diff --git a/src/common/inc/tdataformat.h b/src/common/inc/tdataformat.h
index e1f17b09a98a53f570f581f5164d684c75a92f47..0e57c7317ee6932133414a3e610644d503caa0de 100644
--- a/src/common/inc/tdataformat.h
+++ b/src/common/inc/tdataformat.h
@@ -31,7 +31,7 @@ extern "C" {
   do {                                    \
     VarDataLenT __len = strlen(str);      \
     *(VarDataLenT *)(x) = __len;          \
-    strncpy(varDataVal(x), (str), __len); \
+    memcpy(varDataVal(x), (str), __len); \
   } while (0);
 
 #define STR_WITH_MAXSIZE_TO_VARSTR(x, str, _maxs)      \
@@ -43,7 +43,7 @@ extern "C" {
 #define STR_WITH_SIZE_TO_VARSTR(x, str, _size) \
   do {                                         \
     *(VarDataLenT *)(x) = (_size);             \
-    strncpy(varDataVal(x), (str), (_size));    \
+    memcpy(varDataVal(x), (str), (_size));    \
   } while (0);
 
 // ----------------- TSDB COLUMN DEFINITION
diff --git a/src/dnode/src/dnodeShell.c b/src/dnode/src/dnodeShell.c
index 95e4c494221b7882c680ab71232723ce37887af0..117059ae668dd4e5812e63f2c30c5300a2b37228 100644
--- a/src/dnode/src/dnodeShell.c
+++ b/src/dnode/src/dnodeShell.c
@@ -203,7 +203,7 @@ void *dnodeSendCfgTableToRecv(int32_t vgId, int32_t sid) {
     int16_t   numOfTags = htons(pTable->numOfTags);
     int32_t   sid = htonl(pTable->sid);
     uint64_t  uid = htobe64(pTable->uid);
-    dPrint("table:%s, numOfColumns:%d numOfTags:%d sid:%d uid:" PRIu64, pTable->tableId, numOfColumns, numOfTags, sid, uid);
+    dPrint("table:%s, numOfColumns:%d numOfTags:%d sid:%d uid:%" PRIu64, pTable->tableId, numOfColumns, numOfTags, sid, uid);
 
     return rpcRsp.pCont;
   }
diff --git a/src/mnode/src/mnodeDb.c b/src/mnode/src/mnodeDb.c
index c80dc3036f786f33b3065c8e7da796a42bfe4059..3666d61adc8b2c10b1c7615422b4db7031bc1251 100644
--- a/src/mnode/src/mnodeDb.c
+++ b/src/mnode/src/mnodeDb.c
@@ -882,7 +882,7 @@ static SDbCfg mnodeGetAlterDbOption(SDbObj *pDb, SCMAlterDbMsg *pAlter) {
     }
 
     if (pDb->cfg.replications - replications >= 2) {
-      mError("db:%s, replica number can't change from 3 to 1", pDb->name, replications);
+      mError("db:%s, replica number can't change from %d to %d", pDb->name, pDb->cfg.replications, replications);
       terrno = TSDB_CODE_MND_INVALID_DB_OPTION;
     }
   }
diff --git a/src/mnode/src/mnodeDnode.c b/src/mnode/src/mnodeDnode.c
index 6fd565b5e6a42c757cb1f90603597ae0afabd733..d2af86badb2869b47501a1fdc47e464554b2e83f 100644
--- a/src/mnode/src/mnodeDnode.c
+++ b/src/mnode/src/mnodeDnode.c
@@ -90,7 +90,7 @@ static int32_t mnodeDnodeActionDelete(SSdbOper *pOper) {
 static int32_t mnodeDnodeActionUpdate(SSdbOper *pOper) {
   SDnodeObj *pDnode = pOper->pObj;
   SDnodeObj *pSaved = mnodeGetDnode(pDnode->dnodeId);
-  if (pDnode != pSaved) {
+  if (pDnode != pSaved && pDnode != NULL && pSaved != NULL) {
     memcpy(pSaved, pDnode, pOper->rowSize);
     free(pDnode);
   }
@@ -237,7 +237,9 @@ void mnodeUpdateDnode(SDnodeObj *pDnode) {
     .pObj = pDnode
   };
 
