diff --git a/.gitignore b/.gitignore
index bb9a70e9b284194c308ff5a6d57bd3edfdce6799..77c52b2ee2d00da281cc6ddec32d4003c9b90c2b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -64,4 +64,5 @@ CMakeError.log
 /out/isenseconfig/WSL-Clang-Debug
 /out/isenseconfig/WSL-GCC-Debug
 /test/cfg
-/src/.vs
+/src/.vs
+*.o
diff --git a/src/client/src/tscSub.c b/src/client/src/tscSub.c
index 9baf49ff211667e8fd83b5494824aa8ba793aba0..1a1305825bb32cd3a300e990a33cca52ec7633b9 100644
--- a/src/client/src/tscSub.c
+++ b/src/client/src/tscSub.c
@@ -301,7 +301,9 @@ void tscSaveSubscriptionProgress(void* sub) {
   char path[256];
   sprintf(path, "%s/subscribe", tsDataDir);
   if (access(path, 0) != 0) {
-    mkdir(path, 0777);
+    if (mkdir(path, 0777) != 0 && errno != EEXIST) {
+      tscError("failed to create subscribe dir: %s", path);
+    }
   }
 
   sprintf(path, "%s/subscribe/%s", tsDataDir, pSub->topic);
diff --git a/src/client/src/tscSystem.c b/src/client/src/tscSystem.c
index ea1c656a5f36111ca35c0ecb959d9200435da423..6a403a2acf0e14270c4c296924003242dd4d677b 100644
--- a/src/client/src/tscSystem.c
+++ b/src/client/src/tscSystem.c
@@ -80,9 +80,8 @@ int32_t tscInitRpc(const char *user, const char *secret, void** pDnodeConn) {
 }
 
 void taos_init_imp() {
-  char        temp[128];
-  struct stat dirstat;
-
+  char temp[128];
+  
   errno = TSDB_CODE_SUCCESS;
   srand(taosGetTimestampSec());
   deltaToUtcInitOnce();
@@ -94,7 +93,9 @@ void taos_init_imp() {
     taosReadGlobalLogCfg();
 
     // For log directory
-    if (stat(tsLogDir, &dirstat) < 0) mkdir(tsLogDir, 0755);
+    if (mkdir(tsLogDir, 0755) != 0 && errno != EEXIST) {
+      printf("failed to create log dir:%s\n", tsLogDir);
+    }
 
     sprintf(temp, "%s/taoslog", tsLogDir);
     if (taosInitLog(temp, tsNumOfLogLines, 10) < 0) {
@@ -200,7 +201,7 @@ static int taos_options_imp(TSDB_OPTION option, const char *pStr) {
         tscPrint("set shellActivityTimer:%d", tsShellActivityTimer);
       } else {
         tscWarn("config option:%s, input value:%s, is configured by %s, use %d", cfg->option, pStr,
-                tsCfgStatusStr[cfg->cfgStatus], (int32_t *)cfg->ptr);
+                tsCfgStatusStr[cfg->cfgStatus], *(int32_t *)cfg->ptr);
       }
       break;
 
diff --git a/src/connector/python/linux/python2/taos/cursor.py b/src/connector/python/linux/python2/taos/cursor.py
index f7c840442e2e5acbed76c354e9800a27d6b3eeca..8c268d8afba2b971709fba6f157abfebdc8dfd1a 100644
--- a/src/connector/python/linux/python2/taos/cursor.py
+++ b/src/connector/python/linux/python2/taos/cursor.py
@@ -137,7 +137,7 @@ class TDengineCursor(object):
         else:
             raise ProgrammingError(
                 CTaosInterface.errStr(
-                    self._result ))
+                    self._result ), errno)
 
     def executemany(self, operation, seq_of_parameters):
         """Prepare a database operation (query or command) and then execute it against all parameter sequences or mappings found in the sequence seq_of_parameters.
diff --git a/src/connector/python/linux/python3/taos/cursor.py b/src/connector/python/linux/python3/taos/cursor.py
index 5db5365eb3566d815f6c9984f5f72132b1cae7e0..06d6a1946213cdf4b348d5430433749f05a120d3 100644
--- a/src/connector/python/linux/python3/taos/cursor.py
+++ b/src/connector/python/linux/python3/taos/cursor.py
@@ -139,7 +139,7 @@ class TDengineCursor(object):
         else:
             raise ProgrammingError(
                 CTaosInterface.errStr(
-                    self._result ))
+                    self._result), errno)
 
     def executemany(self, operation, seq_of_parameters):
         """Prepare a database operation (query or command) and then execute it against all parameter sequences or mappings found in the sequence seq_of_parameters.
diff --git a/src/connector/python/windows/python2/taos/cursor.py b/src/connector/python/windows/python2/taos/cursor.py
index 1da726638a8b42edf0fb18d3b806191cb21b6745..7eee3bfc8f8559454f53aa967f5ad0294a1cb2bf 100644
--- a/src/connector/python/windows/python2/taos/cursor.py
+++ b/src/connector/python/windows/python2/taos/cursor.py
@@ -117,7 +117,7 @@ class TDengineCursor(object):
                 self._fields = CTaosInterface.useResult(self._result)
                 return self._handle_result()
         else:
-            raise ProgrammingError(CTaosInterface.errStr(self._result))
+            raise ProgrammingError(CTaosInterface.errStr(self._result), errno)
 
     def executemany(self, operation, seq_of_parameters):
         """Prepare a database operation (query or command) and then execute it against all parameter sequences or mappings found in the sequence seq_of_parameters.
diff --git a/src/connector/python/windows/python3/taos/cursor.py b/src/connector/python/windows/python3/taos/cursor.py
index 2dcd0aaccb216647e328c89281e00f0bad75ae33..5f5aa4e1d7d9b454132f533a9e84cca2859db735 100644
--- a/src/connector/python/windows/python3/taos/cursor.py
+++ b/src/connector/python/windows/python3/taos/cursor.py
@@ -117,7 +117,7 @@ class TDengineCursor(object):
                 self._fields = CTaosInterface.useResult(self._result )
                 return self._handle_result()
         else:
-            raise ProgrammingError(CTaosInterface.errStr(self._result ))
+            raise ProgrammingError(CTaosInterface.errStr(self._result ), errno)
 
     def executemany(self, operation, seq_of_parameters):
         """Prepare a database operation (query or command) and then execute it against all parameter sequences or mappings found in the sequence seq_of_parameters.
diff --git a/src/dnode/src/dnodeSystem.c b/src/dnode/src/dnodeSystem.c
index 97cf6f7eeb4170d4ff7771db8498e35ec5652458..0a983362c2d65c5b57f382a379b1578612ad0f05 100644
--- a/src/dnode/src/dnodeSystem.c
+++ b/src/dnode/src/dnodeSystem.c
@@ -92,6 +92,7 @@ int32_t main(int32_t argc, char *argv[]) {
   // Initialize the system
   if (dnodeInitSystem() < 0) {
     syslog(LOG_ERR, "Error initialize TDengine system");
+    dPrint("Failed to start TDengine, please check the log at:%s", tsLogDir);
     closelog();
     exit(EXIT_FAILURE);
   }
diff --git a/src/inc/taoserror.h b/src/inc/taoserror.h
index 6012efa3595ac782e7a67c37ad7426b23204d0b1..5379b371ef05150af0fc02c2a9693e3f6111bd5a 100644
--- a/src/inc/taoserror.h
+++ b/src/inc/taoserror.h
@@ -136,16 +136,17 @@ TAOS_DEFINE_ERROR(TSDB_CODE_MND_TOO_MANY_USERS,           0, 0x0355, "mnode too
 
 TAOS_DEFINE_ERROR(TSDB_CODE_MND_TABLE_ALREADY_EXIST,      0, 0x0360, "mnode table already exist")
 TAOS_DEFINE_ERROR(TSDB_CODE_MND_INVALID_TABLE_ID,         0, 0x0361, "mnode invalid table id")
-TAOS_DEFINE_ERROR(TSDB_CODE_MND_INVALID_TABLE_TYPE,       0, 0x0362, "mnode invalid table type")
-TAOS_DEFINE_ERROR(TSDB_CODE_MND_TOO_MANY_TAGS,            0, 0x0363, "mnode too many tags")
-TAOS_DEFINE_ERROR(TSDB_CODE_MND_TOO_MANY_TABLES,          0, 0x0364, "mnode too many tables")
-TAOS_DEFINE_ERROR(TSDB_CODE_MND_TOO_MANY_TIMESERIES,      0, 0x0365, "mnode not enough time series")
-TAOS_DEFINE_ERROR(TSDB_CODE_MND_NOT_SUPER_TABLE,          0, 0x0366, "mnode no super table")           // operation only available for super table
-TAOS_DEFINE_ERROR(TSDB_CODE_MND_COL_NAME_TOO_LONG,        0, 0x0367, "mnode column name too long")
-TAOS_DEFINE_ERROR(TSDB_CODE_MND_TAG_ALREAY_EXIST,         0, 0x0368, "mnode tag already exist")
-TAOS_DEFINE_ERROR(TSDB_CODE_MND_TAG_NOT_EXIST,            0, 0x0369, "mnode tag not exist")
-TAOS_DEFINE_ERROR(TSDB_CODE_MND_FIELD_ALREAY_EXIST,       0, 0x036A, "mnode field already exist")
-TAOS_DEFINE_ERROR(TSDB_CODE_MND_FIELD_NOT_EXIST,          0, 0x036B, "mnode field not exist")
+TAOS_DEFINE_ERROR(TSDB_CODE_MND_INVALID_TABLE_NAME,       0, 0x0362, "mnode invalid table name")
+TAOS_DEFINE_ERROR(TSDB_CODE_MND_INVALID_TABLE_TYPE,       0, 0x0363, "mnode invalid table type")
+TAOS_DEFINE_ERROR(TSDB_CODE_MND_TOO_MANY_TAGS,            0, 0x0364, "mnode too many tags")
+TAOS_DEFINE_ERROR(TSDB_CODE_MND_TOO_MANY_TABLES,          0, 0x0365, "mnode too many tables")
+TAOS_DEFINE_ERROR(TSDB_CODE_MND_TOO_MANY_TIMESERIES,      0, 0x0366, "mnode not enough time series")
+TAOS_DEFINE_ERROR(TSDB_CODE_MND_NOT_SUPER_TABLE,          0, 0x0367, "mnode no super table")           // operation only available for super table
+TAOS_DEFINE_ERROR(TSDB_CODE_MND_COL_NAME_TOO_LONG,        0, 0x0368, "mnode column name too long")
+TAOS_DEFINE_ERROR(TSDB_CODE_MND_TAG_ALREAY_EXIST,         0, 0x0369, "mnode tag already exist")
+TAOS_DEFINE_ERROR(TSDB_CODE_MND_TAG_NOT_EXIST,            0, 0x036A, "mnode tag not exist")
+TAOS_DEFINE_ERROR(TSDB_CODE_MND_FIELD_ALREAY_EXIST,       0, 0x036B, "mnode field already exist")
+TAOS_DEFINE_ERROR(TSDB_CODE_MND_FIELD_NOT_EXIST,          0, 0x036C, "mnode field not exist")
 
 TAOS_DEFINE_ERROR(TSDB_CODE_MND_DB_NOT_SELECTED,          0, 0x0380, "mnode db not selected")
 TAOS_DEFINE_ERROR(TSDB_CODE_MND_DB_ALREADY_EXIST,         0, 0x0381, "mnode database aleady exist")
diff --git a/src/kit/shell/src/shellEngine.c b/src/kit/shell/src/shellEngine.c
index 954f2cb8a30b2d4bff75c9580f2e6c9be1f9b909..f04607f6fadf931b836d36fa7dc6fa4998f8bd71 100644
--- a/src/kit/shell/src/shellEngine.c
+++ b/src/kit/shell/src/shellEngine.c
@@ -727,10 +727,6 @@ void read_history() {
   char f_history[TSDB_FILENAME_LEN];
   get_history_path(f_history);
 
-  if (access(f_history, R_OK) == -1) {
-    return;
-  }
-
   FILE *f = fopen(f_history, "r");
   if (f == NULL) {
     fprintf(stderr, "Opening file %s\n", f_history);
@@ -809,14 +805,6 @@ void source_file(TAOS *con, char *fptr) {
     return;
   }
   
