diff --git a/src/client/inc/tscUtil.h b/src/client/inc/tscUtil.h
index 6065feedea79e627da88c709823d36eab055b23c..3c5cb4f23a2dfd28e8c8be8255c350b751856fa5 100644
--- a/src/client/inc/tscUtil.h
+++ b/src/client/inc/tscUtil.h
@@ -359,39 +359,39 @@ typedef struct {
   SSubmitBlk* pSubmitBlk;
 } SMemRowBuilder;
 
-int     tdInitMemRowBuilder(SMemRowBuilder* pBuilder);
-void    tdDestroyMemRowBuilder(SMemRowBuilder* pBuilder);
-void    tdResetMemRowBuilder(SMemRowBuilder* pBuilder);
-SMemRow tdGetMemRowFromBuilder(SMemRowBuilder* pBuilder);
-
-static FORCE_INLINE int tdAddColToMemRow(SMemRowBuilder* pBuilder, int16_t colId, int8_t type, void* value) {
-  // TODO
-
-  if (pBuilder->nCols >= pBuilder->tCols) {
-    pBuilder->tCols *= 2;
-    pBuilder->pColIdx = (SColIdx*)realloc((void*)(pBuilder->pColIdx), sizeof(SColIdx) * pBuilder->tCols);
-    if (pBuilder->pColIdx == NULL) return -1;
-  }
-
-  pBuilder->pColIdx[pBuilder->nCols].colId = colId;
-  pBuilder->pColIdx[pBuilder->nCols].offset = pBuilder->size;
-
-  pBuilder->nCols++;
-
-  int tlen = IS_VAR_DATA_TYPE(type) ? varDataTLen(value) : TYPE_BYTES[type];
-  if (tlen > pBuilder->alloc - pBuilder->size) {
-    while (tlen > pBuilder->alloc - pBuilder->size) {
-      pBuilder->alloc *= 2;
-    }
-    pBuilder->buf = realloc(pBuilder->buf, pBuilder->alloc);
-    if (pBuilder->buf == NULL) return -1;
-  }
-
-  memcpy(POINTER_SHIFT(pBuilder->buf, pBuilder->size), value, tlen);
-  pBuilder->size += tlen;
-
-  return 0;
-}
+// int     tdInitMemRowBuilder(SMemRowBuilder* pBuilder);
+// void    tdDestroyMemRowBuilder(SMemRowBuilder* pBuilder);
+// void    tdResetMemRowBuilder(SMemRowBuilder* pBuilder);
+SMemRow tdGenMemRowFromBuilder(SMemRowBuilder* pBuilder);
+
+// static FORCE_INLINE int tdAddColToMemRow(SMemRowBuilder* pBuilder, int16_t colId, int8_t type, void* value) {
+//   // TODO
+
+//   if (pBuilder->nCols >= pBuilder->tCols) {
+//     pBuilder->tCols *= 2;
+//     pBuilder->pColIdx = (SColIdx*)realloc((void*)(pBuilder->pColIdx), sizeof(SColIdx) * pBuilder->tCols);
+//     if (pBuilder->pColIdx == NULL) return -1;
+//   }
+
+//   pBuilder->pColIdx[pBuilder->nCols].colId = colId;
+//   pBuilder->pColIdx[pBuilder->nCols].offset = pBuilder->size;
+
+//   pBuilder->nCols++;
+
+//   int tlen = IS_VAR_DATA_TYPE(type) ? varDataTLen(value) : TYPE_BYTES[type];
+//   if (tlen > pBuilder->alloc - pBuilder->size) {
+//     while (tlen > pBuilder->alloc - pBuilder->size) {
+//       pBuilder->alloc *= 2;
+//     }
+//     pBuilder->buf = realloc(pBuilder->buf, pBuilder->alloc);
+//     if (pBuilder->buf == NULL) return -1;
+//   }
+
+//   memcpy(POINTER_SHIFT(pBuilder->buf, pBuilder->size), value, tlen);
+//   pBuilder->size += tlen;
+
+//   return 0;
+// }
 
