diff --git a/src/common/src/tvariant.c b/src/common/src/tvariant.c
index 005def6dc597361436b03c15535840af2bd3461e..bfd6ca01841b565174bd7814dcc080064d242177 100644
--- a/src/common/src/tvariant.c
+++ b/src/common/src/tvariant.c
@@ -151,8 +151,11 @@ void tVariantAssign(tVariant *pDst, const tVariant *pSrc) {
     if (pSrc->nType == TSDB_DATA_TYPE_NCHAR) {
       len = len * TSDB_NCHAR_SIZE;
     }
-    
-    pDst->pz = calloc(1, len);
+
+    char* p = realloc(pDst->pz, len);
+    assert(p);
+
+    memset(pDst->pz, 0, len);
     memcpy(pDst->pz, pSrc->pz, len);
     return;
   }