-  if (access(fname, R_OK) != 0) {
-    fprintf(stderr, "ERROR: file %s is not readable\n", fptr);
-  
-    wordfree(&full_path);
-    free(cmd);
-    return;
-  }
-
   FILE *f = fopen(fname, "r");
   if (f == NULL) {
     fprintf(stderr, "ERROR: failed to open file %s\n", fname);
diff --git a/src/kit/shell/src/shellImport.c b/src/kit/shell/src/shellImport.c
index 1dea6bca702e761850b5fefbba308791655aa00a..347f99671db1bc9147c98d97ec708a3bf8bcf689 100644
--- a/src/kit/shell/src/shellImport.c
+++ b/src/kit/shell/src/shellImport.c
@@ -148,7 +148,11 @@ static void shellSourceFile(TAOS *con, char *fptr) {
   }
 
   char *fname = full_path.we_wordv[0];
-  
+  if (fname == NULL) {
+    fprintf(stderr, "ERROR: invalid filename\n");
+    return;
+  }
+
   if (access(fname, F_OK) != 0) {
     fprintf(stderr, "ERROR: file %s is not exist\n", fptr);
     
@@ -169,6 +173,7 @@ static void shellSourceFile(TAOS *con, char *fptr) {
   if (f == NULL) {
     fprintf(stderr, "ERROR: failed to open file %s\n", fname);
     wordfree(&full_path);
+    free(cmd);
     return;
   }
 
diff --git a/src/kit/taosdemo/taosdemo.c b/src/kit/taosdemo/taosdemo.c
index 595beea641e9e6445cb0eb7461abc39dde711fb5..47616b250919abaec4e2987c633c8fdc8d389e8c 100644
--- a/src/kit/taosdemo/taosdemo.c
+++ b/src/kit/taosdemo/taosdemo.c
@@ -43,6 +43,7 @@ extern char configDir[];
 #define MAX_DATA_SIZE    1024
 #define MAX_NUM_DATATYPE 8
 #define OPT_ABORT        1 /* –abort */
+#define STRING_LEN       512
 
 /* The options we understand. */
 static struct argp_option options[] = {
@@ -380,10 +381,11 @@ int main(int argc, char *argv[]) {
   bool insert_only = arguments.insert_only;
   char **data_type = arguments.datatype;
   int count_data_type = 0;
-  char dataString[512];
+  char dataString[STRING_LEN];
   bool do_aggreFunc = true;
 
-  memset(dataString, 0, 512);
+  memset(dataString, 0, STRING_LEN);
+  int len = 0;
 
   if (strcasecmp(data_type[0], "BINARY") == 0 || strcasecmp(data_type[0], "BOOL") == 0) {
     do_aggreFunc = false;
@@ -392,8 +394,8 @@ int main(int argc, char *argv[]) {
     if (strcasecmp(data_type[count_data_type], "") == 0) {
       break;
     }
-    strcat(dataString, data_type[count_data_type]);
-    strcat(dataString, " ");
+
+    len += snprintf(dataString + len, STRING_LEN - len, "%s ", data_type[count_data_type]);
   }
 
   FILE *fp = fopen(arguments.output_file, "a");
@@ -473,32 +475,29 @@ int main(int argc, char *argv[]) {
   sprintf(command, "create database %s;", db_name);
   taos_query(taos, command);
 
-  char cols[512] = "\0";
+  char cols[STRING_LEN] = "\0";
   int colIndex = 0;
+  len = 0;
 
   for (; colIndex < ncols_per_record - 1; colIndex++) {
     if (strcasecmp(data_type[colIndex % count_data_type], "BINARY") != 0) {
-      sprintf(command, ",f%d %s", colIndex + 1, data_type[colIndex % count_data_type]);
-      strcat(cols, command);
+      len += snprintf(cols + len, STRING_LEN - len, ",f%d %s", colIndex + 1, data_type[colIndex % count_data_type]);
     } else {
-      sprintf(command, ",f%d %s(%d)", colIndex + 1, data_type[colIndex % count_data_type], len_of_binary);
-      strcat(cols, command);
+      len += snprintf(cols + len, STRING_LEN - len, ",f%d %s(%d)", colIndex + 1, data_type[colIndex % count_data_type], len_of_binary);
     }
   }
 
   if (strcasecmp(data_type[colIndex % count_data_type], "BINARY") != 0) {
-    sprintf(command, ",f%d %s)", colIndex + 1, data_type[colIndex % count_data_type]);
+    len += snprintf(cols + len, STRING_LEN - len, ",f%d %s)", colIndex + 1, data_type[colIndex % count_data_type]);
   } else {
-    sprintf(command, ",f%d %s(%d))", colIndex + 1, data_type[colIndex % count_data_type], len_of_binary);
+    len += snprintf(cols + len, STRING_LEN - len, ",f%d %s(%d))", colIndex + 1, data_type[colIndex % count_data_type], len_of_binary);
   }
 
-  strcat(cols, command);
-
   if (!use_metric) {
     /* Create all the tables; */
     printf("Creating %d table(s)......\n", ntables);
     for (int i = 0; i < ntables; i++) {
-      sprintf(command, "create table %s.%s%d (ts timestamp%s;", db_name, tb_prefix, i, cols);
+      snprintf(command, BUFFER_SIZE, "create table %s.%s%d (ts timestamp%s;", db_name, tb_prefix, i, cols);
       queryDB(taos, command);
     }
 
@@ -508,7 +507,7 @@ int main(int argc, char *argv[]) {
   } else {
     /* Create metric table */
     printf("Creating meters super table...\n");
-    sprintf(command, "create table %s.meters (ts timestamp%s tags (areaid int, loc binary(10))", db_name, cols);
+    snprintf(command, BUFFER_SIZE, "create table %s.meters (ts timestamp%s tags (areaid int, loc binary(10))", db_name, cols);
     queryDB(taos, command);
     printf("meters created!\n");
 
@@ -522,10 +521,10 @@ int main(int argc, char *argv[]) {
         j = i % 10;
       }
     if (j % 2 == 0) {
-       sprintf(command, "create table %s.%s%d using %s.meters tags (%d,\"%s\");", db_name, tb_prefix, i, db_name, j,"shanghai");
-      } else {
-       sprintf(command, "create table %s.%s%d using %s.meters tags (%d,\"%s\");", db_name, tb_prefix, i, db_name, j,"beijing");
-      }
+      snprintf(command, BUFFER_SIZE, "create table %s.%s%d using %s.meters tags (%d,\"%s\");", db_name, tb_prefix, i, db_name, j, "shanghai");
+    } else {
+      snprintf(command, BUFFER_SIZE, "create table %s.%s%d using %s.meters tags (%d,\"%s\");", db_name, tb_prefix, i, db_name, j, "beijing");
+    }
       queryDB(taos, command);
     }
 
diff --git a/src/kit/taosdump/taosdump.c b/src/kit/taosdump/taosdump.c
index 7875ef732ce5e3b526675a26f1c2b7c1940ea445..d96f80ed206a2f5541daf7bbbd0f4036da4ab7b3 100644
--- a/src/kit/taosdump/taosdump.c
+++ b/src/kit/taosdump/taosdump.c
@@ -117,8 +117,8 @@ typedef struct {
 } SDbInfo;
 
 typedef struct {
-  char name[TSDB_TABLE_NAME_LEN + 1];
-  char metric[TSDB_TABLE_NAME_LEN + 1];
+  char name[TSDB_TABLE_NAME_LEN];
+  char metric[TSDB_TABLE_NAME_LEN];
 } STableRecord;
 
 typedef struct {
@@ -646,10 +646,9 @@ int taosDumpDb(SDbInfo *dbInfo, SDumpArguments *arguments, FILE *fp) {
     taosDumpTable(tableRecord.name, tableRecord.metric, arguments, fp);
   }
 
-  tclose(fd);
-  remove(".table.tmp");
+  close(fd);
 
-  return 0;
+  return remove(".table.tmp");
 }
 
 void taosDumpCreateTableClause(STableDef *tableDes, int numOfCols, SDumpArguments *arguments, FILE *fp) {
@@ -871,7 +870,7 @@ int32_t taosDumpMetric(char *metric, SDumpArguments *arguments, FILE *fp) {
   int fd = -1;
   STableRecord tableRecord;
 
-  strcpy(tableRecord.metric, metric);
+  tstrncpy(tableRecord.metric, metric, TSDB_TABLE_NAME_LEN);
 
   sprintf(command, "select tbname from %s", metric);
   result = taos_query(taos, command);
diff --git a/src/mnode/src/mnodeAcct.c b/src/mnode/src/mnodeAcct.c
index 9634d2c645d8be6a7cab1147b4a551b099209d53..7ea5188b96a47981f5c42e9c28389f8cd0410409 100644
--- a/src/mnode/src/mnodeAcct.c
+++ b/src/mnode/src/mnodeAcct.c
@@ -27,7 +27,7 @@
 
 void *  tsAcctSdb = NULL;
 static int32_t tsAcctUpdateSize;
-static void    mnodeCreateRootAcct();
+static int32_t mnodeCreateRootAcct();
 
 static int32_t mnodeAcctActionDestroy(SSdbOper *pOper) {
   SAcctObj *pAcct = pOper->pObj;
@@ -79,7 +79,11 @@ static int32_t mnodeAcctActionDecode(SSdbOper *pOper) {
 
 static int32_t mnodeAcctActionRestored() {
   if (dnodeIsFirstDeploy()) {
-    mnodeCreateRootAcct();
+    int32_t code = mnodeCreateRootAcct();
+    if (code != TSDB_CODE_SUCCESS) {
+      mError("failed to create root account, reason:%s", tstrerror(code));
+      return code;
+    }
   }
 
   acctInit();
@@ -161,9 +165,9 @@ void mnodeDropUserFromAcct(SAcctObj *pAcct, SUserObj *pUser) {
   mnodeDecAcctRef(pAcct);
 }
 
-static void mnodeCreateRootAcct() {
+static int32_t mnodeCreateRootAcct() {
   int32_t numOfAccts = sdbGetNumOfRows(tsAcctSdb);
-  if (numOfAccts != 0) return;
+  if (numOfAccts != 0) return TSDB_CODE_SUCCESS;
 
   SAcctObj *pAcct = malloc(sizeof(SAcctObj));
   memset(pAcct, 0, sizeof(SAcctObj));
@@ -190,7 +194,8 @@ static void mnodeCreateRootAcct() {
     .table = tsAcctSdb,
     .pObj = pAcct,
   };
-  sdbInsertRow(&oper);
+
+  return sdbInsertRow(&oper);
 }
 
 #ifndef _ACCT
diff --git a/src/mnode/src/mnodeMain.c b/src/mnode/src/mnodeMain.c
index 298d10993beee3262a5dbebc6184a8f5a40d8b73..57bb1b2bac5c0293aabec3e81c74d8661a89fd00 100644
--- a/src/mnode/src/mnodeMain.c
+++ b/src/mnode/src/mnodeMain.c
@@ -88,9 +88,9 @@ int32_t mnodeStartSystem() {
   }
 
   mPrint("starting to initialize mnode ...");
-  struct stat dirstat;
-  if (stat(tsMnodeDir, &dirstat) < 0) {
-    mkdir(tsMnodeDir, 0755);
+  if (mkdir(tsMnodeDir, 0755) != 0 && errno != EEXIST) {
+    mError("failed to init mnode dir:%s, reason:%s", tsMnodeDir, strerror(errno));
+    return -1;
   }
 
   dnodeAllocateMnodeWqueue();
diff --git a/src/mnode/src/mnodeShow.c b/src/mnode/src/mnodeShow.c
index 920ec3843b76a26833fc05ea24eae2dc356f8625..cb448bb564a752a33f9c0c119d47c7bcf7ecb342 100644
--- a/src/mnode/src/mnodeShow.c
+++ b/src/mnode/src/mnodeShow.c
@@ -316,7 +316,7 @@ static int32_t mnodeProcessConnectMsg(SMnodeMsg *pMsg) {
   }
 
   sprintf(pConnectRsp->acctId, "%x", pAcct->acctId);
-  strcpy(pConnectRsp->serverVersion, version);
+  memcpy(pConnectRsp->serverVersion, version, TSDB_VERSION_LEN);
   pConnectRsp->writeAuth = pUser->writeAuth;
   pConnectRsp->superAuth = pUser->superAuth;
   
diff --git a/src/mnode/src/mnodeTable.c b/src/mnode/src/mnodeTable.c
index 2077d6f43eee4266f49e320779670dd8853e74bd..119ba1627dfd188d99518c3345f1037f0641589f 100644
--- a/src/mnode/src/mnodeTable.c
+++ b/src/mnode/src/mnodeTable.c
@@ -714,7 +714,7 @@ static int32_t mnodeProcessDropTableMsg(SMnodeMsg *pMsg) {
       return TSDB_CODE_SUCCESS;
     } else {
       mError("table:%s, failed to drop table, table not exist", pDrop->tableId);
-      return TSDB_CODE_MND_INVALID_TABLE_ID;
+      return TSDB_CODE_MND_INVALID_TABLE_NAME;
     }
   }
 
