diff --git a/cmake/install.inc b/cmake/install.inc
index b37cf751fb..30aa801122 100755
--- a/cmake/install.inc
+++ b/cmake/install.inc
@@ -32,7 +32,7 @@ ELSEIF (TD_WINDOWS)
   #INSTALL(TARGETS taos RUNTIME DESTINATION driver)
   #INSTALL(TARGETS shell RUNTIME DESTINATION .)
   IF (TD_MVN_INSTALLED)
-    INSTALL(FILES ${LIBRARY_OUTPUT_PATH}/taos-jdbcdriver-2.0.31.jar DESTINATION connector/jdbc)
+    INSTALL(FILES ${LIBRARY_OUTPUT_PATH}/taos-jdbcdriver-2.0.32-dist.jar DESTINATION connector/jdbc)
   ENDIF ()
 ELSEIF (TD_DARWIN)
   SET(TD_MAKE_INSTALL_SH "${TD_COMMUNITY_DIR}/packaging/tools/make_install.sh")
diff --git a/documentation20/cn/08.connector/docs.md b/documentation20/cn/08.connector/docs.md
index aa5fa50b66..454d896fc2 100644
--- a/documentation20/cn/08.connector/docs.md
+++ b/documentation20/cn/08.connector/docs.md
@@ -557,6 +557,13 @@ c1.close()
 conn.close()
 ```
 
+#### 关于纳秒 (nanosecon) 在 Python 连接器中的说明
+
+由于目前 Python 对 nanosecond 支持的不完善(参见链接 1. 2. )，目前的实现方式是在 nanosecond 精度时返回整数，而不是 ms 和 us 返回的 datetime 类型，应用开发者需要自行处理，建议使用 pandas 的 to_datetime()。未来如果 Python 正式完整支持了纳秒，涛思数据可能会修改相关接口。
+
+1. https://stackoverflow.com/questions/10611328/parsing-datetime-strings-containing-nanoseconds
+2. https://www.python.org/dev/peps/pep-0564/
+
 #### 帮助信息
 
 用户可通过python的帮助信息直接查看模块的使用信息，或者参考tests/examples/python中的示例程序。以下为部分常用类和方法：
diff --git a/documentation20/cn/11.administrator/docs.md b/documentation20/cn/11.administrator/docs.md
index 10951ed1fb..dce2f50d9e 100644
--- a/documentation20/cn/11.administrator/docs.md
+++ b/documentation20/cn/11.administrator/docs.md
@@ -465,43 +465,44 @@ TDengine的所有可执行文件默认存放在 _/usr/local/taos/bin_ 目录下
 
 目前 TDengine 有将近 200 个内部保留关键字，这些关键字无论大小写均不可以用作库名、表名、STable 名、数据列名及标签列名等。这些关键字列表如下：
 
-| 关键字列表 |             |              |            |           |
-| ---------- | ----------- | ------------ | ---------- | --------- |
-| ABLOCKS    | CONNECTIONS | HAVING       | MODULES    | SMALLINT  |
-| ABORT      | COPY        | ID           | NCHAR      | SPREAD    |
-| ACCOUNT    | COUNT       | IF           | NE         | STABLE    |
-| ACCOUNTS   | CREATE      | IGNORE       | NONE       | STABLES   |
-| ADD        | CTIME       | IMMEDIATE    | NOT        | STAR      |
-| AFTER      | DATABASE    | IMPORT       | NOTNULL    | STATEMENT |
-| ALL        | DATABASES   | IN           | NOW        | STDDEV    |
-| ALTER      | DAYS        | INITIALLY    | OF         | STREAM    |
-| AND        | DEFERRED    | INSERT       | OFFSET     | STREAMS   |
-| AS         | DELIMITERS  | INSTEAD      | OR         | STRING    |
-| ASC        | DESC        | INTEGER      | ORDER      | SUM       |
-| ATTACH     | DESCRIBE    | INTERVAL     | PASS       | TABLE     |
-| AVG        | DETACH      | INTO         | PERCENTILE | TABLES    |
-| BEFORE     | DIFF        | IP           | PLUS       | TAG       |
-| BEGIN      | DISTINCT    | IS           | PRAGMA     | TAGS      |
-| BETWEEN    | DIVIDE      | ISNULL       | PREV       | TBLOCKS   |
-| BIGINT     | DNODE       | JOIN         | PRIVILEGE  | TBNAME    |
-| BINARY     | DNODES      | KEEP         | QUERIES    | TIMES     |
-| BITAND     | DOT         | KEY          | QUERY      | TIMESTAMP |
-| BITNOT     | DOUBLE      | KILL         | RAISE      | TINYINT   |
-| BITOR      | DROP        | LAST         | REM        | TOP       |
-| BOOL       | EACH        | LE           | REPLACE    | TOPIC     |
-| BOTTOM     | END         | LEASTSQUARES | REPLICA    | TRIGGER   |
-| BY         | EQ          | LIKE         | RESET      | UMINUS    |
-| CACHE      | EXISTS      | LIMIT        | RESTRICT   | UNION     |
-| CASCADE    | EXPLAIN     | LINEAR       | ROW        | UPLUS     |
-| CHANGE     | FAIL        | LOCAL        | ROWS       | USE       |
-| CLOG       | FILL        | LP           | RP         | USER      |
-| CLUSTER    | FIRST       | LSHIFT       | RSHIFT     | USERS     |
