diff --git a/2.0/src/client/src/tscSql.c b/2.0/src/client/src/tscSql.c
index ab1fffd5a2fdb0bbbd9cc93550280d4bd11b52ff..c1f7306e871965025ea7c64dff1e0d581c466026 100644
--- a/2.0/src/client/src/tscSql.c
+++ b/2.0/src/client/src/tscSql.c
@@ -51,7 +51,7 @@ static bool validPassword(const char* passwd) {
 }
 
 static SSqlObj *taosConnectImpl(const char *ip, const char *user, const char *pass, const char *auth, const char *db,
-                         uint16_t port, void (*fp)(void *, TAOS_RES *, int), void *param, TAOS **taos) {
+                         void (*fp)(void *, TAOS_RES *, int), void *param, TAOS **taos) {
   if (taos_init()) {
     return NULL;
   }
@@ -186,7 +186,7 @@ static void syncConnCallback(void *param, TAOS_RES *tres, int code) {
 TAOS *taos_connect_internal(const char *ip, const char *user, const char *pass, const char *auth, const char *db,
                             uint16_t port) {
   STscObj *pObj = NULL;
-  SSqlObj *pSql = taosConnectImpl(ip, user, pass, auth, db, port, syncConnCallback, NULL, (void **)&pObj);
+  SSqlObj *pSql = taosConnectImpl(ip, user, pass, auth, db, syncConnCallback, NULL, (void **)&pObj);
   if (pSql != NULL) {
     pSql->fp = syncConnCallback;
     pSql->param = pSql;
@@ -262,7 +262,7 @@ static void asyncConnCallback(void *param, TAOS_RES *tres, int code) {
 TAOS *taos_connect_a(char *ip, char *user, char *pass, char *db, uint16_t port, void (*fp)(void *, TAOS_RES *, int),
                      void *param, TAOS **taos) {
   STscObj *pObj = NULL;
-  SSqlObj *pSql = taosConnectImpl(ip, user, pass, NULL, db, port, asyncConnCallback, param, (void **)&pObj);
+  SSqlObj *pSql = taosConnectImpl(ip, user, pass, NULL, db, asyncConnCallback, param, (void **)&pObj);
   if (pSql == NULL) {
     return NULL;
   }
diff --git a/source/client/inc/clientInt.h b/source/client/inc/clientInt.h
index 296fbba6348ee45fdb0967da81b34f5b57732baa..c61f3da6bd456058e9754918be10907486dd7b77 100644
--- a/source/client/inc/clientInt.h
+++ b/source/client/inc/clientInt.h
@@ -101,13 +101,13 @@ struct SAppInstInfo {
 };
 
 typedef struct SAppInfo {
-  int64_t        startTime;
-  char           appName[TSDB_APP_NAME_LEN];
-  char          *ep;
-  int32_t        pid;
-  int32_t        numOfThreads;
-
-  SHashObj      *pInstMap;
+  int64_t         startTime;
+  char            appName[TSDB_APP_NAME_LEN];
+  char           *ep;
+  int32_t         pid;
+  int32_t         numOfThreads;
+  SHashObj       *pInstMap;
+  pthread_mutex_t mutex;
 } SAppInfo;
 
 typedef struct STscObj {
@@ -192,7 +192,7 @@ uint64_t generateRequestId();
 void *createRequest(STscObj* pObj, __taos_async_fn_t fp, void* param, int32_t type);
 void  destroyRequest(SRequestObj* pRequest);
 
-char *getConnectionDB(STscObj* pObj);
+char *getDbOfConnection(STscObj* pObj);
 void  setConnectionDB(STscObj* pTscObj, const char* db);
 
 void taos_init_imp(void);
diff --git a/source/client/src/clientEnv.c b/source/client/src/clientEnv.c
index 1f2048608ab1049638cabd1555c11cf89bd3242f..890c4aa425336afccb4b4f718d5258f28da6f1c1 100644
--- a/source/client/src/clientEnv.c
+++ b/source/client/src/clientEnv.c
@@ -253,10 +253,11 @@ void taos_init_imp(void) {
   clientReqRefPool  = taosOpenRef(40960, doDestroyRequest);
 
   taosGetAppName(appInfo.appName, NULL);
+  pthread_mutex_init(&appInfo.mutex, NULL);
+
   appInfo.pid       = taosGetPId();
   appInfo.startTime = taosGetTimestampMs();
   appInfo.pInstMap  = taosHashInit(4, taosGetDefaultHashFunction(TSDB_DATA_TYPE_BINARY), true, HASH_ENTRY_LOCK);
-
   tscDebug("client is initialized successfully");
 }
 
diff --git a/source/client/src/clientImpl.c b/source/client/src/clientImpl.c
index 7d5199dfafd38e958cc70eabe278080f91719caf..cc86bf26509addfd733a89ae51432d9ec8d4c65e 100644
--- a/source/client/src/clientImpl.c
+++ b/source/client/src/clientImpl.c
@@ -58,7 +58,7 @@ static char* getClusterKey(const char* user, const char* auth, const char* ip, i
   return strdup(key);
 }
 
-static STscObj* taosConnectImpl(const char *user, const char *auth, const char *db, uint16_t port, __taos_async_fn_t fp, void *param, SAppInstInfo* pAppInfo);
+static STscObj* taosConnectImpl(const char *user, const char *auth, const char *db, __taos_async_fn_t fp, void *param, SAppInstInfo* pAppInfo);
 static void setResSchemaInfo(SReqResultInfo* pResInfo, const SSchema* pSchema, int32_t numOfCols);
 
 TAOS *taos_connect_internal(const char *ip, const char *user, const char *pass, const char *auth, const char *db, uint16_t port) {
@@ -110,9 +110,11 @@ TAOS *taos_connect_internal(const char *ip, const char *user, const char *pass,
   }
 
   char* key = getClusterKey(user, secretEncrypt, ip, port);
+  SAppInstInfo** pInst = NULL;
 
