diff --git a/src/client/src/tscServer.c b/src/client/src/tscServer.c
index c3cf63bd26739dc63e89c7f6ac7ed1d84f306eb1..7fc47947c85913a2f64cb8a58092d4616a4779f9 100644
--- a/src/client/src/tscServer.c
+++ b/src/client/src/tscServer.c
@@ -1496,7 +1496,9 @@ int tscBuildAlterTableMsg(SSqlObj *pSql, SSqlInfo *pInfo) {
 
   pMsg = (char *)pSchema;
   pAlterTableMsg->tagValLen = htonl(pAlterInfo->tagData.dataLen);
-  memcpy(pMsg, pAlterInfo->tagData.data, pAlterInfo->tagData.dataLen);
+  if (pAlterInfo->tagData.dataLen > 0) {
+ 	 memcpy(pMsg, pAlterInfo->tagData.data, pAlterInfo->tagData.dataLen);
+  }
   pMsg += pAlterInfo->tagData.dataLen;
 
   msgLen = (int32_t)(pMsg - (char*)pAlterTableMsg);
diff --git a/src/kit/taosdemo/taosdemo.c b/src/kit/taosdemo/taosdemo.c
index 33ee2a9bc2fc2df5b2b8074e4acdd78449603ffa..40168e5e97100b81d16f39a4ebf1be2df8c86459 100644
--- a/src/kit/taosdemo/taosdemo.c
+++ b/src/kit/taosdemo/taosdemo.c
@@ -90,7 +90,7 @@ enum TEST_MODE {
 #define OPT_ABORT          1 /* –abort */
 #define STRING_LEN         60000
 #define MAX_PREPARED_RAND  1000000
-#define MAX_FILE_NAME_LEN  256
+#define MAX_FILE_NAME_LEN  128
 
 #define   MAX_SAMPLES_ONCE_FROM_FILE   10000
 #define   MAX_NUM_DATATYPE 10
diff --git a/src/mnode/src/mnodeTable.c b/src/mnode/src/mnodeTable.c
index ae37f74fa32313d8f80090dd010cdaae77b40570..20edb02c381b92ac3e04be546f63e41e5d21830e 100644
--- a/src/mnode/src/mnodeTable.c
+++ b/src/mnode/src/mnodeTable.c
@@ -1068,7 +1068,9 @@ static int32_t mnodeProcessCreateSuperTableMsg(SMnodeMsg *pMsg) {
   pStable->info.tableId = strdup(pCreate->tableName);
   pStable->info.type    = TSDB_SUPER_TABLE;
   pStable->createdTime  = taosGetTimestampMs();
-  pStable->uid          = (us << 24) + ((sdbGetVersion() & ((1ul << 16) - 1ul)) << 8) + (taosRand() & ((1ul << 8) - 1ul));
+  int64_t x = (us&0x000000FFFFFFFFFF);
+  x = x<<24;
+  pStable->uid          = x + ((sdbGetVersion() & ((1ul << 16) - 1ul)) << 8) + (taosRand() & ((1ul << 8) - 1ul));
   pStable->sversion     = 0;
   pStable->tversion     = 0;
   pStable->numOfColumns = numOfColumns;
diff --git a/tests/tsim/src/simMain.c b/tests/tsim/src/simMain.c
index 6a9d96bc3b2e6056c73fad73b1fa9f1b7dee6cbf..7d74c62c7daf391fed1bf1afac233f51b84c8f0b 100644
--- a/tests/tsim/src/simMain.c
+++ b/tests/tsim/src/simMain.c
@@ -35,7 +35,7 @@ int32_t main(int32_t argc, char *argv[]) {
 
   for (int32_t i = 1; i < argc; ++i) {
     if (strcmp(argv[i], "-c") == 0 && i < argc - 1) {
-      tstrncpy(configDir, argv[++i], MAX_FILE_NAME_LEN);
+      tstrncpy(configDir, argv[++i], 128);
     } else if (strcmp(argv[i], "-f") == 0 && i < argc - 1) {
       strcpy(scriptFile, argv[++i]);
     } else if (strcmp(argv[i], "-a") == 0) {
@@ -75,4 +75,4 @@ int32_t main(int32_t argc, char *argv[]) {
   simInfo("execute result %d", ret);
 
   return ret;
-}
\ No newline at end of file
+}