diff --git a/src/client/inc/tsclient.h b/src/client/inc/tsclient.h
index fc88fc7cf7..bedaab1b2f 100644
--- a/src/client/inc/tsclient.h
+++ b/src/client/inc/tsclient.h
@@ -71,6 +71,7 @@ typedef struct STableMeta {
 typedef struct STableMetaInfo {
   STableMeta * pTableMeta;       // table meta, cached in client side and acquried by name
   SVgroupsInfo* vgroupList;
+  
   /*
    * 1. keep the vnode index during the multi-vnode super table projection query
    * 2. keep the vnode index for multi-vnode insertion
diff --git a/src/client/src/tscServer.c b/src/client/src/tscServer.c
index 26987858bd..cbfcab5bea 100644
--- a/src/client/src/tscServer.c
+++ b/src/client/src/tscServer.c
@@ -651,19 +651,22 @@ int tscBuildQueryMsg(SSqlObj *pSql, SSqlInfo *pInfo) {
     pQueryMsg->head.vgId = htonl(pTableMeta->vgroupInfo.vgId);
     tscTrace("%p queried tables:%d, table id: %s", pSql, 1, pTableMetaInfo->name);
   } else {  // query super table
+    int32_t index = pTableMetaInfo->vgroupIndex;
     
-    if (pTableMetaInfo->vgroupIndex < 0) {
-      tscError("%p error vnodeIdx:%d", pSql, pTableMetaInfo->vgroupIndex);
+    if (index < 0) {
+      tscError("%p error vgroupIndex:%d", pSql, index);
       return -1;
     }
     
-    pSql->ipList.numOfIps = 1; // todo fix me
+    SCMVgroupInfo* pVgroupInfo = &pTableMetaInfo->vgroupList->vgroups[index];
+    
+    pSql->ipList.numOfIps = pVgroupInfo->numOfIps; // todo fix me
     pSql->ipList.port     = tsDnodeShellPort;
     pSql->ipList.inUse    = 0;
   
-    // todo extract method
-    SCMVgroupInfo* pVgroupInfo = &pTableMetaInfo->vgroupList->vgroups[pTableMetaInfo->vgroupIndex];
-    pSql->ipList.ip[0] = pVgroupInfo->ipAddr[0].ip;
+    for(int32_t i = 0; i < pVgroupInfo->numOfIps; ++i) {
+      pSql->ipList.ip[i] = pVgroupInfo->ipAddr[i].ip;
+    }
     
 #if 0
     SVnodeSidList *pVnodeSidList = tscGetVnodeSidList(pMetricMeta, pTableMetaInfo->vgroupIndex);
@@ -676,8 +679,7 @@ int tscBuildQueryMsg(SSqlObj *pSql, SSqlInfo *pInfo) {
     }
 #endif
     
-    tscTrace("%p query on super table, numOfVgroup:%d, vgroupIndex:%d", pSql, pTableMetaInfo->vgroupList->numOfVgroups,
-        pTableMetaInfo->vgroupIndex);
+    tscTrace("%p query on super table, numOfVgroup:%d, vgroupIndex:%d", pSql, pTableMetaInfo->vgroupList->numOfVgroups, index);
     
     pQueryMsg->head.vgId = htonl(pVgroupInfo->vgId);
     numOfTables = 1;
@@ -2133,10 +2135,11 @@ _error_clean:
   
   for(int32_t i = 0; i < pInfo->vgroupList->numOfVgroups; ++i) {
     SCMVgroupInfo* pVgroups = &pInfo->vgroupList->vgroups[i];
-    pVgroups->numOfIps = htonl(pVgroups->numOfIps);
-    pVgroups->vgId = htonl(pVgroups->vgId);
     
-    for(int32_t j = 0; j < tListLen(pVgroups->ipAddr); ++j) {
+    pVgroups->vgId = htonl(pVgroups->vgId);
+    assert(pVgroups->numOfIps >= 1);
+    
+    for(int32_t j = 0; j < pVgroups->numOfIps; ++j) {
       pVgroups->ipAddr[j].ip = htonl(pVgroups->ipAddr[j].ip);
       pVgroups->ipAddr[j].port = htons(pVgroups->ipAddr[j].port);
     }
diff --git a/src/client/src/tscUtil.c b/src/client/src/tscUtil.c
index d70e2bb7f6..f714611539 100644
--- a/src/client/src/tscUtil.c
+++ b/src/client/src/tscUtil.c
@@ -2128,27 +2128,23 @@ SSqlObj* createSubqueryObj(SSqlObj* pSql, int16_t tableIndex, void (*fp)(), void
 
   if (pPrevSql == NULL) {
     STableMeta* pTableMeta = taosCacheAcquireByName(tscCacheHandle, name);
-    
-//    SSuperTableMeta* pMetricMeta = NULL;
-//    if (cmd == TSDB_SQL_SELECT) {
-//      pMetricMeta = taosCacheAcquireByName(tscCacheHandle, key);
-//    }
 
     pFinalInfo = tscAddTableMetaInfo(pNewQueryInfo, name, pTableMeta, pTableMetaInfo->vgroupList, pTableMetaInfo->numOfTags,
                                      pTableMetaInfo->tagColumnIndex);
-  } else {  // transfer the ownership of pTableMeta/pMetricMeta to the newly create sql object.
-//    STableMetaInfo* pPrevInfo = tscGetTableMetaInfoFromCmd(&pPrevSql->cmd, pPrevSql->cmd.clauseIndex, 0);
+  } else {  // transfer the ownership of pTableMeta to the newly create sql object.
+    STableMetaInfo* pPrevInfo = tscGetTableMetaInfoFromCmd(&pPrevSql->cmd, pPrevSql->cmd.clauseIndex, 0);
 
-//    STableMeta*  pPrevMeterMeta = taosCacheTransfer(tscCacheHandle, (void**)&pPrevInfo->pTableMeta);
-//    SSuperTableMeta* pPrevMetricMeta = taosCacheTransfer(tscCacheHandle, (void**)&pPrevInfo->pMetricMeta);
-
-//    pFinalInfo = tscAddTableMetaInfo(pNewQueryInfo, name, pPrevMeterMeta, pPrevMetricMeta, pTableMetaInfo->numOfTags,
-//                                     pTableMetaInfo->tagColumnIndex);
+    STableMeta*  pPrevTableMeta = taosCacheTransfer(tscCacheHandle, (void**)&pPrevInfo->pTableMeta);
+    SVgroupsInfo* pVgroupsInfo = pPrevInfo->vgroupList;
+    pPrevInfo->vgroupList = NULL;
+    
+    pFinalInfo = tscAddTableMetaInfo(pNewQueryInfo, name, pPrevTableMeta, pVgroupsInfo, pTableMetaInfo->numOfTags,
+                                     pTableMetaInfo->tagColumnIndex);
   }
 
   assert(pFinalInfo->pTableMeta != NULL && pNewQueryInfo->numOfTables == 1);
   if (UTIL_TABLE_IS_SUPERTABLE(pTableMetaInfo)) {
-//    assert(pFinalInfo->pMetricMeta != NULL);
+    assert(pFinalInfo->vgroupList != NULL);
   }
   
   if (cmd == TSDB_SQL_SELECT) {
diff --git a/src/query/inc/queryExecutor.h b/src/query/inc/queryExecutor.h
index fb8a908910..b230b77950 100644
--- a/src/query/inc/queryExecutor.h
+++ b/src/query/inc/queryExecutor.h
@@ -18,6 +18,7 @@
 #include "os.h"
 