@@ -742,7 +742,7 @@ static int32_t mnodeProcessTableMetaMsg(SMnodeMsg *pMsg) {
   if (pMsg->pTable == NULL) {
     if (!pInfo->createFlag) {
       mError("table:%s, failed to get table meta, table not exist", pInfo->tableId);
-      return TSDB_CODE_MND_INVALID_TABLE_ID;
+      return TSDB_CODE_MND_INVALID_TABLE_NAME;
     } else {
       mTrace("table:%s, failed to get table meta, start auto create table ", pInfo->tableId);
       return mnodeAutoCreateChildTable(pMsg);
@@ -779,7 +779,7 @@ static int32_t mnodeProcessCreateSuperTableMsg(SMnodeMsg *pMsg) {
   if (pStable->schema == NULL) {
     free(pStable);
     mError("table:%s, failed to create, no schema input", pCreate->tableId);
-    return TSDB_CODE_MND_INVALID_TABLE_ID;
+    return TSDB_CODE_MND_INVALID_TABLE_NAME;
   }
   memcpy(pStable->schema, pCreate->schema, numOfCols * sizeof(SSchema));
 
@@ -1340,7 +1340,7 @@ static int32_t mnodeProcessSuperTableVgroupMsg(SMnodeMsg *pMsg) {
 
   if (pRsp->numOfTables != numOfTable) {
     rpcFreeCont(pRsp);
-    return TSDB_CODE_MND_INVALID_TABLE_ID;
+    return TSDB_CODE_MND_INVALID_TABLE_NAME;
   } else {
     pRsp->numOfTables = htonl(pRsp->numOfTables);
     pMsg->rpcRsp.rsp = pRsp;
@@ -1452,7 +1452,7 @@ static SChildTableObj* mnodeDoCreateChildTable(SCMCreateTableMsg *pCreate, SVgOb
     if (pSuperTable == NULL) {
       mError("table:%s, corresponding super table:%s does not exist", pCreate->tableId, pTagData->name);
       mnodeDestroyChildTable(pTable);
-      terrno = TSDB_CODE_MND_INVALID_TABLE_ID;
+      terrno = TSDB_CODE_MND_INVALID_TABLE_NAME;
       return NULL;
     }
     mnodeDecTableRef(pSuperTable);
@@ -2212,7 +2212,7 @@ static int32_t mnodeProcessAlterTableMsg(SMnodeMsg *pMsg) {
   if (pMsg->pTable == NULL) pMsg->pTable = mnodeGetTable(pAlter->tableId);
   if (pMsg->pTable == NULL) {
     mError("table:%s, failed to alter table, table not exist", pMsg->pTable->tableId);
-    return TSDB_CODE_MND_INVALID_TABLE_ID;
+    return TSDB_CODE_MND_INVALID_TABLE_NAME;
   }
 
   pAlter->type = htons(pAlter->type);
diff --git a/src/mnode/src/mnodeVgroup.c b/src/mnode/src/mnodeVgroup.c
index 7274c879c643fa42e49128f7510972737f237113..25b9daf00c446799f322cac399925b7a4861a8eb 100644
--- a/src/mnode/src/mnodeVgroup.c
+++ b/src/mnode/src/mnodeVgroup.c
@@ -383,11 +383,11 @@ int32_t mnodeGetVgroupMeta(STableMetaMsg *pMeta, SShowObj *pShow, void *pConn) {
     pTable = mnodeGetTable(pShow->payload);
     if (NULL == pTable || pTable->type == TSDB_SUPER_TABLE) {
       mnodeDecTableRef(pTable);
-      return TSDB_CODE_MND_INVALID_TABLE_ID;
+      return TSDB_CODE_MND_INVALID_TABLE_NAME;
     }
     mnodeDecTableRef(pTable);
     pVgroup = mnodeGetVgroup(((SChildTableObj*)pTable)->vgId);
-    if (NULL == pVgroup) return TSDB_CODE_MND_INVALID_TABLE_ID;
+    if (NULL == pVgroup) return TSDB_CODE_MND_INVALID_TABLE_NAME;
     mnodeDecVgroupRef(pVgroup);
     maxReplica = pVgroup->numOfVnodes > maxReplica ? pVgroup->numOfVnodes : maxReplica;
   } else {
diff --git a/src/os/linux/src/linuxSysPara.c b/src/os/linux/src/linuxSysPara.c
index af2d3c2633fef495c0876b7e4be7f90d336d51fe..b270eb14cf4c652a531cb0228c949868dc58f7a9 100644
--- a/src/os/linux/src/linuxSysPara.c
+++ b/src/os/linux/src/linuxSysPara.c
@@ -229,7 +229,7 @@ static void taosGetSystemLocale() {  // get and set default locale
       uError("can't get locale from system, set it to en_US.UTF-8");
       strcpy(tsLocale, "en_US.UTF-8");
     } else {
-      strncpy(tsLocale, locale, tListLen(tsLocale));
+      tstrncpy(tsLocale, locale, tListLen(tsLocale));
       uError("locale not configured, set to system default:%s", tsLocale);
     }
   }
@@ -331,66 +331,7 @@ bool taosGetDisk() {
   return true;
 }
 
-static bool taosGetCardName(char *ip, char *name) {
-  struct ifaddrs *ifaddr, *ifa;
-  int             family, s;
-  char            host[NI_MAXHOST];
-  bool            ret = false;
-
-  if (getifaddrs(&ifaddr) == -1) {
-    return false;
-  }
-
-  /* Walk through linked list, maintaining head pointer so we can free list
-   * later */
-  for (ifa = ifaddr; ifa != NULL; ifa = ifa->ifa_next) {
-    if (ifa->ifa_addr == NULL) continue;
-
-    family = ifa->ifa_addr->sa_family;
-    if (family != AF_INET) {
-      continue;
-    }
-
-    s = getnameinfo(ifa->ifa_addr, (family == AF_INET) ? sizeof(struct sockaddr_in) : sizeof(struct sockaddr_in6), host,
-                    NI_MAXHOST, NULL, 0, NI_NUMERICHOST);
-    if (s != 0) {
-      break;
-    }
-
-    if (strcmp(host, "127.0.0.1") == 0) {
-      continue;
-    }
-
-    // TODO: the ip not config
-    // if (strcmp(host, ip) == 0) {
-    strcpy(name, ifa->ifa_name);
-    ret = true;
-    // }
-  }
-
-  freeifaddrs(ifaddr);
-  return ret;
-}
-
 static bool taosGetCardInfo(int64_t *bytes) {
-  static char tsPublicCard[1000] = {0};
-  static char tsPrivateIp[40];
-
-  if (tsPublicCard[0] == 0) {
-    if (!taosGetCardName(tsPrivateIp, tsPublicCard)) {
-      uError("can't get card name from ip:%s", tsPrivateIp);
-      return false;
-    }
-    int cardNameLen = (int)strlen(tsPublicCard);
-    for (int i = 0; i < cardNameLen; ++i) {
-      if (tsPublicCard[i] == ':') {
-        tsPublicCard[i] = 0;
-        break;
-      }
-    }
-    // uTrace("card name of public ip:%s is %s", tsPublicIp, tsPublicCard);
-  }
-
   FILE *fp = fopen(tsSysNetFile, "r");
   if (fp == NULL) {
     uError("open file:%s failed", tsSysNetFile);
@@ -403,6 +344,7 @@ static bool taosGetCardInfo(int64_t *bytes) {
 
   size_t len;
   char * line = NULL;
+  *bytes = 0;
 
   while (!feof(fp)) {
     tfree(line);
@@ -411,23 +353,20 @@ static bool taosGetCardInfo(int64_t *bytes) {
     if (line == NULL) {
       break;
     }
-    if (strstr(line, tsPublicCard) != NULL) {
-      break;
+    if (strstr(line, "lo:") != NULL) {
+      continue;
     }
+
+    sscanf(line,
+           "%s %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64,
+           nouse0, &rbytes, &rpackts, &nouse1, &nouse2, &nouse3, &nouse4, &nouse5, &nouse6, &tbytes, &tpackets);
+    *bytes += (rbytes + tbytes);
   }
-  if (line != NULL) {
-    sscanf(line, "%s %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64 " %" PRId64, nouse0, &rbytes, &rpackts, &nouse1, &nouse2, &nouse3,
-           &nouse4, &nouse5, &nouse6, &tbytes, &tpackets);
-    *bytes = rbytes + tbytes;
-    tfree(line);
-    fclose(fp);
-    return true;
-  } else {
-    uWarn("can't get card:%s info from device:%s", tsPublicCard, tsSysNetFile);
-    *bytes = 0;
-    fclose(fp);
-    return false;
-  }
+
+  tfree(line);
+  fclose(fp);
+
+  return true;
 }
 
 bool taosGetBandSpeed(float *bandSpeedKb) {
@@ -443,13 +382,15 @@ bool taosGetBandSpeed(float *bandSpeedKb) {
   if (lastTime == 0 || lastBytes == 0) {
     lastTime = curTime;
     lastBytes = curBytes;
-    return false;
+    *bandSpeedKb = 0;
+    return true;
   }
 
   if (lastTime >= curTime || lastBytes > curBytes) {
     lastTime = curTime;
     lastBytes = curBytes;
-    return false;
+    *bandSpeedKb = 0;
+    return true;
   }
 
   double totalBytes = (double)(curBytes - lastBytes) / 1024 * 8;  // Kb
diff --git a/src/plugins/http/src/gcHandle.c b/src/plugins/http/src/gcHandle.c
index fbe6757ccbcdea09bce8d8feabfae95e2691a549..41209801233c6621c9f5a7d233c7d01718d54ba4 100644
--- a/src/plugins/http/src/gcHandle.c
+++ b/src/plugins/http/src/gcHandle.c
@@ -22,9 +22,27 @@
 #include "taosdef.h"
 
 static HttpDecodeMethod gcDecodeMethod = {"grafana", gcProcessRequest};
-static HttpEncodeMethod gcHeartBeatMethod = {NULL, gcSendHeartBeatResp, NULL, NULL, NULL, NULL, NULL, NULL};
+static HttpEncodeMethod gcHeartBeatMethod = {
+  .startJsonFp          = NULL,         
+  .stopJsonFp           = gcSendHeartBeatResp, 
+  .buildQueryJsonFp     = NULL,
+  .buildAffectRowJsonFp = NULL, 
+  .initJsonFp           = NULL, 
+  .cleanJsonFp          = NULL,
+  .checkFinishedFp      = NULL,
+  .setNextCmdFp         = NULL
+};
+
 static HttpEncodeMethod gcQueryMethod = {
-    NULL, gcStopQueryJson, gcBuildQueryJson, NULL, gcInitQueryJson, gcCleanQueryJson, NULL, NULL};
+  .startJsonFp          = NULL,         
+  .stopJsonFp           = gcStopQueryJson, 
+  .buildQueryJsonFp     = gcBuildQueryJson,
+  .buildAffectRowJsonFp = NULL, 
+  .initJsonFp           = gcInitQueryJson, 
+  .cleanJsonFp          = gcCleanQueryJson,
+  .checkFinishedFp      = NULL,
+  .setNextCmdFp         = NULL
+};
 
 void gcInitHandle(HttpServer* pServer) { httpAddMethod(pServer, &gcDecodeMethod); }
 
