From 6402c2b053125ac9eb4f10a92d85358bf7f6566f Mon Sep 17 00:00:00 2001
From: Haojun Liao <hjliao@taosdata.com>
Date: Sun, 17 Jan 2021 22:50:23 +0800
Subject: [PATCH] [TD-225]refactor codes.

---
 src/client/inc/tscLocalMerge.h |   8 +-
 src/client/inc/tscUtil.h       |   4 +-
 src/client/inc/tsclient.h      |   4 +-
 src/client/src/tscLocalMerge.c | 345 ++++++++++++++++-----------------
 src/client/src/tscServer.c     |   2 +-
 src/client/src/tscSubquery.c   |   6 +-
 src/client/src/tscUtil.c       |  21 +-
 src/query/src/qExecutor.c      |   4 +-
 src/util/inc/tarray.h          |   2 +-
 src/util/src/tarray.c          |   2 +-
 10 files changed, 196 insertions(+), 202 deletions(-)

diff --git a/src/client/inc/tscLocalMerge.h b/src/client/inc/tscLocalMerge.h
index 0617645188..581cd37cbd 100644
--- a/src/client/inc/tscLocalMerge.h
+++ b/src/client/inc/tscLocalMerge.h
@@ -38,7 +38,7 @@ typedef struct SLocalDataSource {
   tFilePage      filePage;
 } SLocalDataSource;
 
-typedef struct SLocalReducer {
+typedef struct SLocalMerger {
   SLocalDataSource **    pLocalDataSrc;
   int32_t                numOfBuffer;
   int32_t                numOfCompleted;
@@ -62,7 +62,7 @@ typedef struct SLocalReducer {
   bool                   discard;
   int32_t                offset;             // limit offset value
   bool                   orderPrjOnSTable;   // projection query on stable
-} SLocalReducer;
+} SLocalMerger;
 
 typedef struct SRetrieveSupport {
   tExtMemBuffer **  pExtMemBuffer;     // for build loser tree
@@ -89,10 +89,10 @@ int32_t tscFlushTmpBuffer(tExtMemBuffer *pMemoryBuf, tOrderDescriptor *pDesc, tF
 /*
  * create local reducer to launch the second-stage reduce process at client site
  */
-void tscCreateLocalReducer(tExtMemBuffer **pMemBuffer, int32_t numOfBuffer, tOrderDescriptor *pDesc,
+void tscCreateLocalMerger(tExtMemBuffer **pMemBuffer, int32_t numOfBuffer, tOrderDescriptor *pDesc,
                            SColumnModel *finalModel, SColumnModel *pFFModel, SSqlObj* pSql);
 
-void tscDestroyLocalReducer(SSqlObj *pSql);
+void tscDestroyLocalMerger(SSqlObj *pSql);
 
 int32_t tscDoLocalMerge(SSqlObj *pSql);
 
diff --git a/src/client/inc/tscUtil.h b/src/client/inc/tscUtil.h
index 633512e324..45a5c2e578 100644
--- a/src/client/inc/tscUtil.h
+++ b/src/client/inc/tscUtil.h
@@ -225,7 +225,7 @@ void tscInitQueryInfo(SQueryInfo* pQueryInfo);
 
 void tscClearSubqueryInfo(SSqlCmd* pCmd);
 void tscFreeVgroupTableInfo(SArray* pVgroupTables);
-SArray* tscVgroupTableInfoClone(SArray* pVgroupTables);
+SArray* tscVgroupTableInfoDup(SArray* pVgroupTables);
 void tscRemoveVgroupTableGroup(SArray* pVgroupTable, int32_t index);
 void tscVgroupTableCopy(SVgroupTableInfo* info, SVgroupTableInfo* pInfo);
 
@@ -292,7 +292,7 @@ uint32_t tscGetTableMetaSize(STableMeta* pTableMeta);
 CChildTableMeta* tscCreateChildMeta(STableMeta* pTableMeta);
 uint32_t tscGetTableMetaMaxSize();
 int32_t tscCreateTableMetaFromCChildMeta(STableMeta* pChild, const char* name);
-STableMeta* tscTableMetaClone(STableMeta* pTableMeta);
+STableMeta* tscTableMetaDup(STableMeta* pTableMeta);
 
 
 void* malloc_throw(size_t size);
diff --git a/src/client/inc/tsclient.h b/src/client/inc/tsclient.h
index 83eaeeb321..8c3daeb656 100644
--- a/src/client/inc/tsclient.h
+++ b/src/client/inc/tsclient.h
@@ -39,7 +39,7 @@ extern "C" {
 
 // forward declaration
 struct SSqlInfo;
-struct SLocalReducer;
+struct SLocalMerger;
 
 // data source from sql string or from file
 enum {
@@ -292,7 +292,7 @@ typedef struct {
   SColumnIndex*  pColumnIndex;
 
   SArithmeticSupport   *pArithSup;   // support the arithmetic expression calculation on agg functions
-  struct SLocalReducer *pLocalReducer;
+  struct SLocalMerger  *pLocalMerger;
 } SSqlRes;
 
 typedef struct STscObj {
diff --git a/src/client/src/tscLocalMerge.c b/src/client/src/tscLocalMerge.c
index 6280cc520a..a3619dddc2 100644
--- a/src/client/src/tscLocalMerge.c
+++ b/src/client/src/tscLocalMerge.c
@@ -56,7 +56,7 @@ int32_t treeComparator(const void *pLeft, const void *pRight, void *param) {
   }
 }
 
-static void tscInitSqlContext(SSqlCmd *pCmd, SLocalReducer *pReducer, tOrderDescriptor *pDesc) {
+static void tscInitSqlContext(SSqlCmd *pCmd, SLocalMerger *pReducer, tOrderDescriptor *pDesc) {
   /*
    * the fields and offset attributes in pCmd and pModel may be different due to
    * merge requirement. So, the final result in pRes structure is formatted in accordance with the pCmd object.
@@ -166,7 +166,7 @@ static SFillColInfo* createFillColInfo(SQueryInfo* pQueryInfo) {
   return pFillCol;
 }
 
-void tscCreateLocalReducer(tExtMemBuffer **pMemBuffer, int32_t numOfBuffer, tOrderDescriptor *pDesc,
+void tscCreateLocalMerger(tExtMemBuffer **pMemBuffer, int32_t numOfBuffer, tOrderDescriptor *pDesc,
                            SColumnModel *finalmodel, SColumnModel *pFFModel, SSqlObj* pSql) {
   SSqlCmd* pCmd = &pSql->cmd;
   SSqlRes* pRes = &pSql->res;
@@ -212,9 +212,9 @@ void tscCreateLocalReducer(tExtMemBuffer **pMemBuffer, int32_t numOfBuffer, tOrd
     return;
   }
 
-  size_t size = sizeof(SLocalReducer) + POINTER_BYTES * numOfFlush;
+  size_t size = sizeof(SLocalMerger) + POINTER_BYTES * numOfFlush;
   
-  SLocalReducer *pReducer = (SLocalReducer *) calloc(1, size);
+  SLocalMerger *pReducer = (SLocalMerger *) calloc(1, size);
   if (pReducer == NULL) {
     tscError("%p failed to create local merge structure, out of memory", pSql);
 
@@ -372,7 +372,7 @@ void tscCreateLocalReducer(tExtMemBuffer **pMemBuffer, int32_t numOfBuffer, tOrd
 
   pReducer->offset = (int32_t)pQueryInfo->limit.offset;
 
-  pRes->pLocalReducer = pReducer;
+  pRes->pLocalMerger = pReducer;
   pRes->numOfGroups = 0;
 
   STableMetaInfo *pTableMetaInfo = tscGetTableMetaInfoFromCmd(pCmd, pCmd->clauseIndex, 0);
@@ -477,13 +477,13 @@ int32_t saveToBuffer(tExtMemBuffer *pMemoryBuf, tOrderDescriptor *pDesc, tFilePa
   return 0;
 }
 
-void tscDestroyLocalReducer(SSqlObj *pSql) {
+void tscDestroyLocalMerger(SSqlObj *pSql) {
   if (pSql == NULL) {
     return;
   }
 
   SSqlRes *pRes = &(pSql->res);
-  if (pRes->pLocalReducer == NULL) {
+  if (pRes->pLocalMerger == NULL) {
     return;
   }
 
@@ -491,14 +491,14 @@ void tscDestroyLocalReducer(SSqlObj *pSql) {
   SQueryInfo *pQueryInfo = tscGetQueryInfoDetail(pCmd, pCmd->clauseIndex);
 
   // there is no more result, so we release all allocated resource
-  SLocalReducer *pLocalReducer = (SLocalReducer *)atomic_exchange_ptr(&pRes->pLocalReducer, NULL);
-  if (pLocalReducer != NULL) {
-    pLocalReducer->pFillInfo = taosDestroyFillInfo(pLocalReducer->pFillInfo);
+  SLocalMerger *pLocalMerge = (SLocalMerger *)atomic_exchange_ptr(&pRes->pLocalMerger, NULL);
+  if (pLocalMerge != NULL) {
+    pLocalMerge->pFillInfo = taosDestroyFillInfo(pLocalMerge->pFillInfo);
 