 #ifdef __cplusplus
 }
diff --git a/src/client/src/tscUtil.c b/src/client/src/tscUtil.c
index bda309a15938c3274388b08db462b6a847735c82..2c53d90cea73a7d63734027e20f2c0e1bebc36c2 100644
--- a/src/client/src/tscUtil.c
+++ b/src/client/src/tscUtil.c
@@ -14,7 +14,7 @@
  */
 
 #include "tscUtil.h"
-#include "hash.h" 
+#include "hash.h"
 #include "os.h"
 #include "taosmsg.h"
 #include "texpr.h"
@@ -1640,35 +1640,34 @@ int32_t tscGetDataBlockFromList(SHashObj* pHashList, int64_t id, int32_t size, i
   return TSDB_CODE_SUCCESS;
 }
 
-int tdInitMemRowBuilder(SMemRowBuilder* pBuilder) {
-  pBuilder->pSchema = NULL;
-  pBuilder->sversion = 0;
-  pBuilder->tCols = 128;
-  pBuilder->nCols = 0;
-  pBuilder->pColIdx = (SColIdx*)malloc(sizeof(SColIdx) * pBuilder->tCols);
-  if (pBuilder->pColIdx == NULL) return -1;
-  pBuilder->alloc = 1024;
-  pBuilder->size = 0;
-  pBuilder->buf = malloc(pBuilder->alloc);
-  if (pBuilder->buf == NULL) {
-    free(pBuilder->pColIdx);
-    return -1;
-  }
-  return 0;
-}
-
-void tdDestroyMemRowBuilder(SMemRowBuilder* pBuilder) {
-  tfree(pBuilder->pColIdx);
-  tfree(pBuilder->buf);
-}
-
-void tdResetMemRowBuilder(SMemRowBuilder* pBuilder) {
-  pBuilder->nCols = 0;
-  pBuilder->size = 0;
-}
-
-#define KvRowNullColRatio 0.75  // If nullable column ratio larger than 0.75, utilize SKVRow, otherwise SDataRow.
-#define KvRowNColsThresh 1   // default value: 32
+// int tdInitMemRowBuilder(SMemRowBuilder* pBuilder) {
+//   pBuilder->pSchema = NULL;
+//   pBuilder->sversion = 0;
+//   pBuilder->tCols = 128;
+//   pBuilder->nCols = 0;
+//   pBuilder->pColIdx = (SColIdx*)malloc(sizeof(SColIdx) * pBuilder->tCols);
+//   if (pBuilder->pColIdx == NULL) return -1;
+//   pBuilder->alloc = 1024;
+//   pBuilder->size = 0;
+//   pBuilder->buf = malloc(pBuilder->alloc);
+//   if (pBuilder->buf == NULL) {
+//     free(pBuilder->pColIdx);
+//     return -1;
+//   }
+//   return 0;
+// }
+
+// void tdDestroyMemRowBuilder(SMemRowBuilder* pBuilder) {
+//   tfree(pBuilder->pColIdx);
+//   tfree(pBuilder->buf);
+// }
+
+// void tdResetMemRowBuilder(SMemRowBuilder* pBuilder) {
+//   pBuilder->nCols = 0;
+//   pBuilder->size = 0;
+// }
+
+#define KvRowNColsThresh 1  // default value: 32       TODO: for test, restore to 32 after test finished
 
 static FORCE_INLINE uint8_t tdRowTypeJudger(SSchema* pSchema, void* pData, int32_t nCols, int32_t flen,
                                             uint16_t* nColsNotNull) {
@@ -1701,7 +1700,8 @@ static FORCE_INLINE uint8_t tdRowTypeJudger(SSchema* pSchema, void* pData, int32
     p += pSchema[i].bytes;
   }
 
-  tscInfo("prop:nColsNull %d, nCols: %d, kvRowLen: %d, dataRowLen: %d", nColsNull, nCols, kvRowLength, dataRowLength);
+  tscDebug("prop:nColsNull %d, nCols: %d, kvRowLen: %d, dataRowLen: %d", (int32_t)nColsNull, nCols, kvRowLength,
+           dataRowLength);
 
   if (kvRowLength < dataRowLength) {
     if (nColsNotNull) {
@@ -1713,7 +1713,7 @@ static FORCE_INLINE uint8_t tdRowTypeJudger(SSchema* pSchema, void* pData, int32
   return SMEM_ROW_DATA;
 }
 
