
-      tscTrace("%p sub:%p completed, completed:%d, total:%d", pParentSql, tres, finished, numOfTotal);
+    // for projection query, need to try next vnode if current vnode is exhausted
+    if ((++pTableMetaInfo->vgroupIndex) < pTableMetaInfo->vgroupList->numOfVgroups) {
+      pState->numOfRemain = 1;
+      pState->numOfTotal = 1;
+
+      pSql->cmd.command = TSDB_SQL_SELECT;
+      pSql->fp = tscJoinQueryCallback;
+      tscProcessSql(pSql);
+
+      return;
+    }
+  }
+
+  if (atomic_sub_fetch_32(&pState->numOfRemain, 1) > 0) {
+    tscTrace("%p sub:%p completed, remain:%d, total:%d", pParentSql, tres, pState->numOfRemain, pState->numOfTotal);
+    return;
+  }
+
+  tscTrace("%p all %d secondary subqueries retrieval completed, code:%d", tres, pState->numOfTotal, pParentSql->res.code);
+
+  if (pParentSql->res.code != TSDB_CODE_SUCCESS) {
+    freeJoinSubqueryObj(pParentSql);
+    pParentSql->res.completed = true;
+  }
+
+  // update the records for each subquery in parent sql object.
+  for (int32_t i = 0; i < pParentSql->numOfSubs; ++i) {
+    if (pParentSql->pSubs[i] == NULL) {
+      continue;
     }
+
+    SSqlRes* pRes1 = &pParentSql->pSubs[i]->res;
+    pRes1->numOfClauseTotal += pRes1->numOfRows;
   }
+
+  // data has retrieved to client, build the join results
+  tscBuildResFromSubqueries(pParentSql);
 }
 
 static SJoinSupporter* tscUpdateSubqueryStatus(SSqlObj* pSql, int32_t numOfFetch) {
@@ -902,7 +933,7 @@ static SJoinSupporter* tscUpdateSubqueryStatus(SSqlObj* pSql, int32_t numOfFetch
   }
   
   pState->numOfTotal = pSql->numOfSubs;
-  pState->numOfCompleted = pSql->numOfSubs - numOfFetch;
+  pState->numOfRemain = numOfFetch;
   
   return pSupporter;
 }
@@ -990,7 +1021,7 @@ void tscFetchDatablockFromSubquery(SSqlObj* pSql) {
                pSupporter->subqueryIndex, pTableMetaInfo->vgroupIndex);
 
       tscResetForNextRetrieve(pRes1);
-      pSql1->fp = joinRetrieveCallback;
+      pSql1->fp = joinRetrieveFinalResCallback;
 
       if (pCmd1->command < TSDB_SQL_LOCAL) {
         pCmd1->command = (pCmd1->command > TSDB_SQL_MGMT) ? TSDB_SQL_RETRIEVE : TSDB_SQL_FETCH;
@@ -1008,8 +1039,9 @@ void tscSetupOutputColumnIndex(SSqlObj* pSql) {
 
   tscTrace("%p all subquery response, retrieve data", pSql);
 
+  // the column transfer support struct has been built
   if (pRes->pColumnIndex != NULL) {
-    return;  // the column transfer support struct has been built
+    return;
   }
 
   SQueryInfo* pQueryInfo = tscGetQueryInfoDetail(pCmd, pCmd->clauseIndex);
@@ -1045,68 +1077,76 @@ void tscSetupOutputColumnIndex(SSqlObj* pSql) {
 
 void tscJoinQueryCallback(void* param, TAOS_RES* tres, int code) {
   SSqlObj* pSql = (SSqlObj*)tres;
-  
+
   SJoinSupporter* pSupporter = (SJoinSupporter*)param;
-  
+  SSqlObj* pParentSql = pSupporter->pObj;
+
   // There is only one subquery and table for each subquery.
   SQueryInfo* pQueryInfo = tscGetQueryInfoDetail(&pSql->cmd, 0);
   assert(pQueryInfo->numOfTables == 1 && pSql->cmd.numOfClause == 1);
-  
-  if (!TSDB_QUERY_HAS_TYPE(pQueryInfo->type, TSDB_QUERY_TYPE_JOIN_SEC_STAGE)) {
-    if (code != TSDB_CODE_SUCCESS) {  // direct call joinRetrieveCallback and set the error code
-      joinRetrieveCallback(param, pSql, code);
-    } else {  // first stage query, continue to retrieve compressed time stamp data
-      pSql->fp = joinRetrieveCallback;
-      pSql->cmd.command = TSDB_SQL_FETCH;
-      tscProcessSql(pSql);
-    }
 