-    if (pLocalReducer->pCtx != NULL) {
+    if (pLocalMerge->pCtx != NULL) {
       int32_t numOfExprs = (int32_t) tscSqlExprNumOfExprs(pQueryInfo);
       for (int32_t i = 0; i < numOfExprs; ++i) {
-        SQLFunctionCtx *pCtx = &pLocalReducer->pCtx[i];
+        SQLFunctionCtx *pCtx = &pLocalMerge->pCtx[i];
 
         tVariantDestroy(&pCtx->tag);
         tfree(pCtx->resultInfo);
@@ -508,31 +508,31 @@ void tscDestroyLocalReducer(SSqlObj *pSql) {
         }
       }
 
-      tfree(pLocalReducer->pCtx);
+      tfree(pLocalMerge->pCtx);
     }
 
-    tfree(pLocalReducer->prevRowOfInput);
+    tfree(pLocalMerge->prevRowOfInput);
 
-    tfree(pLocalReducer->pTempBuffer);
-    tfree(pLocalReducer->pResultBuf);
+    tfree(pLocalMerge->pTempBuffer);
+    tfree(pLocalMerge->pResultBuf);
 
-    if (pLocalReducer->pLoserTree) {
-      tfree(pLocalReducer->pLoserTree->param);
-      tfree(pLocalReducer->pLoserTree);
+    if (pLocalMerge->pLoserTree) {
+      tfree(pLocalMerge->pLoserTree->param);
+      tfree(pLocalMerge->pLoserTree);
     }
 
-    tfree(pLocalReducer->pFinalRes);
-    tfree(pLocalReducer->discardData);
+    tfree(pLocalMerge->pFinalRes);
+    tfree(pLocalMerge->discardData);
 
-    tscLocalReducerEnvDestroy(pLocalReducer->pExtMemBuffer, pLocalReducer->pDesc, pLocalReducer->resColModel, pLocalReducer->finalModel,
-                              pLocalReducer->numOfVnode);
-    for (int32_t i = 0; i < pLocalReducer->numOfBuffer; ++i) {
-      tfree(pLocalReducer->pLocalDataSrc[i]);
+    tscLocalReducerEnvDestroy(pLocalMerge->pExtMemBuffer, pLocalMerge->pDesc, pLocalMerge->resColModel, pLocalMerge->finalModel,
+                              pLocalMerge->numOfVnode);
+    for (int32_t i = 0; i < pLocalMerge->numOfBuffer; ++i) {
+      tfree(pLocalMerge->pLocalDataSrc[i]);
     }
 
-    pLocalReducer->numOfBuffer = 0;
-    pLocalReducer->numOfCompleted = 0;
-    free(pLocalReducer);
+    pLocalMerge->numOfBuffer = 0;
+    pLocalMerge->numOfCompleted = 0;
+    free(pLocalMerge);
   } else {
     tscDebug("%p already freed or another free function is invoked", pSql);
   }
@@ -604,7 +604,7 @@ static int32_t createOrderDescriptor(tOrderDescriptor **pOrderDesc, SSqlCmd *pCm
   }
 }
 
-bool isSameGroup(SSqlCmd *pCmd, SLocalReducer *pReducer, char *pPrev, tFilePage *tmpBuffer) {
+bool isSameGroup(SSqlCmd *pCmd, SLocalMerger *pReducer, char *pPrev, tFilePage *tmpBuffer) {
   SQueryInfo *pQueryInfo = tscGetQueryInfoDetail(pCmd, pCmd->clauseIndex);
 
   // disable merge procedure for column projection query
@@ -795,12 +795,12 @@ void tscLocalReducerEnvDestroy(tExtMemBuffer **pMemBuffer, tOrderDescriptor *pDe
 
 /**
  *
- * @param pLocalReducer
+ * @param pLocalMerge
  * @param pOneInterDataSrc
  * @param treeList
  * @return the number of remain input source. if ret == 0, all data has been handled
  */
-int32_t loadNewDataFromDiskFor(SLocalReducer *pLocalReducer, SLocalDataSource *pOneInterDataSrc,
+int32_t loadNewDataFromDiskFor(SLocalMerger *pLocalMerge, SLocalDataSource *pOneInterDataSrc,
                                bool *needAdjustLoserTree) {
   pOneInterDataSrc->rowIdx = 0;
   pOneInterDataSrc->pageId += 1;
@@ -817,17 +817,17 @@ int32_t loadNewDataFromDiskFor(SLocalReducer *pLocalReducer, SLocalDataSource *p
 #endif
     *needAdjustLoserTree = true;
   } else {
-    pLocalReducer->numOfCompleted += 1;
+    pLocalMerge->numOfCompleted += 1;
 
     pOneInterDataSrc->rowIdx = -1;
     pOneInterDataSrc->pageId = -1;
     *needAdjustLoserTree = true;
   }
 
-  return pLocalReducer->numOfBuffer;
+  return pLocalMerge->numOfBuffer;
 }
 
-void adjustLoserTreeFromNewData(SLocalReducer *pLocalReducer, SLocalDataSource *pOneInterDataSrc,
+void adjustLoserTreeFromNewData(SLocalMerger *pLocalMerge, SLocalDataSource *pOneInterDataSrc,
                                 SLoserTreeInfo *pTree) {
   /*
    * load a new data page into memory for intermediate dataset source,
@@ -835,7 +835,7 @@ void adjustLoserTreeFromNewData(SLocalReducer *pLocalReducer, SLocalDataSource *
    */
   bool needToAdjust = true;
   if (pOneInterDataSrc->filePage.num <= pOneInterDataSrc->rowIdx) {
-    loadNewDataFromDiskFor(pLocalReducer, pOneInterDataSrc, &needToAdjust);
+    loadNewDataFromDiskFor(pLocalMerge, pOneInterDataSrc, &needToAdjust);
   }
 
   /*
@@ -843,7 +843,7 @@ void adjustLoserTreeFromNewData(SLocalReducer *pLocalReducer, SLocalDataSource *
    * if the loser tree is rebuild completed, we do not need to adjust
    */
   if (needToAdjust) {
-    int32_t leafNodeIdx = pTree->pNode[0].index + pLocalReducer->numOfBuffer;
+    int32_t leafNodeIdx = pTree->pNode[0].index + pLocalMerge->numOfBuffer;
 
 #ifdef _DEBUG_VIEW
     printf("before adjust:\t");
@@ -860,7 +860,7 @@ void adjustLoserTreeFromNewData(SLocalReducer *pLocalReducer, SLocalDataSource *
   }
 }
 
-void savePrevRecordAndSetupFillInfo(SLocalReducer *pLocalReducer, SQueryInfo *pQueryInfo, SFillInfo *pFillInfo) {
+void savePrevRecordAndSetupFillInfo(SLocalMerger *pLocalMerge, SQueryInfo *pQueryInfo, SFillInfo *pFillInfo) {
   // discard following dataset in the same group and reset the interpolation information
   STableMetaInfo *pTableMetaInfo = tscGetMetaInfo(pQueryInfo, 0);
 
@@ -873,28 +873,28 @@ void savePrevRecordAndSetupFillInfo(SLocalReducer *pLocalReducer, SQueryInfo *pQ
     taosResetFillInfo(pFillInfo, revisedSTime);
   }
 
-  pLocalReducer->discard = true;
-  pLocalReducer->discardData->num = 0;
+  pLocalMerge->discard = true;
+  pLocalMerge->discardData->num = 0;
 
-  SColumnModel *pModel = pLocalReducer->pDesc->pColumnModel;
-  tColModelAppend(pModel, pLocalReducer->discardData, pLocalReducer->prevRowOfInput, 0, 1, 1);
+  SColumnModel *pModel = pLocalMerge->pDesc->pColumnModel;
+  tColModelAppend(pModel, pLocalMerge->discardData, pLocalMerge->prevRowOfInput, 0, 1, 1);
 }
 
-static void genFinalResWithoutFill(SSqlRes* pRes, SLocalReducer *pLocalReducer, SQueryInfo* pQueryInfo) {
+static void genFinalResWithoutFill(SSqlRes* pRes, SLocalMerger *pLocalMerge, SQueryInfo* pQueryInfo) {
   assert(pQueryInfo->interval.interval == 0 || pQueryInfo->fillType == TSDB_FILL_NONE);
 
-  tFilePage * pBeforeFillData = pLocalReducer->pResultBuf;
+  tFilePage * pBeforeFillData = pLocalMerge->pResultBuf;
 