-SMemRow tdGetMemRowFromBuilder(SMemRowBuilder* pBuilder) {
+SMemRow tdGenMemRowFromBuilder(SMemRowBuilder* pBuilder) {
   SSchema* pSchema = pBuilder->pSchema;
   char*    p = (char*)pBuilder->buf;
 
@@ -1840,7 +1840,7 @@ static int trimDataBlock(void* pDataBlock, STableDataBlocks* pTableDataBlock, bo
     pDataBlock = (char*)pDataBlock + dataRowLen(trow);  // next SDataRow
     pBlock->dataLen += dataRowLen(trow);                // SSubmitBlk data length
 #endif
-    tdGetMemRowFromBuilder(&mRowBuilder);
+    tdGenMemRowFromBuilder(&mRowBuilder);
   }
 
   int32_t len = pBlock->dataLen + pBlock->schemaLen;
diff --git a/src/common/inc/tdataformat.h b/src/common/inc/tdataformat.h
index 4b69192b7be678af371aa5ae2182f2e3206245c3..5c3ccdd781cc45e9d5aa985ea9812a5ae40ac2e2 100644
--- a/src/common/inc/tdataformat.h
+++ b/src/common/inc/tdataformat.h
@@ -224,10 +224,10 @@ typedef void *SMemRow;
 #define dataRowMaxBytesFromSchema(s) (schemaTLen(s) + TD_DATA_ROW_HEAD_SIZE)
 #define dataRowDeleted(r) TKEY_IS_DELETED(dataRowTKey(r))
 
-// SDataRow tdNewDataRowFromSchema(STSchema *pSchema);
-// void     tdFreeDataRow(SDataRow row);
+SDataRow tdNewDataRowFromSchema(STSchema *pSchema);
+void     tdFreeDataRow(SDataRow row);
 void     tdInitDataRow(SDataRow row, STSchema *pSchema);
-// SDataRow tdDataRowDup(SDataRow row);
+SDataRow tdDataRowDup(SDataRow row);
 SMemRow tdMemRowDup(SMemRow row);
 
 // offset here not include dataRow header length
@@ -253,6 +253,16 @@ static FORCE_INLINE int tdAppendColVal(SDataRow row, const void *value, int8_t t
   return 0;
 }
 
+// NOTE: offset here including the header size
+static FORCE_INLINE void *tdGetRowDataOfCol(void *row, int8_t type, int32_t offset) {
+  if (IS_VAR_DATA_TYPE(type)) {
+    return POINTER_SHIFT(row, *(VarDataOffsetT *)POINTER_SHIFT(row, offset));
+  } else {
+    return POINTER_SHIFT(row, offset);
+  }
+  return NULL;
+}
+
 // ----------------- Data column structure
 typedef struct SDataCol {
   int8_t          type;       // column type
@@ -519,27 +529,26 @@ static FORCE_INLINE int tdAddColToKVRow(SKVRowBuilder *pBuilder, int16_t colId,
   return 0;
 }
 
-// ----------------- Data row structure
-
 // ----------------- Sequential Data row structure
-/* A sequential data row, the format is like below:
- * |<--------------------+--------------------------- len ---------------------------------->|
- * |<--     Head      -->|<---------   flen -------------->|                                 |
- * +---------------------+---------------------------------+---------------------------------+
- * | uint16_t |  int16_t |                                 |                                 |
- * +----------+----------+---------------------------------+---------------------------------+
- * |   len    | sversion |           First part            |             Second part         |
- * +----------+----------+---------------------------------+---------------------------------+
+/*
+ * |-------------------------------+--------------------------- len ---------------------------------->|
+ * |<--------     Head      ------>|<---------   flen -------------->|                                 |
+ * |---------+---------------------+---------------------------------+---------------------------------+
+ * | uint8_t | uint16_t |  int16_t |                                 |                                 |
+ * |---------+----------+----------+---------------------------------+---------------------------------+
+ * |  flag   |   len    | sversion |           First part            |             Second part         |
+ * +---------+----------+----------+---------------------------------+---------------------------------+
  *
  * NOTE: timestamp in this row structure is TKEY instead of TSKEY
  */
+
 // ----------------- K-V data row structure
 /*
- * +----------+----------+---------------------------------+---------------------------------+
- * |  int16_t |  int16_t |                                 |                                 |
- * +----------+----------+---------------------------------+---------------------------------+
- * |    len   |   ncols  |           cols index            |             data part           |
- * +----------+----------+---------------------------------+---------------------------------+
+ * |--------------------+----------+---------------------------------+---------------------------------+
+ * | uint8_t | uint16_t |  int16_t |                                 |                                 |
+ * |---------+----------+----------+---------------------------------+---------------------------------+
+ * |   flag  |    len   |   ncols  |           cols index            |             data part           |
+ * |---------+----------+----------+---------------------------------+---------------------------------+
  */
 
