diff --git a/src/client/src/tscSubquery.c b/src/client/src/tscSubquery.c
index 902ff989c763af1c95d95753d47b4a41a08bd600..d58b44b92f2bf845a4a76ff5fb7ee329802d20ca 100644
--- a/src/client/src/tscSubquery.c
+++ b/src/client/src/tscSubquery.c
@@ -32,11 +32,15 @@ typedef struct SInsertSupporter {
 static void freeJoinSubqueryObj(SSqlObj* pSql);
 static bool tscHasRemainDataInSubqueryResultSet(SSqlObj *pSql);
 
-static bool tsCompare(int32_t order, int64_t left, int64_t right) {
+static int32_t tsCompare(int32_t order, int64_t left, int64_t right) {
+  if (left == right) {
+    return 0;
+  }
+
   if (order == TSDB_ORDER_ASC) {
-    return left < right;
+    return left < right? -1:1;
   } else {
-    return left > right;
+    return left > right? -1:1;
   }
 }
 
@@ -51,10 +55,10 @@ static int64_t doTSBlockIntersect(SSqlObj* pSql, SJoinSupporter* pSupporter1, SJ
 
   SLimitVal* pLimit = &pQueryInfo->limit;
   int32_t    order = pQueryInfo->order.order;
-  
+
   SQueryInfo* pSubQueryInfo1 = tscGetQueryInfoDetail(&pSql->pSubs[0]->cmd, 0);
   SQueryInfo* pSubQueryInfo2 = tscGetQueryInfoDetail(&pSql->pSubs[1]->cmd, 0);
-  
+
   pSubQueryInfo1->tsBuf = output1;
   pSubQueryInfo2->tsBuf = output2;
 
@@ -88,59 +92,106 @@ static int64_t doTSBlockIntersect(SSqlObj* pSql, SJoinSupporter* pSupporter1, SJ
   int64_t numOfInput1 = 1;
   int64_t numOfInput2 = 1;
 
-  while (1) {
-    STSElem elem1 = tsBufGetElem(pSupporter1->pTSBuf);
-    STSElem elem2 = tsBufGetElem(pSupporter2->pTSBuf);
+  int32_t  numOfVnodes = 0;
+  int32_t* idList = NULL;
+  tsBufGetVnodeIdList(pSupporter2->pTSBuf, &numOfVnodes, &idList);
 
-#ifdef _DEBUG_VIEW
-    tscInfo("%" PRId64 ", tags:%"PRId64" \t %" PRId64 ", tags:%"PRId64, elem1.ts, elem1.tag.i64Key, elem2.ts, elem2.tag.i64Key);
-#endif
+  bool completed = false;
+  while(1) {
+    STSElem elem = tsBufGetElem(pSupporter1->pTSBuf);
 
-    int32_t res = tVariantCompare(elem1.tag, elem2.tag);
-    if (res == -1 || (res == 0 && tsCompare(order, elem1.ts, elem2.ts))) {
-      if (!tsBufNextPos(pSupporter1->pTSBuf)) {
-        break;
-      }
+    // no data in pSupporter1 anymore, jump out of loop
+    if (elem.vnode < 0 || completed) {
+      break;
+    }
 
-      numOfInput1++;
-    } else if ((res > 0) || (res == 0 && tsCompare(order, elem2.ts, elem1.ts))) {
-      if (!tsBufNextPos(pSupporter2->pTSBuf)) {
+    bool f = false;
+    for (int32_t i = 0; i < numOfVnodes; ++i) {
+      STSElem el = tsBufGetElemStartPos(pSupporter2->pTSBuf, idList[i], elem.tag);
+      if (el.vnode == idList[i]) {
+        f = true;
         break;
       }
+    }
 
-      numOfInput2++;
-    } else {
-      /*
-       * in case of stable query, limit/offset is not applied here. the limit/offset is applied to the
-       * final results which is acquired after the secondry merge of in the client.
-       */
-      if (pLimit->offset == 0 || pQueryInfo->interval.interval > 0 || QUERY_IS_STABLE_QUERY(pQueryInfo->type)) {
-        if (win->skey > elem1.ts) {
-          win->skey = elem1.ts;
-        }
-  
-        if (win->ekey < elem1.ts) {
-          win->ekey = elem1.ts;
-        }
-        
-        tsBufAppend(output1, elem1.vnode, elem1.tag, (const char*)&elem1.ts, sizeof(elem1.ts));
-        tsBufAppend(output2, elem2.vnode, elem2.tag, (const char*)&elem2.ts, sizeof(elem2.ts));
+    /**
+     * there are elements in pSupporter2 with the same tag, continue
+     */
+    if (f) {
+      while (1) {
+        STSElem elem1 = tsBufGetElem(pSupporter1->pTSBuf);
+        STSElem elem2 = tsBufGetElem(pSupporter2->pTSBuf);
+
+        /*
+         * in case of stable query, limit/offset is not applied here. the limit/offset is applied to the
+         * final results which is acquired after the secondry merge of in the client.
+         */
+        int32_t re = tsCompare(order, elem1.ts, elem2.ts);
+        if (re < 0) {
+          if (!tsBufNextPos(pSupporter1->pTSBuf)) {
+            completed = true;
+            break;
+          }
 
-      } else {
-        pLimit->offset -= 1;
-      }
+          numOfInput1++;
+        } else if (re > 0) {
+          if (!tsBufNextPos(pSupporter2->pTSBuf)) {
+            completed = true;
+            break;
+          }
 