 #include "hash.h"
+#include "tsdb.h"
 #include "qinterpolation.h"
 #include "qresultBuf.h"
 #include "qsqlparser.h"
@@ -89,7 +90,7 @@ typedef struct SColumnFilterElem {
 } SColumnFilterElem;
 
 typedef struct SSingleColumnFilterInfo {
-  SColumnInfoData      info;
+  SColumnInfoData    info;
   int32_t            numOfFilters;
   SColumnFilterElem* pFilters;
   void*              pData;
@@ -108,8 +109,8 @@ typedef struct STableQueryInfo {
 } STableQueryInfo;
 
 typedef struct STableDataInfo {
-  int32_t          numOfBlocks;
-  int32_t          start;     // start block index
+//  int32_t          numOfBlocks;
+//  int32_t          start;     // start block index
   int32_t          tableIndex;
   int32_t          groupIdx;  // group id in table list
   STableQueryInfo* pTableQInfo;
@@ -171,7 +172,7 @@ typedef struct SQInfo {
   int32_t          pointsInterpo;
   int32_t          code;          // error code to returned to client
   sem_t            dataReady;
-  SArray*          pTableList;    // table id list
+  STableGroupInfo  groupInfo;     // table id list
   void*            tsdb;
   
   SQueryRuntimeEnv runtimeEnv;
@@ -187,7 +188,7 @@ typedef struct SQInfo {
    */
   int32_t         tableIndex;
   int32_t         numOfGroupResultPages;
-  STableDataInfo* pTableDataInfo;
+//  STableDataInfo* pTableDataInfo;
   TSKEY*          tsList;
 } SQInfo;
 
diff --git a/src/query/src/queryExecutor.c b/src/query/src/queryExecutor.c
index a507bf3184..082341d049 100644
--- a/src/query/src/queryExecutor.c
+++ b/src/query/src/queryExecutor.c
@@ -12,6 +12,7 @@
  * 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 <tsdbMain.h>
 #include "os.h"
 
 #include "hash.h"
@@ -92,7 +93,7 @@ enum {
   TS_JOIN_TAG_NOT_EQUALS = 2,
 };
 
-static int32_t mergeIntoGroupResultImpl(SQInfo *pQInfo, STableDataInfo *pTableDataInfo, int32_t start, int32_t end);
+static int32_t mergeIntoGroupResultImpl(SQInfo *pQInfo, SArray* group);
 static void setWindowResOutputBuf(SQueryRuntimeEnv *pRuntimeEnv, SWindowResult *pResult);
 
 static void    resetMergeResultBuf(SQuery *pQuery, SQLFunctionCtx *pCtx, SResultInfo *pResultInfo);
@@ -104,7 +105,7 @@ static void setExecParams(SQuery *pQuery, SQLFunctionCtx *pCtx, void *inputData,
                           int32_t functionId, SDataStatis *pStatis, bool hasNull, void *param, int32_t scanFlag);
 static void initCtxOutputBuf(SQueryRuntimeEnv *pRuntimeEnv);
 static void destroyMeterQueryInfo(STableQueryInfo *pTableQueryInfo, int32_t numOfCols);
-static int32_t setAdditionalInfo(SQInfo *pQInfo, int32_t meterIdx, STableQueryInfo *pTableQueryInfo);
+static int32_t setAdditionalInfo(SQInfo *pQInfo, STable* pTable, STableQueryInfo *pTableQueryInfo);
 static void    resetCtxOutputBuf(SQueryRuntimeEnv *pRuntimeEnv);
 static bool    hasMainOutput(SQuery *pQuery);
 
@@ -2185,7 +2186,7 @@ static int32_t getInitialPageNum(SQInfo *pQInfo) {
   if (isGroupbyNormalCol(pQuery->pGroupbyExpr)) {
     num = 128;
   } else if (isIntervalQuery(pQuery)) {  // time window query, allocate one page for each table
-    size_t s = taosArrayGetSize(pQInfo->pTableList);
+    size_t s = pQInfo->groupInfo.numOfTables;
     num = MAX(s, INITIAL_RESULT_ROWS_VALUE);
   } else {  // for super table query, one page for each subset
     num = 1;//pQInfo->pSidSet->numOfSubSet;
@@ -2253,7 +2254,7 @@ int32_t UNUSED_FUNC vnodeSTableQueryPrepare(SQInfo *pQInfo, SQuery *pQuery, void
 
   // get one queried meter
   assert(0);
-  //  SMeterObj *pMeter = getMeterObj(pQInfo->pTableList, pQInfo->pSidSet->pTableIdList[0]->sid);
+  //  SMeterObj *pMeter = getMeterObj(pQInfo->groupInfo, pQInfo->pSidSet->pTableIdList[0]->sid);
 
   pRuntimeEnv->pTSBuf = param;
   pRuntimeEnv->cur.vnodeIndex = -1;
@@ -2298,10 +2299,8 @@ int32_t UNUSED_FUNC vnodeSTableQueryPrepare(SQInfo *pQInfo, SQuery *pQuery, void
     .colList = pQuery->colList,
   };
   
-  SArray *sa = taosArrayInit(1, POINTER_BYTES);
-
   //  for(int32_t i = 0; i < pQInfo->pSidSet->numOfTables; ++i) {
-  //    SMeterObj *p1 = getMeterObj(pQInfo->pTableList, pQInfo->pSidSet->pTableIdList[i]->sid);
+  //    SMeterObj *p1 = getMeterObj(pQInfo->groupInfo, pQInfo->pSidSet->pTableIdList[i]->sid);
   //    taosArrayPush(sa, &p1);
   //  }
 
@@ -2310,7 +2309,7 @@ int32_t UNUSED_FUNC vnodeSTableQueryPrepare(SQInfo *pQInfo, SQuery *pQuery, void
     taosArrayPush(cols, &pQuery->colList[i]);
   }
 
-  pRuntimeEnv->pQueryHandle = tsdbQueryTables(NULL, &cond, sa, cols);
+  pRuntimeEnv->pQueryHandle = tsdbQueryTables(NULL, &cond, &pQInfo->groupInfo, cols);
 
   // metric query do not invoke interpolation, it will be done at the second-stage merge
   if (!isPointInterpoQuery(pQuery)) {
@@ -2331,18 +2330,18 @@ int32_t UNUSED_FUNC vnodeSTableQueryPrepare(SQInfo *pQInfo, SQuery *pQuery, void
  */
 void vnodeDecMeterRefcnt(SQInfo *pQInfo) {
   if (pQInfo != NULL) {
-    //    assert(taosHashGetSize(pQInfo->pTableList) >= 1);
+    //    assert(taosHashGetSize(pQInfo->groupInfo) >= 1);
   }
 