-  // TODO: race condition here.
-  SAppInstInfo** pInst = taosHashGet(appInfo.pInstMap, key, strlen(key));
+  pthread_mutex_lock(&appInfo.mutex);
+
+  pInst = taosHashGet(appInfo.pInstMap, key, strlen(key));
   if (pInst == NULL) {
     SAppInstInfo* p = calloc(1, sizeof(struct SAppInstInfo));
     p->mgmtEp       = epSet;
@@ -123,8 +125,10 @@ TAOS *taos_connect_internal(const char *ip, const char *user, const char *pass,
     pInst = &p;
   }
 
+  pthread_mutex_unlock(&appInfo.mutex);
+
   tfree(key);
-  return taosConnectImpl(user, &secretEncrypt[0], localDb, port, NULL, NULL, *pInst);
+  return taosConnectImpl(user, &secretEncrypt[0], localDb, NULL, NULL, *pInst);
 }
 
 int32_t buildRequest(STscObj *pTscObj, const char *sql, int sqlLen, SRequestObj** pRequest) {
@@ -155,7 +159,7 @@ int32_t parseSql(SRequestObj* pRequest, SQueryNode** pQuery) {
   SParseContext cxt = {
     .requestId = pRequest->requestId,
     .acctId    = pTscObj->acctId,
-    .db        = getConnectionDB(pTscObj),
+    .db        = getDbOfConnection(pTscObj),
     .pSql      = pRequest->sqlstr,
     .sqlLen    = pRequest->sqlLen,
     .pMsg      = pRequest->msgBuf,
@@ -541,7 +545,7 @@ int initEpSetFromCfg(const char *firstEp, const char *secondEp, SCorEpSet *pEpSe
   return 0;
 }
 
-STscObj* taosConnectImpl(const char *user, const char *auth, const char *db, uint16_t port, __taos_async_fn_t fp, void *param, SAppInstInfo* pAppInfo) {
+STscObj* taosConnectImpl(const char *user, const char *auth, const char *db, __taos_async_fn_t fp, void *param, SAppInstInfo* pAppInfo) {
   STscObj *pTscObj = createTscObj(user, auth, db, pAppInfo);
   if (NULL == pTscObj) {
     terrno = TSDB_CODE_TSC_OUT_OF_MEMORY;
@@ -599,7 +603,7 @@ static SMsgSendInfo* buildConnectMsg(SRequestObj *pRequest) {
 
   STscObj *pObj = pRequest->pTscObj;
 
-  char* db = getConnectionDB(pObj);
+  char* db = getDbOfConnection(pObj);
   if (db != NULL) {
     tstrncpy(pConnect->db, db, sizeof(pConnect->db));
   }
@@ -831,7 +835,7 @@ void setResultDataPtr(SReqResultInfo* pResultInfo, TAOS_FIELD* pFields, int32_t
   }
 }
 
-char* getConnectionDB(STscObj* pObj) {
+char* getDbOfConnection(STscObj* pObj) {
   char *p = NULL;
   pthread_mutex_lock(&pObj->mutex);
   size_t len = strlen(pObj->db);
diff --git a/source/client/test/clientTests.cpp b/source/client/test/clientTests.cpp
index ee23567705c8c2799309e5ef04aec0dec5390e06..552295f69b4fe33484a2a2a25f4815c4c6c1c50c 100644
--- a/source/client/test/clientTests.cpp
+++ b/source/client/test/clientTests.cpp
@@ -53,416 +53,419 @@ TEST(testCase, driverInit_Test) {
 //  taos_init();
 }
 