-| COLON      | FLOAT       | LT           | SCORES     | USING     |
-| COLUMN     | FOR         | MATCH        | SELECT     | VALUES    |
-| COMMA      | FROM        | MAX          | SEMI       | VARIABLE  |
-| COMP       | GE          | METRIC       | SET        | VGROUPS   |
-| CONCAT     | GLOB        | METRICS      | SHOW       | VIEW      |
-| CONFIGS    | GRANTS      | MIN          | SLASH      | WAVG      |
-| CONFLICT   | GROUP       | MINUS        | SLIDING    | WHERE     |
-| CONNECTION | GT          | MNODES       | SLIMIT     |           |
+|  关键字列表  |              |              |              |              |
+| ------------ | ------------ | ------------ | ------------ | ------------ |
+| ABORT        | CREATE       | IGNORE       | NULL         | STAR         |
+| ACCOUNT      | CTIME        | IMMEDIATE    | OF           | STATE        |
+| ACCOUNTS     | DATABASE     | IMPORT       | OFFSET       | STATEMENT    |
+| ADD          | DATABASES    | IN           | OR           | STATE_WINDOW |
+| AFTER        | DAYS         | INITIALLY    | ORDER        | STORAGE      |
+| ALL          | DBS          | INSERT       | PARTITIONS   | STREAM       |
+| ALTER        | DEFERRED     | INSTEAD      | PASS         | STREAMS      |
+| AND          | DELIMITERS   | INT          | PLUS         | STRING       |
+| AS           | DESC         | INTEGER      | PPS          | SYNCDB       |
+| ASC          | DESCRIBE     | INTERVAL     | PRECISION    | TABLE        |
+| ATTACH       | DETACH       | INTO         | PREV         | TABLES       |
+| BEFORE       | DISTINCT     | IS           | PRIVILEGE    | TAG          |
+| BEGIN        | DIVIDE       | ISNULL       | QTIME        | TAGS         |
+| BETWEEN      | DNODE        | JOIN         | QUERIES      | TBNAME       |
+| BIGINT       | DNODES       | KEEP         | QUERY        | TIMES        |
+| BINARY       | DOT          | KEY          | QUORUM       | TIMESTAMP    |
+| BITAND       | DOUBLE       | KILL         | RAISE        | TINYINT      |
+| BITNOT       | DROP         | LE           | REM          | TOPIC        |
+| BITOR        | EACH         | LIKE         | REPLACE      | TOPICS       |
+| BLOCKS       | END          | LIMIT        | REPLICA      | TRIGGER      |
+| BOOL         | EQ           | LINEAR       | RESET        | TSERIES      |
+| BY           | EXISTS       | LOCAL        | RESTRICT     | UMINUS       |
+| CACHE        | EXPLAIN      | LP           | ROW          | UNION        |
+| CACHELAST    | FAIL         | LSHIFT       | RP           | UNSIGNED     |
+| CASCADE      | FILE         | LT           | RSHIFT       | UPDATE       |
+| CHANGE       | FILL         | MATCH        | SCORES       | UPLUS        |
+| CLUSTER      | FLOAT        | MAXROWS      | SELECT       | USE          |
+| COLON        | FOR          | MINROWS      | SEMI         | USER         |
+| COLUMN       | FROM         | MINUS        | SESSION      | USERS        |
+| COMMA        | FSYNC        | MNODES       | SET          | USING        |
+| COMP         | GE           | MODIFY       | SHOW         | VALUES       |
+| COMPACT      | GLOB         | MODULES      | SLASH        | VARIABLE     |
+| CONCAT       | GRANTS       | NCHAR        | SLIDING      | VARIABLES    |
+| CONFLICT     | GROUP        | NE           | SLIMIT       | VGROUPS      |
+| CONNECTION   | GT           | NONE         | SMALLINT     | VIEW         |
+| CONNECTIONS  | HAVING       | NOT          | SOFFSET      | VNODES       |
+| CONNS        | ID           | NOTNULL      | STABLE       | WAL          |
+| COPY         | IF           | NOW          | STABLES      | WHERE        |
 
diff --git a/documentation20/cn/12.taos-sql/docs.md b/documentation20/cn/12.taos-sql/docs.md
index 844865f6db..2a1112fd16 100644
--- a/documentation20/cn/12.taos-sql/docs.md