 #define TD_MEM_ROW_TYPE_SIZE sizeof(uint8_t)
@@ -572,24 +581,11 @@ static FORCE_INLINE int tdAddColToKVRow(SKVRowBuilder *pBuilder, int16_t colId,
 #define memRowMaxBytesFromSchema(s) (schemaTLen(s) + TD_MEM_ROW_HEAD_SIZE)
 #define memRowDeleted(r) TKEY_IS_DELETED(memRowTKey(r))
 
-// #define memRowNCols(r) (*(int16_t *)POINTER_SHIFT(r, TD_MEM_ROW_TYPE_SIZE + sizeof(int16_t)))      // for SKVRow
-// #define memRowSetNCols(r, n) memRowNCols(r) = (n)                                                  // for SKVRow
-// #define memRowColIdx(r) (SColIdx *)POINTER_SHIFT(r, TD_MEM_ROW_HEAD_SIZE)                          // for SKVRow
-// #define memRowValues(r) POINTER_SHIFT(r, TD_MEM_ROW_HEAD_SIZE + sizeof(SColIdx) * memRowNCols(r))  // for SKVRow
-
 // NOTE: offset here including the header size
-static FORCE_INLINE void *tdGetRowDataOfCol(void *row, int8_t type, int32_t offset) {
-  if (IS_VAR_DATA_TYPE(type)) {
-    return POINTER_SHIFT(row, *(VarDataOffsetT *)POINTER_SHIFT(row, offset));
-  } else {
-    return POINTER_SHIFT(row, offset);
-  }
-  return NULL;
-}
 static FORCE_INLINE void *tdGetKvRowDataOfCol(void *row, int8_t type, int32_t offset) {
   return POINTER_SHIFT(row, offset);
 }
-
+// NOTE: offset here including the header size
 static FORCE_INLINE void *tdGetMemRowDataOfCol(void *row, int8_t type, int32_t offset) {
   if (isDataRow(row)) {
     return tdGetRowDataOfCol(row, type, offset);
@@ -601,12 +597,6 @@ static FORCE_INLINE void *tdGetMemRowDataOfCol(void *row, int8_t type, int32_t o
   return NULL;
 }
 
-// #define kvRowCpy(dst, r) memcpy((dst), (r), kvRowLen(r))
-// #define kvRowColVal(r, colIdx) POINTER_SHIFT(kvRowValues(r), (colIdx)->offset)
-// #define kvRowColIdxAt(r, i) (kvRowColIdx(r) + (i))
-// #define kvRowFree(r) tfree(r)
-// #define kvRowEnd(r) POINTER_SHIFT(r, kvRowLen(r))
-
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/common/src/tdataformat.c b/src/common/src/tdataformat.c
index f962e5255bc1d9e052d606bdec1f39b4eab6c3c7..ac7b15ea025f0c2d3699ab40f97915e97f030ec7 100644
--- a/src/common/src/tdataformat.c
+++ b/src/common/src/tdataformat.c
@@ -188,30 +188,30 @@ void tdInitDataRow(SDataRow row, STSchema *pSchema) {
   dataRowSetVersion(row, schemaVersion(pSchema));
 }
 
-// SDataRow tdNewDataRowFromSchema(STSchema *pSchema) {
-//   int32_t size = dataRowMaxBytesFromSchema(pSchema);
+SDataRow tdNewDataRowFromSchema(STSchema *pSchema) {
+  int32_t size = dataRowMaxBytesFromSchema(pSchema);
 