diff --git a/src/plugins/http/src/httpJson.c b/src/plugins/http/src/httpJson.c
index 950258533fb35daadf3ac610eaef2fd380d5539c..e5e69ae02a048e3bb7110e11d09891dcca922e8c 100644
--- a/src/plugins/http/src/httpJson.c
+++ b/src/plugins/http/src/httpJson.c
@@ -445,7 +445,7 @@ void httpJsonPairStatus(JsonBuf* buf, int code) {
       httpJsonItemToken(buf);
       if (code == TSDB_CODE_MND_DB_NOT_SELECTED) {
         httpJsonPair(buf, "desc", 4, "failed to create database", 23);
-      } else if (code == TSDB_CODE_MND_INVALID_TABLE_ID) {
+      } else if (code == TSDB_CODE_MND_INVALID_TABLE_NAME) {
         httpJsonPair(buf, "desc", 4, "failed to create table", 22);
       } else
         httpJsonPair(buf, "desc", 4, (char*)tstrerror(code), (int)strlen(tstrerror(code)));
diff --git a/src/plugins/http/src/httpSql.c b/src/plugins/http/src/httpSql.c
index af9ad8e38acdfdf7752bbdf14ea8daf54bcc2152..6ff93b3e8a728d72d33e717991d9a1917e5e3c55 100644
--- a/src/plugins/http/src/httpSql.c
+++ b/src/plugins/http/src/httpSql.c
@@ -87,7 +87,7 @@ void httpProcessMultiSqlCallBack(void *param, TAOS_RES *result, int code) {
   }
 
   if (code < 0) {
-    if (encode->checkFinishedFp != NULL && !encode->checkFinishedFp(pContext, singleCmd, code >= 0 ? 0 : code)) {
+    if (encode->checkFinishedFp != NULL && !encode->checkFinishedFp(pContext, singleCmd, -code)) {
       singleCmd->code = code;
       httpTrace("context:%p, fd:%d, ip:%s, user:%s, process pos jump to:%d, last code:%s, last sql:%s",
                 pContext, pContext->fd, pContext->ipstr, pContext->user, multiCmds->pos + 1, tstrerror(code), sql);
diff --git a/src/plugins/http/src/httpUtil.c b/src/plugins/http/src/httpUtil.c
index 77fc3992723fb719b165fd5d9b22674d006b4a6e..b91b89e21cf5d322b4091e24d36dd3d25a7d2cd0 100644
--- a/src/plugins/http/src/httpUtil.c
+++ b/src/plugins/http/src/httpUtil.c
@@ -32,12 +32,12 @@ bool httpCheckUsedbSql(char *sql) {
 
 void httpTimeToString(time_t t, char *buf, int buflen) {
   memset(buf, 0, (size_t)buflen);
-  char ts[30] = {0};
+  char ts[32] = {0};
 
   struct tm *ptm;
   time_t     tt = t / 1000;
   ptm = localtime(&tt);
-  strftime(ts, 64, "%Y-%m-%d %H:%M:%S", ptm);
+  strftime(ts, 31, "%Y-%m-%d %H:%M:%S", ptm);
   sprintf(buf, "%s.%03ld", ts, t % 1000);
 }
 
diff --git a/src/plugins/http/src/restHandle.c b/src/plugins/http/src/restHandle.c
index a2dc7d06a1a75fd51fa17f910599b67ea6129575..d481a654d89e41ee296645fe32cb5fff38abf521 100644
--- a/src/plugins/http/src/restHandle.c
+++ b/src/plugins/http/src/restHandle.c
@@ -22,11 +22,37 @@
 static HttpDecodeMethod restDecodeMethod = {"rest", restProcessRequest};
 static HttpDecodeMethod restDecodeMethod2 = {"restful", restProcessRequest};
 static HttpEncodeMethod restEncodeSqlTimestampMethod = {
-    restStartSqlJson, restStopSqlJson, restBuildSqlTimestampJson, restBuildSqlAffectRowsJson, NULL, NULL, NULL, NULL};
+  .startJsonFp          = restStartSqlJson,         
+  .stopJsonFp           = restStopSqlJson, 
+  .buildQueryJsonFp     = restBuildSqlTimestampJson,
+  .buildAffectRowJsonFp = restBuildSqlAffectRowsJson, 
+  .initJsonFp           = NULL, 
+  .cleanJsonFp          = NULL,
+  .checkFinishedFp      = NULL,
+  .setNextCmdFp         = NULL
+};
+
 static HttpEncodeMethod restEncodeSqlLocalTimeStringMethod = {
-    restStartSqlJson, restStopSqlJson, restBuildSqlLocalTimeStringJson, restBuildSqlAffectRowsJson, NULL, NULL, NULL, NULL};
+  .startJsonFp          = restStartSqlJson,         
+  .stopJsonFp           = restStopSqlJson, 
+  .buildQueryJsonFp     = restBuildSqlLocalTimeStringJson,
+  .buildAffectRowJsonFp = restBuildSqlAffectRowsJson, 
+  .initJsonFp           = NULL, 
+  .cleanJsonFp          = NULL,
+  .checkFinishedFp      = NULL,
+  .setNextCmdFp         = NULL
+};
+
 static HttpEncodeMethod restEncodeSqlUtcTimeStringMethod = {
-    restStartSqlJson, restStopSqlJson, restBuildSqlUtcTimeStringJson, restBuildSqlAffectRowsJson, NULL, NULL, NULL, NULL};
+  .startJsonFp          = restStartSqlJson,         
+  .stopJsonFp           = restStopSqlJson, 
+  .buildQueryJsonFp     = restBuildSqlUtcTimeStringJson,
+  .buildAffectRowJsonFp = restBuildSqlAffectRowsJson, 
+  .initJsonFp           = NULL, 
+  .cleanJsonFp          = NULL,
+  .checkFinishedFp      = NULL,
+  .setNextCmdFp         = NULL
+};
 
 void restInitHandle(HttpServer* pServer) {
   httpAddMethod(pServer, &restDecodeMethod);
diff --git a/src/plugins/http/src/tgHandle.c b/src/plugins/http/src/tgHandle.c
index 61f9da63688f6d0f541a1fbae56b4d2037978269..c6a2230bfb28fb3bffb5d760937423291190a787 100644
--- a/src/plugins/http/src/tgHandle.c
+++ b/src/plugins/http/src/tgHandle.c
@@ -62,9 +62,16 @@
 #define TG_MAX_SORT_TAG_SIZE 20
 
 static HttpDecodeMethod tgDecodeMethod = {"telegraf", tgProcessRquest};
-static HttpEncodeMethod tgQueryMethod = {tgStartQueryJson,         tgStopQueryJson, NULL,
-                                         tgBuildSqlAffectRowsJson, tgInitQueryJson, tgCleanQueryJson,
-                                         tgCheckFinished,          tgSetNextCmd};
+static HttpEncodeMethod tgQueryMethod = {
+  .startJsonFp          = tgStartQueryJson,         
+  .stopJsonFp           = tgStopQueryJson, 
+  .buildQueryJsonFp     = NULL,
+  .buildAffectRowJsonFp = tgBuildSqlAffectRowsJson, 
+  .initJsonFp           = tgInitQueryJson, 
+  .cleanJsonFp          = tgCleanQueryJson,
+  .checkFinishedFp      = tgCheckFinished,
+  .setNextCmdFp         = tgSetNextCmd
+};
 
 static const char DEFAULT_TELEGRAF_CFG[] =
         "{\"metrics\":["
@@ -303,7 +310,7 @@ bool tgGetUserFromUrl(HttpContext *pContext) {
     return false;
   }
 
-  strcpy(pContext->user, pParser->path[TG_USER_URL_POS].pos);
+  tstrncpy(pContext->user, pParser->path[TG_USER_URL_POS].pos, TSDB_USER_LEN);
   return true;
 }
 
@@ -313,7 +320,7 @@ bool tgGetPassFromUrl(HttpContext *pContext) {
     return false;
   }
 
-  strcpy(pContext->pass, pParser->path[TG_PASS_URL_POS].pos);
+  tstrncpy(pContext->pass, pParser->path[TG_PASS_URL_POS].pos, TSDB_PASSWORD_LEN);
   return true;
 }
 
diff --git a/src/plugins/http/src/tgJson.c b/src/plugins/http/src/tgJson.c
index 6c0b3c86633407e817f4a5887ac2bad65f56ec1c..ed33f51d46649dc5fdad767b6e9205cbea5b2338 100644
--- a/src/plugins/http/src/tgJson.c
+++ b/src/plugins/http/src/tgJson.c
@@ -111,7 +111,7 @@ bool tgCheckFinished(struct HttpContext *pContext, HttpSqlCmd *cmd, int code) {
                     pContext->ipstr);
           return false;
         }
-      } else if (code == TSDB_CODE_MND_INVALID_TABLE_ID) {
+      } else if (code == TSDB_CODE_MND_INVALID_TABLE_NAME) {
         cmd->cmdState = HTTP_CMD_STATE_RUN_FINISHED;
         if (multiCmds->cmds[multiCmds->pos - 1].cmdState == HTTP_CMD_STATE_NOT_RUN_YET) {
           multiCmds->pos = (int16_t)(multiCmds->pos - 2);
diff --git a/src/rpc/src/rpcTcp.c b/src/rpc/src/rpcTcp.c
index 04a269502e0a79063ca1a9d8db09e8bb5e31c6e8..7035b30b66ec1d0b0d1a1e50cfb1d74f83ff904f 100644
--- a/src/rpc/src/rpcTcp.c
+++ b/src/rpc/src/rpcTcp.c
@@ -67,7 +67,7 @@ static void   *taosProcessTcpData(void *param);
 static SFdObj *taosMallocFdObj(SThreadObj *pThreadObj, int fd);
 static void    taosFreeFdObj(SFdObj *pFdObj);
 static void    taosReportBrokenLink(SFdObj *pFdObj);
-static void*   taosAcceptTcpConnection(void *arg);
+static void   *taosAcceptTcpConnection(void *arg);
 
 void *taosInitTcpServer(uint32_t ip, uint16_t port, char *label, int numOfThreads, void *fp, void *shandle) {
   SServerObj *pServerObj;
@@ -80,6 +80,7 @@ void *taosInitTcpServer(uint32_t ip, uint16_t port, char *label, int numOfThread
     return NULL;
   }
 
+  pServerObj->fd = -1;
   pServerObj->thread = 0;
   pServerObj->ip = ip;
   pServerObj->port = port;
@@ -99,6 +100,7 @@ void *taosInitTcpServer(uint32_t ip, uint16_t port, char *label, int numOfThread
   pthread_attr_init(&thattr);
   pthread_attr_setdetachstate(&thattr, PTHREAD_CREATE_JOINABLE);
 
+  // initialize parameters in case it may encounter error later 
   pThreadObj = pServerObj->pThreadObj;
   for (int i = 0; i < numOfThreads; ++i) {
     pThreadObj->pollFd = -1;
@@ -106,18 +108,21 @@ void *taosInitTcpServer(uint32_t ip, uint16_t port, char *label, int numOfThread
     pThreadObj->processData = fp;
     tstrncpy(pThreadObj->label, label, sizeof(pThreadObj->label));
     pThreadObj->shandle = shandle;
+    pThreadObj++;
+  }
 
+  // initialize mutex, thread, fd which may fail
+  pThreadObj = pServerObj->pThreadObj;
+  for (int i = 0; i < numOfThreads; ++i) {
     code = pthread_mutex_init(&(pThreadObj->mutex), NULL);
     if (code < 0) {
       tError("%s failed to init TCP process data mutex(%s)", label, strerror(errno));
-      terrno = TAOS_SYSTEM_ERROR(errno); 
       break;;
     }
 
     pThreadObj->pollFd = epoll_create(10);  // size does not matter
     if (pThreadObj->pollFd < 0) {
       tError("%s failed to create TCP epoll", label);
-      terrno = TAOS_SYSTEM_ERROR(errno); 
       code = -1;
       break;
     }
@@ -125,7 +130,6 @@ void *taosInitTcpServer(uint32_t ip, uint16_t port, char *label, int numOfThread
     code = pthread_create(&(pThreadObj->thread), &thattr, taosProcessTcpData, (void *)(pThreadObj));
     if (code != 0) {
       tError("%s failed to create TCP process data thread(%s)", label, strerror(errno));
-      terrno = TAOS_SYSTEM_ERROR(errno); 
       break;
     }
 