+++ b/documentation20/cn/12.taos-sql/docs.md
@@ -89,13 +89,13 @@ TDengine 缺省的时间戳是毫秒精度，但通过在 CREATE DATABASE 时传
     ```mysql
     USE db_name;
     ```
-    使用/切换数据库
+    使用/切换数据库（在 RESTful 连接方式下无效）。
 
 - **删除数据库**
     ```mysql
     DROP DATABASE [IF EXISTS] db_name;
     ```
-    删除数据库。所包含的全部数据表将被删除，谨慎使用
+    删除数据库。指定 Database 所包含的全部数据表将被删除，谨慎使用！
 
 - **修改数据库参数**
     ```mysql
@@ -703,22 +703,24 @@ Query OK, 1 row(s) in set (0.001091s)
 
 ### 支持的条件过滤操作
 
-| **Operation**   | **Note**                      | **Applicable Data Types**             |
-| --------------- | ----------------------------- | ------------------------------------- |
-| >               | larger than                   | **`timestamp`** and all numeric types |
-| <               | smaller than                  | **`timestamp`** and all numeric types |
-| >=              | larger than or equal to       | **`timestamp`** and all numeric types |
-| <=              | smaller than or equal to      | **`timestamp`** and all numeric types |
-| =               | equal to                      | all types                             |
-| <>              | not equal to                  | all types                             |
-| between and     | within a certain range        | **`timestamp`** and all numeric types |
-| %               | match with any char sequences | **`binary`** **`nchar`**              |
-| _               | match with a single char      | **`binary`** **`nchar`**              |
+| **Operation**   | **Note**                      | **Applicable Data Types**                 |
+| --------------- | ----------------------------- | ----------------------------------------- |
+| >               | larger than                   | **`timestamp`** and all numeric types     |
+| <               | smaller than                  | **`timestamp`** and all numeric types     |
+| >=              | larger than or equal to       | **`timestamp`** and all numeric types     |
+| <=              | smaller than or equal to      | **`timestamp`** and all numeric types     |
+| =               | equal to                      | all types                                 |
+| <>              | not equal to                  | all types                                 |
+| between and     | within a certain range        | **`timestamp`** and all numeric types     |
+| in              | matches any value in a set    | all types except first column `timestamp` |
+| %               | match with any char sequences | **`binary`** **`nchar`**                  |
+| _               | match with a single char      | **`binary`** **`nchar`**                  |
 
 1. <> 算子也可以写为 != ，请注意，这个算子不能用于数据表第一列的 timestamp 字段。
 2. 同时进行多个字段的范围过滤，需要使用关键词 AND 来连接不同的查询条件，暂不支持 OR 连接的不同列之间的查询过滤条件。
-3. 针对单一字段的过滤，如果是时间过滤条件，则一条语句中只支持设定一个；但针对其他的（普通）列或标签列，则可以使用 `OR` 关键字进行组合条件的查询过滤。例如：((value > 20 AND value < 30) OR (value < 12)) 。
-4. 从 2.0.17 版本开始，条件过滤开始支持 BETWEEN AND 语法，例如 `WHERE col2 BETWEEN 1.5 AND 3.25` 表示查询条件为“1.5 ≤ col2 ≤ 3.25”。
+3. 针对单一字段的过滤，如果是时间过滤条件，则一条语句中只支持设定一个；但针对其他的（普通）列或标签列，则可以使用 `OR` 关键字进行组合条件的查询过滤。例如： `((value > 20 AND value < 30) OR (value < 12))`。
+4. 从 2.0.17.0 版本开始，条件过滤开始支持 BETWEEN AND 语法，例如 `WHERE col2 BETWEEN 1.5 AND 3.25` 表示查询条件为“1.5 ≤ col2 ≤ 3.25”。
+5. 从 2.1.4.0 版本开始，条件过滤开始支持 IN 算子，例如 `WHERE city IN ('Beijing', 'Shanghai')`。说明：BOOL 类型写作 `{true, false}` 或 `{0, 1}` 均可，但不能写作 0、1 之外的整数；FLOAT 和 DOUBLE 类型会受到浮点数精度影响，集合内的值在精度范围内认为和数据行的值完全相等才能匹配成功。<!-- REPLACE_OPEN_TO_ENTERPRISE__IN_OPERATOR_AND_UNSIGNED_INTEGER -->
 
 <!-- 
 <a class="anchor" id="having"></a>
diff --git a/src/connector/jdbc/CMakeLists.txt b/src/connector/jdbc/CMakeLists.txt
index 1db8361faf..9642b0490f 100644
--- a/src/connector/jdbc/CMakeLists.txt
+++ b/src/connector/jdbc/CMakeLists.txt
@@ -8,7 +8,7 @@ IF (TD_MVN_INSTALLED)
   ADD_CUSTOM_COMMAND(OUTPUT ${JDBC_CMD_NAME}
     POST_BUILD