-//TEST(testCase, connect_Test) {
-//  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
-//  if (pConn == NULL) {
-//    printf("failed to connect to server, reason:%s\n", taos_errstr(NULL));
-//  }
-//  taos_close(pConn);
-//}
-//
-//TEST(testCase, create_user_Test) {
-//  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
-//  assert(pConn != NULL);
-//
-//  TAOS_RES* pRes = taos_query(pConn, "create user abc pass 'abc'");
-//  if (taos_errno(pRes) != TSDB_CODE_SUCCESS) {
-//    printf("failed to create user, reason:%s\n", taos_errstr(pRes));
-//  }
-//
-//  taos_free_result(pRes);
-//  taos_close(pConn);
-//}
-//
-//TEST(testCase, create_account_Test) {
-//  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
-//  assert(pConn != NULL);
-//
-//  TAOS_RES* pRes = taos_query(pConn, "create account aabc pass 'abc'");
-//  if (taos_errno(pRes) != TSDB_CODE_SUCCESS) {
-//    printf("failed to create user, reason:%s\n", taos_errstr(pRes));
-//  }
-//
-//  taos_free_result(pRes);
-//  taos_close(pConn);
-//}
-//
-//TEST(testCase, drop_account_Test) {
-//  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
-//  assert(pConn != NULL);
-//
-//  TAOS_RES* pRes = taos_query(pConn, "drop account aabc");
-//  if (taos_errno(pRes) != TSDB_CODE_SUCCESS) {
-//    printf("failed to create user, reason:%s\n", taos_errstr(pRes));
-//  }
-//
-//  taos_free_result(pRes);
-//  taos_close(pConn);
-//}
-//
-//TEST(testCase, show_user_Test) {
-//  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
-//  assert(pConn != NULL);
-//
-//  TAOS_RES* pRes = taos_query(pConn, "show users");
-//  TAOS_ROW  pRow = NULL;
-//
-//  TAOS_FIELD* pFields = taos_fetch_fields(pRes);
-//  int32_t     numOfFields = taos_num_fields(pRes);
-//
-//  char str[512] = {0};
-//  while ((pRow = taos_fetch_row(pRes)) != NULL) {
-//    int32_t code = taos_print_row(str, pRow, pFields, numOfFields);
-//    printf("%s\n", str);
-//  }
-//
-//  taos_free_result(pRes);
-//  taos_close(pConn);
-//}
-//
-//TEST(testCase, drop_user_Test) {
-//  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
-//  assert(pConn != NULL);
-//
-//  TAOS_RES* pRes = taos_query(pConn, "drop user abc");
-//  if (taos_errno(pRes) != TSDB_CODE_SUCCESS) {
-//    printf("failed to create user, reason:%s\n", taos_errstr(pRes));
-//  }
-//
-//  taos_free_result(pRes);
-//  taos_close(pConn);
-//}
-//
-//TEST(testCase, show_db_Test) {
-//  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
-//  assert(pConn != NULL);
-//
-//  TAOS_RES* pRes = taos_query(pConn, "show databases");
-//  TAOS_ROW  pRow = NULL;
-//
-//  TAOS_FIELD* pFields = taos_fetch_fields(pRes);
-//  int32_t     numOfFields = taos_num_fields(pRes);
-//
-//  char str[512] = {0};
-//  while ((pRow = taos_fetch_row(pRes)) != NULL) {
-//    int32_t code = taos_print_row(str, pRow, pFields, numOfFields);
-//    printf("%s\n", str);
-//  }
-//
-//  taos_close(pConn);
-//}
-//
-//TEST(testCase, create_db_Test) {
-//  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
-//  assert(pConn != NULL);
-//
-//  TAOS_RES* pRes = taos_query(pConn, "create database abc1 vgroups 2");
-//  if (taos_errno(pRes) != 0) {
-//    printf("error in create db, reason:%s\n", taos_errstr(pRes));
-//  }
-//
-//  TAOS_FIELD* pFields = taos_fetch_fields(pRes);
-//  ASSERT_TRUE(pFields == NULL);
-//
-//  int32_t numOfFields = taos_num_fields(pRes);
-//  ASSERT_EQ(numOfFields, 0);
-//
-//  taos_free_result(pRes);
-//
-//  pRes = taos_query(pConn, "create database abc1 vgroups 4");
-//  if (taos_errno(pRes) != 0) {
-//    printf("error in create db, reason:%s\n", taos_errstr(pRes));
-//  }
-//  taos_close(pConn);
-//}
-//
-//TEST(testCase, create_dnode_Test) {
-//  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
-//  assert(pConn != NULL);
-//
-//  TAOS_RES* pRes = taos_query(pConn, "create dnode abc1 port 7000");
-//  if (taos_errno(pRes) != 0) {
-//    printf("error in create dnode, reason:%s\n", taos_errstr(pRes));
-//  }
-//  taos_free_result(pRes);
-//
-//  pRes = taos_query(pConn, "create dnode 1.1.1.1 port 9000");
-//  if (taos_errno(pRes) != 0) {
-//    printf("failed to create dnode, reason:%s\n", taos_errstr(pRes));
-//  }
-//  taos_free_result(pRes);
-//
-//  taos_close(pConn);
-//}
-//
-//TEST(testCase, drop_dnode_Test) {
-//  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
-//  assert(pConn != NULL);
-//
-//  TAOS_RES* pRes = taos_query(pConn, "drop dnode 3");
-//  if (taos_errno(pRes) != 0) {
-//    printf("error in drop dnode, reason:%s\n", taos_errstr(pRes));
-//  }
-//
-//  TAOS_FIELD* pFields = taos_fetch_fields(pRes);
-//  ASSERT_TRUE(pFields == NULL);
-//
-//  int32_t numOfFields = taos_num_fields(pRes);
-//  ASSERT_EQ(numOfFields, 0);
-//
-//  pRes = taos_query(pConn, "drop dnode 4");
-//  if (taos_errno(pRes) != 0) {
-//    printf("error in drop dnode, reason:%s\n", taos_errstr(pRes));
-//  }
-//
-//  taos_free_result(pRes);
-//  taos_close(pConn);
-//}
-//
-//TEST(testCase, use_db_test) {
-//  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
-//  assert(pConn != NULL);
-//
-//  TAOS_RES* pRes = taos_query(pConn, "use abc1");
-//  if (taos_errno(pRes) != 0) {
-//    printf("error in use db, reason:%s\n", taos_errstr(pRes));
-//  }
-//
-//  TAOS_FIELD* pFields = taos_fetch_fields(pRes);
-//  ASSERT_TRUE(pFields == NULL);
-//
-//  int32_t numOfFields = taos_num_fields(pRes);
-//  ASSERT_EQ(numOfFields, 0);
-//
-//  taos_close(pConn);
-//}
-//
-// TEST(testCase, drop_db_test) {
-//  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
-//  assert(pConn != NULL);
-//
-//  showDB(pConn);
-//
-//  TAOS_RES* pRes = taos_query(pConn, "drop database abc1");
-//  if (taos_errno(pRes) != 0) {
-//    printf("failed to drop db, reason:%s\n", taos_errstr(pRes));
-//  }
-//  taos_free_result(pRes);
-//
-//  showDB(pConn);
-//
-//  pRes = taos_query(pConn, "create database abc1");
-//  if (taos_errno(pRes) != 0) {