-  } else {  // second stage join subquery
-    SSqlObj* pParentSql = pSupporter->pObj;
+  // retrieve actual query results from vnode during the second stage join subquery
+  if (pParentSql->res.code != TSDB_CODE_SUCCESS) {
+    tscError("%p abort query due to other subquery failure. code:%d, global code:%d", pSql, code, pParentSql->res.code);
+    quitAllSubquery(pParentSql, pSupporter);
+    tscQueueAsyncRes(pParentSql);
 
-    if (pSupporter->pState->code != TSDB_CODE_SUCCESS) {
-      tscError("%p abort query due to other subquery failure. code:%d, global code:%d", pSql, code,
-               pSupporter->pState->code);
-      quitAllSubquery(pParentSql, pSupporter);
+    return;
+  }
 
-      return;
-    }
+  // TODO here retry is required, not directly returns to client
+  if (taos_errno(pSql) != TSDB_CODE_SUCCESS) {
+    assert(taos_errno(pSql) == code);
 
-    if (code != TSDB_CODE_SUCCESS) {
-      tscError("%p sub query failed, code:%s, set global code:%s, index:%d", pSql, tstrerror(code), tstrerror(code),
-               pSupporter->subqueryIndex);
-      
-      pSupporter->pState->code = code;
-      quitAllSubquery(pParentSql, pSupporter);
+    tscError("%p abort query, code:%d, global code:%d", pSql, code, pParentSql->res.code);
+    pParentSql->res.code = code;
+
+    quitAllSubquery(pParentSql, pSupporter);
+    tscQueueAsyncRes(pParentSql);
+
+    return;
+  }
+
+  // retrieve <tid, tag> tuples from vnode
+  if (TSDB_QUERY_HAS_TYPE(pQueryInfo->type, TSDB_QUERY_TYPE_TAG_FILTER_QUERY)) {
+    pSql->fp = tidTagRetrieveCallback;
+    pSql->cmd.command = TSDB_SQL_FETCH;
+    tscProcessSql(pSql);
+    return;
+  }
+
+  // retrieve ts_comp info from vnode
+  if (!TSDB_QUERY_HAS_TYPE(pQueryInfo->type, TSDB_QUERY_TYPE_JOIN_SEC_STAGE)) {
+    pSql->fp = tsCompRetrieveCallback;
+    pSql->cmd.command = TSDB_SQL_FETCH;
+    tscProcessSql(pSql);
+    return;
+  }
+
+  // wait for the other subqueries response from vnode
+  if (atomic_sub_fetch_32(&pSupporter->pState->numOfRemain, 1) > 0) {
+    return;
+  }
+
+  tscSetupOutputColumnIndex(pParentSql);
+  STableMetaInfo* pTableMetaInfo = tscGetMetaInfo(pQueryInfo, 0);
+
+  /**
+   * if the query is a continue query (vgroupIndex > 0 for projection query) for next vnode, do the retrieval of
+   * data instead of returning to its invoker
+   */
+  if (pTableMetaInfo->vgroupIndex > 0 && tscNonOrderedProjectionQueryOnSTable(pQueryInfo, 0)) {
+    pSupporter->pState->numOfRemain = pSupporter->pState->numOfTotal;  // reset the record value
+
+    pSql->fp = joinRetrieveFinalResCallback;  // continue retrieve data
+    pSql->cmd.command = TSDB_SQL_FETCH;
+    tscProcessSql(pSql);
+  } else {  // first retrieve from vnode during the secondary stage sub-query
+    // set the command flag must be after the semaphore been correctly set.
+    if (pParentSql->res.code == TSDB_CODE_SUCCESS) {
+      (*pParentSql->fp)(pParentSql->param, pParentSql, 0);
     } else {
-      int32_t numOfTotal = pSupporter->pState->numOfTotal;
-      int32_t finished = atomic_add_fetch_32(&pSupporter->pState->numOfCompleted, 1);
-      
-      if (finished >= numOfTotal) {
-        assert(finished == numOfTotal);
-        
-        tscSetupOutputColumnIndex(pParentSql);
-        STableMetaInfo* pTableMetaInfo = tscGetMetaInfo(pQueryInfo, 0);
-
-        /**
-         * if the query is a continue query (vgroupIndex > 0 for projection query) for next vnode, do the retrieval of
-         * data instead of returning to its invoker
-         */
-        if (pTableMetaInfo->vgroupIndex > 0 && tscNonOrderedProjectionQueryOnSTable(pQueryInfo, 0)) {
-          pSupporter->pState->numOfCompleted = 0;  // reset the record value
-
-          pSql->fp = joinRetrieveCallback;  // continue retrieve data
-          pSql->cmd.command = TSDB_SQL_FETCH;
-          tscProcessSql(pSql);
-        } else {  // first retrieve from vnode during the secondary stage sub-query
-          // set the command flag must be after the semaphore been correctly set.
-          if (pParentSql->res.code == TSDB_CODE_SUCCESS) {
-            (*pParentSql->fp)(pParentSql->param, pParentSql, 0);
-          } else {
-            tscQueueAsyncRes(pParentSql);
-          }
-        }
-      }
+      tscQueueAsyncRes(pParentSql);
     }
   }
 }
@@ -1257,14 +1297,15 @@ int32_t tscHandleMasterJoinQuery(SSqlObj* pSql) {
   