     COMMAND mvn -Dmaven.test.skip=true install -f ${CMAKE_CURRENT_SOURCE_DIR}/pom.xml
-    COMMAND ${CMAKE_COMMAND} -E copy ${CMAKE_CURRENT_SOURCE_DIR}/target/taos-jdbcdriver-2.0.31.jar ${LIBRARY_OUTPUT_PATH}
+    COMMAND ${CMAKE_COMMAND} -E copy ${CMAKE_CURRENT_SOURCE_DIR}/target/taos-jdbcdriver-2.0.32-dist.jar ${LIBRARY_OUTPUT_PATH}
     COMMAND mvn -Dmaven.test.skip=true clean -f ${CMAKE_CURRENT_SOURCE_DIR}/pom.xml
     COMMENT "build jdbc driver")
   ADD_CUSTOM_TARGET(${JDBC_TARGET_NAME} ALL WORKING_DIRECTORY ${EXECUTABLE_OUTPUT_PATH} DEPENDS ${JDBC_CMD_NAME})
diff --git a/src/connector/jdbc/deploy-pom.xml b/src/connector/jdbc/deploy-pom.xml
index 8f77582d30..06122372f0 100755
--- a/src/connector/jdbc/deploy-pom.xml
+++ b/src/connector/jdbc/deploy-pom.xml
@@ -5,7 +5,7 @@
 
   <groupId>com.taosdata.jdbc</groupId>
   <artifactId>taos-jdbcdriver</artifactId>
-  <version>2.0.31</version>
+  <version>2.0.32</version>
   <packaging>jar</packaging>
 
   <name>JDBCDriver</name>
diff --git a/src/connector/jdbc/pom.xml b/src/connector/jdbc/pom.xml
index a3a36d54cf..61d7fb85ef 100644
--- a/src/connector/jdbc/pom.xml
+++ b/src/connector/jdbc/pom.xml
@@ -3,7 +3,7 @@
     <modelVersion>4.0.0</modelVersion>
     <groupId>com.taosdata.jdbc</groupId>
     <artifactId>taos-jdbcdriver</artifactId>
-    <version>2.0.31</version>
+    <version>2.0.32</version>
     <packaging>jar</packaging>
     <name>JDBCDriver</name>
     <url>https://github.com/taosdata/TDengine/tree/master/src/connector/jdbc</url>
@@ -113,16 +113,16 @@
                         <include>**/*Test.java</include>
                     </includes>
                     <excludes>
-                        <exclude>**/TSDBJNIConnectorTest.java</exclude>
-                        <exclude>**/UnsignedNumberJniTest.java</exclude>
-                        <exclude>**/DatetimeBefore1970Test.java</exclude>
                         <exclude>**/AppMemoryLeakTest.java</exclude>
                         <exclude>**/AuthenticationTest.java</exclude>
-                        <exclude>**/TaosInfoMonitorTest.java</exclude>
+                        <exclude>**/ConnectMultiTaosdByRestfulWithDifferentTokenTest.java</exclude>
+                        <exclude>**/DatetimeBefore1970Test.java</exclude>
                         <exclude>**/FailOverTest.java</exclude>
                         <exclude>**/InvalidResultSetPointerTest.java</exclude>
                         <exclude>**/RestfulConnectionTest.java</exclude>
-                        <exclude>**/ConnectMultiTaosdByRestfulWithDifferentTokenTest.java</exclude>
+                        <exclude>**/TSDBJNIConnectorTest.java</exclude>
+                        <exclude>**/TaosInfoMonitorTest.java</exclude>
+                        <exclude>**/UnsignedNumberJniTest.java</exclude>
                     </excludes>
                     <testFailureIgnore>true</testFailureIgnore>
                 </configuration>
diff --git a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/AbstractConnection.java b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/AbstractConnection.java
index 686ef36262..b3887d436b 100644
--- a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/AbstractConnection.java
+++ b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/AbstractConnection.java
@@ -1,6 +1,6 @@
 package com.taosdata.jdbc;
 
-import com.taosdata.jdbc.rs.enums.TimestampFormat;
+import com.taosdata.jdbc.enums.TimestampFormat;
 
 import java.sql.*;
 import java.util.Enumeration;
@@ -306,9 +306,6 @@ public abstract class AbstractConnection extends WrapperImpl implements Connecti
 
     @Override
     public Statement createStatement(int resultSetType, int resultSetConcurrency, int resultSetHoldability) throws SQLException {
-        if (isClosed())
-            throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_CONNECTION_CLOSED);
-