-//    printf("create to drop db, reason:%s\n", taos_errstr(pRes));
-//  }
-//  taos_free_result(pRes);
-//  taos_close(pConn);
-//}
-//
-//TEST(testCase, create_stable_Test) {
-//  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
-//  assert(pConn != NULL);
-//
-//  TAOS_RES* pRes = taos_query(pConn, "create database if not exists abc1 vgroups 2");
-//  if (taos_errno(pRes) != 0) {
-//    printf("error in create db, reason:%s\n", taos_errstr(pRes));
-//  }
-//  taos_free_result(pRes);
-//
-//  pRes = taos_query(pConn, "create table if not exists abc1.st1(ts timestamp, k int) tags(a int)");
-//  if (taos_errno(pRes) != 0) {
-//    printf("error in create stable, reason:%s\n", taos_errstr(pRes));
-//  }
-//
-//  TAOS_FIELD* pFields = taos_fetch_fields(pRes);
-//  ASSERT_TRUE(pFields == NULL);
-//
-//  int32_t numOfFields = taos_num_fields(pRes);
-//  ASSERT_EQ(numOfFields, 0);
-//  taos_free_result(pRes);
-//
-//  pRes = taos_query(pConn, "create stable if not exists abc1.`123_$^)` (ts timestamp, `abc` int) tags(a int)");
-//  if (taos_errno(pRes) != 0) {
-//    printf("failed to create super table 123_$^), reason:%s\n", taos_errstr(pRes));
-//  }
-//
-//  pRes = taos_query(pConn, "use abc1");
-//  taos_free_result(pRes);
-//  pRes = taos_query(pConn, "drop stable `123_$^)`");
-//  if (taos_errno(pRes) != 0) {
-//    printf("failed to drop super table 123_$^), reason:%s\n", taos_errstr(pRes));
-//  }
-//
-//  taos_close(pConn);
-//}
-//
-//TEST(testCase, create_table_Test) {
-//  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
-//  assert(pConn != NULL);
-//
-//  TAOS_RES* pRes = taos_query(pConn, "use abc1");
-//  taos_free_result(pRes);
-//
-//  pRes = taos_query(pConn, "create table if not exists tm0(ts timestamp, k int)");
-//  ASSERT_EQ(taos_errno(pRes), 0);
-//
-//  taos_free_result(pRes);
-//
-//  pRes = taos_query(pConn, "create table if not exists tm0(ts timestamp, k blob)");
-//  ASSERT_NE(taos_errno(pRes), 0);
-//
-//  taos_free_result(pRes);
-//  taos_close(pConn);
-//}
-//
-//TEST(testCase, create_ctable_Test) {
-//  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
-//  assert(pConn != NULL);
-//
-//  TAOS_RES* pRes = taos_query(pConn, "use abc1");
-//  if (taos_errno(pRes) != 0) {
-//    printf("failed to use db, reason:%s\n", taos_errstr(pRes));
-//  }
-//  taos_free_result(pRes);
-//
-//  pRes = taos_query(pConn, "create stable if not exists st1 (ts timestamp, k int ) tags(a int)");
-//  if (taos_errno(pRes) != 0) {
-//    printf("failed to create stable, reason:%s\n", taos_errstr(pRes));
-//  }
-//  taos_free_result(pRes);
-//
-//  pRes = taos_query(pConn, "create table tm0 using st1 tags(1)");
-//  if (taos_errno(pRes) != 0) {
-//    printf("failed to create child table tm0, reason:%s\n", taos_errstr(pRes));
-//  }
-//
-//  taos_free_result(pRes);
-//  taos_close(pConn);
-//}
-//
-//TEST(testCase, show_stable_Test) {
-//  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
-//  assert(pConn != nullptr);
-//
-//  TAOS_RES* pRes = taos_query(pConn, "show abc1.stables");
-//  if (taos_errno(pRes) != 0) {
-//    printf("failed to show stables, reason:%s\n", taos_errstr(pRes));
-//    taos_free_result(pRes);
-//    ASSERT_TRUE(false);
-//  }
-//
-//  TAOS_ROW    pRow = NULL;
-//  TAOS_FIELD* pFields = taos_fetch_fields(pRes);
-//  int32_t     numOfFields = taos_num_fields(pRes);
-//
-//  char str[512] = {0};
-//  while ((pRow = taos_fetch_row(pRes)) != NULL) {
-//    int32_t code = taos_print_row(str, pRow, pFields, numOfFields);
-//    printf("%s\n", str);
-//  }
-//
-//  taos_free_result(pRes);
-//  taos_close(pConn);
-//}
-//
-//TEST(testCase, show_vgroup_Test) {
-//  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
-//  assert(pConn != NULL);
-//
-//  TAOS_RES* pRes = taos_query(pConn, "use abc1");
-//  if (taos_errno(pRes) != 0) {
-//    printf("failed to use db, reason:%s\n", taos_errstr(pRes));
-//  }
-//  taos_free_result(pRes);
-//
-//  pRes = taos_query(pConn, "show vgroups");
-//  if (taos_errno(pRes) != 0) {
-//    printf("failed to show vgroups, reason:%s\n", taos_errstr(pRes));
-//    taos_free_result(pRes);
-//    ASSERT_TRUE(false);
-//  }
-//
-//  TAOS_ROW pRow = NULL;
-//
-//  TAOS_FIELD* pFields = taos_fetch_fields(pRes);
-//  int32_t     numOfFields = taos_num_fields(pRes);
-//
-//  char str[512] = {0};
-//  while ((pRow = taos_fetch_row(pRes)) != NULL) {
-//    int32_t code = taos_print_row(str, pRow, pFields, numOfFields);
-//    printf("%s\n", str);
-//  }
-//
-//  taos_free_result(pRes);
-//  taos_close(pConn);
-//}
-//
-//TEST(testCase, create_multiple_tables) {
-//  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
-//  ASSERT_NE(pConn, nullptr);
-//
-//  TAOS_RES* pRes = taos_query(pConn, "use abc1");
-//  if (taos_errno(pRes) != 0) {
-//    printf("failed to use db, reason:%s\n", taos_errstr(pRes));
-//    taos_free_result(pRes);
-//    taos_close(pConn);
-//    return;
-//  }
-//
-//  taos_free_result(pRes);
-//
-//  pRes = taos_query(pConn, "create table t_2 using st1 tags(1)");
-//  if (taos_errno(pRes) != 0) {
-//    printf("failed to create multiple tables, reason:%s\n", taos_errstr(pRes));
-//    taos_free_result(pRes);
-//    ASSERT_TRUE(false);
-//  }
-//
-//  taos_free_result(pRes);
-//  pRes = taos_query(pConn, "create table t_3 using st1 tags(2)");
-//  if (taos_errno(pRes) != 0) {
-//    printf("failed to create multiple tables, reason:%s\n", taos_errstr(pRes));
-//    taos_free_result(pRes);
-//    ASSERT_TRUE(false);
-//  }
-//
-//  TAOS_ROW    pRow = NULL;
-//  TAOS_FIELD* pFields = taos_fetch_fields(pRes);
-//  int32_t     numOfFields = taos_num_fields(pRes);
-//
-//  char str[512] = {0};
-//  while ((pRow = taos_fetch_row(pRes)) != NULL) {
-//    int32_t code = taos_print_row(str, pRow, pFields, numOfFields);
-//    printf("%s\n", str);
-//  }
-//
-//  taos_free_result(pRes);
-//
-//  for (int32_t i = 0; i < 20; ++i) {
-//    char sql[512] = {0};
-//    snprintf(sql, tListLen(sql),