 #if 0
-  if (pQInfo == NULL || pQInfo->numOfTables == 1) {
+  if (pQInfo == NULL || pQInfo->groupInfo.numOfTables == 1) {
     atomic_fetch_sub_32(&pQInfo->pObj->numOfQueries, 1);
     dTrace("QInfo:%p vid:%d sid:%d meterId:%s, query is over, numOfQueries:%d", pQInfo, pQInfo->pObj->vnode,
            pQInfo->pObj->sid, pQInfo->pObj->meterId, pQInfo->pObj->numOfQueries);
   } else {
     int32_t num = 0;
-    for (int32_t i = 0; i < pQInfo->numOfTables; ++i) {
-      SMeterObj *pMeter = getMeterObj(pQInfo->pTableList, pQInfo->pSidSet->pTableIdList[i]->sid);
+    for (int32_t i = 0; i < pQInfo->groupInfo.numOfTables; ++i) {
+      SMeterObj *pMeter = getMeterObj(pQInfo->groupInfo, pQInfo->pSidSet->pTableIdList[i]->sid);
       atomic_fetch_sub_32(&(pMeter->numOfQueries), 1);
       
       if (pMeter->numOfQueries > 0) {
@@ -2356,9 +2355,9 @@ void vnodeDecMeterRefcnt(SQInfo *pQInfo) {
      * in order to reduce log output, for all meters of which numOfQueries count are 0,
      * we do not output corresponding information
      */
-    num = pQInfo->numOfTables - num;
+    num = pQInfo->groupInfo.numOfTables - num;
     dTrace("QInfo:%p metric query is over, dec query ref for %d meters, numOfQueries on %d meters are 0", pQInfo,
-           pQInfo->numOfTables, num);
+           pQInfo->groupInfo.numOfTables, num);
   }
 #endif
 }
@@ -2663,32 +2662,27 @@ static void updatelastkey(SQuery *pQuery, STableQueryInfo *pTableQInfo) { pTable
  * set tag value in SQLFunctionCtx
  * e.g.,tag information into input buffer
  */
-static void doSetTagValueInParam(SColumnModel *pTagSchema, int32_t tagColIdx, void *pMeterSidInfo, tVariant *param) {
+static void doSetTagValueInParam(void* tsdb, STableId id, int32_t tagColIdx, tVariant *param) {
   assert(tagColIdx >= 0);
-#if 0
-  int16_t offset = getColumnModelOffset(pTagSchema, tagColIdx);
-  
-  void *   pStr = (char *)pMeterSidInfo->tags + offset;
-  SSchema *pCol = getColumnModelSchema(pTagSchema, tagColIdx);
   
   tVariantDestroy(param);
-  
-  if (isNull(pStr, pCol->type)) {
-    param->nType = TSDB_DATA_TYPE_NULL;
-  } else {
-    tVariantCreateFromBinary(param, pStr, pCol->bytes, pCol->type);
-  }
-#endif
+
+  char* val = NULL;
+  int16_t bytes = 0;
+  int16_t type = 0;
+
+  tsdbGetTableTagVal(tsdb, id, tagColIdx, &type, &bytes, &val);
+  tVariantCreateFromBinary(param, val, bytes, type);
 }
 
-void vnodeSetTagValueInParam(STableGroupList *pSidSet, SQueryRuntimeEnv *pRuntimeEnv, void *pMeterSidInfo) {
+void vnodeSetTagValueInParam(STableGroupInfo *groupList, SQueryRuntimeEnv *pRuntimeEnv, STableId id, void* tsdb) {
   SQuery *      pQuery = pRuntimeEnv->pQuery;
-  SColumnModel *pTagSchema = NULL;//pSidSet->pColumnModel;
+//  SColumnModel *pTagSchema = NULL;//pSidSet->pColumnModel;
 
   SSqlFuncExprMsg *pFuncMsg = &pQuery->pSelectExpr[0].pBase;
   if (pQuery->numOfOutputCols == 1 && pFuncMsg->functionId == TSDB_FUNC_TS_COMP) {
     assert(pFuncMsg->numOfParams == 1);
-    doSetTagValueInParam(pTagSchema, pFuncMsg->arg->argValue.i64, pMeterSidInfo, &pRuntimeEnv->pCtx[0].tag);
+    doSetTagValueInParam(tsdb, id, pFuncMsg->arg->argValue.i64, &pRuntimeEnv->pCtx[0].tag);
   } else {
     // set tag value, by which the results are aggregated.
     for (int32_t idx = 0; idx < pQuery->numOfOutputCols; ++idx) {
@@ -2699,14 +2693,14 @@ void vnodeSetTagValueInParam(STableGroupList *pSidSet, SQueryRuntimeEnv *pRuntim
         continue;
       }
 
-      doSetTagValueInParam(pTagSchema, pColEx->colIndex, pMeterSidInfo, &pRuntimeEnv->pCtx[idx].tag);
+      doSetTagValueInParam(tsdb, id, pColEx->colIndex, &pRuntimeEnv->pCtx[idx].tag);
     }
 
     // set the join tag for first column
     if (pFuncMsg->functionId == TSDB_FUNC_TS && pFuncMsg->colInfo.colIndex == PRIMARYKEY_TIMESTAMP_COL_INDEX &&
         pRuntimeEnv->pTSBuf != NULL) {
       assert(pFuncMsg->numOfParams == 1);
-      doSetTagValueInParam(pTagSchema, pFuncMsg->arg->argValue.i64, pMeterSidInfo, &pRuntimeEnv->pCtx[0].tag);
+//      doSetTagValueInParam(pTagSchema, pFuncMsg->arg->argValue.i64, pMeterSidInfo, &pRuntimeEnv->pCtx[0].tag);
     }
   }
 }
@@ -2915,10 +2909,11 @@ int32_t mergeIntoGroupResult(SQInfo *pQInfo) {
   int32_t ret = TSDB_CODE_SUCCESS;
 
 //  while (pQInfo->subgroupIdx < pQInfo->pSidSet->numOfSubSet) {
-    int32_t start = 0;//pQInfo->pSidSet->starterPos[pQInfo->subgroupIdx];
-    int32_t end = taosArrayGetSize(pQInfo->pTableList) - 1;//pQInfo->pSidSet->starterPos[pQInfo->subgroupIdx + 1];
+//    int32_t start = 0;//pQInfo->pSidSet->starterPos[pQInfo->subgroupIdx];
+//    int32_t end = pQInfo->groupInfo.numOfTables - 1;//pQInfo->pSidSet->starterPos[pQInfo->subgroupIdx + 1];
 
-    ret = mergeIntoGroupResultImpl(pQInfo, pQInfo->pTableDataInfo, start, end);
+    SArray* group = taosArrayGetP(pQInfo->groupInfo.pGroupList, 0);
+    ret = mergeIntoGroupResultImpl(pQInfo, group);
     if (ret < 0) {  // not enough disk space to save the data into disk
       return -1;
     }
@@ -3015,22 +3010,26 @@ int64_t getNumOfResultWindowRes(SQueryRuntimeEnv *pRuntimeEnv, SWindowResult *pW
   return maxOutput;
 }
 
-int32_t mergeIntoGroupResultImpl(SQInfo *pQInfo, STableDataInfo *pTableDataInfo, int32_t start, int32_t end) {
+int32_t mergeIntoGroupResultImpl(SQInfo *pQInfo, SArray* pGroup) {
   SQueryRuntimeEnv *pRuntimeEnv = &pQInfo->runtimeEnv;
   SQuery *pQuery = pRuntimeEnv->pQuery;
 
-  tFilePage **     buffer = (tFilePage **)pQuery->sdata;
-  int32_t *        posList = calloc((end - start), sizeof(int32_t));
-  STableDataInfo **pTableList = malloc(POINTER_BYTES * (end - start));
+  size_t size = taosArrayGetSize(pGroup);
+  
+  tFilePage **buffer = (tFilePage **)pQuery->sdata;
+  int32_t *posList = calloc(size, sizeof(int32_t));
+  
+  STableDataInfo **pTableList = malloc(POINTER_BYTES * size);
 
