diff --git a/src/client/inc/tscUtil.h b/src/client/inc/tscUtil.h
index 0f27fbc027b7a4e2e2b568233bb56cf140a32bb1..c59ad5ba267c3e383b6a1538d61fd66ca7caeb4f 100644
--- a/src/client/inc/tscUtil.h
+++ b/src/client/inc/tscUtil.h
@@ -149,7 +149,7 @@ void*  tscDestroyUdfArrayList(SArray* pUdfList);
 void*   tscDestroyBlockHashTable(SSqlObj* pSql, SHashObj* pBlockHashTable, bool removeMeta);
 
 int32_t tscCopyDataBlockToPayload(SSqlObj* pSql, STableDataBlocks* pDataBlock);
-int32_t tscMergeKVPayLoadSqlObj(SArray* statements, SSqlObj **result);
+int32_t tscMergeKVPayLoadSqlObj(SArray* statements, SSqlObj *result);
 int32_t tscMergeTableDataBlocks(SSqlObj *pSql, SInsertStatementParam *pInsertParam, bool freeBlockMap);
 int32_t tscGetDataBlockFromList(SHashObj* pHashList, int64_t id, int32_t size, int32_t startOffset, int32_t rowSize, SName* pName, STableMeta* pTableMeta,
                                 STableDataBlocks** dataBlocks, SArray* pBlockList);
diff --git a/src/client/src/tscBulkWrite.c b/src/client/src/tscBulkWrite.c
index 972793a5d6bcbbc4427dd6b039cd9d9fdb512c1c..509bedb0f4e0b52d2d3095222591a820b73069c4 100644
--- a/src/client/src/tscBulkWrite.c
+++ b/src/client/src/tscBulkWrite.c
@@ -131,17 +131,23 @@ int32_t dispatcherStatementMerge(SArray* statements, SSqlObj** result) {
 
   // merge the statements into single one.
   tscDebug("start to merge %zu sql objs", count);
-  int32_t code = tscMergeKVPayLoadSqlObj(statements, result);
+  SSqlObj *pSql = *((SSqlObj**)taosArrayGet(statements, 0));
+  SSqlObj *pNew = createSimpleSubObj(pSql, batchResultCallback, context, TSDB_SQL_INSERT);
+  if (!pNew) {
+    free(context);
+    return TSDB_CODE_TSC_OUT_OF_MEMORY;
+  }
+  
+  int32_t code = tscMergeKVPayLoadSqlObj(statements, pNew);
   if (code != TSDB_CODE_SUCCESS) {
     const char* msg = tstrerror(code);
     tscDebug("failed to merge sql objects: %s", msg);
     free(context);
-  } else {
-    // set the merged sql object callback.
-    (*result)->fp = batchResultCallback;
-    (*result)->fetchFp = (*result)->fp;
-    (*result)->param = context;
+    taosReleaseRef(tscObjRef, pNew->self);
+    return code;
   }
+  
+  *result = pNew;
   return code;
 }
 
diff --git a/src/client/src/tscUtil.c b/src/client/src/tscUtil.c
index a8b5d91be31e18ec66c8709d047097a55b2df148..d18e48eff46d5896678e1d5f63c61d3a8384afb8 100644
--- a/src/client/src/tscUtil.c
+++ b/src/client/src/tscUtil.c
@@ -2212,29 +2212,6 @@ static void extractTableNameList(SSqlObj *pSql, SInsertStatementParam *pInsertPa
   }
 }
 