-//             "create table t_x_%d using st1 tags(2) t_x_%d using st1 tags(5) t_x_%d using st1 tags(911)", i,
-//             (i + 1) * 30, (i + 2) * 40);
-//    TAOS_RES* pres = taos_query(pConn, sql);
-//    if (taos_errno(pres) != 0) {
-//      printf("failed to create table %d\n, reason:%s", i, taos_errstr(pres));
-//    }
-//    taos_free_result(pres);
-//  }
-//
-//  taos_close(pConn);
-//}
+TEST(testCase, connect_Test) {
+  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
+  if (pConn == NULL) {
+    printf("failed to connect to server, reason:%s\n", taos_errstr(NULL));
+  }
+  taos_close(pConn);
+}
+
+TEST(testCase, create_user_Test) {
+  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
+  assert(pConn != NULL);
+
+  TAOS_RES* pRes = taos_query(pConn, "create user abc pass 'abc'");
+  if (taos_errno(pRes) != TSDB_CODE_SUCCESS) {
+    printf("failed to create user, reason:%s\n", taos_errstr(pRes));
+  }
+
+  taos_free_result(pRes);
+  taos_close(pConn);
+}
+
+TEST(testCase, create_account_Test) {
+  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
+  assert(pConn != NULL);
+
+  TAOS_RES* pRes = taos_query(pConn, "create account aabc pass 'abc'");
+  if (taos_errno(pRes) != TSDB_CODE_SUCCESS) {
+    printf("failed to create user, reason:%s\n", taos_errstr(pRes));
+  }
+
+  taos_free_result(pRes);
+  taos_close(pConn);
+}
+
+TEST(testCase, drop_account_Test) {
+  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
+  assert(pConn != NULL);
+
+  TAOS_RES* pRes = taos_query(pConn, "drop account aabc");
+  if (taos_errno(pRes) != TSDB_CODE_SUCCESS) {
+    printf("failed to create user, reason:%s\n", taos_errstr(pRes));
+  }
+
+  taos_free_result(pRes);
+  taos_close(pConn);
+}
+
+TEST(testCase, show_user_Test) {
+  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
+  assert(pConn != NULL);
+
+  TAOS_RES* pRes = taos_query(pConn, "show users");
+  TAOS_ROW  pRow = NULL;
+
+  TAOS_FIELD* pFields = taos_fetch_fields(pRes);
+  int32_t     numOfFields = taos_num_fields(pRes);
+
+  char str[512] = {0};
+  while ((pRow = taos_fetch_row(pRes)) != NULL) {
+    int32_t code = taos_print_row(str, pRow, pFields, numOfFields);
+    printf("%s\n", str);
+  }
+
+  taos_free_result(pRes);
+  taos_close(pConn);
+}
+
+TEST(testCase, drop_user_Test) {
+  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
+  assert(pConn != NULL);
+
+  TAOS_RES* pRes = taos_query(pConn, "drop user abc");
+  if (taos_errno(pRes) != TSDB_CODE_SUCCESS) {
+    printf("failed to create user, reason:%s\n", taos_errstr(pRes));
+  }
+
+  taos_free_result(pRes);
+  taos_close(pConn);
+}
+
+TEST(testCase, show_db_Test) {
+  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
+  assert(pConn != NULL);
+
+  TAOS_RES* pRes = taos_query(pConn, "show databases");
+  TAOS_ROW  pRow = NULL;
+
+  TAOS_FIELD* pFields = taos_fetch_fields(pRes);
+  int32_t     numOfFields = taos_num_fields(pRes);
+
+  char str[512] = {0};
+  while ((pRow = taos_fetch_row(pRes)) != NULL) {
+    int32_t code = taos_print_row(str, pRow, pFields, numOfFields);
+    printf("%s\n", str);
+  }
+
+  taos_close(pConn);
+}
+
+TEST(testCase, create_db_Test) {
+  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
+  assert(pConn != NULL);
+
+  TAOS_RES* pRes = taos_query(pConn, "create database abc1 vgroups 2");
+  if (taos_errno(pRes) != 0) {
+    printf("error in create db, reason:%s\n", taos_errstr(pRes));
+  }
+
+  TAOS_FIELD* pFields = taos_fetch_fields(pRes);
+  ASSERT_TRUE(pFields == NULL);
+
+  int32_t numOfFields = taos_num_fields(pRes);
+  ASSERT_EQ(numOfFields, 0);
+
+  taos_free_result(pRes);
+
+  pRes = taos_query(pConn, "create database abc1 vgroups 4");
+  if (taos_errno(pRes) != 0) {
+    printf("error in create db, reason:%s\n", taos_errstr(pRes));
+  }
+  taos_close(pConn);
+}
+
+TEST(testCase, create_dnode_Test) {
+  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
+  assert(pConn != NULL);
+
+  TAOS_RES* pRes = taos_query(pConn, "create dnode abc1 port 7000");
+  if (taos_errno(pRes) != 0) {
+    printf("error in create dnode, reason:%s\n", taos_errstr(pRes));
+  }
+  taos_free_result(pRes);
+
+  pRes = taos_query(pConn, "create dnode 1.1.1.1 port 9000");
+  if (taos_errno(pRes) != 0) {
+    printf("failed to create dnode, reason:%s\n", taos_errstr(pRes));
+  }
+  taos_free_result(pRes);
+
+  taos_close(pConn);
+}
+
+TEST(testCase, drop_dnode_Test) {
+  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
+  assert(pConn != NULL);
+
+  TAOS_RES* pRes = taos_query(pConn, "drop dnode 3");
+  if (taos_errno(pRes) != 0) {
+    printf("error in drop dnode, reason:%s\n", taos_errstr(pRes));
+  }
+
+  TAOS_FIELD* pFields = taos_fetch_fields(pRes);
+  ASSERT_TRUE(pFields == NULL);
+
+  int32_t numOfFields = taos_num_fields(pRes);
+  ASSERT_EQ(numOfFields, 0);
+
+  pRes = taos_query(pConn, "drop dnode 4");
+  if (taos_errno(pRes) != 0) {
+    printf("error in drop dnode, reason:%s\n", taos_errstr(pRes));
+  }
+
+  taos_free_result(pRes);
+  taos_close(pConn);
+}
+
+TEST(testCase, use_db_test) {
+  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
+  assert(pConn != NULL);
+
+  TAOS_RES* pRes = taos_query(pConn, "use abc1");
+  if (taos_errno(pRes) != 0) {
+    printf("error in use db, reason:%s\n", taos_errstr(pRes));
+  }
+
+  TAOS_FIELD* pFields = taos_fetch_fields(pRes);
+  ASSERT_TRUE(pFields == NULL);
+
+  int32_t numOfFields = taos_num_fields(pRes);
+  ASSERT_EQ(numOfFields, 0);
+
+  taos_close(pConn);
+}
+
+ TEST(testCase, drop_db_test) {
+  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
+  assert(pConn != NULL);
+
+  showDB(pConn);
+
+  TAOS_RES* pRes = taos_query(pConn, "drop database abc1");
+  if (taos_errno(pRes) != 0) {
+    printf("failed to drop db, reason:%s\n", taos_errstr(pRes));
+  }
+  taos_free_result(pRes);
+
+  showDB(pConn);
+
+  pRes = taos_query(pConn, "create database abc1");
+  if (taos_errno(pRes) != 0) {
+    printf("create to drop db, reason:%s\n", taos_errstr(pRes));