   SSubqueryState *pState = calloc(1, sizeof(SSubqueryState));
   pState->numOfTotal = pQueryInfo->numOfTables;
-  
+  pState->numOfRemain = pState->numOfTotal;
+
   tscTrace("%p start launch subquery, total:%d", pSql, pQueryInfo->numOfTables);
   for (int32_t i = 0; i < pQueryInfo->numOfTables; ++i) {
     SJoinSupporter *pSupporter = tscCreateJoinSupporter(pSql, pState, i);
     
     if (pSupporter == NULL) {  // failed to create support struct, abort current query
       tscError("%p tableIndex:%d, failed to allocate join support object, abort further query", pSql, i);
-      pState->numOfCompleted = pQueryInfo->numOfTables - i - 1;
+      pState->numOfRemain = i;
       pSql->res.code = TSDB_CODE_TSC_OUT_OF_MEMORY;
       
       return pSql->res.code;
@@ -1342,6 +1383,8 @@ int32_t tscHandleMasterSTableQuery(SSqlObj *pSql) {
   tscTrace("%p retrieved query data from %d vnode(s)", pSql, pSql->numOfSubs);
   SSubqueryState *pState = calloc(1, sizeof(SSubqueryState));
   pState->numOfTotal = pSql->numOfSubs;
+  pState->numOfRemain = pSql->numOfSubs;
+
   pRes->code = TSDB_CODE_SUCCESS;
   
   int32_t i = 0;
@@ -1436,7 +1479,7 @@ static void tscFreeSubSqlObj(SRetrieveSupport *trsupport, SSqlObj *pSql) {
 static void tscRetrieveFromDnodeCallBack(void *param, TAOS_RES *tres, int numOfRows);
 static void tscHandleSubqueryError(SRetrieveSupport *trsupport, SSqlObj *pSql, int numOfRows);
 
-static void tscAbortFurtherRetryRetrieval(SRetrieveSupport *trsupport, TAOS_RES *tres, int32_t errCode) {
+static void tscAbortFurtherRetryRetrieval(SRetrieveSupport *trsupport, TAOS_RES *tres, int32_t code) {
 // set no disk space error info
 #ifdef WINDOWS
   LPVOID lpMsgBuf;
@@ -1448,44 +1491,44 @@ static void tscAbortFurtherRetryRetrieval(SRetrieveSupport *trsupport, TAOS_RES
 #else
   tscError("sub:%p failed to flush data to disk:reason:%s", tres, strerror(errno));
 #endif
-  
-  trsupport->pState->code = -errCode;
+
+  SSqlObj* pParentSql = trsupport->pParentSqlObj;
+
+  pParentSql->res.code = code;
   trsupport->numOfRetry = MAX_NUM_OF_SUBQUERY_RETRY;
   
   pthread_mutex_unlock(&trsupport->queryMutex);
   