   // todo opt for the case of one table per group
   int32_t numOfTables = 0;
-  for (int32_t i = start; i < end; ++i) {
-    int32_t tid = pTableDataInfo[i].pTableQInfo->tid;
-
-    SIDList list = getDataBufPagesIdList(pRuntimeEnv->pResultBuf, tid);
-    if (list.size > 0 && pTableDataInfo[i].pTableQInfo->windowResInfo.size > 0) {
-      pTableList[numOfTables] = &pTableDataInfo[i];
+  for (int32_t i = 0; i < size; ++i) {
+    SPair* p = taosArrayGet(pGroup, i);
+    STableQueryInfo* pInfo = p->sec;
+    
+    SIDList list = getDataBufPagesIdList(pRuntimeEnv->pResultBuf, pInfo->tid);
+    if (list.size > 0 && pInfo->windowResInfo.size > 0) {
+//      pTableList[numOfTables] = &pTableDataInfo[i];
       numOfTables += 1;
     }
   }
@@ -3258,14 +3257,12 @@ void disableFuncForReverseScan(SQInfo *pQInfo, int32_t order) {
   }
 
   if (isIntervalQuery(pQuery)) {
-    size_t numOfTables = taosArrayGetSize(pQInfo->pTableList);
-
-    for (int32_t i = 0; i < numOfTables; ++i) {
-      STableQueryInfo *pTableQueryInfo = pQInfo->pTableDataInfo[i].pTableQInfo;
-      SWindowResInfo * pWindowResInfo = &pTableQueryInfo->windowResInfo;
-
-      doDisableFunctsForSupplementaryScan(pQuery, pWindowResInfo, order);
-    }
+//    for (int32_t i = 0; i < pQInfo->groupInfo.numOfTables; ++i) {
+//      STableQueryInfo *pTableQueryInfo = pQInfo->pTableDataInfo[i].pTableQInfo;
+//      SWindowResInfo * pWindowResInfo = &pTableQueryInfo->windowResInfo;
+//
+//      doDisableFunctsForSupplementaryScan(pQuery, pWindowResInfo, order);
+//    }
   } else {
     SWindowResInfo *pWindowResInfo = &pRuntimeEnv->windowResInfo;
     doDisableFunctsForSupplementaryScan(pQuery, pWindowResInfo, order);
@@ -3557,7 +3554,7 @@ void scanAllDataBlocks(SQueryRuntimeEnv *pRuntimeEnv) {
     }
   
     if (pRuntimeEnv->pSecQueryHandle != NULL) {
-      pRuntimeEnv->pSecQueryHandle = tsdbQueryTables(pQInfo->tsdb, &cond, pQInfo->pTableList, cols);
+      pRuntimeEnv->pSecQueryHandle = tsdbQueryTables(pQInfo->tsdb, &cond, &pQInfo->groupInfo, cols);
     }
     
     taosArrayDestroy(cols);
@@ -3654,7 +3651,7 @@ STableQueryInfo *createTableQueryInfo(SQueryRuntimeEnv *pRuntimeEnv, int32_t tid
   return pTableQueryInfo;
 }
 
-void destroyMeterQueryInfo(STableQueryInfo *pTableQueryInfo, int32_t numOfCols) {
+UNUSED_FUNC void destroyMeterQueryInfo(STableQueryInfo *pTableQueryInfo, int32_t numOfCols) {
   if (pTableQueryInfo == NULL) {
     return;
   }
@@ -3700,7 +3697,7 @@ void restoreIntervalQueryRange(SQueryRuntimeEnv *pRuntimeEnv, STableQueryInfo *p
  * @param pRuntimeEnv
  * @param pDataBlockInfo
  */
-void setExecutionContext(SQInfo *pQInfo, STableQueryInfo *pTableQueryInfo, int32_t meterIdx, int32_t groupIdx,
+void setExecutionContext(SQInfo *pQInfo, STableQueryInfo *pTableQueryInfo, STable* pTable, int32_t groupIdx,
                          TSKEY nextKey) {
   SQueryRuntimeEnv *pRuntimeEnv = &pQInfo->runtimeEnv;
   SWindowResInfo *  pWindowResInfo = &pRuntimeEnv->windowResInfo;
@@ -3726,7 +3723,7 @@ void setExecutionContext(SQInfo *pQInfo, STableQueryInfo *pTableQueryInfo, int32
   initCtxOutputBuf(pRuntimeEnv);
 
   pTableQueryInfo->lastKey = nextKey;
-  setAdditionalInfo(pQInfo, meterIdx, pTableQueryInfo);
+  setAdditionalInfo(pQInfo, pTable, pTableQueryInfo);
 }
 
 static void setWindowResOutputBuf(SQueryRuntimeEnv *pRuntimeEnv, SWindowResult *pResult) {
@@ -3754,11 +3751,11 @@ static void setWindowResOutputBuf(SQueryRuntimeEnv *pRuntimeEnv, SWindowResult *
   }
 }
 
-int32_t setAdditionalInfo(SQInfo *pQInfo, int32_t meterIdx, STableQueryInfo *pTableQueryInfo) {
+int32_t setAdditionalInfo(SQInfo *pQInfo, STable* pTable, STableQueryInfo *pTableQueryInfo) {
   SQueryRuntimeEnv *pRuntimeEnv = &pQInfo->runtimeEnv;
   assert(pTableQueryInfo->lastKey > 0);
 
-  //  vnodeSetTagValueInParam(pQInfo->pSidSet, pRuntimeEnv, pQInfo->pMeterSidExtInfo[meterIdx]);
+  vnodeSetTagValueInParam(&pQInfo->groupInfo, pRuntimeEnv, pTable->tableId, pQInfo->tsdb);
 
   // both the master and supplement scan needs to set the correct ts comp start position
   if (pRuntimeEnv->pTSBuf != NULL) {
@@ -3866,7 +3863,7 @@ static int32_t getNumOfSubset(SQInfo *pQInfo) {
   if (isGroupbyNormalCol(pQuery->pGroupbyExpr) || (isIntervalQuery(pQuery))) {
     totalSubset = numOfClosedTimeWindow(&pQInfo->runtimeEnv.windowResInfo);
   } else {
-    totalSubset = 1;//pQInfo->pSidSet->numOfSubSet;
+    totalSubset = taosArrayGetSize(pQInfo->groupInfo.pGroupList);
   }
 
   return totalSubset;
@@ -4193,7 +4190,7 @@ int32_t doInitQInfo(SQInfo *pQInfo, void *param, void* tsdb, bool isSTableQuery)
     taosArrayPush(cols, &pQuery->colList[i]);
   }
   
-  pRuntimeEnv->pQueryHandle = tsdbQueryTables(tsdb, &cond, pQInfo->pTableList, cols);
+  pRuntimeEnv->pQueryHandle = tsdbQueryTables(tsdb, &cond, &pQInfo->groupInfo, cols);
   taosArrayDestroy(cols);
   pQInfo->tsdb = tsdb;
   
@@ -4294,7 +4291,7 @@ int32_t doInitQInfo(SQInfo *pQInfo, void *param, void* tsdb, bool isSTableQuery)
   return TSDB_CODE_SUCCESS;
 }
 
-static UNUSED_FUNC bool isGroupbyEachTable(SSqlGroupbyExpr *pGroupbyExpr, STableGroupList *pSidset) {
+static UNUSED_FUNC bool isGroupbyEachTable(SSqlGroupbyExpr *pGroupbyExpr, STableGroupInfo *pSidset) {
   if (pGroupbyExpr == NULL || pGroupbyExpr->numOfGroupCols == 0) {
     return false;
   }
@@ -4335,7 +4332,6 @@ static int64_t queryOnDataBlocks(SQInfo *pQInfo) {
   SQuery *          pQuery = pRuntimeEnv->pQuery;
   
   int64_t st = taosGetTimestampMs();
-  size_t numOfTables = taosArrayGetSize(pQInfo->pTableList);
   
   tsdb_query_handle_t *pQueryHandle = pRuntimeEnv->pQueryHandle;
   while (tsdbNextDataBlock(pQueryHandle)) {
@@ -4345,15 +4341,26 @@ static int64_t queryOnDataBlocks(SQInfo *pQInfo) {
 