         switch (resultSetHoldability) {
             case ResultSet.HOLD_CURSORS_OVER_COMMIT:
                 break;
@@ -322,11 +319,7 @@ public abstract class AbstractConnection extends WrapperImpl implements Connecti
     }
 
     @Override
-    public PreparedStatement prepareStatement(String sql, int resultSetType, int resultSetConcurrency, int resultSetHoldability)
-            throws SQLException {
-        if (isClosed())
-            throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_CONNECTION_CLOSED);
-
+    public PreparedStatement prepareStatement(String sql, int resultSetType, int resultSetConcurrency, int resultSetHoldability) throws SQLException {
         switch (resultSetHoldability) {
             case ResultSet.HOLD_CURSORS_OVER_COMMIT:
                 break;
@@ -425,7 +418,7 @@ public abstract class AbstractConnection extends WrapperImpl implements Connecti
                 status = resultSet.getInt("server_status()");
                 resultSet.close();
             }
-            return status == 1 ? true : false;
+            return status == 1;
         });
 
         boolean status = false;
@@ -434,9 +427,7 @@ public abstract class AbstractConnection extends WrapperImpl implements Connecti
                 status = future.get();
             else
                 status = future.get(timeout, TimeUnit.SECONDS);
-        } catch (InterruptedException e) {
-            e.printStackTrace();
-        } catch (ExecutionException e) {
+        } catch (InterruptedException | ExecutionException e) {
             e.printStackTrace();
         } catch (TimeoutException e) {
             future.cancel(true);
@@ -452,8 +443,7 @@ public abstract class AbstractConnection extends WrapperImpl implements Connecti
         if (isClosed)
             throw (SQLClientInfoException) TSDBError.createSQLException(TSDBErrorNumbers.ERROR_SQLCLIENT_EXCEPTION_ON_CONNECTION_CLOSED);
 
-        if (clientInfoProps != null)
-            clientInfoProps.setProperty(name, value);
+        clientInfoProps.setProperty(name, value);
     }
 
     @Override
@@ -461,8 +451,8 @@ public abstract class AbstractConnection extends WrapperImpl implements Connecti
         if (isClosed)
             throw (SQLClientInfoException) TSDBError.createSQLException(TSDBErrorNumbers.ERROR_SQLCLIENT_EXCEPTION_ON_CONNECTION_CLOSED);
 
-        for (Enumeration<Object> enumer = properties.keys(); enumer.hasMoreElements(); ) {
-            String name = (String) enumer.nextElement();
+        for (Enumeration<Object> enumeration = properties.keys(); enumeration.hasMoreElements(); ) {
+            String name = (String) enumeration.nextElement();
             clientInfoProps.put(name, properties.getProperty(name));
         }
     }
@@ -528,14 +518,13 @@ public abstract class AbstractConnection extends WrapperImpl implements Connecti
         if (milliseconds < 0)
             throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_INVALID_VARIABLE);
 
-        throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_UNSUPPORTED_METHOD);
+        // do nothing
     }
 
     @Override
     public int getNetworkTimeout() throws SQLException {
         if (isClosed())
             throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_CONNECTION_CLOSED);
-
-        throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_UNSUPPORTED_METHOD);
+        return 0;
     }
 }
diff --git a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/AbstractDatabaseMetaData.java b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/AbstractDatabaseMetaData.java
index 48811d30a6..3c9c784f59 100644
--- a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/AbstractDatabaseMetaData.java
+++ b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/AbstractDatabaseMetaData.java
@@ -12,8 +12,7 @@ public abstract class AbstractDatabaseMetaData extends WrapperImpl implements Da