@@ -133,15 +137,18 @@ void *taosInitTcpServer(uint32_t ip, uint16_t port, char *label, int numOfThread
     pThreadObj++;
   }
 
+  pServerObj->fd = taosOpenTcpServerSocket(pServerObj->ip, pServerObj->port);
+  if (pServerObj->fd < 0) code = -1; 
+
   if (code == 0) { 
-    code = pthread_create(&(pServerObj->thread), &thattr, (void *)taosAcceptTcpConnection, (void *)(pServerObj));
+    code = pthread_create(&pServerObj->thread, &thattr, taosAcceptTcpConnection, (void *)pServerObj);
     if (code != 0) {
-      terrno = TAOS_SYSTEM_ERROR(errno); 
       tError("%s failed to create TCP accept thread(%s)", label, strerror(errno));
     }
   }
 
   if (code != 0) {
+    terrno = TAOS_SYSTEM_ERROR(errno); 
     taosCleanUpTcpServer(pServerObj);
     pServerObj = NULL;
   } else {
@@ -204,7 +211,7 @@ void taosCleanUpTcpServer(void *handle) {
   tfree(pServerObj);
 }
 
-static void* taosAcceptTcpConnection(void *arg) {
+static void *taosAcceptTcpConnection(void *arg) {
   int                connFd = -1;
   struct sockaddr_in caddr;
   int                threadId = 0;
@@ -212,10 +219,6 @@ static void* taosAcceptTcpConnection(void *arg) {
   SServerObj        *pServerObj;
 
   pServerObj = (SServerObj *)arg;
-
-  pServerObj->fd = taosOpenTcpServerSocket(pServerObj->ip, pServerObj->port);
-  if (pServerObj->fd < 0) return NULL; 
-
   tTrace("%s TCP server is ready, ip:0x%x:%hu", pServerObj->label, pServerObj->ip, pServerObj->port);
 
   while (1) {
diff --git a/src/rpc/src/rpcUdp.c b/src/rpc/src/rpcUdp.c
index 7e2fe0db61a0ffa7e6923679f1c82f84c991382f..279cf7ed49be70d31b3afc86d53b07453578806f 100644
--- a/src/rpc/src/rpcUdp.c
+++ b/src/rpc/src/rpcUdp.c
@@ -19,6 +19,7 @@
 #include "ttimer.h"
 #include "tutil.h"
 #include "taosdef.h"
+#include "taoserror.h"
 #include "rpcLog.h"
 #include "rpcUdp.h"
 #include "rpcHead.h"
@@ -65,6 +66,7 @@ void *taosInitUdpConnection(uint32_t ip, uint16_t port, char *label, int threads
   pSet = (SUdpConnSet *)malloc((size_t)size);
   if (pSet == NULL) {
     tError("%s failed to allocate UdpConn", label);
+    terrno = TAOS_SYSTEM_ERROR(errno);
     return NULL;
   }
 
@@ -73,30 +75,34 @@ void *taosInitUdpConnection(uint32_t ip, uint16_t port, char *label, int threads
   pSet->port = port;
   pSet->shandle = shandle;
   pSet->fp = fp;
+  pSet->threads = threads;
   tstrncpy(pSet->label, label, sizeof(pSet->label));
 
+  pthread_attr_t thAttr;
+  pthread_attr_init(&thAttr);
+  pthread_attr_setdetachstate(&thAttr, PTHREAD_CREATE_JOINABLE);
+
+  int i;
   uint16_t ownPort;
-  for (int i = 0; i < threads; ++i) {
+  for (i = 0; i < threads; ++i) {
     pConn = pSet->udpConn + i;
     ownPort = (port ? port + i : 0);
     pConn->fd = taosOpenUdpSocket(ip, ownPort);
     if (pConn->fd < 0) {
       tError("%s failed to open UDP socket %x:%hu", label, ip, port);
-      taosCleanUpUdpConnection(pSet);
-      return NULL;
+      break;
     }
 
     pConn->buffer = malloc(RPC_MAX_UDP_SIZE);
     if (NULL == pConn->buffer) {
       tError("%s failed to malloc recv buffer", label);
-      taosCleanUpUdpConnection(pSet);
-      return NULL;
+      break;
     }
 
     struct sockaddr_in sin;
     unsigned int addrlen = sizeof(sin);
-    if (getsockname(pConn->fd, (struct sockaddr *)&sin, &addrlen) == 0 && sin.sin_family == AF_INET &&
-        addrlen == sizeof(sin)) {
+    if (getsockname(pConn->fd, (struct sockaddr *)&sin, &addrlen) == 0 && 
+        sin.sin_family == AF_INET && addrlen == sizeof(sin)) {
       pConn->localPort = (uint16_t)ntohs(sin.sin_port);
     }
 
@@ -107,23 +113,22 @@ void *taosInitUdpConnection(uint32_t ip, uint16_t port, char *label, int threads
     pConn->pSet = pSet;
     pConn->signature = pConn;
 
-    pthread_attr_t thAttr;
-    pthread_attr_init(&thAttr);
-    pthread_attr_setdetachstate(&thAttr, PTHREAD_CREATE_JOINABLE);
     int code = pthread_create(&pConn->thread, &thAttr, taosRecvUdpData, pConn);
-    pthread_attr_destroy(&thAttr);
     if (code != 0) {
-      tError("%s failed to create thread to process UDP data, reason:%s", label, strerror(errno));
-      taosCloseSocket(pConn->fd);
-      taosCleanUpUdpConnection(pSet);
-      return NULL;
+      tError("%s failed to create thread to process UDP data(%s)", label, strerror(errno));
+      break;
     }
-
-    ++pSet->threads;
   }
 
-  tTrace("%s UDP connection is initialized, ip:%x port:%hu threads:%d", label, ip, port, threads);
+  pthread_attr_destroy(&thAttr);
 
+  if (i != threads) { 
+    terrno = TAOS_SYSTEM_ERROR(errno);
+    taosCleanUpUdpConnection(pSet);
+    return NULL;
+  }
+
+  tTrace("%s UDP connection is initialized, ip:%x:%hu threads:%d", label, ip, port, threads);
   return pSet;
 }
 
@@ -136,16 +141,17 @@ void taosCleanUpUdpConnection(void *handle) {
   for (int i = 0; i < pSet->threads; ++i) {
     pConn = pSet->udpConn + i;
     pConn->signature = NULL;
+
     // shutdown to signal the thread to exit
-    shutdown(pConn->fd, SHUT_RD);
+    if ( pConn->fd >=0) shutdown(pConn->fd, SHUT_RD);
   }
 
   for (int i = 0; i < pSet->threads; ++i) {
     pConn = pSet->udpConn + i;
-    pthread_join(pConn->thread, NULL);
-    free(pConn->buffer);
-    taosCloseSocket(pConn->fd);
-    tTrace("chandle:%p is closed", pConn);
+    if (pConn->thread) pthread_join(pConn->thread, NULL);
+    if (pConn->fd >=0) taosCloseSocket(pConn->fd);
+    tfree(pConn->buffer);
+    tTrace("UDP chandle:%p is closed", pConn);
   }
 
   tfree(pSet);
@@ -159,7 +165,7 @@ void *taosOpenUdpConnection(void *shandle, void *thandle, uint32_t ip, uint16_t
   SUdpConn *pConn = pSet->udpConn + pSet->index;
   pConn->port = port;
 
-  tTrace("%s UDP connection is setup, ip:%x:%hu, local:%x:%d", pConn->label, ip, port, pSet->ip, pConn->localPort);
+  tTrace("%s UDP connection is setup, ip:%x:%hu", pConn->label, ip, port);
 
   return pConn;
 }
diff --git a/src/tsdb/src/tsdbMeta.c b/src/tsdb/src/tsdbMeta.c
index 05c3b303773bd2542f9c35e535fb6309f5eb58ce..40e566789389a24e0a5572db5917ce4b4f1b6b45 100644
--- a/src/tsdb/src/tsdbMeta.c
+++ b/src/tsdb/src/tsdbMeta.c
@@ -74,14 +74,16 @@ void tsdbEncodeTable(STable *pTable, char *buf, int *contLen) {
 STable *tsdbDecodeTable(void *cont, int contLen) {
   STable *pTable = (STable *)calloc(1, sizeof(STable));
   if (pTable == NULL) return NULL;
-  pTable->schema = (STSchema **)malloc(sizeof(STSchema *) * TSDB_MAX_TABLE_SCHEMAS);
-  if (pTable->schema == NULL) {
-    free(pTable);
-    return NULL;
-  }
 
   void *ptr = cont;
   T_READ_MEMBER(ptr, int8_t, pTable->type);
+  if (pTable->type != TSDB_CHILD_TABLE) {
+    pTable->schema = (STSchema **)malloc(sizeof(STSchema *) * TSDB_MAX_TABLE_SCHEMAS);
+    if (pTable->schema == NULL) {
+      free(pTable);
+      return NULL;
+    }
+  }
   int len = *(int *)ptr;
   ptr = (char *)ptr + sizeof(int);
   pTable->name = calloc(1, len + VARSTR_HEADER_SIZE + 1);
@@ -620,7 +622,10 @@ static int tsdbFreeTable(STable *pTable) {
   if (pTable->type == TSDB_CHILD_TABLE) {
     kvRowFree(pTable->tagVal);
   } else {
-    for (int i = 0; i < pTable->numOfSchemas; i++) tdFreeSchema(pTable->schema[i]);
+    if (pTable->schema) {
+      for (int i = 0; i < pTable->numOfSchemas; i++) tdFreeSchema(pTable->schema[i]);
+      free(pTable->schema);
+    }
   }
 
   if (pTable->type == TSDB_STREAM_TABLE) {
diff --git a/src/tsdb/src/tsdbRWHelper.c b/src/tsdb/src/tsdbRWHelper.c
index eab70b591349cacfc382c206e393a4846283a559..add484b5f4136b2776e47e0baa4547fd606f1705 100644
--- a/src/tsdb/src/tsdbRWHelper.c
+++ b/src/tsdb/src/tsdbRWHelper.c
@@ -764,8 +764,8 @@ static bool tsdbShouldCreateNewLast(SRWHelper *pHelper) {
 
 static int tsdbWriteBlockToFile(SRWHelper *pHelper, SFile *pFile, SDataCols *pDataCols, int rowsToWrite, SCompBlock *pCompBlock,
                                 bool isLast, bool isSuperBlock) {
-  ASSERT(rowsToWrite > 0 && rowsToWrite <= pDataCols->numOfRows &&
-         rowsToWrite <= pHelper->config.maxRowsPerFileBlock);
+  ASSERT(rowsToWrite > 0 && rowsToWrite <= pDataCols->numOfRows && rowsToWrite <= pHelper->config.maxRowsPerFileBlock);
+  ASSERT(isLast ? rowsToWrite < pHelper->config.minRowsPerFileBlock : true);
 
   SCompData *pCompData = (SCompData *)(pHelper->pBuffer);
   int64_t offset = 0;
@@ -905,14 +905,15 @@ static int tsdbMergeDataWithBlock(SRWHelper *pHelper, int blkIdx, SDataCols *pDa
 
     rowsWritten = MIN((defaultRowsToWrite - blockAtIdx(pHelper, blkIdx)->numOfRows), pDataCols->numOfRows);
     if ((blockAtIdx(pHelper, blkIdx)->numOfSubBlocks < TSDB_MAX_SUBBLOCKS) &&
-        (blockAtIdx(pHelper, blkIdx)->numOfRows + rowsWritten < pHelper->config.minRowsPerFileBlock) && (pHelper->files.nLastF.fd) > 0) {
+        (blockAtIdx(pHelper, blkIdx)->numOfRows + rowsWritten < pHelper->config.minRowsPerFileBlock) &&
+        (pHelper->files.nLastF.fd) < 0) {
       if (tsdbWriteBlockToFile(pHelper, &(pHelper->files.lastF), pDataCols, rowsWritten, &compBlock, true, false) < 0)
         goto _err;
       if (tsdbAddSubBlock(pHelper, &compBlock, blkIdx, rowsWritten) < 0) goto _err;
     } else {
       // Load
       if (tsdbLoadBlockData(pHelper, blockAtIdx(pHelper, blkIdx), NULL) < 0) goto _err;
-      ASSERT(pHelper->pDataCols[0]->numOfRows == blockAtIdx(pHelper, blkIdx)->numOfRows);
+      ASSERT(pHelper->pDataCols[0]->numOfRows <= blockAtIdx(pHelper, blkIdx)->numOfRows);
       // Merge
       if (tdMergeDataCols(pHelper->pDataCols[0], pDataCols, rowsWritten) < 0) goto _err;
       // Write
@@ -936,21 +937,21 @@ static int tsdbMergeDataWithBlock(SRWHelper *pHelper, int blkIdx, SDataCols *pDa
     // Key must overlap with the block
     ASSERT(keyFirst <= blockAtIdx(pHelper, blkIdx)->keyLast);
 