     SDataBlockInfo blockInfo = tsdbRetrieveDataBlockInfo(pQueryHandle);
     STableDataInfo* pTableDataInfo = NULL;
+    STable* pTable = NULL;
     
-    // todo opt performance
-    for(int32_t i = 0; i < numOfTables; ++i) {
-      if (pQInfo->pTableDataInfo[i].pTableQInfo->tid == blockInfo.sid) {
-        pTableDataInfo = &pQInfo->pTableDataInfo[i];
-        break;
+    // todo opt performance using hash table
+    size_t numOfGroup = taosArrayGetSize(pQInfo->groupInfo.pGroupList);
+    for(int32_t i = 0; i < numOfGroup; ++i) {
+      SArray* group = taosArrayGetP(pQInfo->groupInfo.pGroupList, i);
+      
+      size_t num = taosArrayGetSize(group);
+      for(int32_t j = 0; j < num; ++j) {
+        SPair* p = taosArrayGet(group, j);
+        STableDataInfo* pInfo = p->sec;
+        
+        if (pInfo->pTableQInfo->tid == blockInfo.sid) {
+          pTableDataInfo = p->sec;
+          pTable = p->first;
+          break;
+        }
       }
     }
-
+    
     assert(pTableDataInfo != NULL && pTableDataInfo->pTableQInfo != NULL);
     STableQueryInfo *pTableQueryInfo = pTableDataInfo->pTableQInfo;
 
@@ -4364,10 +4371,10 @@ static int64_t queryOnDataBlocks(SQInfo *pQInfo) {
 
     TSKEY nextKey = blockInfo.window.ekey;
     if (!isIntervalQuery(pQuery)) {
-      setExecutionContext(pQInfo, pTableQueryInfo, pTableDataInfo->tableIndex, pTableDataInfo->groupIdx, nextKey);
+      setExecutionContext(pQInfo, pTableQueryInfo, pTable, pTableDataInfo->groupIdx, nextKey);
     } else {  // interval query
       setIntervalQueryRange(pTableQueryInfo, pQInfo, nextKey);
-      int32_t ret = setAdditionalInfo(pQInfo, pTableDataInfo->tableIndex, pTableQueryInfo);
+      int32_t ret = setAdditionalInfo(pQInfo, pTable, pTableQueryInfo);
       
       if (ret != TSDB_CODE_SUCCESS) {
         pQInfo->code = ret;
@@ -4493,7 +4500,7 @@ static void vnodeSTableSeqProcessor(SQInfo *pQInfo) {
   setQueryStatus(pQuery, QUERY_COMPLETED);
   
 #if 0
-//  STableGroupList *pTableIdList = pSupporter->pSidSet;
+//  STableGroupInfo *pTableIdList = pSupporter->pSidSet;
   
   int32_t vid = getMeterObj(pSupporter->pMetersHashTable, pMeterSidExtInfo[0]->sid)->vnode;
   
@@ -4747,35 +4754,40 @@ static void createTableDataInfo(SQInfo* pQInfo) {
   SQuery* pQuery = pQInfo->runtimeEnv.pQuery;
   
   // todo make sure the table are added the reference count to gauranteed that all involved tables are valid
-  int32_t numOfTables = taosArrayGetSize(pQInfo->pTableList);
-  
-  if (pQInfo->pTableDataInfo == NULL) {
-    pQInfo->pTableDataInfo = (STableDataInfo *)calloc(1, sizeof(STableDataInfo) * numOfTables);
-    if (pQInfo->pTableDataInfo == NULL) {
-      dError("QInfo:%p failed to allocate memory, %s", pQInfo, strerror(errno));
-      pQInfo->code = -TSDB_CODE_SERV_OUT_OF_MEMORY;
-      return;
-    }
+//  if (pQInfo->pTableDataInfo == NULL) {
+//    pQInfo->pTableDataInfo = (STableDataInfo *)calloc(1, sizeof(STableDataInfo) * pQInfo->groupInfo.numOfTables);
+//    if (pQInfo->pTableDataInfo == NULL) {
+//      dError("QInfo:%p failed to allocate memory, %s", pQInfo, strerror(errno));
+//      pQInfo->code = -TSDB_CODE_SERV_OUT_OF_MEMORY;
+//      return;
+//    }
     
-    int32_t groupId = 0;
-    for (int32_t i = 0; i < numOfTables; ++i) {  // load all meter meta info
-      STableId *id = taosArrayGet(pQInfo->pTableList, i);
-      STableDataInfo *pInfo = &pQInfo->pTableDataInfo[i];
+  size_t numOfGroups = taosArrayGetSize(pQInfo->groupInfo.pGroupList);
+  int32_t index = 0;
+  for (int32_t i = 0; i < numOfGroups; ++i) {  // load all meter meta info
+    SArray *group = *(SArray**) taosArrayGet(pQInfo->groupInfo.pGroupList, i);
+    
+    size_t s = taosArrayGetSize(group);
+    for(int32_t j = 0; j < s; ++j) {
+      SPair* p = (SPair*) taosArrayGet(group, j);
+      STableDataInfo* pInfo = calloc(1, sizeof(STableDataInfo));
       
-      setTableDataInfo(pInfo, i, groupId);
-      pInfo->pTableQInfo = createTableQueryInfo(&pQInfo->runtimeEnv, id->tid, pQuery->window);
+      setTableDataInfo(pInfo, index, i);
+      pInfo->pTableQInfo = createTableQueryInfo(&pQInfo->runtimeEnv, ((STable*)(p->first))->tableId.tid, pQuery->window);
+      
+      p->sec = pInfo;
+      index += 1;
     }
   }
 }
 
 static void prepareQueryInfoForReverseScan(SQInfo *pQInfo) {
-  SQuery *pQuery = pQInfo->runtimeEnv.pQuery;
-  size_t numOfTables = taosArrayGetSize(pQInfo->pTableList);
+//  SQuery *pQuery = pQInfo->runtimeEnv.pQuery;
   
-  for (int32_t i = 0; i < numOfTables; ++i) {
-    STableQueryInfo *pTableQueryInfo = pQInfo->pTableDataInfo[i].pTableQInfo;
-    changeMeterQueryInfoForSuppleQuery(pQuery, pTableQueryInfo);
-  }
+//  for (int32_t i = 0; i < pQInfo->groupInfo.numOfTables; ++i) {
+//    STableQueryInfo *pTableQueryInfo = pQInfo->pTableDataInfo[i].pTableQInfo;
+//    changeMeterQueryInfoForSuppleQuery(pQuery, pTableQueryInfo);
+//  }
 }
 
 static void doSaveContext(SQInfo* pQInfo) {
@@ -4809,12 +4821,23 @@ static void doRestoreContext(SQInfo* pQInfo) {
 
 static void doCloseAllTimeWindowAfterScan(SQInfo* pQInfo) {
   SQuery* pQuery = pQInfo->runtimeEnv.pQuery;
-  size_t numOfTables = taosArrayGetSize(pQInfo->pTableList);
   