-      if (!tsBufNextPos(pSupporter1->pTSBuf)) {
-        break;
+          numOfInput2++;
+        } else {
+          if (pLimit->offset == 0 || pQueryInfo->interval.interval > 0 || QUERY_IS_STABLE_QUERY(pQueryInfo->type)) {
+            if (win->skey > elem1.ts) {
+              win->skey = elem1.ts;
+            }
+
+            if (win->ekey < elem1.ts) {
+              win->ekey = elem1.ts;
+            }
+
+            tsBufAppend(output1, elem1.vnode, elem1.tag, (const char*)&elem1.ts, sizeof(elem1.ts));
+            tsBufAppend(output2, elem2.vnode, elem2.tag, (const char*)&elem2.ts, sizeof(elem2.ts));
+          } else {
+            pLimit->offset -= 1;
+          }
+
+          if (!tsBufNextPos(pSupporter1->pTSBuf)) {
+            completed = true;
+            break;
+          }
+
+          numOfInput1++;
+
+          if (!tsBufNextPos(pSupporter2->pTSBuf)) {
+            completed = true;
+            break;
+          }
+
+          numOfInput2++;
+        }
       }
+    } else {  // no data in pSupporter2, ignore current data in pSupporter2
+      tVariant tag = {0};
+      tVariantAssign(&tag, elem.tag);
 
-      numOfInput1++;
+      // ignore all records with the same tag
+      while (tsBufNextPos(pSupporter1->pTSBuf)) {
+        STSElem el1 = tsBufGetElem(pSupporter1->pTSBuf);
+        int32_t res = tVariantCompare(el1.tag, &tag);
 
-      if (!tsBufNextPos(pSupporter2->pTSBuf)) {
-        break;
+        // it is a record with new tag
+        if (res != 0) {
+          break;
+        }
       }
 
-      numOfInput2++;
+      STSElem el1 = tsBufGetElem(pSupporter1->pTSBuf);
+      if (el1.vnode < 0) {  // no data exists, abort
+        completed = true;
+        break;
+      }
     }
   }
 
@@ -162,8 +213,9 @@ static int64_t doTSBlockIntersect(SSqlObj* pSql, SJoinSupporter* pSupporter1, SJ
 
   TSKEY et = taosGetTimestampUs();
   tscDebug("%p input1:%" PRId64 ", input2:%" PRId64 ", final:%" PRId64 " in %d vnodes for secondary query after ts blocks "
-           "intersecting, skey:%" PRId64 ", ekey:%" PRId64 ", numOfVnode:%d, elasped time:%"PRId64" us", pSql, numOfInput1, numOfInput2, output1->numOfTotal,
-           output1->numOfVnodes, win->skey, win->ekey, tsBufGetNumOfVnodes(output1), et - st);
+           "intersecting, skey:%" PRId64 ", ekey:%" PRId64 ", numOfVnode:%d, elapsed time:%" PRId64 " us",
+           pSql, numOfInput1, numOfInput2, output1->numOfTotal, output1->numOfVnodes, win->skey, win->ekey,
+           tsBufGetNumOfVnodes(output1), et - st);
 
   return output1->numOfTotal;
 }
@@ -517,18 +569,29 @@ void tscBuildVgroupTableInfo(SSqlObj* pSql, STableMetaInfo* pTableMetaInfo, SArr
 
       vgTables = taosArrayInit(4, sizeof(STableIdInfo));
       info.itemList = vgTables;
+
+      if (taosArrayGetSize(result) > 0) {
+        SVgroupTableInfo* prevGroup = taosArrayGet(result, taosArrayGetSize(result) - 1);
+        tscDebug("%p vgId:%d, tables:%"PRId64, pSql, prevGroup->vgInfo.vgId, taosArrayGetSize(prevGroup->itemList));
+      }
+
       taosArrayPush(result, &info);
     }
 
     STableIdInfo item = {.uid = tt->uid, .tid = tt->tid, .key = INT64_MIN};
     taosArrayPush(vgTables, &item);
 
-    tscDebug("%p tid:%d, uid:%"PRIu64",vgId:%d added, total:%d", pSql, tt->tid, tt->uid, tt->vgId, (int32_t) taosArrayGetSize(vgTables));
+    tscTrace("%p tid:%d, uid:%"PRIu64",vgId:%d added", pSql, tt->tid, tt->uid, tt->vgId);
     prev = tt;
   }
 
   pTableMetaInfo->pVgroupTables = result;
   pTableMetaInfo->vgroupIndex = 0;
+
+  if (taosArrayGetSize(result) > 0) {
+    SVgroupTableInfo* g = taosArrayGet(result, taosArrayGetSize(result) - 1);
+    tscDebug("%p vgId:%d, tables:%"PRId64, pSql, g->vgInfo.vgId, taosArrayGetSize(g->itemList));
+  }
 }
 
 static void issueTSCompQuery(SSqlObj* pSql, SJoinSupporter* pSupporter, SSqlObj* pParent) {
@@ -656,6 +719,18 @@ static int32_t getIntersectionOfTableTuple(SQueryInfo* pQueryInfo, SSqlObj* pPar
   qsort((*s1)->pData, t1, size, tidTagsCompar);
   qsort((*s2)->pData, t2, size, tidTagsCompar);
 
+#if 0
+  for(int32_t k = 0; k < t1; ++k) {
+    STidTags* p =  (*s1)->pData + size * k;
+    printf("%d, tag:%s\n", p->vgId, ((tstr*)(p->tag))->data);
+  }
+
+  for(int32_t k = 0; k < t1; ++k) {
+    STidTags* p =  (*s2)->pData + size * k;
+    printf("%d, tag:%s\n", p->vgId, ((tstr*)(p->tag))->data);
+  }
+#endif
+
   tscDebug("%p tags match complete, result: %"PRId64", %"PRId64, pParentSql, t1, t2);
   return TSDB_CODE_SUCCESS;
 }