-  pRes->data = pLocalReducer->pFinalRes;
+  pRes->data = pLocalMerge->pFinalRes;
   pRes->numOfRows = (int32_t) pBeforeFillData->num;
 
   if (pQueryInfo->limit.offset > 0) {
     if (pQueryInfo->limit.offset < pRes->numOfRows) {
       int32_t prevSize = (int32_t) pBeforeFillData->num;
-      tColModelErase(pLocalReducer->finalModel, pBeforeFillData, prevSize, 0, (int32_t)pQueryInfo->limit.offset - 1);
+      tColModelErase(pLocalMerge->finalModel, pBeforeFillData, prevSize, 0, (int32_t)pQueryInfo->limit.offset - 1);
 
       /* remove the hole in column model */
-      tColModelCompact(pLocalReducer->finalModel, pBeforeFillData, prevSize);
+      tColModelCompact(pLocalMerge->finalModel, pBeforeFillData, prevSize);
 
       pRes->numOfRows -= (int32_t) pQueryInfo->limit.offset;
       pQueryInfo->limit.offset = 0;
@@ -907,7 +907,7 @@ static void genFinalResWithoutFill(SSqlRes* pRes, SLocalReducer *pLocalReducer,
   if (pRes->numOfRowsGroup >= pQueryInfo->limit.limit && pQueryInfo->limit.limit > 0) {
     pRes->numOfRows = 0;
     pBeforeFillData->num = 0;
-    pLocalReducer->discard = true;
+    pLocalMerge->discard = true;
     return;
   }
 
@@ -923,29 +923,29 @@ static void genFinalResWithoutFill(SSqlRes* pRes, SLocalReducer *pLocalReducer,
     pRes->numOfRows -= overflow;
     pBeforeFillData->num -= overflow;
 
-    tColModelCompact(pLocalReducer->finalModel, pBeforeFillData, prevSize);
+    tColModelCompact(pLocalMerge->finalModel, pBeforeFillData, prevSize);
 
     // set remain data to be discarded, and reset the interpolation information
-    savePrevRecordAndSetupFillInfo(pLocalReducer, pQueryInfo, pLocalReducer->pFillInfo);
+    savePrevRecordAndSetupFillInfo(pLocalMerge, pQueryInfo, pLocalMerge->pFillInfo);
   }
 
-  memcpy(pRes->data, pBeforeFillData->data, (size_t)(pRes->numOfRows * pLocalReducer->finalModel->rowSize));
+  memcpy(pRes->data, pBeforeFillData->data, (size_t)(pRes->numOfRows * pLocalMerge->finalModel->rowSize));
 
   pRes->numOfClauseTotal += pRes->numOfRows;
   pBeforeFillData->num = 0;
 }
 
 /*
- * Note: pRes->pLocalReducer may be null, due to the fact that "tscDestroyLocalReducer" is called
+ * Note: pRes->pLocalMerge may be null, due to the fact that "tscDestroyLocalMerger" is called
  * by "interuptHandler" function in shell
  */
-static void doFillResult(SSqlObj *pSql, SLocalReducer *pLocalReducer, bool doneOutput) {
+static void doFillResult(SSqlObj *pSql, SLocalMerger *pLocalMerge, bool doneOutput) {
   SSqlCmd *pCmd = &pSql->cmd;
   SSqlRes *pRes = &pSql->res;
   
-  tFilePage  *pBeforeFillData = pLocalReducer->pResultBuf;
+  tFilePage  *pBeforeFillData = pLocalMerge->pResultBuf;
   SQueryInfo *pQueryInfo = tscGetQueryInfoDetail(pCmd, pCmd->clauseIndex);
-  SFillInfo  *pFillInfo = pLocalReducer->pFillInfo;
+  SFillInfo  *pFillInfo = pLocalMerge->pFillInfo;
 
   // todo extract function
   int64_t actualETime = (pQueryInfo->order.order == TSDB_ORDER_ASC)? pQueryInfo->window.ekey: pQueryInfo->window.skey;
@@ -953,11 +953,11 @@ static void doFillResult(SSqlObj *pSql, SLocalReducer *pLocalReducer, bool doneO
   tFilePage **pResPages = malloc(POINTER_BYTES * pQueryInfo->fieldsInfo.numOfOutput);
   for (int32_t i = 0; i < pQueryInfo->fieldsInfo.numOfOutput; ++i) {
     TAOS_FIELD *pField = tscFieldInfoGetField(&pQueryInfo->fieldsInfo, i);
-    pResPages[i] = calloc(1, sizeof(tFilePage) + pField->bytes * pLocalReducer->resColModel->capacity);
+    pResPages[i] = calloc(1, sizeof(tFilePage) + pField->bytes * pLocalMerge->resColModel->capacity);
   }
 
   while (1) {
-    int64_t newRows = taosFillResultDataBlock(pFillInfo, pResPages, pLocalReducer->resColModel->capacity);
+    int64_t newRows = taosFillResultDataBlock(pFillInfo, pResPages, pLocalMerge->resColModel->capacity);
 
     if (pQueryInfo->limit.offset < newRows) {
       newRows -= pQueryInfo->limit.offset;
@@ -970,7 +970,7 @@ static void doFillResult(SSqlObj *pSql, SLocalReducer *pLocalReducer, bool doneO
         }
       }
 
-      pRes->data = pLocalReducer->pFinalRes;
+      pRes->data = pLocalMerge->pFinalRes;
       pRes->numOfRows = (int32_t) newRows;
 
       pQueryInfo->limit.offset = 0;
@@ -985,7 +985,7 @@ static void doFillResult(SSqlObj *pSql, SLocalReducer *pLocalReducer, bool doneO
         }
 
         // all output in current group are completed
-        int32_t totalRemainRows = (int32_t)getNumOfResultsAfterFillGap(pFillInfo, actualETime, pLocalReducer->resColModel->capacity);
+        int32_t totalRemainRows = (int32_t)getNumOfResultsAfterFillGap(pFillInfo, actualETime, pLocalMerge->resColModel->capacity);
         if (totalRemainRows <= 0) {
           break;
         }
@@ -1003,7 +1003,7 @@ static void doFillResult(SSqlObj *pSql, SLocalReducer *pLocalReducer, bool doneO
       assert(pRes->numOfRows >= 0);
 
       /* set remain data to be discarded, and reset the interpolation information */
-      savePrevRecordAndSetupFillInfo(pLocalReducer, pQueryInfo, pFillInfo);
+      savePrevRecordAndSetupFillInfo(pLocalMerge, pQueryInfo, pFillInfo);
     }
 
     int32_t offset = 0;
@@ -1025,8 +1025,8 @@ static void doFillResult(SSqlObj *pSql, SLocalReducer *pLocalReducer, bool doneO
   tfree(pResPages);
 }
 
-static void savePreviousRow(SLocalReducer *pLocalReducer, tFilePage *tmpBuffer) {
-  SColumnModel *pColumnModel = pLocalReducer->pDesc->pColumnModel;
+static void savePreviousRow(SLocalMerger *pLocalMerge, tFilePage *tmpBuffer) {
+  SColumnModel *pColumnModel = pLocalMerge->pDesc->pColumnModel;
   assert(pColumnModel->capacity == 1 && tmpBuffer->num == 1);
 
   // copy to previous temp buffer
@@ -1034,20 +1034,20 @@ static void savePreviousRow(SLocalReducer *pLocalReducer, tFilePage *tmpBuffer)
     SSchema *pSchema = getColumnModelSchema(pColumnModel, i);
     int16_t  offset = getColumnModelOffset(pColumnModel, i);
 
-    memcpy(pLocalReducer->prevRowOfInput + offset, tmpBuffer->data + offset, pSchema->bytes);
+    memcpy(pLocalMerge->prevRowOfInput + offset, tmpBuffer->data + offset, pSchema->bytes);
   }
 
   tmpBuffer->num = 0;
-  pLocalReducer->hasPrevRow = true;
+  pLocalMerge->hasPrevRow = true;
 }
 
-static void doExecuteSecondaryMerge(SSqlCmd *pCmd, SLocalReducer *pLocalReducer, bool needInit) {
+static void doExecuteSecondaryMerge(SSqlCmd *pCmd, SLocalMerger *pLocalMerge, bool needInit) {
   // the tag columns need to be set before all functions execution
   SQueryInfo *pQueryInfo = tscGetQueryInfoDetail(pCmd, pCmd->clauseIndex);
 
   size_t size = tscSqlExprNumOfExprs(pQueryInfo);
   for (int32_t j = 0; j < size; ++j) {
-    SQLFunctionCtx *pCtx = &pLocalReducer->pCtx[j];
+    SQLFunctionCtx *pCtx = &pLocalMerge->pCtx[j];
 
