diff --git a/src/tsdb/src/tsdbMemTable.c b/src/tsdb/src/tsdbMemTable.c
index 9ac5503e5f..ee9dadd9b7 100644
--- a/src/tsdb/src/tsdbMemTable.c
+++ b/src/tsdb/src/tsdbMemTable.c
@@ -1019,7 +1019,7 @@ static void updateTableLatestColumn(STsdbRepo *pRepo, STable *pTable, SMemRow ro
 
     if (isDataRow) {
       value = tdGetRowDataOfCol(memRowDataBody(row), (int8_t)pTCol->type,
-                                TD_DATA_ROW_HEAD_SIZE + pSchema->columns[j].offset);
+                                TD_DATA_ROW_HEAD_SIZE + pTCol->offset);
     } else {
       // SKVRow
       SColIdx *pColIdx = tdGetKVRowIdxOfCol(memRowKvBody(row), pTCol->colId);
@@ -1034,14 +1034,17 @@ static void updateTableLatestColumn(STsdbRepo *pRepo, STable *pTable, SMemRow ro
 
     SDataCol *pDataCol = &(pLatestCols[idx]);
     if (pDataCol->pData == NULL) {
-      pDataCol->pData = malloc(pSchema->columns[j].bytes);
-      pDataCol->bytes = pSchema->columns[j].bytes;
-    } else if (pDataCol->bytes < pSchema->columns[j].bytes) {
-      pDataCol->pData = realloc(pDataCol->pData, pSchema->columns[j].bytes);
-      pDataCol->bytes = pSchema->columns[j].bytes;
+      pDataCol->pData = malloc(pTCol->bytes);
+      pDataCol->bytes = pTCol->bytes;
+    } else if (pDataCol->bytes < pTCol->bytes) {
+      pDataCol->pData = realloc(pDataCol->pData, pTCol->bytes);
+      pDataCol->bytes = pTCol->bytes;
     }
-
-    memcpy(pDataCol->pData, value, pDataCol->bytes);
+    // the actual value size
+    uint16_t bytes = IS_VAR_DATA_TYPE(pTCol->type) ? varDataTLen(value) : pTCol->bytes;
+    // the actual data size CANNOT larger than column size
+    assert(pTCol->bytes >= bytes);
+    memcpy(pDataCol->pData, value, bytes);
     //tsdbInfo("updateTableLatestColumn vgId:%d cache column %d for %d,%s", REPO_ID(pRepo), j, pDataCol->bytes, (char*)pDataCol->pData);
     pDataCol->ts = memRowKey(row);
   }