-  tscHandleSubqueryError(trsupport, tres, trsupport->pState->code);
+  tscHandleSubqueryError(trsupport, tres, pParentSql->res.code);
 }
 
 void tscHandleSubqueryError(SRetrieveSupport *trsupport, SSqlObj *pSql, int numOfRows) {
-  SSqlObj *pPObj = trsupport->pParentSqlObj;
+  SSqlObj *pParentSql = trsupport->pParentSqlObj;
   int32_t  subqueryIndex = trsupport->subqueryIndex;
   
   assert(pSql != NULL);
   SSubqueryState* pState = trsupport->pState;
-  assert(pState->numOfCompleted < pState->numOfTotal && pState->numOfCompleted >= 0 &&
-      pPObj->numOfSubs == pState->numOfTotal);
+  assert(pState->numOfRemain <= pState->numOfTotal && pState->numOfRemain >= 0 && pParentSql->numOfSubs == pState->numOfTotal);
   
   // retrieved in subquery failed. OR query cancelled in retrieve phase.
-  if (pState->code == TSDB_CODE_SUCCESS && pPObj->res.code != TSDB_CODE_SUCCESS) {
-    pState->code = pPObj->res.code;
-    
+  if (taos_errno(pSql) == TSDB_CODE_SUCCESS && pParentSql->res.code != TSDB_CODE_SUCCESS) {
+
     /*
      * kill current sub-query connection, which may retrieve data from vnodes;
      * Here we get: pPObj->res.code == TSDB_CODE_TSC_QUERY_CANCELLED
      */
     pSql->res.numOfRows = 0;
     trsupport->numOfRetry = MAX_NUM_OF_SUBQUERY_RETRY;  // disable retry efforts
-    tscTrace("%p query is cancelled, sub:%p, orderOfSub:%d abort retrieve, code:%d", trsupport->pParentSqlObj, pSql,
-             subqueryIndex, pState->code);
+    tscTrace("%p query is cancelled, sub:%p, orderOfSub:%d abort retrieve, code:%d", pParentSql, pSql,
+             subqueryIndex, pParentSql->res.code);
   }
   
   if (numOfRows >= 0) {  // current query is successful, but other sub query failed, still abort current query.
-    tscTrace("%p sub:%p retrieve numOfRows:%d,orderOfSub:%d", pPObj, pSql, numOfRows, subqueryIndex);
-    tscError("%p sub:%p abort further retrieval due to other queries failure,orderOfSub:%d,code:%d", pPObj, pSql,
-             subqueryIndex, pState->code);
+    tscTrace("%p sub:%p retrieve numOfRows:%d,orderOfSub:%d", pParentSql, pSql, numOfRows, subqueryIndex);
+    tscError("%p sub:%p abort further retrieval due to other queries failure,orderOfSub:%d,code:%d", pParentSql, pSql,
+             subqueryIndex, pParentSql->res.code);
   } else {
-    if (trsupport->numOfRetry++ < MAX_NUM_OF_SUBQUERY_RETRY && pState->code == TSDB_CODE_SUCCESS) {
+    if (trsupport->numOfRetry++ < MAX_NUM_OF_SUBQUERY_RETRY && pParentSql->res.code == TSDB_CODE_SUCCESS) {
       /*
        * current query failed, and the retry count is less than the available
        * count, retry query clear previous retrieved data, then launch a new sub query
@@ -1503,8 +1546,8 @@ void tscHandleSubqueryError(SRetrieveSupport *trsupport, SSqlObj *pSql, int numO
       if (pNew == NULL) {
         tscError("%p sub:%p failed to create new subquery sqlObj due to out of memory, abort retry",
                  trsupport->pParentSqlObj, pSql);
-        
-        pState->code = TSDB_CODE_TSC_OUT_OF_MEMORY;
+
+        pParentSql->res.code = TSDB_CODE_TSC_OUT_OF_MEMORY;
         trsupport->numOfRetry = MAX_NUM_OF_SUBQUERY_RETRY;
         return;
       }
@@ -1512,24 +1555,24 @@ void tscHandleSubqueryError(SRetrieveSupport *trsupport, SSqlObj *pSql, int numO
       tscProcessSql(pNew);
       return;
     } else {  // reach the maximum retry count, abort
-      atomic_val_compare_exchange_32(&pState->code, TSDB_CODE_SUCCESS, numOfRows);
-      tscError("%p sub:%p retrieve failed,code:%s,orderOfSub:%d failed.no more retry,set global code:%s", pPObj, pSql,
-               tstrerror(numOfRows), subqueryIndex, tstrerror(pState->code));
+      atomic_val_compare_exchange_32(&pParentSql->res.code, TSDB_CODE_SUCCESS, numOfRows);
+      tscError("%p sub:%p retrieve failed,code:%s,orderOfSub:%d failed.no more retry,set global code:%s", pParentSql, pSql,
+               tstrerror(numOfRows), subqueryIndex, tstrerror(pParentSql->res.code));
     }
   }
-  
-  int32_t numOfTotal = pState->numOfTotal;
-  
-  int32_t finished = atomic_add_fetch_32(&pState->numOfCompleted, 1);
-  if (finished < numOfTotal) {
-    tscTrace("%p sub:%p orderOfSub:%d freed, finished subqueries:%d", pPObj, pSql, trsupport->subqueryIndex, finished);
+
+  int32_t remain = -1;
+  if ((remain = atomic_sub_fetch_32(&pState->numOfRemain, 1)) > 0) {
+    tscTrace("%p sub:%p orderOfSub:%d freed, finished subqueries:%d", pParentSql, pSql, trsupport->subqueryIndex,
+        pState->numOfTotal - remain);
+
     return tscFreeSubSqlObj(trsupport, pSql);
   }
   