     // tags/tags_dummy function, the tag field of SQLFunctionCtx is from the input buffer
     int32_t functionId = pCtx->functionId;
@@ -1074,20 +1074,20 @@ static void doExecuteSecondaryMerge(SSqlCmd *pCmd, SLocalReducer *pLocalReducer,
   }
 
   for (int32_t j = 0; j < size; ++j) {
-    int32_t functionId = pLocalReducer->pCtx[j].functionId;
+    int32_t functionId = pLocalMerge->pCtx[j].functionId;
     if (functionId == TSDB_FUNC_TAG_DUMMY || functionId == TSDB_FUNC_TS_DUMMY) {
       continue;
     }
 
-    aAggs[functionId].mergeFunc(&pLocalReducer->pCtx[j]);
+    aAggs[functionId].mergeFunc(&pLocalMerge->pCtx[j]);
   }
 }
 
-static void handleUnprocessedRow(SSqlCmd *pCmd, SLocalReducer *pLocalReducer, tFilePage *tmpBuffer) {
-  if (pLocalReducer->hasUnprocessedRow) {
-    pLocalReducer->hasUnprocessedRow = false;
-    doExecuteSecondaryMerge(pCmd, pLocalReducer, true);
-    savePreviousRow(pLocalReducer, tmpBuffer);
+static void handleUnprocessedRow(SSqlCmd *pCmd, SLocalMerger *pLocalMerge, tFilePage *tmpBuffer) {
+  if (pLocalMerge->hasUnprocessedRow) {
+    pLocalMerge->hasUnprocessedRow = false;
+    doExecuteSecondaryMerge(pCmd, pLocalMerge, true);
+    savePreviousRow(pLocalMerge, tmpBuffer);
   }
 }
 
@@ -1120,7 +1120,7 @@ static int64_t getNumOfResultLocal(SQueryInfo *pQueryInfo, SQLFunctionCtx *pCtx)
  * filled with the same result, which is the tags, specified in group by clause
  *
  */
-static void fillMultiRowsOfTagsVal(SQueryInfo *pQueryInfo, int32_t numOfRes, SLocalReducer *pLocalReducer) {
+static void fillMultiRowsOfTagsVal(SQueryInfo *pQueryInfo, int32_t numOfRes, SLocalMerger *pLocalMerge) {
   int32_t maxBufSize = 0;  // find the max tags column length to prepare the buffer
   size_t size = tscSqlExprNumOfExprs(pQueryInfo);
   
@@ -1135,7 +1135,7 @@ static void fillMultiRowsOfTagsVal(SQueryInfo *pQueryInfo, int32_t numOfRes, SLo
 
   char *buf = malloc((size_t)maxBufSize);
   for (int32_t k = 0; k < size; ++k) {
-    SQLFunctionCtx *pCtx = &pLocalReducer->pCtx[k];
+    SQLFunctionCtx *pCtx = &pLocalMerge->pCtx[k];
     if (pCtx->functionId != TSDB_FUNC_TAG) {
       continue;
     }
@@ -1153,20 +1153,20 @@ static void fillMultiRowsOfTagsVal(SQueryInfo *pQueryInfo, int32_t numOfRes, SLo
   free(buf);
 }
 
-int32_t finalizeRes(SQueryInfo *pQueryInfo, SLocalReducer *pLocalReducer) {
+int32_t finalizeRes(SQueryInfo *pQueryInfo, SLocalMerger *pLocalMerge) {
   size_t size = tscSqlExprNumOfExprs(pQueryInfo);
   
   for (int32_t k = 0; k < size; ++k) {
-    SQLFunctionCtx* pCtx = &pLocalReducer->pCtx[k];
+    SQLFunctionCtx* pCtx = &pLocalMerge->pCtx[k];
     aAggs[pCtx->functionId].xFinalize(pCtx);
   }
 
-  pLocalReducer->hasPrevRow = false;
+  pLocalMerge->hasPrevRow = false;
 
-  int32_t numOfRes = (int32_t)getNumOfResultLocal(pQueryInfo, pLocalReducer->pCtx);
-  pLocalReducer->pResultBuf->num += numOfRes;
+  int32_t numOfRes = (int32_t)getNumOfResultLocal(pQueryInfo, pLocalMerge->pCtx);
+  pLocalMerge->pResultBuf->num += numOfRes;
 
-  fillMultiRowsOfTagsVal(pQueryInfo, numOfRes, pLocalReducer);
+  fillMultiRowsOfTagsVal(pQueryInfo, numOfRes, pLocalMerge);
   return numOfRes;
 }
 
@@ -1177,22 +1177,22 @@ int32_t finalizeRes(SQueryInfo *pQueryInfo, SLocalReducer *pLocalReducer) {
  * results generated by simple aggregation function, we merge them all into one points
  * *Exception*: column projection query, required no merge procedure
  */
-bool needToMerge(SQueryInfo *pQueryInfo, SLocalReducer *pLocalReducer, tFilePage *tmpBuffer) {
+bool needToMerge(SQueryInfo *pQueryInfo, SLocalMerger *pLocalMerge, tFilePage *tmpBuffer) {
   int32_t ret = 0;  // merge all result by default
 
-  int16_t functionId = pLocalReducer->pCtx[0].functionId;
+  int16_t functionId = pLocalMerge->pCtx[0].functionId;
 
   // todo opt performance
   if ((/*functionId == TSDB_FUNC_PRJ || */functionId == TSDB_FUNC_ARITHM) || (tscIsProjectionQueryOnSTable(pQueryInfo, 0))) {  // column projection query
     ret = 1;                                                            // disable merge procedure
   } else {
-    tOrderDescriptor *pDesc = pLocalReducer->pDesc;
+    tOrderDescriptor *pDesc = pLocalMerge->pDesc;
     if (pDesc->orderInfo.numOfCols > 0) {
       if (pDesc->tsOrder == TSDB_ORDER_ASC) {  // asc
         // todo refactor comparator
-        ret = compare_a(pLocalReducer->pDesc, 1, 0, pLocalReducer->prevRowOfInput, 1, 0, tmpBuffer->data);
+        ret = compare_a(pLocalMerge->pDesc, 1, 0, pLocalMerge->prevRowOfInput, 1, 0, tmpBuffer->data);
       } else {  // desc
-        ret = compare_d(pLocalReducer->pDesc, 1, 0, pLocalReducer->prevRowOfInput, 1, 0, tmpBuffer->data);
+        ret = compare_d(pLocalMerge->pDesc, 1, 0, pLocalMerge->prevRowOfInput, 1, 0, tmpBuffer->data);
       }
     }
   }
@@ -1230,17 +1230,17 @@ static bool saveGroupResultInfo(SSqlObj *pSql) {
 /**
  *
  * @param pSql
- * @param pLocalReducer
+ * @param pLocalMerge
  * @param noMoreCurrentGroupRes
  * @return if current group is skipped, return false, and do NOT record it into pRes->numOfGroups
  */
-bool genFinalResults(SSqlObj *pSql, SLocalReducer *pLocalReducer, bool noMoreCurrentGroupRes) {
+bool genFinalResults(SSqlObj *pSql, SLocalMerger *pLocalMerge, bool noMoreCurrentGroupRes) {
   SSqlCmd *pCmd = &pSql->cmd;
   SSqlRes *pRes = &pSql->res;
 
   SQueryInfo *  pQueryInfo = tscGetQueryInfoDetail(pCmd, pCmd->clauseIndex);
-  tFilePage *   pResBuf = pLocalReducer->pResultBuf;
-  SColumnModel *pModel = pLocalReducer->resColModel;
+  tFilePage *   pResBuf = pLocalMerge->pResultBuf;
+  SColumnModel *pModel = pLocalMerge->resColModel;
 
   pRes->code = TSDB_CODE_SUCCESS;
 
@@ -1251,11 +1251,11 @@ bool genFinalResults(SSqlObj *pSql, SLocalReducer *pLocalReducer, bool noMoreCur
   if (pQueryInfo->slimit.offset > 0) {
     pRes->numOfRows = 0;
     pQueryInfo->slimit.offset -= 1;
-    pLocalReducer->discard = !noMoreCurrentGroupRes;
+    pLocalMerge->discard = !noMoreCurrentGroupRes;
 
-    if (pLocalReducer->discard) {
-      SColumnModel *pInternModel = pLocalReducer->pDesc->pColumnModel;
-      tColModelAppend(pInternModel, pLocalReducer->discardData, pLocalReducer->pTempBuffer->data, 0, 1, 1);
+    if (pLocalMerge->discard) {
+      SColumnModel *pInternModel = pLocalMerge->pDesc->pColumnModel;
+      tColModelAppend(pInternModel, pLocalMerge->discardData, pLocalMerge->pTempBuffer->data, 0, 1, 1);
     }
 
     return false;
@@ -1264,19 +1264,14 @@ bool genFinalResults(SSqlObj *pSql, SLocalReducer *pLocalReducer, bool noMoreCur
   tColModelCompact(pModel, pResBuf, pModel->capacity);
 
   if (tscIsSecondStageQuery(pQueryInfo)) {
-    doArithmeticCalculate(pQueryInfo, pResBuf, pModel->rowSize, pLocalReducer->finalModel->rowSize);
+    doArithmeticCalculate(pQueryInfo, pResBuf, pModel->rowSize, pLocalMerge->finalModel->rowSize);
   }
 
