diff --git a/source/dnode/vnode/src/tsdb/tsdbCache.c b/source/dnode/vnode/src/tsdb/tsdbCache.c
index e2ffe398bf..ec0944193a 100644
--- a/source/dnode/vnode/src/tsdb/tsdbCache.c
+++ b/source/dnode/vnode/src/tsdb/tsdbCache.c
@@ -279,7 +279,8 @@ int32_t tsdbCacheInsertLastrow(SLRUCache *pCache, STsdb *pTsdb, tb_uid_t uid, ST
             SLastCol lastCol = {.ts = keyTs, .colVal = colVal};
             if (IS_VAR_DATA_TYPE(colVal.type) && colVal.value.nData > 0) {
               SLastCol *pLastCol = (SLastCol *)taosArrayGet(pLast, iCol);
-              taosMemoryFree(pLastCol->colVal.value.pData);
+              if (pLastCol->colVal.value.nData > 0 && NULL != pLastCol->colVal.value.pData)
+                taosMemoryFree(pLastCol->colVal.value.pData);
 
               lastCol.colVal.value.pData = taosMemoryMalloc(colVal.value.nData);
               if (lastCol.colVal.value.pData == NULL) {
@@ -361,7 +362,8 @@ int32_t tsdbCacheInsertLast(SLRUCache *pCache, tb_uid_t uid, STSRow *row, STsdb
             SLastCol lastCol = {.ts = keyTs, .colVal = colVal};
             if (IS_VAR_DATA_TYPE(colVal.type) && colVal.value.nData > 0) {
               SLastCol *pLastCol = (SLastCol *)taosArrayGet(pLast, iCol);
-              taosMemoryFree(pLastCol->colVal.value.pData);
+              if (pLastCol->colVal.value.nData > 0 && NULL != pLastCol->colVal.value.pData)
+                taosMemoryFree(pLastCol->colVal.value.pData);
 
               lastCol.colVal.value.pData = taosMemoryMalloc(colVal.value.nData);
               if (lastCol.colVal.value.pData == NULL) {