   // all subqueries are failed
-  tscError("%p retrieve from %d vnode(s) completed,code:%s.FAILED.", pPObj, pState->numOfTotal, tstrerror(pState->code));
-  pPObj->res.code = pState->code;
-  
+  tscError("%p retrieve from %d vnode(s) completed,code:%s.FAILED.", pParentSql, pState->numOfTotal,
+      tstrerror(pParentSql->res.code));
+
   // release allocated resource
   tscLocalReducerEnvDestroy(trsupport->pExtMemBuffer, trsupport->pOrderDescriptor, trsupport->pFinalColModel,
                             pState->numOfTotal);
@@ -1538,13 +1581,13 @@ void tscHandleSubqueryError(SRetrieveSupport *trsupport, SSqlObj *pSql, int numO
   tscFreeSubSqlObj(trsupport, pSql);
   
   // in case of second stage join subquery, invoke its callback function instead of regular QueueAsyncRes
-  SQueryInfo *pQueryInfo = tscGetQueryInfoDetail(&pPObj->cmd, 0);
+  SQueryInfo *pQueryInfo = tscGetQueryInfoDetail(&pParentSql->cmd, 0);
   
   if (!TSDB_QUERY_HAS_TYPE(pQueryInfo->type, TSDB_QUERY_TYPE_JOIN_SEC_STAGE)) {
-    (*pPObj->fp)(pPObj->param, pPObj, pPObj->res.code);
+    (*pParentSql->fp)(pParentSql->param, pParentSql, pParentSql->res.code);
   } else {  // regular super table query
-    if (pPObj->res.code != TSDB_CODE_SUCCESS) {
-      tscQueueAsyncRes(pPObj);
+    if (pParentSql->res.code != TSDB_CODE_SUCCESS) {
+      tscQueueAsyncRes(pParentSql);
     }
   }
 }
@@ -1590,14 +1633,11 @@ static void tscAllDataRetrievedFromDnode(SRetrieveSupport *trsupport, SSqlObj* p
     return tscAbortFurtherRetryRetrieval(trsupport, pSql, TSDB_CODE_TSC_NO_DISKSPACE);
   }
   
-  // keep this value local variable, since the pState variable may be released by other threads, if atomic_add opertion
-  // increases the finished value up to pState->numOfTotal value, which means all subqueries are completed.
-  // In this case, the comparsion between finished value and released pState->numOfTotal is not safe.
-  int32_t numOfTotal = pState->numOfTotal;
-  
-  int32_t finished = atomic_add_fetch_32(&pState->numOfCompleted, 1);
-  if (finished < numOfTotal) {
-    tscTrace("%p sub:%p orderOfSub:%d freed, finished subqueries:%d", pPObj, pSql, trsupport->subqueryIndex, finished);
+  int32_t remain = -1;
+  if ((remain = atomic_sub_fetch_32(&pState->numOfRemain, 1)) > 0) {
+    tscTrace("%p sub:%p orderOfSub:%d freed, finished subqueries:%d", pPObj, pSql, trsupport->subqueryIndex,
+        pState->numOfTotal - remain);
+
     return tscFreeSubSqlObj(trsupport, pSql);
   }
   