-#ifdef _DEBUG_VIEW
-  printf("final result before interpo:\n");
-//  tColModelDisplay(pLocalReducer->resColModel, pLocalReducer->pBufForInterpo, pResBuf->num, pResBuf->num);
-#endif
-
   // no interval query, no fill operation
   if (pQueryInfo->interval.interval == 0 || pQueryInfo->fillType == TSDB_FILL_NONE) {
-    genFinalResWithoutFill(pRes, pLocalReducer, pQueryInfo);
+    genFinalResWithoutFill(pRes, pLocalMerge, pQueryInfo);
   } else {
-    SFillInfo* pFillInfo = pLocalReducer->pFillInfo;
+    SFillInfo* pFillInfo = pLocalMerge->pFillInfo;
     if (pFillInfo != NULL) {
       TSKEY ekey = (pQueryInfo->order.order == TSDB_ORDER_ASC)? pQueryInfo->window.ekey: pQueryInfo->window.skey;
 
@@ -1284,34 +1279,34 @@ bool genFinalResults(SSqlObj *pSql, SLocalReducer *pLocalReducer, bool noMoreCur
       taosFillCopyInputDataFromOneFilePage(pFillInfo, pResBuf);
     }
     
-    doFillResult(pSql, pLocalReducer, noMoreCurrentGroupRes);
+    doFillResult(pSql, pLocalMerge, noMoreCurrentGroupRes);
   }
 
   return true;
 }
 
-void resetOutputBuf(SQueryInfo *pQueryInfo, SLocalReducer *pLocalReducer) {// reset output buffer to the beginning
+void resetOutputBuf(SQueryInfo *pQueryInfo, SLocalMerger *pLocalMerge) {// reset output buffer to the beginning
   size_t t = tscSqlExprNumOfExprs(pQueryInfo);
   for (int32_t i = 0; i < t; ++i) {
     SSqlExpr* pExpr = tscSqlExprGet(pQueryInfo, i);
-    pLocalReducer->pCtx[i].aOutputBuf = pLocalReducer->pResultBuf->data + pExpr->offset * pLocalReducer->resColModel->capacity;
+    pLocalMerge->pCtx[i].aOutputBuf = pLocalMerge->pResultBuf->data + pExpr->offset * pLocalMerge->resColModel->capacity;
 
     if (pExpr->functionId == TSDB_FUNC_TOP || pExpr->functionId == TSDB_FUNC_BOTTOM || pExpr->functionId == TSDB_FUNC_DIFF) {
-      pLocalReducer->pCtx[i].ptsOutputBuf = pLocalReducer->pCtx[0].aOutputBuf;
+      pLocalMerge->pCtx[i].ptsOutputBuf = pLocalMerge->pCtx[0].aOutputBuf;
     }
   }
 
-  memset(pLocalReducer->pResultBuf, 0, pLocalReducer->nResultBufSize + sizeof(tFilePage));
+  memset(pLocalMerge->pResultBuf, 0, pLocalMerge->nResultBufSize + sizeof(tFilePage));
 }
 
-static void resetEnvForNewResultset(SSqlRes *pRes, SSqlCmd *pCmd, SLocalReducer *pLocalReducer) {
+static void resetEnvForNewResultset(SSqlRes *pRes, SSqlCmd *pCmd, SLocalMerger *pLocalMerge) {
   // In handling data in other groups, we need to reset the interpolation information for a new group data
   pRes->numOfRows = 0;
   pRes->numOfRowsGroup = 0;
 
   SQueryInfo *pQueryInfo = tscGetQueryInfoDetail(pCmd, pCmd->clauseIndex);
 
-  pQueryInfo->limit.offset = pLocalReducer->offset;
+  pQueryInfo->limit.offset = pLocalMerge->offset;
 
   STableMetaInfo *pTableMetaInfo = tscGetTableMetaInfoFromCmd(pCmd, pCmd->clauseIndex, 0);
   STableComInfo tinfo = tscGetTableInfo(pTableMetaInfo->pTableMeta);
@@ -1320,12 +1315,12 @@ static void resetEnvForNewResultset(SSqlRes *pRes, SSqlCmd *pCmd, SLocalReducer
   if (pQueryInfo->fillType != TSDB_FILL_NONE) {
     TSKEY skey = (pQueryInfo->order.order == TSDB_ORDER_ASC)? pQueryInfo->window.skey:pQueryInfo->window.ekey;//MIN(pQueryInfo->window.skey, pQueryInfo->window.ekey);
     int64_t newTime = taosTimeTruncate(skey, &pQueryInfo->interval, tinfo.precision);
-    taosResetFillInfo(pLocalReducer->pFillInfo, newTime);
+    taosResetFillInfo(pLocalMerge->pFillInfo, newTime);
   }
 }
 
-static bool isAllSourcesCompleted(SLocalReducer *pLocalReducer) {
-  return (pLocalReducer->numOfBuffer == pLocalReducer->numOfCompleted);
+static bool isAllSourcesCompleted(SLocalMerger *pLocalMerge) {
+  return (pLocalMerge->numOfBuffer == pLocalMerge->numOfCompleted);
 }
 
 static bool doBuildFilledResultForGroup(SSqlObj *pSql) {
@@ -1333,19 +1328,19 @@ static bool doBuildFilledResultForGroup(SSqlObj *pSql) {
   SSqlRes *pRes = &pSql->res;
 
   SQueryInfo *pQueryInfo = tscGetQueryInfoDetail(pCmd, pCmd->clauseIndex);
-  SLocalReducer *pLocalReducer = pRes->pLocalReducer;
-  SFillInfo *pFillInfo = pLocalReducer->pFillInfo;
+  SLocalMerger *pLocalMerge = pRes->pLocalMerger;
+  SFillInfo *pFillInfo = pLocalMerge->pFillInfo;
 
   if (pFillInfo != NULL && taosFillHasMoreResults(pFillInfo)) {
     assert(pQueryInfo->fillType != TSDB_FILL_NONE);
 
-    tFilePage *pFinalDataBuf = pLocalReducer->pResultBuf;
+    tFilePage *pFinalDataBuf = pLocalMerge->pResultBuf;
     int64_t etime = *(int64_t *)(pFinalDataBuf->data + TSDB_KEYSIZE * (pFillInfo->numOfRows - 1));
 
     // the first column must be the timestamp column
-    int32_t rows = (int32_t) getNumOfResultsAfterFillGap(pFillInfo, etime, pLocalReducer->resColModel->capacity);
+    int32_t rows = (int32_t) getNumOfResultsAfterFillGap(pFillInfo, etime, pLocalMerge->resColModel->capacity);
     if (rows > 0) {  // do fill gap
-      doFillResult(pSql, pLocalReducer, false);
+      doFillResult(pSql, pLocalMerge, false);
     }
 
     return true;
@@ -1358,23 +1353,23 @@ static bool doHandleLastRemainData(SSqlObj *pSql) {
   SSqlCmd *pCmd = &pSql->cmd;
   SSqlRes *pRes = &pSql->res;
 
-  SLocalReducer *pLocalReducer = pRes->pLocalReducer;
-  SFillInfo     *pFillInfo = pLocalReducer->pFillInfo;
+  SLocalMerger *pLocalMerge = pRes->pLocalMerger;
+  SFillInfo     *pFillInfo = pLocalMerge->pFillInfo;
 
-  bool prevGroupCompleted = (!pLocalReducer->discard) && pLocalReducer->hasUnprocessedRow;
+  bool prevGroupCompleted = (!pLocalMerge->discard) && pLocalMerge->hasUnprocessedRow;
 
   SQueryInfo *pQueryInfo = tscGetQueryInfoDetail(pCmd, pCmd->clauseIndex);
 
-  if ((isAllSourcesCompleted(pLocalReducer) && !pLocalReducer->hasPrevRow) || pLocalReducer->pLocalDataSrc[0] == NULL ||
+  if ((isAllSourcesCompleted(pLocalMerge) && !pLocalMerge->hasPrevRow) || pLocalMerge->pLocalDataSrc[0] == NULL ||
       prevGroupCompleted) {
     // if fillType == TSDB_FILL_NONE, return directly
     if (pQueryInfo->fillType != TSDB_FILL_NONE &&
       ((pRes->numOfRowsGroup < pQueryInfo->limit.limit && pQueryInfo->limit.limit > 0) || (pQueryInfo->limit.limit < 0))) {
       int64_t etime = (pQueryInfo->order.order == TSDB_ORDER_ASC)? pQueryInfo->window.ekey : pQueryInfo->window.skey;
 