+  }
+  taos_free_result(pRes);
+  taos_close(pConn);
+}
+
+TEST(testCase, create_stable_Test) {
+  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
+  assert(pConn != NULL);
+
+  TAOS_RES* pRes = taos_query(pConn, "create database if not exists abc1 vgroups 2");
+  if (taos_errno(pRes) != 0) {
+    printf("error in create db, reason:%s\n", taos_errstr(pRes));
+  }
+  taos_free_result(pRes);
+
+  pRes = taos_query(pConn, "create table if not exists abc1.st1(ts timestamp, k int) tags(a int)");
+  if (taos_errno(pRes) != 0) {
+    printf("error in create stable, reason:%s\n", taos_errstr(pRes));
+  }
+
+  TAOS_FIELD* pFields = taos_fetch_fields(pRes);
+  ASSERT_TRUE(pFields == NULL);
+
+  int32_t numOfFields = taos_num_fields(pRes);
+  ASSERT_EQ(numOfFields, 0);
+  taos_free_result(pRes);
+
+  pRes = taos_query(pConn, "create stable if not exists abc1.`123_$^)` (ts timestamp, `abc` int) tags(a int)");
+  if (taos_errno(pRes) != 0) {
+    printf("failed to create super table 123_$^), reason:%s\n", taos_errstr(pRes));
+  }
+
+  pRes = taos_query(pConn, "use abc1");
+  taos_free_result(pRes);
+  pRes = taos_query(pConn, "drop stable `123_$^)`");
+  if (taos_errno(pRes) != 0) {
+    printf("failed to drop super table 123_$^), reason:%s\n", taos_errstr(pRes));
+  }
+
+  taos_close(pConn);
+}
+
+TEST(testCase, create_table_Test) {
+  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
+  assert(pConn != NULL);
+
+  TAOS_RES* pRes = taos_query(pConn, "use abc1");
+  taos_free_result(pRes);
+
+  pRes = taos_query(pConn, "create table if not exists tm0(ts timestamp, k int)");
+  ASSERT_EQ(taos_errno(pRes), 0);
+
+  taos_free_result(pRes);
+
+  pRes = taos_query(pConn, "create table if not exists tm0(ts timestamp, k blob)");
+  ASSERT_NE(taos_errno(pRes), 0);
+
+  taos_free_result(pRes);
+  taos_close(pConn);
+}
+
+TEST(testCase, create_ctable_Test) {
+  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
+  assert(pConn != NULL);
+
+  TAOS_RES* pRes = taos_query(pConn, "use abc1");
+  if (taos_errno(pRes) != 0) {
+    printf("failed to use db, reason:%s\n", taos_errstr(pRes));
+  }
+  taos_free_result(pRes);
+
+  pRes = taos_query(pConn, "create stable if not exists st1 (ts timestamp, k int ) tags(a int)");
+  if (taos_errno(pRes) != 0) {
+    printf("failed to create stable, reason:%s\n", taos_errstr(pRes));
+  }
+  taos_free_result(pRes);
+
+  pRes = taos_query(pConn, "create table tm0 using st1 tags(1)");
+  if (taos_errno(pRes) != 0) {
+    printf("failed to create child table tm0, reason:%s\n", taos_errstr(pRes));
+  }
+
+  taos_free_result(pRes);
+  taos_close(pConn);
+}
+
+TEST(testCase, show_stable_Test) {
+  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
+  assert(pConn != nullptr);
+
+  TAOS_RES* pRes = taos_query(pConn, "show abc1.stables");
+  if (taos_errno(pRes) != 0) {
+    printf("failed to show stables, reason:%s\n", taos_errstr(pRes));
+    taos_free_result(pRes);
+    ASSERT_TRUE(false);
+  }
+
+  TAOS_ROW    pRow = NULL;
+  TAOS_FIELD* pFields = taos_fetch_fields(pRes);
+  int32_t     numOfFields = taos_num_fields(pRes);
+
+  char str[512] = {0};
+  while ((pRow = taos_fetch_row(pRes)) != NULL) {
+    int32_t code = taos_print_row(str, pRow, pFields, numOfFields);
+    printf("%s\n", str);
+  }
+
+  taos_free_result(pRes);
+  taos_close(pConn);
+}
+
+TEST(testCase, show_vgroup_Test) {
+  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
+  assert(pConn != NULL);
+
+  TAOS_RES* pRes = taos_query(pConn, "use abc1");
+  if (taos_errno(pRes) != 0) {
+    printf("failed to use db, reason:%s\n", taos_errstr(pRes));
+  }
+  taos_free_result(pRes);
+
+  pRes = taos_query(pConn, "show vgroups");
+  if (taos_errno(pRes) != 0) {
+    printf("failed to show vgroups, reason:%s\n", taos_errstr(pRes));
+    taos_free_result(pRes);
+    ASSERT_TRUE(false);
+  }
+
+  TAOS_ROW pRow = NULL;
+
+  TAOS_FIELD* pFields = taos_fetch_fields(pRes);
+  int32_t     numOfFields = taos_num_fields(pRes);
+
+  char str[512] = {0};
+  while ((pRow = taos_fetch_row(pRes)) != NULL) {
+    int32_t code = taos_print_row(str, pRow, pFields, numOfFields);
+    printf("%s\n", str);
+  }
+
+  taos_free_result(pRes);
+  taos_close(pConn);
+}
+
+TEST(testCase, create_multiple_tables) {
+  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
+  ASSERT_NE(pConn, nullptr);
+
+  TAOS_RES* pRes = taos_query(pConn, "use abc1");
+  if (taos_errno(pRes) != 0) {
+    printf("failed to use db, reason:%s\n", taos_errstr(pRes));
+    taos_free_result(pRes);
+    taos_close(pConn);
+    return;
+  }
+
+  taos_free_result(pRes);
+
+  pRes = taos_query(pConn, "create table t_2 using st1 tags(1)");
+  if (taos_errno(pRes) != 0) {
+    printf("failed to create multiple tables, reason:%s\n", taos_errstr(pRes));
+    taos_free_result(pRes);
+    ASSERT_TRUE(false);
+  }
+
+  taos_free_result(pRes);
+  pRes = taos_query(pConn, "create table t_3 using st1 tags(2)");
+  if (taos_errno(pRes) != 0) {
+    printf("failed to create multiple tables, reason:%s\n", taos_errstr(pRes));
+    taos_free_result(pRes);
+    ASSERT_TRUE(false);
+  }
+
+  TAOS_ROW    pRow = NULL;
+  TAOS_FIELD* pFields = taos_fetch_fields(pRes);
+  int32_t     numOfFields = taos_num_fields(pRes);
+
+  char str[512] = {0};
+  while ((pRow = taos_fetch_row(pRes)) != NULL) {
+    int32_t code = taos_print_row(str, pRow, pFields, numOfFields);
+    printf("%s\n", str);
+  }
+
+  taos_free_result(pRes);
+
+  for (int32_t i = 0; i < 20; ++i) {
+    char sql[512] = {0};
+    snprintf(sql, tListLen(sql),
+             "create table t_x_%d using st1 tags(2) t_x_%d using st1 tags(5) t_x_%d using st1 tags(911)", i,
+             (i + 1) * 30, (i + 2) * 40);
+    TAOS_RES* pres = taos_query(pConn, sql);
+    if (taos_errno(pres) != 0) {
+      printf("failed to create table %d\n, reason:%s", i, taos_errstr(pres));
+    }
+    taos_free_result(pres);
+  }
+
+  taos_close(pConn);
+}
 