-    TSKEY keyLimit =
-        (blkIdx == pIdx->numOfBlocks - 1) ? INT64_MAX : pHelper->pCompInfo->blocks[blkIdx + 1].keyFirst - 1;
+    TSKEY keyLimit = (blkIdx == pIdx->numOfBlocks - 1) ? INT64_MAX : blockAtIdx(pHelper, blkIdx + 1)->keyFirst - 1;
 
     // rows1: number of rows must merge in this block
     int rows1 = tsdbGetRowsInRange(pDataCols, blockAtIdx(pHelper, blkIdx)->keyFirst, blockAtIdx(pHelper, blkIdx)->keyLast);
-    // rows2: max nuber of rows the block can have more
+    // rows2: max number of rows the block can have more
     int rows2 = pHelper->config.maxRowsPerFileBlock - blockAtIdx(pHelper, blkIdx)->numOfRows;
     // rows3: number of rows between this block and the next block
     int rows3 = tsdbGetRowsInRange(pDataCols, blockAtIdx(pHelper, blkIdx)->keyFirst, keyLimit);
 
     ASSERT(rows3 >= rows1);
 
-    if ((rows2 >= rows1) &&
-        (( blockAtIdx(pHelper, blkIdx)->last) ||
-         ((rows1 + blockAtIdx(pHelper, blkIdx)->numOfRows < pHelper->config.minRowsPerFileBlock) && (pHelper->files.nLastF.fd < 0)))) {
+    if ((rows2 >= rows1) && (blockAtIdx(pHelper, blkIdx)->numOfSubBlocks < TSDB_MAX_SUBBLOCKS) &&
+        ((!blockAtIdx(pHelper, blkIdx)->last) ||
+         ((rows1 + blockAtIdx(pHelper, blkIdx)->numOfRows < pHelper->config.minRowsPerFileBlock) &&
+          (pHelper->files.nLastF.fd < 0)))) {
       rowsWritten = rows1;
       bool   isLast = false;
       SFile *pFile = NULL;
@@ -964,7 +965,7 @@ static int tsdbMergeDataWithBlock(SRWHelper *pHelper, int blkIdx, SDataCols *pDa
 
       if (tsdbWriteBlockToFile(pHelper, pFile, pDataCols, rows1, &compBlock, isLast, false) < 0) goto _err;
       if (tsdbAddSubBlock(pHelper, &compBlock, blkIdx, rowsWritten) < 0) goto _err;
-    } else { // Load-Merge-Write
+    } else {  // Load-Merge-Write
       // Load
       if (tsdbLoadBlockData(pHelper, blockAtIdx(pHelper, blkIdx), NULL) < 0) goto _err;
       if (blockAtIdx(pHelper, blkIdx)->last) pHelper->hasOldLastBlock = false;
@@ -1106,16 +1107,16 @@ static int tsdbAddSubBlock(SRWHelper *pHelper, SCompBlock *pCompBlock, int blkId
     for (int i = blkIdx + 1; i < pIdx->numOfBlocks; i++) {
       SCompBlock *pTCompBlock = pHelper->pCompInfo->blocks + i;
       if (pTCompBlock->numOfSubBlocks > 1) {
-        ptr = (void *)((char *)(pHelper->pCompInfo) + pTCompBlock->offset + pTCompBlock->len);
+        ptr = POINTER_SHIFT(pHelper->pCompInfo, pTCompBlock->offset);
         break;
       }
     }
 
-    if (ptr == NULL) ptr = (void *)((char *)(pHelper->pCompInfo) + pIdx->len - sizeof(TSCKSUM));
+    if (ptr == NULL) ptr = POINTER_SHIFT(pHelper->pCompInfo, pIdx->len-sizeof(TSCKSUM));
 
     size_t tsize = pIdx->len - ((char *)ptr - (char *)(pHelper->pCompInfo));
     if (tsize > 0) {
-      memmove((void *)((char *)ptr + sizeof(SCompBlock) * 2), ptr, tsize);
+      memmove(POINTER_SHIFT(ptr, sizeof(SCompBlock) * 2), ptr, tsize);
       for (int i = blkIdx + 1; i < pIdx->numOfBlocks; i++) {
         SCompBlock *pTCompBlock = pHelper->pCompInfo->blocks + i;
         if (pTCompBlock->numOfSubBlocks > 1) pTCompBlock->offset += (sizeof(SCompBlock) * 2);
diff --git a/src/util/inc/tkvstore.h b/src/util/inc/tkvstore.h
new file mode 100644
index 0000000000000000000000000000000000000000..724c94e21dde790cd0fef007d33f029e1e10f1d8
--- /dev/null
+++ b/src/util/inc/tkvstore.h
@@ -0,0 +1,60 @@
+/*
+ * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
+ *
+ * This program is free software: you can use, redistribute, and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3
+ * or later ("AGPL"), as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef _TD_KVSTORE_H_
+#define _TD_KVSTORE_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdint.h>
+
+typedef int (*iterFunc)(void *, void *cont, int contLen);
+typedef void (*afterFunc)(void *);
+
+typedef struct {
+  int64_t size;
+  int64_t tombSize;
+  int64_t nRecords;
+  int64_t nDels;
+} SStoreInfo;
+
+typedef struct {
+  char *     fname;
+  int        fd;
+  char *     fsnap;
+  int        sfd;
+  char *     fnew;
+  int        nfd;
+  SHashObj * map;
+  iterFunc   iFunc;
+  afterFunc  aFunc;
+  void *     appH;
+  SStoreInfo info;
+} SKVStore;
+
+int       tdCreateKVStore(char *fname);
+int       tdDestroyKVStore();
+SKVStore *tdOpenKVStore(char *fname, iterFunc iFunc, afterFunc aFunc, void *appH);
+void      tdCloseKVStore(SKVStore *pStore);
+int       tdKVStoreStartCommit(SKVStore *pStore);
+int       tdUpdateRecordInKVStore(SKVStore *pStore, uint64_t uid, void *cont, int contLen);
+int       tdKVStoreEndCommit(SKVStore *pStore);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
\ No newline at end of file
diff --git a/src/util/src/tdes.c b/src/util/src/tdes.c
index 00474e4ae29a5e6f910a250d48a3c23b95c3826c..3112fb411148925bf064b356df6e8dfc708ce86e 100644
--- a/src/util/src/tdes.c
+++ b/src/util/src/tdes.c
@@ -18,6 +18,7 @@ void generate_key(unsigned char* key);
 void generate_sub_keys(unsigned char* main_key, key_set* key_sets);
 void process_message(unsigned char* message_piece, unsigned char* processed_piece, key_set* key_sets, int mode);
 
+#if 0
 int64_t taosDesGenKey() {
   unsigned int iseed = (unsigned int)time(NULL);
   srand(iseed);
@@ -27,6 +28,7 @@ int64_t taosDesGenKey() {
 