-/**
- * Resize the the data blocks data.
- * 
- * @param dataBlocks the data blocks.
- * @param destSize   the destination size.
- * @return           whether is success.
- */
-static bool resizeDataBlocksData(STableDataBlocks* dataBlocks, size_t destSize) {
-  if (dataBlocks->nAllocSize >= destSize) {
-    return true;
-  }
-  
-  size_t nAllocSize = destSize + (destSize >> 1);
-  char *pData = realloc(dataBlocks->pData, nAllocSize);
-  if (!pData) {
-    return false;
-  }
-  
-  dataBlocks->pData = pData;
-  dataBlocks->nAllocSize = nAllocSize;
-  return true;
-}
-
 /**
  * A builder of SSubmitBlk.
  */
@@ -2279,7 +2256,7 @@ SSubmitBlkBuilder* createSSubmitBlkBuilder(SSubmitBlk* metadata) {
 /**
  * Destroy the SSubmitBlkBuilder.
  * 
- * @param builder 
+ * @param builder the SSubmitBlkBuilder.
  */
 void destroySSubmitBlkBuilder(SSubmitBlkBuilder* builder) {
   if (!builder) {
@@ -2432,6 +2409,15 @@ size_t writeSSubmitMsgBlocksBuilder(SSubmitMsgBlocksBuilder* builder, SSubmitBlk
   return nWrite;
 }
 
+/**
+ * Get the number of block in SSubmitMsgBlocksBuilder.
+ * @param builder the SSubmitMsgBlocksBuilder.
+ * @return        the number of SSubmitBlk block.
+ */
+size_t blockSizeSSubmitMsgBlocksBuilder(SSubmitMsgBlocksBuilder* builder) {
+  return taosHashGetSize(builder->blockBuilders);
+}
+
 /**
  * Destroy the SSubmitMsgBlocksBuilder.
  * 
@@ -2477,6 +2463,7 @@ static SSubmitBlkBuilder* computeIfAbsentSSubmitBlkBuilder(SSubmitMsgBlocksBuild
   
   return blocksBuilder;
 }
+
 /**
  * Append SSubmitMsg* to the SSubmitMsgBlocksBuilder.
  * 
@@ -2504,6 +2491,210 @@ static bool appendSSubmitMsgBlocks(SSubmitMsgBlocksBuilder* builder, SSubmitBlk*
   return true;
 }
 