 TEST(testCase, show_table_Test) {
   TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
   assert(pConn != NULL);
 
   TAOS_RES* pRes = taos_query(pConn, "show tables");
+  ASSERT_NE(taos_errno(pRes), 0);
+
   if (taos_errno(pRes) != 0) {
-    printf("failed to show tables, reason:%s\n", taos_errstr(pRes));
-    taos_free_result(pRes);
+    printf("expected failed to show tables, reason:%s\n", taos_errstr(pRes));
   }
 
+  taos_free_result(pRes);
+
   pRes = taos_query(pConn, "show abc1.tables");
   if (taos_errno(pRes) != 0) {
     printf("failed to show tables, reason:%s\n", taos_errstr(pRes));
@@ -485,88 +488,88 @@ TEST(testCase, show_table_Test) {
   taos_close(pConn);
 }
 
-//TEST(testCase, drop_stable_Test) {
-//  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
-//  assert(pConn != NULL);
-//
-//  TAOS_RES* pRes = taos_query(pConn, "create database abc1");
-//  if (taos_errno(pRes) != 0) {
-//    printf("error in creating db, reason:%s\n", taos_errstr(pRes));
-//  }
-//  taos_free_result(pRes);
-//
-//  pRes = taos_query(pConn, "use abc1");
-//  if (taos_errno(pRes) != 0) {
-//    printf("error in using db, reason:%s\n", taos_errstr(pRes));
-//  }
-//  taos_free_result(pRes);
-//
-//  pRes = taos_query(pConn, "drop stable st1");
-//  if (taos_errno(pRes) != 0) {
-//    printf("failed to drop stable, reason:%s\n", taos_errstr(pRes));
-//  }
-//
-//  taos_free_result(pRes);
-//  taos_close(pConn);
-//}
-//
-//TEST(testCase, generated_request_id_test) {
-//  SHashObj* phash = taosHashInit(10000, taosGetDefaultHashFunction(TSDB_DATA_TYPE_BIGINT), false, HASH_ENTRY_LOCK);
-//
-//  for (int32_t i = 0; i < 50000; ++i) {
-//    uint64_t v = generateRequestId();
-//    void*    result = taosHashGet(phash, &v, sizeof(v));
-//    if (result != nullptr) {
-//      printf("0x%lx, index:%d\n", v, i);
-//    }
-//    assert(result == nullptr);
-//    taosHashPut(phash, &v, sizeof(v), NULL, 0);
-//  }
-//
-//  taosHashCleanup(phash);
-//}
-//
-//TEST(testCase, create_topic_Test) {
-//  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
-//  assert(pConn != NULL);
-//
-//  TAOS_RES* pRes = taos_query(pConn, "use abc1");
-//  if (taos_errno(pRes) != 0) {
-//    printf("error in use db, reason:%s\n", taos_errstr(pRes));
-//  }
-//  taos_free_result(pRes);
-//
-//  TAOS_FIELD* pFields = taos_fetch_fields(pRes);
-//  ASSERT_TRUE(pFields == nullptr);
-//
-//  int32_t numOfFields = taos_num_fields(pRes);
-//  ASSERT_EQ(numOfFields, 0);
-//
-//  taos_free_result(pRes);
-//
-//  char* sql = "select * from tu";
-//  pRes = taos_create_topic(pConn, "test_topic_1", sql, strlen(sql));
-//  taos_free_result(pRes);
-//  taos_close(pConn);
-//}
+TEST(testCase, drop_stable_Test) {
+  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
+  assert(pConn != nullptr);
 