-//   SDataRow row = malloc(size);
-//   if (row == NULL) return NULL;
+  SDataRow row = malloc(size);
+  if (row == NULL) return NULL;
 
-//   tdInitDataRow(row, pSchema);
-//   return row;
-// }
+  tdInitDataRow(row, pSchema);
+  return row;
+}
 
 /**
  * Free the SDataRow object
  */
-// void tdFreeDataRow(SDataRow row) {
-//   if (row) free(row);
-// }
+void tdFreeDataRow(SDataRow row) {
+  if (row) free(row);
+}
 
-// SDataRow tdDataRowDup(SDataRow row) {
-//   SDataRow trow = malloc(dataRowLen(row));
-//   if (trow == NULL) return NULL;
+SDataRow tdDataRowDup(SDataRow row) {
+  SDataRow trow = malloc(dataRowLen(row));
+  if (trow == NULL) return NULL;
 
-//   dataRowCpy(trow, row);
-//   return trow;
-// }
+  dataRowCpy(trow, row);
+  return trow;
+}
 
 SMemRow tdMemRowDup(SMemRow row) {
   SMemRow trow = malloc(memRowTLen(row));
@@ -220,6 +220,7 @@ SMemRow tdMemRowDup(SMemRow row) {
   memRowCpy(trow, row);
   return trow;
 }
+
 void dataColInit(SDataCol *pDataCol, STColumn *pCol, void **pBuf, int maxPoints) {
   pDataCol->type = colType(pCol);
   pDataCol->colId = colColId(pCol);
@@ -436,7 +437,7 @@ void tdResetDataCols(SDataCols *pCols) {
 static void tdAppendDataRowToDataCol(SDataRow row, STSchema *pSchema, SDataCols *pCols) {
   ASSERT(pCols->numOfRows == 0 || dataColsKeyLast(pCols) < dataRowKey(row));
 
-  int rcol = 0;  // rowCol
+  int rcol = 0;
   int dcol = 0;
 
   if (dataRowDeleted(row)) {
diff --git a/src/inc/ttype.h b/src/inc/ttype.h
index 03083795092f1bcbf3f4859a0ac12b00b9b49740..80b8ddcd4eed563b803e54cdccc5812d3a4e582a 100644
--- a/src/inc/ttype.h
+++ b/src/inc/ttype.h
@@ -11,7 +11,7 @@ extern "C" {
 
 // ----------------- For variable data types such as TSDB_DATA_TYPE_BINARY and TSDB_DATA_TYPE_NCHAR
 typedef int32_t VarDataOffsetT;
-typedef int16_t VarDataLenT;  // maxDataLen: 32767
+typedef int16_t VarDataLenT;  // maxVarDataLen: 32767
 
 typedef struct tstr {
   VarDataLenT len;
diff --git a/src/tsdb/src/tsdbRead.c b/src/tsdb/src/tsdbRead.c
index 0c87a7b735888d3bd63a05b821ccc8aa03a7147b..faf099cdd21d19a88d2d4ae36491f86b65e48970 100644
--- a/src/tsdb/src/tsdbRead.c
+++ b/src/tsdb/src/tsdbRead.c
@@ -1442,107 +1442,6 @@ int32_t doCopyRowsFromFileBlock(STsdbQueryHandle* pQueryHandle, int32_t capacity
 