+/**
+ * STableDataBlocksBuilder is a tool to build data blocks by append the existing data blocks in a vnode.
+ */
+typedef struct STableDataBlocksBuilder {
+  SSubmitMsgBlocksBuilder* blocksBuilder;
+  STableDataBlocks* firstBlock;
+  int64_t vgId;
+} STableDataBlocksBuilder;
+
+/**
+ * Create the STableDataBlocksBuilder.
+ * 
+ * @param vgId the vgId of STableDataBlocksBuilder.
+ * @return the STableDataBlocksBuilder.
+ */
+static STableDataBlocksBuilder* createSTableDataBlocksBuilder(int64_t vgId) {
+  STableDataBlocksBuilder* builder = calloc(1, sizeof(STableDataBlocksBuilder));
+  if (!builder) {
+    return NULL;
+  }
+  
+  builder->blocksBuilder = createSSubmitMsgBuilder(vgId);
+  if (!builder->blocksBuilder) {
+    free(builder);
+    return NULL;
+  }
+  
+  builder->vgId = vgId;
+  builder->firstBlock = NULL;
+  return builder;
+}
+
+/**
+ * Destroy the STableDataBlocksBuilder.
+ * @param builder the STableDataBlocksBuilder.
+ */
+static void destroySTableDataBlocksBuilder(STableDataBlocksBuilder *builder) {
+  if (!builder) {
+    return;
+  }
+  
+  destroySSubmitMsgBuilder(builder->blocksBuilder);
+  free(builder);
+}
+
+/**
+ * Append a data blocks to STableDataBlocksBuilder.
+ * @param builder    the STableDataBlocksBuilder.
+ * @param dataBlocks the dataBlocks to append. the vgId of dataBlocks must be same with the STableDataBlocksBuilder.
+ * @return           whether the append is success.
+ */
+static bool appendSTableDataBlocksBuilder(STableDataBlocksBuilder* builder, STableDataBlocks* dataBlocks) {
+  if (!dataBlocks || dataBlocks->vgId != builder->vgId) {
+    return false;
+  }
+  
+  if (!builder->firstBlock) {
+    builder->firstBlock = dataBlocks;
+  }
+
+  SSubmitBlk* pBlocks = (SSubmitBlk *)(dataBlocks->pData + dataBlocks->headerSize);
+  return appendSSubmitMsgBlocks(builder->blocksBuilder, pBlocks, dataBlocks->numOfTables);
+}
+
+/**
+ * Build the data blocks for single vnode.
+ * @param builder the STableDataBlocksBuilder.
+ * @return        the data blocks for single vnode.
+ */
+static STableDataBlocks* buildSTableDataBlocksBuilder(STableDataBlocksBuilder* builder) {
+  SSubmitMsgBlocksBuilder* blocksBuilder = builder->blocksBuilder;
+  STableDataBlocks *firstBlock = builder->firstBlock;
+  if (!firstBlock) {
+    return NULL;
+  }
+  
+  size_t nWriteSize = writenSizeSSubmitMsgBuilder(builder->blocksBuilder);
+  size_t nHeaderSize = firstBlock->headerSize;
+  size_t nAllocSize = nWriteSize + nHeaderSize;
+  
+  STableDataBlocks* dataBlocks = NULL;
+  int32_t code = tscCreateDataBlock(nAllocSize, 0, nHeaderSize, &firstBlock->tableName, firstBlock->pTableMeta, &dataBlocks);
+  if (code != TSDB_CODE_SUCCESS) {
+    return NULL;
+  }
+  
+  dataBlocks->size = nHeaderSize;
+  memcpy(dataBlocks->pData, firstBlock->pData, nHeaderSize);
+  dataBlocks->size += writeSSubmitMsgBlocksBuilder(blocksBuilder, (SSubmitBlk *) (dataBlocks->pData + nHeaderSize));
+  dataBlocks->numOfTables = blockSizeSSubmitMsgBlocksBuilder(blocksBuilder);
+  return dataBlocks;
+}
+
+/**
+ * STableDataBlocksListBuilder is a tool to build vnode data blocks list by appending exist data blocks.
+ */
+typedef struct STableDataBlocksListBuilder {
+  SHashObj* dataBlocksBuilders;
+} STableDataBlocksListBuilder;
+
+/**
+ * Create the STableDataBlocksListBuilder.
+ * 
+ * @return the STableDataBlocksListBuilder.
+ */
+static STableDataBlocksListBuilder* createSTableDataBlocksListBuilder() {
+  STableDataBlocksListBuilder* builder = calloc(1, sizeof(STableDataBlocksListBuilder));
+  if (!builder) {
+    return NULL;
+  }
+  
+  builder->dataBlocksBuilders = taosHashInit(8, taosGetDefaultHashFunction(TSDB_DATA_TYPE_BIGINT), true, false);