     private final static int DRIVER_MAJAR_VERSION = 2;
     private final static int DRIVER_MINOR_VERSION = 0;
 
-    private String precision = "ms";
-    private String database;
+    private String precision = TSDBConstants.DEFAULT_PRECISION;
 
     public boolean allProceduresAreCallable() throws SQLException {
         return false;
@@ -1223,7 +1222,6 @@ public abstract class AbstractDatabaseMetaData extends WrapperImpl implements Da
             ResultSet databases = stmt.executeQuery("show databases");
             while (databases.next()) {
                 String dbname = databases.getString("name");
-                this.database = dbname;
                 this.precision = databases.getString("precision");
                 if (dbname.equalsIgnoreCase(catalog))
                     return true;
diff --git a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/AbstractDriver.java b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/AbstractDriver.java
index 5eaac1cd3b..7d4a268391 100644
--- a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/AbstractDriver.java
+++ b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/AbstractDriver.java
@@ -58,7 +58,7 @@ public abstract class AbstractDriver implements Driver {
                         value = parameterValuePair.substring(indexOfEqual + 1);
                     }
                 }
-                if ((value != null && value.length() > 0) && (parameter != null && parameter.length() > 0)) {
+                if (value != null && value.length() > 0 && parameter.length() > 0) {
                     urlProps.setProperty(parameter, value);
                 }
             }
@@ -87,7 +87,7 @@ public abstract class AbstractDriver implements Driver {
             url = url.substring(0, indexOfColon);
         }
         // parse host
-        if (url != null && url.length() > 0 && url.trim().length() > 0) {
+        if (url.length() > 0 && url.trim().length() > 0) {
             urlProps.setProperty(TSDBDriver.PROPERTY_KEY_HOST, url);
         }
         return urlProps;
diff --git a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/AbstractParameterMetaData.java b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/AbstractParameterMetaData.java
index cb6c7d40ad..7d9d8ee515 100644
--- a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/AbstractParameterMetaData.java
+++ b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/AbstractParameterMetaData.java
@@ -1,7 +1,5 @@
 package com.taosdata.jdbc;
 
-import com.sun.org.apache.xpath.internal.operations.Bool;
-
 import java.sql.ParameterMetaData;
 import java.sql.SQLException;
 import java.sql.Timestamp;
diff --git a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/DatabaseMetaDataResultSet.java b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/DatabaseMetaDataResultSet.java
index cd266529f3..bda3d52212 100644
--- a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/DatabaseMetaDataResultSet.java
+++ b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/DatabaseMetaDataResultSet.java
@@ -15,10 +15,12 @@
 package com.taosdata.jdbc;
 
 import java.math.BigDecimal;
-import java.sql.*;
+import java.sql.ResultSetMetaData;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.sql.Timestamp;
 import java.util.ArrayList;
 import java.util.Calendar;
-import java.util.Iterator;
 import java.util.List;
 
 /*
@@ -130,7 +132,7 @@ public class DatabaseMetaDataResultSet extends AbstractResultSet {
     public Timestamp getTimestamp(int columnIndex) throws SQLException {
         int colType = columnMetaDataList.get(columnIndex - 1).getColType();
         int nativeType = TSDBConstants.jdbcType2TaosType(colType);
-        return rowCursor.getTimestamp(columnIndex,nativeType);
+        return rowCursor.getTimestamp(columnIndex, nativeType);
     }
 
     @Override