-//TEST(testCase, insert_test) {
-//  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
-//  ASSERT_NE(pConn, nullptr);
-//
-//  TAOS_RES* pRes = taos_query(pConn, "use abc1");
-//  taos_free_result(pRes);
-//
-//  pRes = taos_query(pConn, "insert into t_2 values(now, 1)");
-//  if (taos_errno(pRes) != 0) {
-//    printf("failed to create multiple tables, reason:%s\n", taos_errstr(pRes));
-//    taos_free_result(pRes);
-//    ASSERT_TRUE(false);
-//  }
-//
-//  taos_free_result(pRes);
-//  taos_close(pConn);
-//}
+  TAOS_RES* pRes = taos_query(pConn, "create database if not exists abc1");
+  if (taos_errno(pRes) != 0) {
+    printf("error in creating db, reason:%s\n", taos_errstr(pRes));
+  }
+  taos_free_result(pRes);
+
+  pRes = taos_query(pConn, "use abc1");
+  if (taos_errno(pRes) != 0) {
+    printf("error in using db, reason:%s\n", taos_errstr(pRes));
+  }
+  taos_free_result(pRes);
+
+  pRes = taos_query(pConn, "drop stable st1");
+  if (taos_errno(pRes) != 0) {
+    printf("failed to drop stable, reason:%s\n", taos_errstr(pRes));
+  }
+
+  taos_free_result(pRes);
+  taos_close(pConn);
+}
+
+TEST(testCase, generated_request_id_test) {
+  SHashObj* phash = taosHashInit(10000, taosGetDefaultHashFunction(TSDB_DATA_TYPE_BIGINT), false, HASH_ENTRY_LOCK);
+
+  for (int32_t i = 0; i < 50000; ++i) {
+    uint64_t v = generateRequestId();
+    void*    result = taosHashGet(phash, &v, sizeof(v));
+    if (result != nullptr) {
+      printf("0x%lx, index:%d\n", v, i);
+    }
+    assert(result == nullptr);
+    taosHashPut(phash, &v, sizeof(v), NULL, 0);
+  }
+
+  taosHashCleanup(phash);
+}
+
+TEST(testCase, create_topic_Test) {
+  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
+  assert(pConn != NULL);
+
+  TAOS_RES* pRes = taos_query(pConn, "use abc1");
+  if (taos_errno(pRes) != 0) {
+    printf("error in use db, reason:%s\n", taos_errstr(pRes));
+  }
+  taos_free_result(pRes);
+
+  TAOS_FIELD* pFields = taos_fetch_fields(pRes);
+  ASSERT_TRUE(pFields == nullptr);
+
+  int32_t numOfFields = taos_num_fields(pRes);
+  ASSERT_EQ(numOfFields, 0);
+
+  taos_free_result(pRes);
+
+  char* sql = "select * from tu";
+  pRes = taos_create_topic(pConn, "test_topic_1", sql, strlen(sql));
+  taos_free_result(pRes);
+  taos_close(pConn);
+}
+
+TEST(testCase, insert_test) {
+  TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);
+  ASSERT_NE(pConn, nullptr);
+
+  TAOS_RES* pRes = taos_query(pConn, "use abc1");
+  taos_free_result(pRes);
+
+  pRes = taos_query(pConn, "insert into t_2 values(now, 1)");
+  if (taos_errno(pRes) != 0) {
+    printf("failed to create multiple tables, reason:%s\n", taos_errstr(pRes));
+    taos_free_result(pRes);
+    ASSERT_TRUE(false);
+  }
+
+  taos_free_result(pRes);
+  taos_close(pConn);
+}
 
 TEST(testCase, projection_query_tables) {
   TAOS* pConn = taos_connect("localhost", "root", "taosdata", NULL, 0);