+  if (!builder->dataBlocksBuilders) {
+    free(builder);
+    return NULL;
+  }
+  
+  return builder;
+}
+
+/**
+ * Destroy the STableDataBlocksListBuilder.
+ * 
+ * @param builder the STableDataBlocksListBuilder.
+ */
+static void destroySTableDataBlocksListBuilder(STableDataBlocksListBuilder* builder) {
+  if (!builder) {
+    return;
+  }
+  
+  STableDataBlocksBuilder** iter = taosHashIterate(builder->dataBlocksBuilders, NULL);
+  while (iter) {
+    destroySTableDataBlocksBuilder(*iter);
+    iter = taosHashIterate(builder->dataBlocksBuilders, iter);
+  }
+  taosHashCleanup(builder->dataBlocksBuilders);
+  free(builder);
+}
+
+/**
+ * Append a data blocks to STableDataBlocksListBuilder.
+ * 
+ * @param builder       the STableDataBlocksListBuilder.
+ * @param dataBlocks    the data blocks.
+ * @return              whether the append is success.
+ */
+static bool appendSTableDataBlocksListBuilder(STableDataBlocksListBuilder* builder, STableDataBlocks* dataBlocks) {
+  STableDataBlocksBuilder** item = taosHashGet(builder->dataBlocksBuilders, &dataBlocks->vgId, sizeof(dataBlocks->vgId));
+  STableDataBlocksBuilder* blocksBuilder = NULL;
+  if (item) {
+    blocksBuilder = *item;
+  } else {
+    blocksBuilder = createSTableDataBlocksBuilder(dataBlocks->vgId);
+    if (!blocksBuilder) {
+      return false;
+    }
+    
+    if (taosHashPut(builder->dataBlocksBuilders, &dataBlocks->vgId, sizeof(dataBlocks->vgId), &blocksBuilder, sizeof(STableDataBlocksBuilder*))) {
+      destroySTableDataBlocksBuilder(blocksBuilder);
+      return false;
+    }
+  }
+
+  return appendSTableDataBlocksBuilder(blocksBuilder, dataBlocks);
+}
+
+/**
+ * Build the vnode data blocks list.
+ * 
+ * @param builder       the STableDataBlocksListBuilder.
+ * @param numOfTables   the number of tables.
+ * @return              the vnode data blocks list.
+ */
+static SArray* buildSTableDataBlocksListBuilder(STableDataBlocksListBuilder* builder, int32_t* numOfTables) {
+  SArray* pVnodeDataBlockList = taosArrayInit(taosHashGetSize(builder->dataBlocksBuilders), sizeof(STableDataBlocks*));
+  if (!pVnodeDataBlockList) {
+    return NULL;
+  }
+  
+  STableDataBlocksBuilder** iter = taosHashIterate(builder->dataBlocksBuilders, NULL);
+  while (iter) {
+    STableDataBlocksBuilder* dataBlocksBuilder = *iter;
+    STableDataBlocks* dataBlocks = buildSTableDataBlocksBuilder(dataBlocksBuilder);
+    if (!dataBlocks) {
+      goto error;
+    }
+    
+    numOfTables += dataBlocks->numOfTables;
+    
+    taosArrayPush(pVnodeDataBlockList, &dataBlocks);
+    iter = taosHashIterate(builder->dataBlocksBuilders, iter);
+  }
+  
+  return pVnodeDataBlockList;
+  
+error:
+  for (int i = 0; i < taosArrayGetSize(pVnodeDataBlockList); ++i) {
+    STableDataBlocks* dataBlocks = *((STableDataBlocks**)taosArrayGet(pVnodeDataBlockList, i));
+    tscDestroyDataBlock(NULL, dataBlocks, false);
+  }
+  taosArrayDestroy(&pVnodeDataBlockList);
+  return NULL;
+}
+
 /**
  * Merge the KV-PayLoad SQL objects into single one. 
  * The statements here must be an insertion statement and no schema attached.
@@ -2512,129 +2703,54 @@ static bool appendSSubmitMsgBlocks(SSubmitMsgBlocksBuilder* builder, SSubmitBlk*
  * @param result the returned result. result is not null!
  * @return the status code. usually TSDB_CODE_SUCCESS.
  */
-int32_t tscMergeKVPayLoadSqlObj(SArray* statements, SSqlObj **result) {
+int32_t tscMergeKVPayLoadSqlObj(SArray* statements, SSqlObj *result) {
   // statement array is empty.
   if (!statements || !taosArrayGetSize(statements)) {
     return TSDB_CODE_TSC_INVALID_OPERATION;
   }
   
