diff --git a/src/balance/src/balance.c b/src/balance/src/balance.c
index 53638f1025..0d2d9fc778 100644
--- a/src/balance/src/balance.c
+++ b/src/balance/src/balance.c
@@ -118,6 +118,7 @@ static void balanceSwapVnodeGid(SVnodeGid *pVnodeGid1, SVnodeGid *pVnodeGid2) {
 }
 
 int32_t balanceAllocVnodes(SVgObj *pVgroup) {
+  static int32_t randIndex = 0;
   int32_t dnode = 0;
   int32_t vnodes = 0;
 
@@ -160,7 +161,7 @@ int32_t balanceAllocVnodes(SVgObj *pVgroup) {
    */
   if (pVgroup->numOfVnodes == 1) {
   } else if (pVgroup->numOfVnodes == 2) {
-    if (rand() % 2 == 0) {
+    if (randIndex++ % 2 == 0) {
       balanceSwapVnodeGid(pVgroup->vnodeGid, pVgroup->vnodeGid + 1);
     }
   } else {
diff --git a/src/client/src/tscSql.c b/src/client/src/tscSql.c
index 7046bc7725..1bd885466c 100644
--- a/src/client/src/tscSql.c
+++ b/src/client/src/tscSql.c
@@ -67,7 +67,7 @@ SSqlObj *taosConnectImpl(const char *ip, const char *user, const char *pass, con
     taosEncryptPass((uint8_t *)pass, strlen(pass), secretEncrypt);
   } else {
     int   outlen = 0;
-    int   len = strlen(auth);
+    int   len = (int)strlen(auth);
     char *base64 = (char *)base64_decode(auth, len, &outlen);
     if (base64 == NULL || outlen == 0) {
       tscError("invalid auth info:%s", auth);
diff --git a/src/common/src/ttimezone.c b/src/common/src/ttimezone.c
index 62b1e0bb5c..62d4768db8 100644
--- a/src/common/src/ttimezone.c
+++ b/src/common/src/ttimezone.c
@@ -23,7 +23,9 @@
 // TODO refactor to set the tz value through parameter
 void tsSetTimeZone() {
   SGlobalCfg *cfg_timezone = taosGetConfigOption("timezone");
-  uInfo("timezone is set to %s by %s", tsTimezone, tsCfgStatusStr[cfg_timezone->cfgStatus]);
+  if (cfg_timezone != NULL) {
+    uInfo("timezone is set to %s by %s", tsTimezone, tsCfgStatusStr[cfg_timezone->cfgStatus]);
+  }
 
 #ifdef WINDOWS
   char winStr[TSDB_LOCALE_LEN * 2];
diff --git a/src/dnode/src/dnodeMgmt.c b/src/dnode/src/dnodeMgmt.c
index 532f03bcb5..e2b32145a3 100644
--- a/src/dnode/src/dnodeMgmt.c
+++ b/src/dnode/src/dnodeMgmt.c
@@ -710,10 +710,10 @@ static void dnodeSendStatusMsg(void *handle, void *tmrId) {
   pStatus->clusterCfg.statusInterval     = htonl(tsStatusInterval);
   pStatus->clusterCfg.maxtablesPerVnode  = htonl(tsMaxTablePerVnode);
   pStatus->clusterCfg.maxVgroupsPerDb    = htonl(tsMaxVgroupsPerDb);
-  strcpy(pStatus->clusterCfg.arbitrator, tsArbitrator);
-  strcpy(pStatus->clusterCfg.timezone, tsTimezone);
-  strcpy(pStatus->clusterCfg.locale, tsLocale);
-  strcpy(pStatus->clusterCfg.charset, tsCharset);  
+  tstrncpy(pStatus->clusterCfg.arbitrator, tsArbitrator, TSDB_EP_LEN);
+  tstrncpy(pStatus->clusterCfg.timezone, tsTimezone, 64);
+  tstrncpy(pStatus->clusterCfg.locale, tsLocale, TSDB_LOCALE_LEN);
+  tstrncpy(pStatus->clusterCfg.charset, tsCharset, TSDB_LOCALE_LEN);  
   
   vnodeBuildStatusMsg(pStatus);
   contLen = sizeof(SDMStatusMsg) + pStatus->openVnodes * sizeof(SVnodeLoad);
diff --git a/src/mnode/src/mnodeDb.c b/src/mnode/src/mnodeDb.c
index f6249986fd..f828bc5a3d 100644
--- a/src/mnode/src/mnodeDb.c
+++ b/src/mnode/src/mnodeDb.c
@@ -73,9 +73,9 @@ static int32_t mnodeDbActionInsert(SSdbOper *pOper) {
   pthread_mutex_lock(&pDb->mutex);
   pDb->vgListSize = VG_LIST_SIZE;
   pDb->vgList = calloc(pDb->vgListSize, sizeof(SVgObj *));
+  pDb->numOfVgroups = 0;
   pthread_mutex_unlock(&pDb->mutex);
 