   return numOfRows + num;
 }
-#if 0
-static void copyOneRowFromMem(STsdbQueryHandle* pQueryHandle, int32_t capacity, int32_t numOfRows, SMemRow row,
-                              int32_t numOfCols, STable* pTable, STSchema* pSchema) {
-  char* pData = NULL;
-
-  // the schema version info is embedded in SDataRow, and use latest schema version for SKVRow
-  int32_t numOfRowCols = 0;
-  if (pSchema == NULL) {
-    pSchema = tsdbGetTableSchemaByVersion(pTable, memRowVersion(row));
-    numOfRowCols = schemaNCols(pSchema);
-  } else {
-    numOfRowCols = schemaNCols(pSchema);
-  }
-  
-  int32_t i = 0, j = 0;
-  while(i < numOfCols && j < numOfRowCols) {
-    SColumnInfoData* pColInfo = taosArrayGet(pQueryHandle->pColumns, i);
-    if (pSchema->columns[j].colId < pColInfo->info.colId) {
-      j++;
-      continue;
-    }
-
-    if (ASCENDING_TRAVERSE(pQueryHandle->order)) {
-      pData = (char*)pColInfo->pData + numOfRows * pColInfo->info.bytes;
-    } else {
-      pData = (char*)pColInfo->pData + (capacity - numOfRows - 1) * pColInfo->info.bytes;
-    }
-
-    if (pSchema->columns[j].colId == pColInfo->info.colId) {
-      void* value =
-          tdGetMemRowDataOfCol(row, (int8_t)pColInfo->info.type, TD_MEM_ROW_HEAD_SIZE + pSchema->columns[j].offset);
-      switch (pColInfo->info.type) {
-        case TSDB_DATA_TYPE_BINARY:
-        case TSDB_DATA_TYPE_NCHAR:
-          memcpy(pData, value, varDataTLen(value));
-          break;
-        case TSDB_DATA_TYPE_NULL:
-        case TSDB_DATA_TYPE_BOOL:
-        case TSDB_DATA_TYPE_TINYINT:
-        case TSDB_DATA_TYPE_UTINYINT:  
-          *(uint8_t *)pData = *(uint8_t *)value;
-          break;
-        case TSDB_DATA_TYPE_SMALLINT:
-        case TSDB_DATA_TYPE_USMALLINT:
-          *(uint16_t *)pData = *(uint16_t *)value;
-          break;
-        case TSDB_DATA_TYPE_INT:
-        case TSDB_DATA_TYPE_UINT:
-          *(uint32_t *)pData = *(uint32_t *)value;
-          break;
-        case TSDB_DATA_TYPE_BIGINT:
-        case TSDB_DATA_TYPE_UBIGINT:
-          *(uint64_t *)pData = *(uint64_t *)value;
-          break;
-        case TSDB_DATA_TYPE_FLOAT:
-          SET_FLOAT_PTR(pData, value);
-          break;
-        case TSDB_DATA_TYPE_DOUBLE:
-          SET_DOUBLE_PTR(pData, value);
-          break;
-        case TSDB_DATA_TYPE_TIMESTAMP:
-          if (pColInfo->info.colId == PRIMARYKEY_TIMESTAMP_COL_INDEX) {
-            *(TSKEY *)pData = tdGetKey(*(TKEY *)value);
-          } else {
-            *(TSKEY *)pData = *(TSKEY *)value;
-          }
-          break;
-        default:
-          memcpy(pData, value, pColInfo->info.bytes);
-      }
-
-      j++;
-      i++;
-    } else { // pColInfo->info.colId < pSchema->columns[j].colId, it is a NULL data
-      if (pColInfo->info.type == TSDB_DATA_TYPE_BINARY || pColInfo->info.type == TSDB_DATA_TYPE_NCHAR) {
-        setVardataNull(pData, pColInfo->info.type);
-      } else {
-        setNull(pData, pColInfo->info.type, pColInfo->info.bytes);
-      }
-      i++;
-    }
-  }
-
-  while (i < numOfCols) { // the remain columns are all null data
-    SColumnInfoData* pColInfo = taosArrayGet(pQueryHandle->pColumns, i);
-    if (ASCENDING_TRAVERSE(pQueryHandle->order)) {
-      pData = (char*)pColInfo->pData + numOfRows * pColInfo->info.bytes;
-    } else {
-      pData = (char*)pColInfo->pData + (capacity - numOfRows - 1) * pColInfo->info.bytes;
-    }
-
-    if (pColInfo->info.type == TSDB_DATA_TYPE_BINARY || pColInfo->info.type == TSDB_DATA_TYPE_NCHAR) {
-      setVardataNull(pData, pColInfo->info.type);
-    } else {
-      setNull(pData, pColInfo->info.type, pColInfo->info.bytes);
-    }
-
-    i++;
-  }
-}
-#endif
 
 static void copyOneRowFromMem(STsdbQueryHandle* pQueryHandle, int32_t capacity, int32_t numOfRows, SMemRow row,
                               int32_t numOfCols, STable* pTable, STSchema* pSchema) {