diff --git a/source/client/src/clientRawBlockWrite.c b/source/client/src/clientRawBlockWrite.c
index 4ff50692b7..3c8625e832 100644
--- a/source/client/src/clientRawBlockWrite.c
+++ b/source/client/src/clientRawBlockWrite.c
@@ -799,7 +799,7 @@ static void processAlterTable(SMqMetaRsp* metaRsp, cJSON** pJson) {
           if (vAlterTbReq.tagType == TSDB_DATA_TYPE_VARBINARY) {
             bufSize = vAlterTbReq.nTagVal * 2 + 2 + 3;
           } else {
-            bufSize = vAlterTbReq.nTagVal + 3;
+            bufSize = vAlterTbReq.nTagVal + 32;
           }
           buf = taosMemoryCalloc(bufSize, 1);
           RAW_NULL_CHECK(buf);
@@ -2315,8 +2315,6 @@ static void processSimpleMeta(SMqMetaRsp* pMetaRsp, cJSON** meta) {
     processAlterTable(pMetaRsp, meta);
   } else if (pMetaRsp->resMsgType == TDMT_VND_DROP_TABLE) {
     processDropTable(pMetaRsp, meta);
-  } else if (pMetaRsp->resMsgType == TDMT_VND_DROP_TABLE) {
-    processDropTable(pMetaRsp, meta);
   } else if (pMetaRsp->resMsgType == TDMT_VND_DELETE) {
     processDeleteTable(pMetaRsp, meta);
   }
diff --git a/utils/test/c/tmq_write_raw_test.c b/utils/test/c/tmq_write_raw_test.c
index f33fac9a0a..4afaa1ff5c 100644
--- a/utils/test/c/tmq_write_raw_test.c
+++ b/utils/test/c/tmq_write_raw_test.c
@@ -136,6 +136,13 @@ int buildDatabase(TAOS* pConn, TAOS_RES* pRes) {
   }
   taos_free_result(pRes);
 
+  pRes = taos_query(pConn, "alter table ct0 set tag t4=false");
+  if (taos_errno(pRes) != 0) {
+    printf("alter table ct0 set tag t4=false, reason:%s\n", taos_errstr(pRes));
+    return -1;
+  }
+  taos_free_result(pRes);
+
   return 0;
 }