@@ -145,9 +147,7 @@ public class DatabaseMetaDataResultSet extends AbstractResultSet {
 
     @Override
     public int findColumn(String columnLabel) throws SQLException {
-        Iterator<ColumnMetaData> colMetaDataIt = this.columnMetaDataList.iterator();
-        while (colMetaDataIt.hasNext()) {
-            ColumnMetaData colMetaData = colMetaDataIt.next();
+        for (ColumnMetaData colMetaData : this.columnMetaDataList) {
             if (colMetaData.getColName() != null && colMetaData.getColName().equals(columnLabel)) {
                 return colMetaData.getColIndex();
             }
diff --git a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/EmptyResultSet.java b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/EmptyResultSet.java
index b6587b942d..64b4276e93 100644
--- a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/EmptyResultSet.java
+++ b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/EmptyResultSet.java
@@ -23,7 +23,7 @@ import java.util.Calendar;
 import java.util.Map;
 
 /*
- * TDengine only supports a subset of the standard SQL, thus this implemetation of the
+ * TDengine only supports a subset of the standard SQL, thus this implementation of the
  * standard JDBC API contains more or less some adjustments customized for certain
  * compatibility needs.
  */
diff --git a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBConnection.java b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBConnection.java
index 02fee74eb5..8cd8da6de4 100644
--- a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBConnection.java
+++ b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBConnection.java
@@ -20,7 +20,7 @@ import java.util.Properties;
 public class TSDBConnection extends AbstractConnection {
 
     private TSDBJNIConnector connector;
-    private TSDBDatabaseMetaData databaseMetaData;
+    private final TSDBDatabaseMetaData databaseMetaData;
     private boolean batchFetch;
 
     public Boolean getBatchFetch() {
diff --git a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBConstants.java b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBConstants.java
index e6406d2c6d..5b5128e720 100644
--- a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBConstants.java
+++ b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBConstants.java
@@ -54,10 +54,11 @@ public abstract class TSDBConstants {
     public static final int TSDB_DATA_TYPE_USMALLINT = 12;      //unsigned smallint
     public static final int TSDB_DATA_TYPE_UINT = 13;           //unsigned int
     public static final int TSDB_DATA_TYPE_UBIGINT = 14;        //unsigned bigint
+
     // nchar column max length
     public static final int maxFieldSize = 16 * 1024;
 
-    // precision for data types
+    // precision for data types, this is used for metadata
     public static final int BOOLEAN_PRECISION = 1;
     public static final int TINYINT_PRECISION = 4;
     public static final int SMALLINT_PRECISION = 6;
@@ -67,10 +68,12 @@ public abstract class TSDBConstants {
     public static final int DOUBLE_PRECISION = 22;
     public static final int TIMESTAMP_MS_PRECISION = 23;
     public static final int TIMESTAMP_US_PRECISION = 26;
-    // scale for data types
+    // scale for data types, this is used for metadata
     public static final int FLOAT_SCALE = 31;
     public static final int DOUBLE_SCALE = 31;
 
+    public static final String DEFAULT_PRECISION = "ms";
+
     public static int typeName2JdbcType(String type) {
         switch (type.toUpperCase()) {
             case "TIMESTAMP":
diff --git a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBDatabaseMetaData.java b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBDatabaseMetaData.java
index 8b7ede148e..9a5eda4cd8 100644
--- a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBDatabaseMetaData.java