@@ -1632,10 +1672,10 @@ static void tscAllDataRetrievedFromDnode(SRetrieveSupport *trsupport, SSqlObj* p
 
 static void tscRetrieveFromDnodeCallBack(void *param, TAOS_RES *tres, int numOfRows) {
   SRetrieveSupport *trsupport = (SRetrieveSupport *)param;
-  int32_t           idx = trsupport->subqueryIndex;
-  SSqlObj *         pPObj = trsupport->pParentSqlObj;
   tOrderDescriptor *pDesc = trsupport->pOrderDescriptor;
-  
+  int32_t           idx   = trsupport->subqueryIndex;
+  SSqlObj *         pPObj = trsupport->pParentSqlObj;
+
   SSqlObj *pSql = (SSqlObj *)tres;
   if (pSql == NULL) {  // sql object has been released in error process, return immediately
     tscTrace("%p subquery has been released, idx:%d, abort", pPObj, idx);
@@ -1643,13 +1683,12 @@ static void tscRetrieveFromDnodeCallBack(void *param, TAOS_RES *tres, int numOfR
   }
   
   SSubqueryState* pState = trsupport->pState;
-  assert(pState->numOfCompleted < pState->numOfTotal && pState->numOfCompleted >= 0 &&
-      pPObj->numOfSubs == pState->numOfTotal);
+  assert(pState->numOfRemain <= pState->numOfTotal && pState->numOfRemain >= 0 && pPObj->numOfSubs == pState->numOfTotal);
   
   // query process and cancel query process may execute at the same time
   pthread_mutex_lock(&trsupport->queryMutex);
   
-  if (numOfRows < 0 || pState->code < 0 || pPObj->res.code != TSDB_CODE_SUCCESS) {
+  if (numOfRows < 0 || pPObj->res.code != TSDB_CODE_SUCCESS) {
     return tscHandleSubqueryError(trsupport, pSql, numOfRows);
   }
   
@@ -1738,18 +1777,16 @@ void tscRetrieveDataRes(void *param, TAOS_RES *tres, int code) {
   SCMVgroupInfo* pVgroup = &pTableMetaInfo->vgroupList->vgroups[0];
   
   SSubqueryState* pState = trsupport->pState;
-  assert(pState->numOfCompleted < pState->numOfTotal && pState->numOfCompleted >= 0 &&
-      pParentSql->numOfSubs == pState->numOfTotal);
-  
-  if (pParentSql->res.code != TSDB_CODE_SUCCESS || pState->code != TSDB_CODE_SUCCESS) {
+  assert(pState->numOfRemain <= pState->numOfTotal && pState->numOfRemain >= 0 && pParentSql->numOfSubs == pState->numOfTotal);
+
+  // todo set error code
+  if (pParentSql->res.code != TSDB_CODE_SUCCESS) {
     
     // stable query is killed, abort further retry
     trsupport->numOfRetry = MAX_NUM_OF_SUBQUERY_RETRY;
     
     if (pParentSql->res.code != TSDB_CODE_SUCCESS) {
       code = pParentSql->res.code;
-    } else {
-      code = pState->code;
     }
     
     tscTrace("%p query cancelled or failed, sub:%p, orderOfSub:%d abort, code:%s", pParentSql, pSql,
@@ -1766,7 +1803,7 @@ void tscRetrieveDataRes(void *param, TAOS_RES *tres, int code) {
   if (code != TSDB_CODE_SUCCESS) {
     if (trsupport->numOfRetry++ >= MAX_NUM_OF_SUBQUERY_RETRY) {
       tscTrace("%p sub:%p reach the max retry times, set global code:%s", pParentSql, pSql, tstrerror(code));
-      atomic_val_compare_exchange_32(&pState->code, 0, code);
+      atomic_val_compare_exchange_32(&pParentSql->res.code, TSDB_CODE_SUCCESS, code);
     } else {  // does not reach the maximum retry time, go on
       tscTrace("%p sub:%p failed code:%s, retry:%d", pParentSql, pSql, tstrerror(code), trsupport->numOfRetry);
       