-      int32_t rows = (int32_t)getNumOfResultsAfterFillGap(pFillInfo, etime, pLocalReducer->resColModel->capacity);
+      int32_t rows = (int32_t)getNumOfResultsAfterFillGap(pFillInfo, etime, pLocalMerge->resColModel->capacity);
       if (rows > 0) {
-        doFillResult(pSql, pLocalReducer, true);
+        doFillResult(pSql, pLocalMerge, true);
       }
     }
 
@@ -1384,7 +1379,7 @@ static bool doHandleLastRemainData(SSqlObj *pSql) {
      *
      * No results will be generated and query completed.
      */
-    if (pRes->numOfRows > 0 || (isAllSourcesCompleted(pLocalReducer) && (!pLocalReducer->hasUnprocessedRow))) {
+    if (pRes->numOfRows > 0 || (isAllSourcesCompleted(pLocalMerge) && (!pLocalMerge->hasUnprocessedRow))) {
       return true;
     }
 
@@ -1393,7 +1388,7 @@ static bool doHandleLastRemainData(SSqlObj *pSql) {
       return true;
     }
 
-    resetEnvForNewResultset(pRes, pCmd, pLocalReducer);
+    resetEnvForNewResultset(pRes, pCmd, pLocalMerge);
   }
 
   return false;
@@ -1403,12 +1398,12 @@ static void doProcessResultInNextWindow(SSqlObj *pSql, int32_t numOfRes) {
   SSqlCmd *pCmd = &pSql->cmd;
   SSqlRes *pRes = &pSql->res;
 
-  SLocalReducer *pLocalReducer = pRes->pLocalReducer;
+  SLocalMerger *pLocalMerge = pRes->pLocalMerger;
   SQueryInfo *   pQueryInfo = tscGetQueryInfoDetail(pCmd, pCmd->clauseIndex);
   size_t size = tscSqlExprNumOfExprs(pQueryInfo);
 
   for (int32_t k = 0; k < size; ++k) {
-    SQLFunctionCtx *pCtx = &pLocalReducer->pCtx[k];
+    SQLFunctionCtx *pCtx = &pLocalMerge->pCtx[k];
     pCtx->aOutputBuf += pCtx->outputBytes * numOfRes;
 
     // set the correct output timestamp column position
@@ -1417,7 +1412,7 @@ static void doProcessResultInNextWindow(SSqlObj *pSql, int32_t numOfRes) {
     }
   }
 
-  doExecuteSecondaryMerge(pCmd, pLocalReducer, true);
+  doExecuteSecondaryMerge(pCmd, pLocalMerge, true);
 }
 
 int32_t tscDoLocalMerge(SSqlObj *pSql) {
@@ -1426,14 +1421,14 @@ int32_t tscDoLocalMerge(SSqlObj *pSql) {
 
   tscResetForNextRetrieve(pRes);
 
-  if (pSql->signature != pSql || pRes == NULL || pRes->pLocalReducer == NULL) {  // all data has been processed
+  if (pSql->signature != pSql || pRes == NULL || pRes->pLocalMerger == NULL) {  // all data has been processed
     tscError("%p local merge abort due to error occurs, code:%s", pSql, tstrerror(pRes->code));
     return pRes->code;
   }
 
-  SLocalReducer *pLocalReducer = pRes->pLocalReducer;
+  SLocalMerger  *pLocalMerge = pRes->pLocalMerger;
   SQueryInfo    *pQueryInfo = tscGetQueryInfoDetail(pCmd, pCmd->clauseIndex);
-  tFilePage     *tmpBuffer = pLocalReducer->pTempBuffer;
+  tFilePage     *tmpBuffer = pLocalMerge->pTempBuffer;
 
   if (doHandleLastRemainData(pSql)) {
     return TSDB_CODE_SUCCESS;
@@ -1443,24 +1438,24 @@ int32_t tscDoLocalMerge(SSqlObj *pSql) {
     return TSDB_CODE_SUCCESS;
   }
 
-  SLoserTreeInfo *pTree = pLocalReducer->pLoserTree;
+  SLoserTreeInfo *pTree = pLocalMerge->pLoserTree;
 
   // clear buffer
-  handleUnprocessedRow(pCmd, pLocalReducer, tmpBuffer);
-  SColumnModel *pModel = pLocalReducer->pDesc->pColumnModel;
+  handleUnprocessedRow(pCmd, pLocalMerge, tmpBuffer);
+  SColumnModel *pModel = pLocalMerge->pDesc->pColumnModel;
 
   while (1) {
-    if (isAllSourcesCompleted(pLocalReducer)) {
+    if (isAllSourcesCompleted(pLocalMerge)) {
       break;
     }
 
 #ifdef _DEBUG_VIEW
     printf("chosen data in pTree[0] = %d\n", pTree->pNode[0].index);
 #endif
-    assert((pTree->pNode[0].index < pLocalReducer->numOfBuffer) && (pTree->pNode[0].index >= 0) && tmpBuffer->num == 0);
+    assert((pTree->pNode[0].index < pLocalMerge->numOfBuffer) && (pTree->pNode[0].index >= 0) && tmpBuffer->num == 0);
 
     // chosen from loser tree
-    SLocalDataSource *pOneDataSrc = pLocalReducer->pLocalDataSrc[pTree->pNode[0].index];
+    SLocalDataSource *pOneDataSrc = pLocalMerge->pLocalDataSrc[pTree->pNode[0].index];
 
     tColModelAppend(pModel, tmpBuffer, pOneDataSrc->filePage.data, pOneDataSrc->rowIdx, 1,
                     pOneDataSrc->pMemBuffer->pColumnModel->capacity);
@@ -1473,76 +1468,76 @@ int32_t tscDoLocalMerge(SSqlObj *pSql) {
     tColModelDisplayEx(pModel, tmpBuffer->data, tmpBuffer->num, pModel->capacity, colInfo);
 #endif
 
-    if (pLocalReducer->discard) {
-      assert(pLocalReducer->hasUnprocessedRow == false);
+    if (pLocalMerge->discard) {
+      assert(pLocalMerge->hasUnprocessedRow == false);
 
       /* current record belongs to the same group of previous record, need to discard it */
-      if (isSameGroup(pCmd, pLocalReducer, pLocalReducer->discardData->data, tmpBuffer)) {
+      if (isSameGroup(pCmd, pLocalMerge, pLocalMerge->discardData->data, tmpBuffer)) {
         tmpBuffer->num = 0;
         pOneDataSrc->rowIdx += 1;
 
-        adjustLoserTreeFromNewData(pLocalReducer, pOneDataSrc, pTree);
+        adjustLoserTreeFromNewData(pLocalMerge, pOneDataSrc, pTree);
 
         // all inputs are exhausted, abort current process
-        if (isAllSourcesCompleted(pLocalReducer)) {
+        if (isAllSourcesCompleted(pLocalMerge)) {
           break;
         }
 
         // data belongs to the same group needs to be discarded
         continue;
       } else {
-        pLocalReducer->discard = false;
-        pLocalReducer->discardData->num = 0;
+        pLocalMerge->discard = false;
+        pLocalMerge->discardData->num = 0;
 
         if (saveGroupResultInfo(pSql)) {
           return TSDB_CODE_SUCCESS;
         }
 
-        resetEnvForNewResultset(pRes, pCmd, pLocalReducer);
+        resetEnvForNewResultset(pRes, pCmd, pLocalMerge);
       }
     }
 
-    if (pLocalReducer->hasPrevRow) {
-      if (needToMerge(pQueryInfo, pLocalReducer, tmpBuffer)) {
+    if (pLocalMerge->hasPrevRow) {
+      if (needToMerge(pQueryInfo, pLocalMerge, tmpBuffer)) {
         // belong to the group of the previous row, continue process it
-        doExecuteSecondaryMerge(pCmd, pLocalReducer, false);
+        doExecuteSecondaryMerge(pCmd, pLocalMerge, false);
 
         // copy to buffer
-        savePreviousRow(pLocalReducer, tmpBuffer);
+        savePreviousRow(pLocalMerge, tmpBuffer);
       } else {
         /*
          * current row does not belong to the group of previous row.
          * so the processing of previous group is completed.
          */
-        int32_t numOfRes = finalizeRes(pQueryInfo, pLocalReducer);
-        bool   sameGroup = isSameGroup(pCmd, pLocalReducer, pLocalReducer->prevRowOfInput, tmpBuffer);
+        int32_t numOfRes = finalizeRes(pQueryInfo, pLocalMerge);
+        bool   sameGroup = isSameGroup(pCmd, pLocalMerge, pLocalMerge->prevRowOfInput, tmpBuffer);
 
-        tFilePage *pResBuf = pLocalReducer->pResultBuf;
+        tFilePage *pResBuf = pLocalMerge->pResultBuf;
 