-  // a.k.a SHashObj<int64_t, STableDataBlocks*>, the key value represents vgroup id.
-  SHashObj*              pVnodeDataBlockHashList = taosHashInit(128, taosGetDefaultHashFunction(TSDB_DATA_TYPE_BIGINT), true, false); 
-  if (!pVnodeDataBlockHashList) {
+  STableDataBlocksListBuilder* builder = createSTableDataBlocksListBuilder();
+  if (!builder) {
     return TSDB_CODE_TSC_OUT_OF_MEMORY;
   }
   
-  // let the first statement in the array to be the merged result.
-  SSqlObj*               merged = *((SSqlObj**) taosArrayGet(statements, 0));
-  SSqlCmd*               pMergeCmd = &merged->cmd;
-  SInsertStatementParam* pMergeInsertParam = &pMergeCmd->insertParam;
-  SArray*                pMergeDataBlocks = pMergeInsertParam->pDataBlocks;
-  
-  // initialize the `pVnodeDataBlockHashList`.
-  assert(pMergeInsertParam->payloadType == PAYLOAD_TYPE_KV);
-  assert(!pMergeInsertParam->schemaAttached);
-  for (int i = 0; i < taosArrayGetSize(pMergeInsertParam->pDataBlocks); ++i) {
-    STableDataBlocks *pDataBlocks = *((STableDataBlocks** )taosArrayGet(pMergeInsertParam->pDataBlocks, i));
-    if (taosHashPut(pVnodeDataBlockHashList, &pDataBlocks->vgId, sizeof(pDataBlocks->vgId), &pDataBlocks, sizeof(STableDataBlocks *))) {
-      taosHashCleanup(pVnodeDataBlockHashList);
-      return TSDB_CODE_TSC_OUT_OF_MEMORY;
-    }
-  }
-  
-  // merge sql obj statements[i] into sql obj `merged`.
-  for (int i = 1; i < taosArrayGetSize(statements); ++i) {
+  // append the existing data blocks to builder.
+  for (int i = 0; i < taosArrayGetSize(statements); ++i) {
     SSqlObj *pSql = *((SSqlObj**) taosArrayGet(statements, i));
-    SSqlCmd *pCmd = &pSql->cmd;
-    SInsertStatementParam* pInsertParam = &pCmd->insertParam;
+    SInsertStatementParam* pInsertParam = &pSql->cmd.insertParam;
+    if (!pInsertParam->pDataBlocks) {
+      continue;
+    }
     
     assert(pInsertParam->payloadType == PAYLOAD_TYPE_KV);
     assert(!pInsertParam->schemaAttached);
     
-    // merge all the data blocks by vgroup id.
-    for (int j = 0; pInsertParam->pDataBlocks && j < taosArrayGetSize(pInsertParam->pDataBlocks); ++j) {
+    for (int j = 0; j < taosArrayGetSize(pInsertParam->pDataBlocks); ++j) {
       STableDataBlocks * tableBlock = *((STableDataBlocks **) taosArrayGet(pInsertParam->pDataBlocks, j));
-      // SSubmitMsg *pBlocks = (SSubmitMsg *)tableBlock->pData;
-      
-      // get the data blocks of vgroup id.
-      STableDataBlocks *dataBuf = NULL;
-      STableDataBlocks** iter = taosHashGet(pVnodeDataBlockHashList, &tableBlock->vgId, sizeof(tableBlock->vgId));
-      if (iter == NULL) {
-        dataBuf = tableBlock;
-        if (taosHashPut(pVnodeDataBlockHashList, &tableBlock->vgId, sizeof(tableBlock->vgId), &dataBuf, sizeof(STableDataBlocks *))) {
-          taosHashCleanup(pVnodeDataBlockHashList);
-          return TSDB_CODE_TSC_OUT_OF_MEMORY;
-        }
-        
-        if (!taosArrayPush(pMergeDataBlocks, &dataBuf)) {
-          taosHashCleanup(pVnodeDataBlockHashList);
-          return TSDB_CODE_TSC_OUT_OF_MEMORY;
-        }
-      } else {
-        dataBuf = *iter;
-      }
-
-      // header: SMsgDesc + SSubmitMsg(without SSubmitBlk[])
-      assert(dataBuf->headerSize == (sizeof(SMsgDesc) + sizeof(SSubmitMsg)));
-      assert(dataBuf->headerSize == tableBlock->headerSize);
-      const size_t destSize = dataBuf->size + (tableBlock->size - tableBlock->headerSize);
-      
-      if (!resizeDataBlocksData(dataBuf, destSize)) {
-        tscError("0x%" PRIx64 " failed to allocate memory for merging submit block, size:%d", pInsertParam->objectId,
-                 dataBuf->nAllocSize);
-          
-        taosHashCleanup(pVnodeDataBlockHashList);
-        tfree(dataBuf->pData);
+      if (!appendSTableDataBlocksListBuilder(builder, tableBlock)) {
+        destroySTableDataBlocksListBuilder(builder);
         return TSDB_CODE_TSC_OUT_OF_MEMORY;
       }
-      
-      memcpy(dataBuf->pData + dataBuf->size, tableBlock->pData + tableBlock->headerSize, tableBlock->size - tableBlock->headerSize);
-      dataBuf->size = destSize;
-      dataBuf->numOfTables += tableBlock->numOfTables;
-      tscDestroyDataBlock(pSql, tableBlock, false);
     }
-    
-    // free the data blocks and sql objs. (because it is no longer needed).
-    taosArrayDestroy(&pInsertParam->pDataBlocks);
   }
   