@@ -1775,8 +1812,8 @@ void tscRetrieveDataRes(void *param, TAOS_RES *tres, int code) {
       if (pNew == NULL) {
         tscError("%p sub:%p failed to create new subquery due to out of memory, abort retry, vgId:%d, orderOfSub:%d",
                  trsupport->pParentSqlObj, pSql, pVgroup->vgId, trsupport->subqueryIndex);
-        
-        pState->code = TSDB_CODE_TSC_OUT_OF_MEMORY;
+
+        pParentSql->res.code = TSDB_CODE_TSC_OUT_OF_MEMORY;
         trsupport->numOfRetry = MAX_NUM_OF_SUBQUERY_RETRY;
       } else {
         SQueryInfo *pNewQueryInfo = tscGetQueryInfoDetail(&pNew->cmd, 0);
@@ -1789,11 +1826,11 @@ void tscRetrieveDataRes(void *param, TAOS_RES *tres, int code) {
     }
   }
   
-  if (pState->code != TSDB_CODE_SUCCESS) {  // at least one peer subquery failed, abort current query
+  if (pParentSql->res.code != TSDB_CODE_SUCCESS) {  // at least one peer subquery failed, abort current query
     tscTrace("%p sub:%p query failed,ip:%u,vgId:%d,orderOfSub:%d,global code:%d", pParentSql, pSql,
-               pVgroup->ipAddr[0].fqdn, pVgroup->vgId, trsupport->subqueryIndex, pState->code);
+               pVgroup->ipAddr[0].fqdn, pVgroup->vgId, trsupport->subqueryIndex, pParentSql->res.code);
   
-    tscHandleSubqueryError(param, tres, pState->code);
+    tscHandleSubqueryError(param, tres, pParentSql->res.code);
   } else {  // success, proceed to retrieve data from dnode
     tscTrace("%p sub:%p query complete, ip:%s, vgId:%d, orderOfSub:%d, retrieve data", trsupport->pParentSqlObj, pSql,
                pVgroup->ipAddr[0].fqdn, pVgroup->vgId, trsupport->subqueryIndex);
@@ -1813,8 +1850,7 @@ static void multiVnodeInsertMerge(void* param, TAOS_RES* tres, int numOfRows) {
   SSqlCmd* pParentCmd = &pParentObj->cmd;
   
   SSubqueryState* pState = pSupporter->pState;
-  int32_t total = pState->numOfTotal;
-  
+
   // increase the total inserted rows
   if (numOfRows > 0) {
     pParentObj->res.numOfRows += numOfRows;
@@ -1826,8 +1862,7 @@ static void multiVnodeInsertMerge(void* param, TAOS_RES* tres, int numOfRows) {
   }
   
   taos_free_result(tres);
-  int32_t completed = atomic_add_fetch_32(&pState->numOfCompleted, 1);
-  if (completed < total) {
+  if (atomic_sub_fetch_32(&pState->numOfRemain, 1) > 0) {
     return;
   }
   
@@ -2157,5 +2192,3 @@ static bool tscHasRemainDataInSubqueryResultSet(SSqlObj *pSql) {
   
   return hasData;
 }
-
-
diff --git a/src/query/src/qExecutor.c b/src/query/src/qExecutor.c
index bb6eaa68e5a0159c6e1cdeeec848af839e7d1bc2..eb62d6c61a25a41d227fb330eead6fe54eef002b 100644
--- a/src/query/src/qExecutor.c
+++ b/src/query/src/qExecutor.c
@@ -1216,7 +1216,6 @@ static int32_t tableApplyFunctionsOnBlock(SQueryRuntimeEnv *pRuntimeEnv, SDataBl
 
   // interval query with limit applied
   int32_t numOfRes = 0;
-  
   if (isIntervalQuery(pQuery)) {
     numOfRes = doCheckQueryCompleted(pRuntimeEnv, lastKey, pWindowResInfo);
   } else {
diff --git a/src/util/src/terror.c b/src/util/src/terror.c
index c040a11362a01175a126a7d954af4a945285061d..aa6925464e12a1863b8dc510d7389ed97267d142 100644
--- a/src/util/src/terror.c
+++ b/src/util/src/terror.c
@@ -15,7 +15,6 @@
 
 #include <stdint.h>
 #include <pthread.h>
-#include <errno.h>
 #include <stdlib.h>
 #include <string.h>