         /*
          * if the previous group does NOT generate any result (pResBuf->num == 0),
          * continue to process results instead of return results.
          */
-        if ((!sameGroup && pResBuf->num > 0) || (pResBuf->num == pLocalReducer->resColModel->capacity)) {
+        if ((!sameGroup && pResBuf->num > 0) || (pResBuf->num == pLocalMerge->resColModel->capacity)) {
           // does not belong to the same group
-          bool notSkipped = genFinalResults(pSql, pLocalReducer, !sameGroup);
+          bool notSkipped = genFinalResults(pSql, pLocalMerge, !sameGroup);
 
           // this row needs to discard, since it belongs to the group of previous
-          if (pLocalReducer->discard && sameGroup) {
-            pLocalReducer->hasUnprocessedRow = false;
+          if (pLocalMerge->discard && sameGroup) {
+            pLocalMerge->hasUnprocessedRow = false;
             tmpBuffer->num = 0;
           } else { // current row does not belongs to the previous group, so it is not be handled yet.
-            pLocalReducer->hasUnprocessedRow = true;
+            pLocalMerge->hasUnprocessedRow = true;
           }
 
-          resetOutputBuf(pQueryInfo, pLocalReducer);
+          resetOutputBuf(pQueryInfo, pLocalMerge);
           pOneDataSrc->rowIdx += 1;
 
           // here we do not check the return value
-          adjustLoserTreeFromNewData(pLocalReducer, pOneDataSrc, pTree);
+          adjustLoserTreeFromNewData(pLocalMerge, pOneDataSrc, pTree);
 
           if (pRes->numOfRows == 0) {
-            handleUnprocessedRow(pCmd, pLocalReducer, tmpBuffer);
+            handleUnprocessedRow(pCmd, pLocalMerge, tmpBuffer);
 
             if (!sameGroup) {
               /*
@@ -1553,7 +1548,7 @@ int32_t tscDoLocalMerge(SSqlObj *pSql) {
                 return TSDB_CODE_SUCCESS;
               }
 
-              resetEnvForNewResultset(pRes, pCmd, pLocalReducer);
+              resetEnvForNewResultset(pRes, pCmd, pLocalMerge);
             }
           } else {
             /*
@@ -1561,7 +1556,7 @@ int32_t tscDoLocalMerge(SSqlObj *pSql) {
              * We start the process in a new round.
              */
             if (sameGroup) {
-              handleUnprocessedRow(pCmd, pLocalReducer, tmpBuffer);
+              handleUnprocessedRow(pCmd, pLocalMerge, tmpBuffer);
             }
           }
 
@@ -1573,24 +1568,24 @@ int32_t tscDoLocalMerge(SSqlObj *pSql) {
           }
         } else {  // result buffer is not full
           doProcessResultInNextWindow(pSql, numOfRes);
-          savePreviousRow(pLocalReducer, tmpBuffer);
+          savePreviousRow(pLocalMerge, tmpBuffer);
         }
       }
     } else {
-      doExecuteSecondaryMerge(pCmd, pLocalReducer, true);
-      savePreviousRow(pLocalReducer, tmpBuffer);  // copy the processed row to buffer
+      doExecuteSecondaryMerge(pCmd, pLocalMerge, true);
+      savePreviousRow(pLocalMerge, tmpBuffer);  // copy the processed row to buffer
     }
 
     pOneDataSrc->rowIdx += 1;
-    adjustLoserTreeFromNewData(pLocalReducer, pOneDataSrc, pTree);
+    adjustLoserTreeFromNewData(pLocalMerge, pOneDataSrc, pTree);
   }
 
-  if (pLocalReducer->hasPrevRow) {
-    finalizeRes(pQueryInfo, pLocalReducer);
+  if (pLocalMerge->hasPrevRow) {
+    finalizeRes(pQueryInfo, pLocalMerge);
   }
 
-  if (pLocalReducer->pResultBuf->num) {
-    genFinalResults(pSql, pLocalReducer, true);
+  if (pLocalMerge->pResultBuf->num) {
+    genFinalResults(pSql, pLocalMerge, true);
   }
 
   return TSDB_CODE_SUCCESS;
@@ -1598,8 +1593,8 @@ int32_t tscDoLocalMerge(SSqlObj *pSql) {
 
 void tscInitResObjForLocalQuery(SSqlObj *pObj, int32_t numOfRes, int32_t rowLen) {
   SSqlRes *pRes = &pObj->res;
-  if (pRes->pLocalReducer != NULL) {
-    tscDestroyLocalReducer(pObj);
+  if (pRes->pLocalMerger != NULL) {
+    tscDestroyLocalMerger(pObj);
   }
 
   pRes->qhandle = 1;  // hack to pass the safety check in fetch_row function
@@ -1607,17 +1602,17 @@ void tscInitResObjForLocalQuery(SSqlObj *pObj, int32_t numOfRes, int32_t rowLen)
   pRes->row = 0;
 
   pRes->rspType = 0;  // used as a flag to denote if taos_retrieved() has been called yet
-  pRes->pLocalReducer = (SLocalReducer *)calloc(1, sizeof(SLocalReducer));
+  pRes->pLocalMerger = (SLocalMerger *)calloc(1, sizeof(SLocalMerger));
 
   /*
    * we need one additional byte space
    * the sprintf function needs one additional space to put '\0' at the end of string
    */
   size_t allocSize = numOfRes * rowLen + sizeof(tFilePage) + 1;
-  pRes->pLocalReducer->pResultBuf = (tFilePage *)calloc(1, allocSize);
+  pRes->pLocalMerger->pResultBuf = (tFilePage *)calloc(1, allocSize);
 
-  pRes->pLocalReducer->pResultBuf->num = numOfRes;
-  pRes->data = pRes->pLocalReducer->pResultBuf->data;
+  pRes->pLocalMerger->pResultBuf->num = numOfRes;
+  pRes->data = pRes->pLocalMerger->pResultBuf->data;
 }
 
 int32_t doArithmeticCalculate(SQueryInfo* pQueryInfo, tFilePage* pOutput, int32_t rowSize, int32_t finalRowSize) {
diff --git a/src/client/src/tscServer.c b/src/client/src/tscServer.c
index 537e81413f..440bb9dd47 100644
--- a/src/client/src/tscServer.c
+++ b/src/client/src/tscServer.c
@@ -2444,7 +2444,7 @@ int tscGetSTableVgroupInfo(SSqlObj *pSql, int32_t clauseIndex) {
   SQueryInfo *pQueryInfo = tscGetQueryInfoDetail(pCmd, clauseIndex);
   for (int32_t i = 0; i < pQueryInfo->numOfTables; ++i) {
     STableMetaInfo *pMInfo = tscGetMetaInfo(pQueryInfo, i);
-    STableMeta* pTableMeta = tscTableMetaClone(pMInfo->pTableMeta);
+    STableMeta* pTableMeta = tscTableMetaDup(pMInfo->pTableMeta);
     tscAddTableMetaInfo(pNewQueryInfo, pMInfo->name, pTableMeta, NULL, pMInfo->tagColList, pMInfo->pVgroupTables);
   }
 
diff --git a/src/client/src/tscSubquery.c b/src/client/src/tscSubquery.c
index 2622246111..b4723d4b03 100644
--- a/src/client/src/tscSubquery.c
+++ b/src/client/src/tscSubquery.c
@@ -885,10 +885,10 @@ static void tidTagRetrieveCallback(void* param, TAOS_RES* tres, int32_t numOfRow
     tscBuildVgroupTableInfo(pParentSql, pTableMetaInfo2, s2);
 
     SSqlObj* psub1 = pParentSql->pSubs[0];
-    ((SJoinSupporter*)psub1->param)->pVgroupTables =  tscVgroupTableInfoClone(pTableMetaInfo1->pVgroupTables);
+    ((SJoinSupporter*)psub1->param)->pVgroupTables =  tscVgroupTableInfoDup(pTableMetaInfo1->pVgroupTables);
 
     SSqlObj* psub2 = pParentSql->pSubs[1];
-    ((SJoinSupporter*)psub2->param)->pVgroupTables =  tscVgroupTableInfoClone(pTableMetaInfo2->pVgroupTables);
+    ((SJoinSupporter*)psub2->param)->pVgroupTables =  tscVgroupTableInfoDup(pTableMetaInfo2->pVgroupTables);
 
     pParentSql->subState.numOfSub = 2;
     pParentSql->subState.numOfRemain = pParentSql->subState.numOfSub;
@@ -1998,7 +1998,7 @@ static void tscAllDataRetrievedFromDnode(SRetrieveSupport *trsupport, SSqlObj* p
   SQueryInfo *pPQueryInfo = tscGetQueryInfoDetail(&pParentSql->cmd, 0);
   tscClearInterpInfo(pPQueryInfo);
   