   if (isIntervalQuery(pQuery)) {
-    for (int32_t i = 0; i < numOfTables; ++i) {
-      STableQueryInfo *pTableQueryInfo = pQInfo->pTableDataInfo[i].pTableQInfo;
-      closeAllTimeWindow(&pTableQueryInfo->windowResInfo);
+//    for (int32_t i = 0; i < pQInfo->groupInfo.numOfTables; ++i) {
+//      STableQueryInfo *pTableQueryInfo = pQInfo->pTableDataInfo[i].pTableQInfo;
+//      closeAllTimeWindow(&pTableQueryInfo->windowResInfo);
+//    }
+    size_t numOfGroup = taosArrayGetSize(pQInfo->groupInfo.pGroupList);
+    for(int32_t i = 0; i < numOfGroup; ++i) {
+      SArray* group = taosArrayGetP(pQInfo->groupInfo.pGroupList, i);
+    
+      size_t num = taosArrayGetSize(group);
+      for(int32_t j = 0; j < num; ++j) {
+        SPair* p = taosArrayGet(group, j);
+        STableDataInfo* pInfo = p->sec;
+        
+        closeAllTimeWindow(&pInfo->pTableQInfo->windowResInfo);
+      }
     }
   } else {  // close results for group result
     closeAllTimeWindow(&pQInfo->runtimeEnv.windowResInfo);
@@ -5140,15 +5163,15 @@ static void tableQueryImpl(SQInfo* pQInfo) {
   
   // record the total elapsed time
   pQInfo->elapsedTime += (taosGetTimestampUs() - st);
-  assert(taosArrayGetSize(pQInfo->pTableList) == 1);
+  assert(pQInfo->groupInfo.numOfTables == 1);
   
   /* check if query is killed or not */
   if (isQueryKilled(pQInfo)) {
     dTrace("QInfo:%p query is killed", pQInfo);
   } else {
-    STableId* pTableId = taosArrayGet(pQInfo->pTableList, 0);
-    dTrace("QInfo:%p uid:%" PRIu64 " tid:%d, query completed, %" PRId64 " rows returned, numOfTotal:%" PRId64 " rows",
-        pQInfo, pTableId->uid, pTableId->tid, pQuery->rec.rows, pQuery->rec.total + pQuery->rec.rows);
+//    STableId* pTableId = taosArrayGet(pQInfo->groupInfo, 0);
+//    dTrace("QInfo:%p uid:%" PRIu64 " tid:%d, query completed, %" PRId64 " rows returned, numOfTotal:%" PRId64 " rows",
+//        pQInfo, pTableId->uid, pTableId->tid, pQuery->rec.rows, pQuery->rec.total + pQuery->rec.rows);
   }
   
   sem_post(&pQInfo->dataReady);
@@ -5175,8 +5198,7 @@ static void stableQueryImpl(SQInfo* pQInfo) {
 //  taosInterpoSetStartInfo(&pQInfo->runtimeEnv.interpoInfo, pQuery->size, pQInfo->query.interpoType);
   
   if (pQuery->rec.rows == 0) {
-    int32_t numOfTables = taosArrayGetSize(pQInfo->pTableList);
-    dTrace("QInfo:%p over, %d tables queried, %d points are returned", pQInfo, numOfTables, pQuery->rec.total);
+    dTrace("QInfo:%p over, %d tables queried, %d points are returned", pQInfo, pQInfo->groupInfo.numOfTables, pQuery->rec.total);
 //    vnodePrintQueryStatistics(pSupporter);
   }
   
@@ -5710,10 +5732,10 @@ static void doUpdateExprColumnIndex(SQuery* pQuery) {
 }
 
 static SQInfo *createQInfoImpl(SQueryTableMsg *pQueryMsg, SSqlGroupbyExpr *pGroupbyExpr, SSqlFunctionExpr *pExprs,
-                               SArray *pTableList) {
+                               STableGroupInfo *groupInfo) {
   SQInfo *pQInfo = (SQInfo *)calloc(1, sizeof(SQInfo));
   if (pQInfo == NULL) {
-    goto _clean_pQInfo_memory;
+    return NULL;
   }
 
   SQuery *pQuery = calloc(1, sizeof(SQuery));
@@ -5808,7 +5830,7 @@ static SQInfo *createQInfoImpl(SQueryTableMsg *pQueryMsg, SSqlGroupbyExpr *pGrou
 
   // to make sure third party won't overwrite this structure
   pQInfo->signature = pQInfo;
-  pQInfo->pTableList = pTableList;
+  pQInfo->groupInfo = *groupInfo;
 
   pQuery->pos = -1;
   
@@ -5842,7 +5864,6 @@ _clean_memory:
   tfree(pExprs);
   tfree(pGroupbyExpr);
 
-_clean_pQInfo_memory:
   tfree(pQInfo);
 
   return NULL;
@@ -5918,14 +5939,12 @@ static void freeQInfo(SQInfo *pQInfo) {
   sem_destroy(&(pQInfo->dataReady));
   teardownQueryRuntimeEnv(&pQInfo->runtimeEnv);
   
-  if (pQInfo->pTableDataInfo != NULL) {
-    //    size_t num = taosHashGetSize(pQInfo->pTableList);
-    for (int32_t j = 0; j < 0; ++j) {
-      destroyMeterQueryInfo(pQInfo->pTableDataInfo[j].pTableQInfo, pQuery->numOfOutputCols);
-    }
-  }
-  
-  tfree(pQInfo->pTableDataInfo);
+//  if (pQInfo->pTableDataInfo != NULL) {
+    //    size_t num = taosHashGetSize(pQInfo->groupInfo);
+//    for (int32_t j = 0; j < 0; ++j) {
+//      destroyMeterQueryInfo(pQInfo->pTableDataInfo[j].pTableQInfo, pQuery->numOfOutputCols);
+//    }
+//  }
   
   for (int32_t i = 0; i < pQuery->numOfFilterCols; ++i) {
     SSingleColumnFilterInfo *pColFilter = &pQuery->pFilterInfo[i];
@@ -5958,7 +5977,7 @@ static void freeQInfo(SQInfo *pQInfo) {
   tfree(pQuery->pGroupbyExpr);
   tfree(pQuery);
   
-  taosArrayDestroy(pQInfo->pTableList);
+  taosArrayDestroy(pQInfo->groupInfo.pGroupList);
   
   dTrace("QInfo:%p QInfo is freed", pQInfo);
   
@@ -6061,7 +6080,7 @@ int32_t qCreateQueryInfo(void* tsdb, SQueryTableMsg *pQueryMsg, SQInfo **pQInfo)
   }
   
   bool isSTableQuery = false;
-  SArray* pGroupList = NULL;
+  STableGroupInfo* groupInfo = calloc(1, sizeof(STableGroupInfo));
   
   if ((pQueryMsg->queryType & TSDB_QUERY_TYPE_STABLE_QUERY) != 0) {
     isSTableQuery = true;
@@ -6069,8 +6088,8 @@ int32_t qCreateQueryInfo(void* tsdb, SQueryTableMsg *pQueryMsg, SQInfo **pQInfo)
     STableId* id = taosArrayGet(pTableIdList, 0);
     id->uid = -1;  //todo fix me
     
-    /*int32_t ret =*/ tsdbQueryTags(tsdb, id->uid, tagCond, pQueryMsg->tagCondLen, &pGroupList, pGroupColIndex, pQueryMsg->numOfGroupCols);
-    if (taosArrayGetSize(pGroupList) == 0) { // no qualified tables no need to do query
+    /*int32_t ret =*/ tsdbQueryTags(tsdb, id->uid, tagCond, pQueryMsg->tagCondLen, groupInfo, pGroupColIndex, pQueryMsg->numOfGroupCols);
+    if (groupInfo->numOfTables == 0) { // no qualified tables no need to do query
       code = TSDB_CODE_SUCCESS;
       goto _query_over;
     }
@@ -6078,12 +6097,12 @@ int32_t qCreateQueryInfo(void* tsdb, SQueryTableMsg *pQueryMsg, SQInfo **pQInfo)
     assert(taosArrayGetSize(pTableIdList) == 1);
   