-  sdbUpdateRow(&oper);
+  if (sdbUpdateRow(&oper) != 0) {
+    mError("dnodeId:%d, failed update", pDnode->dnodeId);
+  }
 }
 
 static int32_t mnodeProcessCfgDnodeMsg(SMnodeMsg *pMsg) {
@@ -383,7 +385,7 @@ static int32_t mnodeCreateDnode(char *ep) {
   pDnode->createdTime = taosGetTimestampMs();
   pDnode->status = TAOS_DN_STATUS_OFFLINE; 
   pDnode->totalVnodes = TSDB_INVALID_VNODE_NUM; 
-  strcpy(pDnode->dnodeEp, ep);
+  tstrncpy(pDnode->dnodeEp, ep, TSDB_EP_LEN);
   taosGetFqdnPortFromEp(ep, pDnode->dnodeFqdn, &pDnode->dnodePort);
 
   SSdbOper oper = {
diff --git a/src/mnode/src/mnodeMain.c b/src/mnode/src/mnodeMain.c
index 57bb1b2bac5c0293aabec3e81c74d8661a89fd00..96dc70078315ba3ab088fb201088189853f6ec54 100644
--- a/src/mnode/src/mnodeMain.c
+++ b/src/mnode/src/mnodeMain.c
@@ -134,8 +134,12 @@ void mnodeStopSystem() {
   }
   
   mnodeCleanupSystem();
-  mPrint("mnode file is removed");
-  remove(tsMnodeDir);
+
+  if (remove(tsMnodeDir) != 0) {
+    mPrint("failed to remove mnode file, reason:%s", strerror(errno));
+  } else {
+    mPrint("mnode file is removed");
+  }
 }
 
 static void mnodeInitTimer() {
diff --git a/src/mnode/src/mnodeProfile.c b/src/mnode/src/mnodeProfile.c
index 85999f80e7e3e92daf0878d7643127c2771d7e34..bfb92096ecf84ecf4b8afcd77d83ec389468567d 100644
--- a/src/mnode/src/mnodeProfile.c
+++ b/src/mnode/src/mnodeProfile.c
@@ -97,7 +97,7 @@ SConnObj *mnodeCreateConn(char *user, uint32_t ip, uint16_t port) {
     .connId = connId,
     .stime  = taosGetTimestampMs()
   };
-  strcpy(connObj.user, user);
+  tstrncpy(connObj.user, user, TSDB_USER_LEN);
   
   char key[10];
   sprintf(key, "%u", connId);  
diff --git a/src/mnode/src/mnodeSdb.c b/src/mnode/src/mnodeSdb.c
index 8d7482784124264035ed9a2c93afb0f41c93f288..a13c6ca129c3c8b2bf58b73958d925657f655cbd 100644
--- a/src/mnode/src/mnodeSdb.c
+++ b/src/mnode/src/mnodeSdb.c
@@ -30,6 +30,8 @@
 #include "mnodeDnode.h"
 #include "mnodeSdb.h"
 
+#define SDB_TABLE_LEN 12
+
 typedef enum {
   SDB_ACTION_INSERT,
   SDB_ACTION_DELETE,
@@ -43,7 +45,7 @@ typedef enum {
 } ESdbStatus;
 
 typedef struct _SSdbTable {
-  char      tableName[TSDB_DB_NAME_LEN];
+  char      tableName[SDB_TABLE_LEN];
   ESdbTable tableId;
   ESdbKey   keyType;
   int32_t   hashSessions;
@@ -174,10 +176,10 @@ static void sdbRestoreTables() {
 
     totalRows += pTable->numOfRows;
     numOfTables++;
-    sdbTrace("table:%s, is restored, numOfRows:%d", pTable->tableName, pTable->numOfRows);
+    sdbTrace("table:%s, is restored, numOfRows:%" PRId64, pTable->tableName, pTable->numOfRows);
   }
 