   return *((int64_t*)key);
 }
+#endif
 
 char* taosDesImp(unsigned char* key, char* src, unsigned int len, int process_mode) {
   unsigned int  number_of_blocks = len / 8;
diff --git a/src/util/src/tkvstore.c b/src/util/src/tkvstore.c
new file mode 100644
index 0000000000000000000000000000000000000000..148d8235a6fb832183e30a346cd4b6898b60f1cb
--- /dev/null
+++ b/src/util/src/tkvstore.c
@@ -0,0 +1,292 @@
+/*
+ * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
+ *
+ * This program is free software: you can use, redistribute, and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3
+ * or later ("AGPL"), as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <errno.h>
+#include <fcntl.h>
+#include <libgen.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "hash.h"
+#include "os.h"
+#include "taoserror.h"
+#include "tchecksum.h"
+#include "tcoding.h"
+#include "tkvstore.h"
+#include "tulog.h"
+
+#define TD_KVSTORE_HEADER_SIZE 512
+#define TD_KVSTORE_MAJOR_VERSION 1
+#define TD_KVSTORE_MAINOR_VERSION 0
+#define TD_KVSTORE_SNAP_SUFFIX ".snap"
+#define TD_KVSTORE_NEW_SUFFIX ".new"
+
+static int       tdInitKVStoreHeader(int fd, char *fname);
+static void *    tdEncodeStoreInfo(void *buf, SStoreInfo *pInfo);
+// static void *    tdDecodeStoreInfo(void *buf, SStoreInfo *pInfo);
+static SKVStore *tdNewKVStore(char *fname, iterFunc iFunc, afterFunc aFunc, void *appH);
+static char *    tdGetKVStoreSnapshotFname(char *fdata);
+static char *    tdGetKVStoreNewFname(char *fdata);
+static void      tdFreeKVStore(SKVStore *pStore);
+static int       tdUpdateKVStoreHeader(int fd, char *fname, SStoreInfo *pInfo);
+
+int tdCreateKVStore(char *fname) {
+  char *tname = strdup(fname);
+  if (tname == NULL) return TSDB_CODE_COM_OUT_OF_MEMORY;
+
+  int fd = open(fname, O_RDWR | O_CREAT, 0755);
+  if (fd < 0) {
+    uError("failed to open file %s since %s", fname, strerror(errno));
+    return TAOS_SYSTEM_ERROR(errno);
+  }
+
+  int code = tdInitKVStoreHeader(fd, fname);
+  if (code != TSDB_CODE_SUCCESS) return code;
+
+  if (fsync(fd) < 0) {
+    uError("failed to fsync file %s since %s", fname, strerror(errno));
+    return TAOS_SYSTEM_ERROR(errno);
+  }
+
+  if (close(fd) < 0) {
+    uError("failed to close file %s since %s", fname, strerror(errno));
+    return TAOS_SYSTEM_ERROR(errno);
+  }
+
+  return TSDB_CODE_SUCCESS;
+}
+
+SKVStore *tdOpenKVStore(char *fname, iterFunc iFunc, afterFunc aFunc, void *appH) {
+  SKVStore *pStore = tdNewKVStore(fname, iFunc, aFunc, appH);
+  if (pStore == NULL) return NULL;
+
+  pStore->fd = open(pStore->fname, O_RDWR);
+  if (pStore->fd < 0) {
+    uError("failed to open file %s since %s", pStore->fname, strerror(errno));
+    terrno = TAOS_SYSTEM_ERROR(errno);
+    goto _err;
+  }
+
+  if (access(pStore->fsnap, F_OK) == 0) {
+    uTrace("file %s exists, try to recover the KV store", pStore->fsnap);
+    pStore->sfd = open(pStore->fsnap, O_RDONLY);
+    if (pStore->sfd < 0) {
+      uError("failed to open file %s since %s", pStore->fsnap, strerror(errno));
+      terrno = TAOS_SYSTEM_ERROR(errno);
+      goto _err;
+    }
+
+    // TODO: rewind the file
+
+    close(pStore->sfd);
+    pStore->sfd = -1;
+    remove(pStore->fsnap);
+  }
+
+  // TODO: Recover from the file
+
+  return pStore;
+
+_err:
+  if (pStore->fd > 0) {
+    close(pStore->fd);
+    pStore->fd = -1;
+  }
+  if (pStore->sfd > 0) {
+    close(pStore->sfd);
+    pStore->sfd = -1;
+  }
+  tdFreeKVStore(pStore);
+  return NULL;
+}
+
+int tdKVStoreStartCommit(SKVStore *pStore) {
+  pStore->fd = open(pStore->fname, O_RDWR);
+  if (pStore->fd < 0) {
+    uError("failed to open file %s since %s", pStore->fname, strerror(errno));
+    terrno = TAOS_SYSTEM_ERROR(errno);
+    goto _err;
+  }
+
+  pStore->sfd = open(pStore->fsnap, O_WRONLY | O_CREAT, 0755);
+  if (pStore->sfd < 0) {
+    uError("failed to open file %s since %s", pStore->fsnap, strerror(errno));
+    terrno = TAOS_SYSTEM_ERROR(errno);
+    goto _err;
+  }
+
+  if (tsendfile(pStore->sfd, pStore->fd, NULL, TD_KVSTORE_HEADER_SIZE) < TD_KVSTORE_HEADER_SIZE) {
+    uError("failed to send file %d bytes since %s", TD_KVSTORE_HEADER_SIZE, strerror(errno));
+    terrno = TAOS_SYSTEM_ERROR(errno);
+    goto _err;
+  }
+
+  if (fsync(pStore->sfd) < 0) {
+    uError("failed to fsync file %s since %s", pStore->fsnap, strerror(errno));
+    terrno = TAOS_SYSTEM_ERROR(errno);
+    goto _err;
+  }
+
+  if (close(pStore->sfd) < 0) {
+    uError("failed to close file %s since %s", pStore->fsnap, strerror(errno));
+    terrno = TAOS_SYSTEM_ERROR(errno);
+    goto _err;
+  }
+  pStore->sfd = -1;
+
+  return 0;
+
+_err:
+  if (pStore->sfd > 0) {
+    close(pStore->sfd);
+    pStore->sfd = -1;
+    remove(pStore->fsnap);
+  }
+  if (pStore->fd > 0) {
+    close(pStore->fd);
+    pStore->fd = -1;
+  }
+  return -1;
+}
+
+int tdKVStoreEndCommit(SKVStore *pStore) {
+  ASSERT(pStore->fd > 0);
+
+  terrno = tdUpdateKVStoreHeader(pStore->fd, pStore->fname, &(pStore->info));
+  if (terrno != TSDB_CODE_SUCCESS) return -1;
+
+  if (fsync(pStore->fd) < 0) {
+    uError("failed to fsync file %s since %s", pStore->fname, strerror(errno));
+    terrno = TAOS_SYSTEM_ERROR(errno);
+    return -1;
+  }
+
+  if (close(pStore->fd) < 0) {
+    uError("failed to close file %s since %s", pStore->fname, strerror(errno));
+    terrno = TAOS_SYSTEM_ERROR(errno);
+    return -1;
+  }
+
+  remove(pStore->fsnap);
+  return 0;
+}
+
+static int tdUpdateKVStoreHeader(int fd, char *fname, SStoreInfo *pInfo) {
+  char buf[TD_KVSTORE_HEADER_SIZE] = "\0";
+
+  if (lseek(fd, 0, SEEK_SET) < 0) {
+    uError("failed to lseek file %s since %s", fname, strerror(errno));
+    return TAOS_SYSTEM_ERROR(errno);
+  }
+
+  tdEncodeStoreInfo(buf, pInfo);
+  taosCalcChecksumAppend(0, (uint8_t *)buf, TD_KVSTORE_HEADER_SIZE);
+  if (twrite(fd, buf, TD_KVSTORE_HEADER_SIZE) < TD_KVSTORE_HEADER_SIZE) {
+    uError("failed to write file %s %d bytes since %s", fname, TD_KVSTORE_HEADER_SIZE, strerror(errno));
+    return TAOS_SYSTEM_ERROR(errno);
+  }
+
+  return TSDB_CODE_SUCCESS;
+}
+
+static int tdInitKVStoreHeader(int fd, char *fname) {
+  SStoreInfo info = {TD_KVSTORE_HEADER_SIZE, 0, 0, 0};
+
+  return tdUpdateKVStoreHeader(fd, fname, &info);
+}
+
+static void *tdEncodeStoreInfo(void *buf, SStoreInfo *pInfo) {
+  buf = taosEncodeVariantI64(buf, pInfo->size);
+  buf = taosEncodeVariantI64(buf, pInfo->tombSize);
+  buf = taosEncodeVariantI64(buf, pInfo->nRecords);
+  buf = taosEncodeVariantI64(buf, pInfo->nDels);
+
+  return buf;
+}
+
+// static void *tdDecodeStoreInfo(void *buf, SStoreInfo *pInfo) {
+//   buf = taosDecodeVariantI64(buf, &(pInfo->size));
+//   buf = taosDecodeVariantI64(buf, &(pInfo->tombSize));
+//   buf = taosDecodeVariantI64(buf, &(pInfo->nRecords));
+//   buf = taosDecodeVariantI64(buf, &(pInfo->nDels));
+
+//   return buf;
+// }
+
+static SKVStore *tdNewKVStore(char *fname, iterFunc iFunc, afterFunc aFunc, void *appH) {
+  SKVStore *pStore = (SKVStore *)malloc(sizeof(SKVStore));
+  if (pStore == NULL) goto _err;
+
+  pStore->fname = strdup(fname);
+  if (pStore->map == NULL) goto _err;
+
+  pStore->fsnap = tdGetKVStoreSnapshotFname(fname);
+  if (pStore->fsnap == NULL) goto _err;
+
+  pStore->fnew = tdGetKVStoreNewFname(fname);
+  if (pStore->fnew == NULL) goto _err;
+
+  pStore->fd = -1;
+  pStore->sfd = -1;
+  pStore->nfd = -1;
+  pStore->iFunc = iFunc;
+  pStore->aFunc = aFunc;
+  pStore->appH = appH;
+  pStore->map = taosHashInit(4096, taosGetDefaultHashFunction(TSDB_DATA_TYPE_BIGINT), false);
+  if (pStore->map == NULL) {
+    terrno = TSDB_CODE_COM_OUT_OF_MEMORY;
+    goto _err;
+  }
+
+  return pStore;
+
+_err:
+  terrno = TSDB_CODE_COM_OUT_OF_MEMORY;
+  tdFreeKVStore(pStore);
+  return NULL;
+}
+
+static void tdFreeKVStore(SKVStore *pStore) {
+  if (pStore) {
+    tfree(pStore->fname);
+    tfree(pStore->fsnap);
+    tfree(pStore->fnew);
+    taosHashCleanup(pStore->map);
+    free(pStore);
+  }
+}
+
+static char *tdGetKVStoreSnapshotFname(char *fdata) {
+  size_t size = strlen(fdata) + strlen(TD_KVSTORE_SNAP_SUFFIX) + 1;
+  char * fname = malloc(size);
+  if (fname == NULL) {
+    terrno = TSDB_CODE_COM_OUT_OF_MEMORY;
+    return NULL;
+  }
+  sprintf(fname, "%s%s", fdata, TD_KVSTORE_SNAP_SUFFIX);
+  return fname;
+}
+
+static char *tdGetKVStoreNewFname(char *fdata) {
+  size_t size = strlen(fdata) + strlen(TD_KVSTORE_NEW_SUFFIX) + 1;
+  char * fname = malloc(size);
+  if (fname == NULL) {
+    terrno = TSDB_CODE_COM_OUT_OF_MEMORY;
+    return NULL;
+  }
+  sprintf(fname, "%s%s", fdata, TD_KVSTORE_NEW_SUFFIX);
+  return fname;
+}
\ No newline at end of file
diff --git a/src/util/src/tlog.c b/src/util/src/tlog.c
index 47521fc36e594b9f4bfde1171c5cfdb0831a9e2e..01a0eabbca39258951f2e0d6c4e098c7bf009be8 100644
--- a/src/util/src/tlog.c
+++ b/src/util/src/tlog.c
@@ -191,15 +191,14 @@ void taosResetLog() {
 }
 
 static bool taosCheckFileIsOpen(char *logFileName) {
-  int32_t exist = access(logFileName, F_OK);
-  if (exist != 0) {
-    return false;
-  }
-
-  int32_t fd = open(logFileName, O_WRONLY | O_CREAT, S_IRWXU | S_IRWXG | S_IRWXO);
+  int32_t fd = open(logFileName, O_WRONLY, S_IRWXU | S_IRWXG | S_IRWXO);
   if (fd < 0) {
-    printf("\nfailed to open log file:%s, reason:%s\n", logFileName, strerror(errno));
-    return true;
+    if (errno == ENOENT) {
+      return false;
+    } else {
+      printf("\nfailed to open log file:%s, reason:%s\n", logFileName, strerror(errno));
+      return true;
+    }
   }
 
   if (taosLockFile(fd)) {
diff --git a/src/util/src/tnote.c b/src/util/src/tnote.c
index 91d586322d47b97c02e981aa3e324391d431fa0a..31ed6e2f7bded579b75066e590c68b8bc8580a3e 100644
--- a/src/util/src/tnote.c
+++ b/src/util/src/tnote.c
@@ -87,6 +87,10 @@ void *taosThreadToOpenNewNote(void *param)
     umask(0);
 
     int fd = open(name, O_WRONLY | O_CREAT | O_TRUNC, S_IRWXU | S_IRWXG | S_IRWXO);
+    if (fd < 0) {
+      return NULL;
+    }
+
     taosLockNote(fd, pNote);
     lseek(fd, 0, SEEK_SET);
 
diff --git a/src/vnode/src/vnodeMain.c b/src/vnode/src/vnodeMain.c
index 256ef3c72baf0ccc5dd0c39b1f6452a9dfd204d6..9ec982b1decf00be2043d4c68004943c41c93587 100644
--- a/src/vnode/src/vnodeMain.c
+++ b/src/vnode/src/vnodeMain.c
@@ -75,19 +75,29 @@ int32_t vnodeCreate(SMDCreateVnodeMsg *pVnodeCfg) {
     return TSDB_CODE_SUCCESS;
   }
 
-  mkdir(tsVnodeDir, 0755);
+  if (mkdir(tsVnodeDir, 0755) != 0 && errno != EEXIST) {
+    vError("vgId:%d, failed to create vnode, reason:%s dir:%s", pVnodeCfg->cfg.vgId, strerror(errno), tsVnodeDir);
+    if (errno == EACCES) {
+      return TSDB_CODE_VND_NO_DISK_PERMISSIONS;
+    } else if (errno == ENOSPC) {
+      return TSDB_CODE_VND_NO_DISKSPACE;
+    } else if (errno == ENOENT) {
+      return TSDB_CODE_VND_NO_SUCH_FILE_OR_DIR;
+    } else {
+      return TSDB_CODE_VND_INIT_FAILED;
+    }
+  }
 
   char rootDir[TSDB_FILENAME_LEN] = {0};
   sprintf(rootDir, "%s/vnode%d", tsVnodeDir, pVnodeCfg->cfg.vgId);
-  if (mkdir(rootDir, 0755) != 0) {
-    vPrint("vgId:%d, failed to create vnode, reason:%s dir:%s", pVnodeCfg->cfg.vgId, strerror(errno), rootDir);
+  if (mkdir(rootDir, 0755) != 0 && errno != EEXIST) {
+    vError("vgId:%d, failed to create vnode, reason:%s dir:%s", pVnodeCfg->cfg.vgId, strerror(errno), rootDir);
     if (errno == EACCES) {
       return TSDB_CODE_VND_NO_DISK_PERMISSIONS;
     } else if (errno == ENOSPC) {
       return TSDB_CODE_VND_NO_DISKSPACE;
     } else if (errno == ENOENT) {
       return TSDB_CODE_VND_NO_SUCH_FILE_OR_DIR;
-    } else if (errno == EEXIST) {
     } else {
       return TSDB_CODE_VND_INIT_FAILED;
     }
diff --git a/tests/pytest/crash_gen.py b/tests/pytest/crash_gen.py
index dfd2034f7e2ac542848c71083864cb729f38a8d3..c88683aa097c82380503370d342101351b27d38b 100755
--- a/tests/pytest/crash_gen.py
+++ b/tests/pytest/crash_gen.py
@@ -730,13 +730,15 @@ class DbState():
     # when we re-run the test in 3 minutes (180 seconds), basically we should expand time duration
     # by a factor of 500.
     # TODO: what if it goes beyond 10 years into the future
+    # TODO: fix the error as result of above: "tsdb timestamp is out of range"
     def setupLastTick(self):
-        t1 = datetime.datetime(2020, 5, 30)
+        t1 = datetime.datetime(2020, 6, 1)
         t2 = datetime.datetime.now()
-        elSec = t2.timestamp() - t1.timestamp()
+        elSec = int(t2.timestamp() - t1.timestamp()) # maybe a very large number, takes 69 years to exceed Python int range
+        elSec2 = (  elSec % (8 * 12 * 30 * 24 * 60 * 60 / 500 ) ) * 500 # a number representing seconds within 10 years
         # print("elSec = {}".format(elSec))
         t3 = datetime.datetime(2012, 1, 1) # default "keep" is 10 years
-        t4 = datetime.datetime.fromtimestamp( t3.timestamp() + elSec * 500) # see explanation above
+        t4 = datetime.datetime.fromtimestamp( t3.timestamp() + elSec2) # see explanation above
         logger.info("Setting up TICKS to start from: {}".format(t4))
         return t4
 