-  tscCreateLocalReducer(trsupport->pExtMemBuffer, pState->numOfSub, pDesc, trsupport->pFinalColModel, trsupport->pFFColModel, pParentSql);
+  tscCreateLocalMerger(trsupport->pExtMemBuffer, pState->numOfSub, pDesc, trsupport->pFinalColModel, trsupport->pFFColModel, pParentSql);
   tscDebug("%p build loser tree completed", pParentSql);
   
   pParentSql->res.precision = pSql->res.precision;
diff --git a/src/client/src/tscUtil.c b/src/client/src/tscUtil.c
index a153a9147d..70bc2038f5 100644
--- a/src/client/src/tscUtil.c
+++ b/src/client/src/tscUtil.c
@@ -420,7 +420,7 @@ void tscResetSqlCmdObj(SSqlCmd* pCmd) {
 }
 
 void tscFreeSqlResult(SSqlObj* pSql) {
-  tscDestroyLocalReducer(pSql);
+  tscDestroyLocalMerger(pSql);
   
   SSqlRes* pRes = &pSql->res;
   tscDestroyResPointerInfo(pRes);
@@ -612,7 +612,7 @@ int32_t tscCopyDataBlockToPayload(SSqlObj* pSql, STableDataBlocks* pDataBlock) {
       tfree(pTableMetaInfo->pTableMeta);
     }
 
-    pTableMetaInfo->pTableMeta = tscTableMetaClone(pDataBlock->pTableMeta);
+    pTableMetaInfo->pTableMeta = tscTableMetaDup(pDataBlock->pTableMeta);
   } else {
     assert(strncmp(pTableMetaInfo->name, pDataBlock->tableName, tListLen(pDataBlock->tableName)) == 0);
   }
@@ -680,7 +680,7 @@ int32_t tscCreateDataBlock(size_t initialSize, int32_t rowSize, int32_t startOff
   tstrncpy(dataBuf->tableName, name, sizeof(dataBuf->tableName));
 
   //Here we keep the tableMeta to avoid it to be remove by other threads.
-  dataBuf->pTableMeta = tscTableMetaClone(pTableMeta);
+  dataBuf->pTableMeta = tscTableMetaDup(pTableMeta);
   assert(initialSize > 0 && pTableMeta != NULL && dataBuf->pTableMeta != NULL);
 
   *dataBlocks = dataBuf;
@@ -1810,10 +1810,10 @@ void tscVgroupTableCopy(SVgroupTableInfo* info, SVgroupTableInfo* pInfo) {
     info->vgInfo.epAddr[j].fqdn = strdup(pInfo->vgInfo.epAddr[j].fqdn);
   }
 
-  info->itemList = taosArrayClone(pInfo->itemList);
+  info->itemList = taosArrayDup(pInfo->itemList);
 }
 
-SArray* tscVgroupTableInfoClone(SArray* pVgroupTables) {
+SArray* tscVgroupTableInfoDup(SArray* pVgroupTables) {
   if (pVgroupTables == NULL) {
     return NULL;
   }
@@ -1881,7 +1881,7 @@ STableMetaInfo* tscAddTableMetaInfo(SQueryInfo* pQueryInfo, const char* name, ST
     tscColumnListCopy(pTableMetaInfo->tagColList, pTagCols, -1);
   }
 
-  pTableMetaInfo->pVgroupTables = tscVgroupTableInfoClone(pVgroupTables);
+  pTableMetaInfo->pVgroupTables = tscVgroupTableInfoDup(pVgroupTables);
   
   pQueryInfo->numOfTables += 1;
   return pTableMetaInfo;
@@ -2064,7 +2064,7 @@ SSqlObj* createSubqueryObj(SSqlObj* pSql, int16_t tableIndex, __async_cb_func_t
   
   pNewQueryInfo->groupbyExpr = pQueryInfo->groupbyExpr;
   if (pQueryInfo->groupbyExpr.columnInfo != NULL) {
-    pNewQueryInfo->groupbyExpr.columnInfo = taosArrayClone(pQueryInfo->groupbyExpr.columnInfo);
+    pNewQueryInfo->groupbyExpr.columnInfo = taosArrayDup(pQueryInfo->groupbyExpr.columnInfo);
     if (pNewQueryInfo->groupbyExpr.columnInfo == NULL) {
       terrno = TSDB_CODE_TSC_OUT_OF_MEMORY;
       goto _error;
@@ -2119,7 +2119,7 @@ SSqlObj* createSubqueryObj(SSqlObj* pSql, int16_t tableIndex, __async_cb_func_t
   STableMetaInfo* pFinalInfo = NULL;
 
   if (pPrevSql == NULL) {
-    STableMeta* pTableMeta = tscTableMetaClone(pTableMetaInfo->pTableMeta);
+    STableMeta* pTableMeta = tscTableMetaDup(pTableMetaInfo->pTableMeta);
     assert(pTableMeta != NULL);
 
     pFinalInfo = tscAddTableMetaInfo(pNewQueryInfo, name, pTableMeta, pTableMetaInfo->vgroupList,
@@ -2127,7 +2127,7 @@ SSqlObj* createSubqueryObj(SSqlObj* pSql, int16_t tableIndex, __async_cb_func_t
   } else {  // transfer the ownership of pTableMeta to the newly create sql object.
     STableMetaInfo* pPrevInfo = tscGetTableMetaInfoFromCmd(&pPrevSql->cmd, pPrevSql->cmd.clauseIndex, 0);
 
-    STableMeta*  pPrevTableMeta = tscTableMetaClone(pPrevInfo->pTableMeta);
+    STableMeta*  pPrevTableMeta = tscTableMetaDup(pPrevInfo->pTableMeta);
     SVgroupsInfo* pVgroupsInfo = pPrevInfo->vgroupList;
     pFinalInfo = tscAddTableMetaInfo(pNewQueryInfo, name, pPrevTableMeta, pVgroupsInfo, pTableMetaInfo->tagColList,
         pTableMetaInfo->pVgroupTables);
@@ -2297,7 +2297,6 @@ int32_t tscSQLSyntaxErrMsg(char* msg, const char* additionalInfo,  const char* s
   }
 
   return TSDB_CODE_TSC_SQL_SYNTAX_ERROR;
-  
 }
 
 int32_t tscInvalidSQLErrMsg(char* msg, const char* additionalInfo, const char* sql) {
@@ -2695,7 +2694,7 @@ uint32_t tscGetTableMetaMaxSize() {
   return sizeof(STableMeta) + TSDB_MAX_COLUMNS * sizeof(SSchema);
 }
 
-STableMeta* tscTableMetaClone(STableMeta* pTableMeta) {
+STableMeta* tscTableMetaDup(STableMeta* pTableMeta) {
   assert(pTableMeta != NULL);
   uint32_t size = tscGetTableMetaSize(pTableMeta);
   STableMeta* p = calloc(1, size);
diff --git a/src/query/src/qExecutor.c b/src/query/src/qExecutor.c
index 0cf8112eb4..c0f2035286 100644
--- a/src/query/src/qExecutor.c
+++ b/src/query/src/qExecutor.c
@@ -5043,7 +5043,7 @@ static void sequentialTableProcess(SQInfo *pQInfo) {
       STsdbQueryCond cond = createTsdbQueryCond(pQuery, &pQuery->window);
 
       SArray *g1 = taosArrayInit(1, POINTER_BYTES);
-      SArray *tx = taosArrayClone(group);
+      SArray *tx = taosArrayDup(group);
       taosArrayPush(g1, &tx);
 
       STableGroupInfo gp = {.numOfTables = taosArrayGetSize(tx), .pGroupList = g1};
@@ -5103,7 +5103,7 @@ static void sequentialTableProcess(SQInfo *pQInfo) {
       STsdbQueryCond cond = createTsdbQueryCond(pQuery, &pQuery->window);
 
       SArray *g1 = taosArrayInit(1, POINTER_BYTES);
-      SArray *tx = taosArrayClone(group);
+      SArray *tx = taosArrayDup(group);
       taosArrayPush(g1, &tx);
 
       STableGroupInfo gp = {.numOfTables = taosArrayGetSize(tx), .pGroupList = g1};
diff --git a/src/util/inc/tarray.h b/src/util/inc/tarray.h
index bf922fe9c4..35053c278e 100644
--- a/src/util/inc/tarray.h
+++ b/src/util/inc/tarray.h
@@ -110,7 +110,7 @@ void taosArrayCopy(SArray* pDst, const SArray* pSrc);
  * clone a new array
  * @param pSrc
  */
-SArray* taosArrayClone(const SArray* pSrc);
+SArray* taosArrayDup(const SArray* pSrc);
 
 /**
  * clear the array (remove all element)
diff --git a/src/util/src/tarray.c b/src/util/src/tarray.c
index bec2fac7df..45cb6eee0f 100644
--- a/src/util/src/tarray.c
+++ b/src/util/src/tarray.c
@@ -165,7 +165,7 @@ void taosArrayCopy(SArray* pDst, const SArray* pSrc) {
   pDst->size = pSrc->size;
 }
 
-SArray* taosArrayClone(const SArray* pSrc) {
+SArray* taosArrayDup(const SArray* pSrc) {
   assert(pSrc != NULL);
   
   if (pSrc->size == 0) { // empty array list
-- 
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