diff --git a/source/dnode/vnode/src/tsdb/tsdbCacheRead.c b/source/dnode/vnode/src/tsdb/tsdbCacheRead.c
index 417c014b6e1c00047dab1bf4d243714f36766377..750797cd692a5e3e6d1466ff55b4e86385211551 100644
--- a/source/dnode/vnode/src/tsdb/tsdbCacheRead.c
+++ b/source/dnode/vnode/src/tsdb/tsdbCacheRead.c
@@ -22,7 +22,6 @@ typedef struct SLastrowReader {
   SVnode*   pVnode;
   STSchema* pSchema;
   uint64_t  uid;
-  //  int32_t*  pSlotIds;
   char**  transferBuf;  // todo remove it soon
   int32_t numOfCols;
   int32_t type;
@@ -40,15 +39,17 @@ static void saveOneRow(STSRow* pRow, SSDataBlock* pBlock, SLastrowReader* pReade
     if (slotIds[i] == -1) {
       colDataAppend(pColInfoData, numOfRows, (const char*)&pRow->ts, false);
     } else {
-      tTSRowGetVal(pRow, pReader->pSchema, slotIds[i], &colVal);
+      int32_t slotId = slotIds[i];
+
+      tTSRowGetVal(pRow, pReader->pSchema, slotId, &colVal);
 
       if (IS_VAR_DATA_TYPE(colVal.type)) {
         if (colVal.isNull || colVal.isNone) {
           colDataAppendNULL(pColInfoData, numOfRows);
         } else {
-          varDataSetLen(pReader->transferBuf[i], colVal.value.nData);
-          memcpy(varDataVal(pReader->transferBuf[i]), colVal.value.pData, colVal.value.nData);
-          colDataAppend(pColInfoData, numOfRows, pReader->transferBuf[i], false);
+          varDataSetLen(pReader->transferBuf[slotId], colVal.value.nData);
+          memcpy(varDataVal(pReader->transferBuf[slotId]), colVal.value.pData, colVal.value.nData);
+          colDataAppend(pColInfoData, numOfRows, pReader->transferBuf[slotId], false);
         }
       } else {
         colDataAppend(pColInfoData, numOfRows, (const char*)&colVal.value, colVal.isNull || colVal.isNone);
@@ -79,7 +80,7 @@ int32_t tsdbLastRowReaderOpen(void* pVnode, int32_t type, SArray* pTableIdList,
   p->pSchema = metaGetTbTSchema(p->pVnode->pMeta, pKeyInfo->uid, -1);
   p->pTableList = pTableIdList;
 
-  for (int32_t i = 0; i < p->numOfCols; ++i) {
+  for (int32_t i = 0; i < p->pSchema->numOfCols; ++i) {
     if (IS_VAR_DATA_TYPE(p->pSchema->columns[i].type)) {
       p->transferBuf[i] = taosMemoryMalloc(p->pSchema->columns[i].bytes);
     }
@@ -92,10 +93,11 @@ int32_t tsdbLastRowReaderOpen(void* pVnode, int32_t type, SArray* pTableIdList,
 int32_t tsdbLastrowReaderClose(void* pReader) {
   SLastrowReader* p = pReader;
 
-  for (int32_t i = 0; i < p->numOfCols; ++i) {
+  for (int32_t i = 0; i < p->pSchema->numOfCols; ++i) {
     taosMemoryFreeClear(p->transferBuf[i]);
   }
 
+  taosMemoryFree(p->pSchema);
   taosMemoryFree(p->transferBuf);
   taosMemoryFree(pReader);
   return TSDB_CODE_SUCCESS;