     STableId* id = taosArrayGet(pTableIdList, 0);
-    if ((code = tsdbGetOneTableGroup(tsdb, id->uid, &pGroupList)) != TSDB_CODE_SUCCESS) {
+    if ((code = tsdbGetOneTableGroup(tsdb, id->uid, groupInfo)) != TSDB_CODE_SUCCESS) {
       goto _query_over;
     }
   }
   
-  (*pQInfo) = createQInfoImpl(pQueryMsg, pGroupbyExpr, pExprs, pGroupList);
+  (*pQInfo) = createQInfoImpl(pQueryMsg, pGroupbyExpr, pExprs, groupInfo);
   if ((*pQInfo) == NULL) {
     code = TSDB_CODE_SERV_OUT_OF_MEMORY;
   }
diff --git a/src/tsdb/inc/tsdb.h b/src/tsdb/inc/tsdb.h
index e385239dba..72cb16ae3c 100644
--- a/src/tsdb/inc/tsdb.h
+++ b/src/tsdb/inc/tsdb.h
@@ -95,6 +95,8 @@ int  tsdbTableSetTagSchema(STableCfg *config, STSchema *pSchema, bool dup);
 int  tsdbTableSetTagValue(STableCfg *config, SDataRow row, bool dup);
 void tsdbClearTableCfg(STableCfg *config);
 
+int32_t tsdbGetTableTagVal(tsdb_repo_t *repo, STableId id, int32_t col, int16_t* type, int16_t* bytes, char** val);
+
 int tsdbCreateTable(tsdb_repo_t *repo, STableCfg *pCfg);
 int tsdbDropTable(tsdb_repo_t *pRepo, STableId tableId);
 int tsdbAlterTable(tsdb_repo_t *repo, STableCfg *pCfg);
@@ -181,11 +183,6 @@ int32_t tsdbInsertData(tsdb_repo_t *pRepo, SSubmitMsg *pMsg);
 
 typedef void* tsdb_query_handle_t;  // Use void to hide implementation details
 
-typedef struct STableGroupList {    // qualified table object list in group
-  SArray*  pGroupList;
-  int32_t  numOfTables;
-} STableGroupList;
-
 // query condition to build vnode iterator
 typedef struct STsdbQueryCond {
   STimeWindow       twindow;
@@ -216,11 +213,16 @@ typedef struct SDataBlockInfo {
   int32_t     sid;
 } SDataBlockInfo;
 
+typedef struct {
+  size_t  numOfTables;
+  SArray* pGroupList;
+} STableGroupInfo;
+
 typedef struct {
 } SFields;
 
 #define TSDB_TS_GREATER_EQUAL 1
-#define TSDB_TS_LESS_EQUAL 2
+#define TSDB_TS_LESS_EQUAL    2
 
 typedef struct SQueryRowCond {
   int32_t rel;
@@ -235,7 +237,7 @@ typedef void *tsdbpos_t;
  * @param pTableList    table sid list
  * @return
  */
-tsdb_query_handle_t *tsdbQueryTables(tsdb_repo_t* tsdb, STsdbQueryCond *pCond, SArray *idList, SArray *pColumnInfo);
+tsdb_query_handle_t *tsdbQueryTables(tsdb_repo_t* tsdb, STsdbQueryCond *pCond, STableGroupInfo *groupInfo, SArray *pColumnInfo);
 
 /**
  * move to next block
@@ -337,10 +339,10 @@ SArray *tsdbGetTableList(tsdb_query_handle_t *pQueryHandle);
  * @param pTagCond. tag query condition
  *
  */
-int32_t tsdbQueryTags(tsdb_repo_t* tsdb, int64_t uid, const char* pTagCond, size_t len, SArray** pGroupList,
+int32_t tsdbQueryTags(tsdb_repo_t* tsdb, int64_t uid, const char* pTagCond, size_t len, STableGroupInfo* pGroupList,
                       SColIndex* pColIndex, int32_t numOfCols);
 
-int32_t tsdbGetOneTableGroup(tsdb_repo_t* tsdb, int64_t uid, SArray** pGroupList);
+int32_t tsdbGetOneTableGroup(tsdb_repo_t* tsdb, int64_t uid, STableGroupInfo* pGroupInfo);
 
 /**
  * clean up the query handle
diff --git a/src/tsdb/src/tsdbMeta.c b/src/tsdb/src/tsdbMeta.c
index 39a993a106..5d443d2290 100644
--- a/src/tsdb/src/tsdbMeta.c
+++ b/src/tsdb/src/tsdbMeta.c
@@ -214,6 +214,23 @@ STSchema * tsdbGetTableTagSchema(STsdbMeta *pMeta, STable *pTable) {
   }
 }
 
+int32_t tsdbGetTableTagVal(tsdb_repo_t* repo, STableId id, int32_t col, int16_t* type, int16_t* bytes, char** val) {
+  STsdbMeta* pMeta = tsdbGetMeta(repo);
+  STable* pTable = tsdbGetTableByUid(pMeta, id.uid);
+  
+  STSchema* pSchema = tsdbGetTableTagSchema(pMeta, pTable);
+  STColumn* pCol = schemaColAt(pSchema, col);
+  
+  SDataRow row = (SDataRow)pTable->tagVal;
+  char* d = dataRowAt(row, TD_DATA_ROW_HEAD_SIZE);
+  
+  *val = d;
+  *type = pCol->type;
+  *bytes = pCol->bytes;
+  
+  return 0;
+}
+
 int32_t tsdbCreateTableImpl(STsdbMeta *pMeta, STableCfg *pCfg) {
   if (tsdbCheckTableCfg(pCfg) < 0) return -1;
 
diff --git a/src/tsdb/src/tsdbRead.c b/src/tsdb/src/tsdbRead.c
index 495cf8c7f5..5af5be6ac2 100644
--- a/src/tsdb/src/tsdbRead.c
+++ b/src/tsdb/src/tsdbRead.c
@@ -143,7 +143,7 @@ static void tsdbInitCompBlockLoadInfo(SLoadCompBlockInfo* pCompBlockLoadInfo) {
   pCompBlockLoadInfo->fileListIndex = -1;
 }
 
-tsdb_query_handle_t* tsdbQueryTables(tsdb_repo_t* tsdb, STsdbQueryCond* pCond, SArray* groupList, SArray* pColumnInfo) {
+tsdb_query_handle_t* tsdbQueryTables(tsdb_repo_t* tsdb, STsdbQueryCond* pCond, STableGroupInfo* groupList, SArray* pColumnInfo) {
   // todo 1. filter not exist table
   // todo 2. add the reference count for each table that is involved in query
 
@@ -157,22 +157,25 @@ tsdb_query_handle_t* tsdbQueryTables(tsdb_repo_t* tsdb, STsdbQueryCond* pCond, S
   pQueryHandle->isFirstSlot = true;
   pQueryHandle->cur.fid = -1;
 
-  size_t size = taosArrayGetSize(groupList);
-  assert(size >= 1);
+  size_t sizeOfGroup = taosArrayGetSize(groupList->pGroupList);
+  assert(sizeOfGroup >= 1);
 