+  // build the vnode data blocks.
+  int32_t numOfTables = 0;
+  SInsertStatementParam* pInsertParam = &result->cmd.insertParam;
+  SArray* pVnodeDataBlocksList = buildSTableDataBlocksListBuilder(builder, &numOfTables);
+  if (!pVnodeDataBlocksList) {
+    destroySTableDataBlocksListBuilder(builder);
+    return TSDB_CODE_TSC_OUT_OF_MEMORY;
+  }
+  pInsertParam->pDataBlocks = pVnodeDataBlocksList;
+  pInsertParam->numOfTables = numOfTables;
+  
   // clean up.
-  for (int i = 1; i < taosArrayGetSize(statements); ++i) {
+  for (int i = 0; i < taosArrayGetSize(statements); ++i) {
     SSqlObj *pSql = *((SSqlObj**) taosArrayGet(statements, i));
     taosReleaseRef(tscObjRef, pSql->self);
   }
-  
-  taosHashCleanup(pVnodeDataBlockHashList);
-  *result = merged;
-  
-  // rebuild SubmitMsg::blocks.
-  for (int i = 0; i < taosArrayGetSize(pMergeDataBlocks); ++i) {
-    STableDataBlocks* pDataBlocks = *((STableDataBlocks **) taosArrayGet(pMergeDataBlocks, i));
-    SSubmitMsgBlocksBuilder *builder = createSSubmitMsgBuilder(pDataBlocks->vgId);
-    if (!builder) {
-      break ;
-    }
-    
-    SSubmitBlk* pBlock = (SSubmitBlk *) (pDataBlocks->pData + pDataBlocks->headerSize);
-    if (!appendSSubmitMsgBlocks(builder, pBlock, pDataBlocks->numOfTables)) {
-      destroySSubmitMsgBuilder(builder);
-      break;
-    }
-    
-    size_t nAllocSize = pDataBlocks->headerSize + writenSizeSSubmitMsgBuilder(builder);
-    char *pData = calloc(1, nAllocSize);
-    if (!pData) {
-      destroySSubmitMsgBuilder(builder);
-      break;
-    }
-    
-    pDataBlocks->nAllocSize = nAllocSize;
-    pDataBlocks->size = pDataBlocks->headerSize + writeSSubmitMsgBlocksBuilder(builder, (SSubmitBlk*)(pData + pDataBlocks->headerSize));
-    memcpy(pData, pDataBlocks->pData, pDataBlocks->headerSize);
-    free(pDataBlocks->pData);
-    pDataBlocks->pData = pData;
-    
-    destroySSubmitMsgBuilder(builder);
-  }
+  destroySTableDataBlocksListBuilder(builder);
   return TSDB_CODE_SUCCESS;
 }