-  sdbTrace("sdb is restored, version:%d totalRows:%d numOfTables:%d", tsSdbObj.version, totalRows, numOfTables);
+  sdbTrace("sdb is restored, version:%" PRId64 " totalRows:%d numOfTables:%d", tsSdbObj.version, totalRows, numOfTables);
 }
 
 void sdbUpdateMnodeRoles() {
@@ -449,7 +451,7 @@ static int32_t sdbInsertHash(SSdbTable *pTable, SSdbOper *pOper) {
 
   pthread_mutex_unlock(&pTable->mutex);
 
-  sdbTrace("table:%s, insert record:%s to hash, rowSize:%d vnumOfRows:%d version:%" PRIu64, pTable->tableName,
+  sdbTrace("table:%s, insert record:%s to hash, rowSize:%d vnumOfRows:%" PRId64 " version:%" PRIu64, pTable->tableName,
            sdbGetKeyStrFromObj(pTable, pOper->pObj), pOper->rowSize, pTable->numOfRows, sdbGetVersion());
 
   (*pTable->insertFp)(pOper);
@@ -473,7 +475,7 @@ static int32_t sdbDeleteHash(SSdbTable *pTable, SSdbOper *pOper) {
   pTable->numOfRows--;
   pthread_mutex_unlock(&pTable->mutex);
 
-  sdbTrace("table:%s, delete record:%s from hash, numOfRows:%d version:%" PRIu64, pTable->tableName,
+  sdbTrace("table:%s, delete record:%s from hash, numOfRows:%d" PRId64 "version:%" PRIu64, pTable->tableName,
            sdbGetKeyStrFromObj(pTable, pOper->pObj), pTable->numOfRows, sdbGetVersion());
 
   int8_t *updateEnd = pOper->pObj + pTable->refCountPos - 1;
@@ -484,7 +486,7 @@ static int32_t sdbDeleteHash(SSdbTable *pTable, SSdbOper *pOper) {
 }
 
 static int32_t sdbUpdateHash(SSdbTable *pTable, SSdbOper *pOper) {
-  sdbTrace("table:%s, update record:%s in hash, numOfRows:%d version:%" PRIu64, pTable->tableName,
+  sdbTrace("table:%s, update record:%s in hash, numOfRows:%" PRId64 " version:%" PRIu64, pTable->tableName,
            sdbGetKeyStrFromObj(pTable, pOper->pObj), pTable->numOfRows, sdbGetVersion());
 
   (*pTable->updateFp)(pOper);
@@ -717,7 +719,7 @@ void *sdbOpenTable(SSdbTableDesc *pDesc) {
   
   if (pTable == NULL) return NULL;
 
-  strcpy(pTable->tableName, pDesc->tableName);
+  tstrncpy(pTable->tableName, pDesc->tableName, SDB_TABLE_LEN);
   pTable->keyType      = pDesc->keyType;
   pTable->tableId      = pDesc->tableId;
   pTable->hashSessions = pDesc->hashSessions;
diff --git a/src/mnode/src/mnodeShow.c b/src/mnode/src/mnodeShow.c
index cb448bb564a752a33f9c0c119d47c7bcf7ecb342..deb297610dc17566ff9cb27c8b75e2c72ac69890 100644
--- a/src/mnode/src/mnodeShow.c
+++ b/src/mnode/src/mnodeShow.c
@@ -324,6 +324,7 @@ static int32_t mnodeProcessConnectMsg(SMnodeMsg *pMsg) {
 
 connect_over:
   if (code != TSDB_CODE_SUCCESS) {
+    rpcFreeCont(pConnectRsp);
     mLError("user:%s login from %s, result:%s", connInfo.user, taosIpStr(connInfo.clientIp), tstrerror(code));
   } else {
     mLPrint("user:%s login from %s, result:%s", connInfo.user, taosIpStr(connInfo.clientIp), tstrerror(code));