-  pQueryHandle->pTableCheckInfo = taosArrayInit(size, sizeof(STableCheckInfo));
-  for (int32_t i = 0; i < size; ++i) {
-    SArray* group = *(SArray**)taosArrayGet(groupList, i);
+  pQueryHandle->pTableCheckInfo = taosArrayInit(groupList->numOfTables, sizeof(STableCheckInfo));
+  
+  for (int32_t i = 0; i < sizeOfGroup; ++i) {
+    SArray* group = *(SArray**) taosArrayGet(groupList->pGroupList, i);
 
     size_t gsize = taosArrayGetSize(group);
+    assert(gsize > 0);
+    
     for (int32_t j = 0; j < gsize; ++j) {
-      STable* pTable = *(STable**)taosArrayGet(group, j);
-      assert(pTable != NULL);
+      SPair* d = (SPair*) taosArrayGet(group, j);
+      assert(d->first !=  NULL);
       
       STableCheckInfo info = {
           .lastKey = pQueryHandle->window.skey,
-          .tableId = pTable->tableId,
-          .pTableObj = pTable,
+          .tableId = ((STable*) d->first)->tableId,
+          .pTableObj = d->first,
       };
 
       taosArrayPush(pQueryHandle->pTableCheckInfo, &info);
@@ -1143,7 +1146,7 @@ static int32_t getAllTableIdList(STsdbRepo* tsdb, int64_t uid, SArray* list) {
     SSkipListNode* pNode = tSkipListIterGet(iter);
     
     STable* t = *(STable**)SL_GET_NODE_DATA(pNode);
-    taosArrayPush(list, t);
+    taosArrayPush(list, &t);
   }
   
   return TSDB_CODE_SUCCESS;
@@ -1306,26 +1309,31 @@ int32_t tableGroupComparFn(const void *p1, const void *p2, const void *param) {
 }
 
 void createTableGroupImpl(SArray* pGroups, STable** pTables, size_t numOfTables, STableGroupSupporter* pSupp, __ext_compar_fn_t compareFn) {
-  SArray* g = taosArrayInit(16, POINTER_BYTES);
-  taosArrayPush(g, &pTables[0]);
+  SArray* g = taosArrayInit(16, sizeof(SPair));
+  
+  SPair p = {.first = pTables[0]};
+  taosArrayPush(g, &p);
   
   for (int32_t i = 1; i < numOfTables; ++i) {
     int32_t ret = compareFn(&pTables[i - 1], &pTables[i], pSupp);
     assert(ret == 0 || ret == -1);
     
     if (ret == 0) {
-      taosArrayPush(g, &pTables[i]);
+      SPair p1 = {.first = pTables[i]};
+      taosArrayPush(g, &p1);
     } else {
       taosArrayPush(pGroups, &g);  // current group is ended, start a new group
-      
       g = taosArrayInit(16, POINTER_BYTES);
-      taosArrayPush(g, &pTables[i]);
+  
+      SPair p1 = {.first = pTables[i]};
+      taosArrayPush(g, &p1);
     }
   }
 }
 
 SArray* createTableGroup(SArray* pTableList, STSchema* pTagSchema, SColIndex* pCols, int32_t numOfOrderCols) {
-  assert(pTableList != NULL && taosArrayGetSize(pTableList) > 0);
+  assert(pTableList != NULL);
+  
   SArray* pTableGroup = taosArrayInit(1, POINTER_BYTES);
   
   size_t size = taosArrayGetSize(pTableList);
@@ -1335,7 +1343,17 @@ SArray* createTableGroup(SArray* pTableList, STSchema* pTagSchema, SColIndex* pC
   }
   
   if (numOfOrderCols == 0 || size == 1) { // no group by tags clause or only one table
-    taosArrayPush(pTableGroup, pTableList);
+    size_t num = taosArrayGetSize(pTableList);
+    
+    SArray* sa = taosArrayInit(num, sizeof(SPair));
+    for(int32_t i = 0; i < num; ++i) {
+      STable* pTable = taosArrayGetP(pTableList, i);
+      
+      SPair p = {.first = pTable};
+      taosArrayPush(sa, &p);
+    }
+    
+    taosArrayPush(pTableGroup, &sa);
     pTrace("all %d tables belong to one group", size);
     
 #ifdef _DEBUG_VIEW
@@ -1430,7 +1448,7 @@ static int32_t doQueryTableList(STable* pSTable, SArray* pRes, tExprNode* pExpr)
   return TSDB_CODE_SUCCESS;
 }
 
-int32_t tsdbQueryTags(tsdb_repo_t* tsdb, int64_t uid, const char* pTagCond, size_t len, SArray** pGroupList,
+int32_t tsdbQueryTags(tsdb_repo_t* tsdb, int64_t uid, const char* pTagCond, size_t len, STableGroupInfo* pGroupInfo,
     SColIndex* pColIndex, int32_t numOfCols) {
   
   STable* pSTable = tsdbGetTableByUid(tsdbGetMeta(tsdb), uid);
@@ -1448,9 +1466,9 @@ int32_t tsdbQueryTags(tsdb_repo_t* tsdb, int64_t uid, const char* pTagCond, size
       taosArrayDestroy(res);
       return ret;
     }
-    
-    *pGroupList = createTableGroup(res, pTagSchema, pColIndex, numOfCols);
-    taosArrayDestroy(res);
+  
+    pGroupInfo->numOfTables = taosArrayGetSize(res);
+    pGroupInfo->pGroupList  = createTableGroup(res, pTagSchema, pColIndex, numOfCols);
     return ret;
   }
 
@@ -1465,25 +1483,27 @@ int32_t tsdbQueryTags(tsdb_repo_t* tsdb, int64_t uid, const char* pTagCond, size
   }
 
   doQueryTableList(pSTable, res, pExprNode);
-  *pGroupList = createTableGroup(res, pTagSchema, pColIndex, numOfCols);
+  
+  pGroupInfo->numOfTables = taosArrayGetSize(res);
+  pGroupInfo->pGroupList  = createTableGroup(res, pTagSchema, pColIndex, numOfCols);
 
-  taosArrayDestroy(res);
   return ret;
 }
 
-int32_t tsdbGetOneTableGroup(tsdb_repo_t* tsdb, int64_t uid, SArray** pGroupList) {
+int32_t tsdbGetOneTableGroup(tsdb_repo_t* tsdb, int64_t uid, STableGroupInfo* pGroupInfo) {
   STable* pTable = tsdbGetTableByUid(tsdbGetMeta(tsdb), uid);
   if (pTable == NULL) {
     return TSDB_CODE_INVALID_TABLE_ID;
   }
   
   //todo assert table type, add the table ref count
+  pGroupInfo->numOfTables = 1;
+  pGroupInfo->pGroupList = taosArrayInit(1, POINTER_BYTES);
   
-  *pGroupList = taosArrayInit(1, POINTER_BYTES);
   SArray* group = taosArrayInit(1, POINTER_BYTES);
   
   taosArrayPush(group, &pTable);
-  taosArrayPush(*pGroupList, &group);
+  taosArrayPush(pGroupInfo->pGroupList, &group);
   
   return TSDB_CODE_SUCCESS;
 }
diff --git a/src/util/inc/tutil.h b/src/util/inc/tutil.h
index 81cf177e73..a31d71dd19 100644
--- a/src/util/inc/tutil.h
+++ b/src/util/inc/tutil.h
@@ -107,6 +107,11 @@ extern "C" {
 
 #define POW2(x) ((x) * (x))
 
+typedef struct SPair {
+  void* first;
+  void* sec;
+} SPair;
+
 int32_t strdequote(char *src);
 
 void strtrim(char *src);