-  pDb->numOfVgroups = 0;
   pDb->numOfTables = 0;
   pDb->numOfSuperTables = 0;
 
@@ -927,7 +927,7 @@ static SDbCfg mnodeGetAlterDbOption(SDbObj *pDb, SCMAlterDbMsg *pAlter) {
 
   if (quorum >= 0 && quorum != pDb->cfg.quorum) {
     mDebug("db:%s, quorum:%d change to %d", pDb->name, pDb->cfg.quorum, quorum);
-    newCfg.compression = quorum;
+    newCfg.quorum = quorum;
   }
 
   return newCfg;
diff --git a/src/os/src/detail/osSysinfo.c b/src/os/src/detail/osSysinfo.c
index 7c01239490..edf8fe6945 100644
--- a/src/os/src/detail/osSysinfo.c
+++ b/src/os/src/detail/osSysinfo.c
@@ -170,6 +170,7 @@ static void taosGetSystemTimezone() {
     
     fclose(f);
 
+    buf[sizeof(buf) - 1] = 0;
     char *lineEnd = strstr(buf, "\n");
     if (lineEnd != NULL) {
       *lineEnd = 0;
diff --git a/src/plugins/mqtt/src/mqttSystem.c b/src/plugins/mqtt/src/mqttSystem.c
index 0259ea23eb..ab3f3f5d84 100644
--- a/src/plugins/mqtt/src/mqttSystem.c
+++ b/src/plugins/mqtt/src/mqttSystem.c
@@ -70,14 +70,27 @@ int32_t mqttInitSystem() {
     recntStatus.port = strbetween("'1883'", "'", "'");
   }
 
-  topicPath = strbetween(strstr(url, strstr(_begin_hostname, ":") != NULL ? recntStatus.port : recntStatus.hostname),
-                         "/", "/");
-  char* _topic = "+/+/+/";
-  int   _tpsize = strlen(topicPath) + strlen(_topic) + 1;
-  recntStatus.topic = calloc(1, _tpsize);
-  sprintf(recntStatus.topic, "/%s/%s", topicPath, _topic);
-  recntStatus.client_id = strlen(tsMqttBrokerClientId) < 3 ? tsMqttBrokerClientId : "taos_mqtt";
-  mqttConnect = NULL;
+  char* portStr = recntStatus.hostname;
+  if (_begin_hostname != NULL) {
+    char* colonStr = strstr(_begin_hostname, ":");
+    if (colonStr != NULL) {
+      portStr = recntStatus.port;
+    }
+  }
+
+  char* topicStr = strstr(url, portStr);
+  if (topicStr != NULL) {
+    topicPath = strbetween(topicStr, "/", "/");
+    char* _topic = "+/+/+/";
+    int   _tpsize = strlen(topicPath) + strlen(_topic) + 1;
+    recntStatus.topic = calloc(1, _tpsize);
+    sprintf(recntStatus.topic, "/%s/%s", topicPath, _topic);
+    recntStatus.client_id = strlen(tsMqttBrokerClientId) < 3 ? tsMqttBrokerClientId : "taos_mqtt";
+    mqttConnect = NULL;
+  } else {
+    topicPath = NULL;
+  }
+  
   return rc;
 }
 
diff --git a/src/util/src/tsocket.c b/src/util/src/tsocket.c
index 9abda0e196..23f2e5f00a 100644
--- a/src/util/src/tsocket.c
+++ b/src/util/src/tsocket.c
@@ -371,7 +371,7 @@ SOCKET taosOpenTcpServerSocket(uint32_t ip, uint16_t port) {
   serverAdd.sin_addr.s_addr = ip;
   serverAdd.sin_port = (uint16_t)htons(port);
 
-  if ((sockFd = (int)socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0) {
+  if ((sockFd = (int)socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 2) {
     uError("failed to open TCP socket: %d (%s)", errno, strerror(errno));
     return -1;
   }
@@ -382,7 +382,7 @@ SOCKET taosOpenTcpServerSocket(uint32_t ip, uint16_t port) {
     uError("setsockopt SO_REUSEADDR failed: %d (%s)", errno, strerror(errno));
     taosCloseSocket(sockFd);
     return -1;
-  };
+  }
 
   /* bind socket to server address */
   if (bind(sockFd, (struct sockaddr *)&serverAdd, sizeof(serverAdd)) < 0) {