@@ -963,7 +965,7 @@ class Task():
         try:
             self._executeInternal(te, wt) # TODO: no return value?
         except taos.error.ProgrammingError as err:
-            self.logDebug("[=] Taos library exception: errno={}, msg: {}".format(err.errno, err))
+            self.logDebug("[=] Taos library exception: errno={:X}, msg: {}".format(err.errno, err))
             self._err = err
         except:
             self.logDebug("[=] Unexpected exception")
diff --git a/tests/pytest/random-test/random-test-multi-threading-3.py b/tests/pytest/random-test/random-test-multi-threading-3.py
index db85ce2fe058837ecfe12599ddbba418d35e473d..cab17c4c1a91a25db57a88d674b7b60accd55a34 100644
--- a/tests/pytest/random-test/random-test-multi-threading-3.py
+++ b/tests/pytest/random-test/random-test-multi-threading-3.py
@@ -205,7 +205,7 @@ class Test (Thread):
         global written
 
         dnodesDir = tdDnodes.getDnodesRootDir()
-        dataDir = dnodesDir + '/dnode1/*'
+        dataDir = dnodesDir + '/dnode1/data/*'
         deleteCmd = 'rm -rf %s' % dataDir
         os.system(deleteCmd)
 
diff --git a/tests/pytest/random-test/random-test-multi-threading.py b/tests/pytest/random-test/random-test-multi-threading.py
index 7d1a8a155dac8b427ec184b544632c747a6eca6a..1d8a5c3c82f98ffeb5817186b78959a2e160b302 100644
--- a/tests/pytest/random-test/random-test-multi-threading.py
+++ b/tests/pytest/random-test/random-test-multi-threading.py
@@ -208,7 +208,7 @@ class Test (threading.Thread):
         global written
 
         dnodesDir = tdDnodes.getDnodesRootDir()
-        dataDir = dnodesDir + '/dnode1/*'
+        dataDir = dnodesDir + '/dnode1/data/*'
         deleteCmd = 'rm -rf %s' % dataDir
         os.system(deleteCmd)
 
diff --git a/tests/pytest/stream/stream1.py b/tests/pytest/stream/stream1.py
index 7a9d88da3b2aa7bedae0824cac89349dcbeb5040..3b88b4f9f38fa7fb7183b5f29d2f1a65727f8064 100644
--- a/tests/pytest/stream/stream1.py
+++ b/tests/pytest/stream/stream1.py
@@ -31,21 +31,26 @@ class TDTestCase:
         tdSql.prepare()
 
         tdLog.info("===== step1 =====")
-        tdSql.execute("create table stb0(ts timestamp, col1 int, col2 float) tags(tgcol int)")
+        tdSql.execute(
+            "create table stb0(ts timestamp, col1 int, col2 float) tags(tgcol int)")
         for i in range(tbNum):
             tdSql.execute("create table tb%d using stb0 tags(%d)" % (i, i))
             for j in range(rowNum):
-                tdSql.execute("insert into tb%d values (now - %dm, %d, %d)" % (i, 1440 - j, j, j))
+                tdSql.execute(
+                    "insert into tb%d values (now - %dm, %d, %d)" %
+                    (i, 1440 - j, j, j))
         time.sleep(0.1)
 
         tdLog.info("===== step2 =====")
-        tdSql.query("select count(*), count(col1), count(col2) from tb0 interval(1d)")
+        tdSql.query(
+            "select count(*), count(col1), count(col2) from tb0 interval(1d)")
         tdSql.checkData(0, 1, rowNum)
         tdSql.checkData(0, 2, rowNum)
         tdSql.checkData(0, 3, rowNum)
         tdSql.query("show tables")
         tdSql.checkRows(tbNum)
-        tdSql.execute("create table s0 as select count(*), count(col1), count(col2) from tb0 interval(1d)")
+        tdSql.execute(
+            "create table s0 as select count(*), count(col1), count(col2) from tb0 interval(1d)")
         tdSql.query("show tables")
         tdSql.checkRows(tbNum + 1)
 
@@ -67,7 +72,8 @@ class TDTestCase:
 
         tdLog.info("===== step6 =====")
         time.sleep(0.1)
-        tdSql.execute("create table s0 as select count(*), count(col1), count(col2) from tb0 interval(1d)")
+        tdSql.execute(
+            "create table s0 as select count(*), count(col1), count(col2) from tb0 interval(1d)")
         tdSql.query("show tables")
         tdSql.checkRows(tbNum + 1)
 
@@ -81,14 +87,16 @@ class TDTestCase:
         tdSql.checkData(0, 3, rowNum)
 
         tdLog.info("===== step8 =====")
-        tdSql.query("select count(*), count(col1), count(col2) from stb0 interval(1d)")
+        tdSql.query(
+            "select count(*), count(col1), count(col2) from stb0 interval(1d)")
         tdSql.checkData(0, 1, rowNum * tbNum)
         tdSql.checkData(0, 2, rowNum * tbNum)
         tdSql.checkData(0, 3, rowNum * tbNum)
         tdSql.query("show tables")
         tdSql.checkRows(tbNum + 1)
 
-        tdSql.execute("create table s1 as select count(*), count(col1), count(col2) from stb0 interval(1d)")
+        tdSql.execute(
+            "create table s1 as select count(*), count(col1), count(col2) from stb0 interval(1d)")
         tdSql.query("show tables")
         tdSql.checkRows(tbNum + 2)
 
@@ -110,7 +118,8 @@ class TDTestCase:
         tdSql.error("select * from s1")
 
         tdLog.info("===== step12 =====")
-        tdSql.execute("create table s1 as select count(*), count(col1), count(col2) from stb0 interval(1d)")
+        tdSql.execute(
+            "create table s1 as select count(*), count(col1), count(col2) from stb0 interval(1d)")
         tdSql.query("show tables")
         tdSql.checkRows(tbNum + 2)
 
diff --git a/tests/pytest/stream/stream2.py b/tests/pytest/stream/stream2.py
index 96eff3131d5bec3eb7e16f7d002aae25da560bf2..7b77dc7793a280d118229ef128fe833ab932e757 100644
--- a/tests/pytest/stream/stream2.py
+++ b/tests/pytest/stream/stream2.py
@@ -24,7 +24,6 @@ class TDTestCase:
         tdLog.debug("start to execute %s" % __file__)
         tdSql.init(conn.cursor(), logSql)
 
-
     def run(self):
         tbNum = 10
         rowNum = 20
@@ -33,11 +32,14 @@ class TDTestCase:
         tdSql.prepare()
 
         tdLog.info("===== step1 =====")
-        tdSql.execute("create table stb0(ts timestamp, col1 int, col2 float) tags(tgcol int)")
+        tdSql.execute(
+            "create table stb0(ts timestamp, col1 int, col2 float) tags(tgcol int)")
         for i in range(tbNum):
             tdSql.execute("create table tb%d using stb0 tags(%d)" % (i, i))
             for j in range(rowNum):
-                tdSql.execute("insert into tb%d values (now - %dm, %d, %d)" % (i, 1440 - j, j, j))
+                tdSql.execute(
+                    "insert into tb%d values (now - %dm, %d, %d)" %
+                    (i, 1440 - j, j, j))
         time.sleep(0.1)
 
         tdLog.info("===== step2 =====")
@@ -45,7 +47,8 @@ class TDTestCase:
         tdSql.checkData(0, 1, rowNum)
         tdSql.query("show tables")
         tdSql.checkRows(tbNum)
-        tdSql.execute("create table s0 as select count(col1) from tb0 interval(1d)")
+        tdSql.execute(
+            "create table s0 as select count(col1) from tb0 interval(1d)")
         tdSql.query("show tables")
         tdSql.checkRows(tbNum + 1)
 
@@ -63,7 +66,8 @@ class TDTestCase:
         tdSql.error("select * from s0")
 
         tdLog.info("===== step6 =====")
-        tdSql.execute("create table s0 as select count(*), count(col1), count(col2) from tb0 interval(1d)")
+        tdSql.execute(
+            "create table s0 as select count(*), count(col1), count(col2) from tb0 interval(1d)")
         tdSql.query("show tables")
         tdSql.checkRows(tbNum + 1)
 
@@ -75,13 +79,15 @@ class TDTestCase:
         tdSql.checkData(0, 3, rowNum)
 
         tdLog.info("===== step8 =====")
-        tdSql.query("select count(*), count(col1), count(col2) from stb0 interval(1d)")
+        tdSql.query(
+            "select count(*), count(col1), count(col2) from stb0 interval(1d)")
         tdSql.checkData(0, 1, totalNum)
         tdSql.checkData(0, 2, totalNum)
         tdSql.checkData(0, 3, totalNum)
         tdSql.query("show tables")
         tdSql.checkRows(tbNum + 1)
-        tdSql.execute("create table s1 as select count(*), count(col1), count(col2) from stb0 interval(1d)")
+        tdSql.execute(
+            "create table s1 as select count(*), count(col1), count(col2) from stb0 interval(1d)")
         tdSql.query("show tables")
         tdSql.checkRows(tbNum + 2)
 
@@ -101,7 +107,8 @@ class TDTestCase:
         tdSql.error("select * from s1")
 
         tdLog.info("===== step12 =====")
-        tdSql.execute("create table s1 as select count(col1) from stb0 interval(1d)")
+        tdSql.execute(
+            "create table s1 as select count(col1) from stb0 interval(1d)")
         tdSql.query("show tables")
         tdSql.checkRows(tbNum + 2)
 
@@ -112,7 +119,6 @@ class TDTestCase:
         #tdSql.checkData(0, 2, None)
         #tdSql.checkData(0, 3, None)
 
-
     def stop(self):
         tdSql.close()
         tdLog.success("%s successfully executed" % __file__)
diff --git a/tests/pytest/util/dnodes.py b/tests/pytest/util/dnodes.py
index f3ccd58432948739bf96d2a63afb43422c955ac5..e24af473f38274d3a1122362d037fc00099c1528 100644
--- a/tests/pytest/util/dnodes.py
+++ b/tests/pytest/util/dnodes.py
@@ -319,6 +319,7 @@ class TDDnodes:
         self.dnodes.append(TDDnode(8))
         self.dnodes.append(TDDnode(9))
         self.dnodes.append(TDDnode(10))
+        self.simDeployed = False
 
     def init(self, path):
         psCmd = "ps -ef|grep -w taosd| grep -v grep | awk '{print $2}'"
@@ -378,7 +379,10 @@ class TDDnodes:
         self.sim = TDSimClient()
         self.sim.init(self.path)
         self.sim.setTestCluster(self.testCluster)
-        self.sim.deploy()
+
+        if (self.simDeployed == False):
+            self.sim.deploy()
+            self.simDeployed = True
 
         self.check(index)
         self.dnodes[index - 1].setTestCluster(self.testCluster)
diff --git a/tests/script/general/http/restful_full.sim b/tests/script/general/http/restful_full.sim
index 7194f7cbe01ba794c6153bab6c52504cf7ca8ef1..aa667daee48b10b8759a55def48eb6ac6dfff44e 100644
--- a/tests/script/general/http/restful_full.sim
+++ b/tests/script/general/http/restful_full.sim
@@ -147,7 +147,7 @@ print ===============  step3 - db
 
 system_content curl -H 'Authorization: Taosd /KfeAzX/f9na8qdtNZmtONryp201ma04bEl8LcvLUd7a8qdtNZmtONryp201ma04'  -d ' select * from d1.t1;' 127.0.0.1:6020/rest/sql
 print 21-> $system_content
-if $system_content != @{"status":"error","code":1000,"desc":"mnode invalid table id"}@ then
+if $system_content != @{"status":"error","code":1000,"desc":"mnode invalid table name"}@ then
   return -1
 endi