diff --git a/source/dnode/mnode/impl/src/mndSma.c b/source/dnode/mnode/impl/src/mndSma.c
index d666f80fd3..44842084c5 100644
--- a/source/dnode/mnode/impl/src/mndSma.c
+++ b/source/dnode/mnode/impl/src/mndSma.c
@@ -1324,7 +1324,14 @@ static int32_t mndRetrieveIdx(SRpcMsg *pReq, SShowObj *pShow, SSDataBlock *pBloc
     pShow->pIter = taosMemoryCalloc(1, sizeof(SSmaAndTagIter));
   }
   int32_t read = mndRetrieveSma(pReq, pShow, pBlock, rows);
-  if (read < rows) read += mndRetrieveTagIdx(pReq, pShow, pBlock, rows - read);
+  if (read < rows) {
+    read += mndRetrieveTagIdx(pReq, pShow, pBlock, rows - read);
+  }
+  // no more to read
+  if (read < rows) {
+    taosMemoryFree(pShow->pIter);
+    pShow->pIter = NULL;
+  }
   return read;
 }
 static void mndCancelRetrieveIdx(SMnode *pMnode, void *pIter) {