+++ b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBDatabaseMetaData.java
@@ -20,8 +20,8 @@ import java.sql.SQLException;
 
 public class TSDBDatabaseMetaData extends AbstractDatabaseMetaData {
 
-    private String url;
-    private String userName;
+    private final String url;
+    private final String userName;
     private Connection conn;
 
     public TSDBDatabaseMetaData(String url, String userName) {
diff --git a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBDriver.java b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBDriver.java
index 55533bd28c..98a7d1929b 100755
--- a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBDriver.java
+++ b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBDriver.java
@@ -176,7 +176,7 @@ public class TSDBDriver extends AbstractDriver {
         int beginningOfSlashes = url.indexOf("//");
         int index = url.indexOf("?");
         if (index != -1) {
-            String paramString = url.substring(index + 1, url.length());
+            String paramString = url.substring(index + 1);
             url = url.substring(0, index);
             StringTokenizer queryParams = new StringTokenizer(paramString, "&");
             while (queryParams.hasMoreElements()) {
@@ -213,7 +213,7 @@ public class TSDBDriver extends AbstractDriver {
             url = url.substring(0, indexOfColon);
         }
 
-        if (url != null && url.length() > 0 && url.trim().length() > 0) {
+        if (url.length() > 0 && url.trim().length() > 0) {
             urlProps.setProperty(TSDBDriver.PROPERTY_KEY_HOST, url);
         }
 
@@ -233,7 +233,7 @@ public class TSDBDriver extends AbstractDriver {
         return false;
     }
 
-    public Logger getParentLogger() throws SQLFeatureNotSupportedException {
+    public Logger getParentLogger() {
         return null;
     }
 
diff --git a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBError.java b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBError.java
index 411a61eb86..da89081428 100644
--- a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBError.java
+++ b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBError.java
@@ -8,7 +8,7 @@ import java.util.HashMap;
 import java.util.Map;
 
 public class TSDBError {
-    private static Map<Integer, String> TSDBErrorMap = new HashMap<>();
+    private static final Map<Integer, String> TSDBErrorMap = new HashMap<>();
 
     static {
         TSDBErrorMap.put(TSDBErrorNumbers.ERROR_CONNECTION_CLOSED, "connection already closed");
@@ -34,9 +34,8 @@ public class TSDBError {
         TSDBErrorMap.put(TSDBErrorNumbers.ERROR_UNKNOWN_TAOS_TYPE_IN_TDENGINE, "unknown taos type in tdengine");
         TSDBErrorMap.put(TSDBErrorNumbers.ERROR_UNKNOWN_TIMESTAMP_PERCISION, "unknown timestamp precision");
 
-        /**************************************************/
         TSDBErrorMap.put(TSDBErrorNumbers.ERROR_UNKNOWN, "unknown error");
-        /**************************************************/
+
         TSDBErrorMap.put(TSDBErrorNumbers.ERROR_SUBSCRIBE_FAILED, "failed to create subscription");
         TSDBErrorMap.put(TSDBErrorNumbers.ERROR_UNSUPPORTED_ENCODING, "Unsupported encoding");
         TSDBErrorMap.put(TSDBErrorNumbers.ERROR_JNI_TDENGINE_ERROR, "internal error of database");
diff --git a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBErrorNumbers.java b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBErrorNumbers.java
index 9f0ba5afab..714162b563 100644
--- a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBErrorNumbers.java
+++ b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBErrorNumbers.java
@@ -1,6 +1,7 @@
 package com.taosdata.jdbc;
 
 import java.util.HashSet;
+import java.util.Set;
 
 public class TSDBErrorNumbers {
 
@@ -39,10 +40,9 @@ public class TSDBErrorNumbers {
     public static final int ERROR_JNI_FETCH_END = 0x2358;       // fetch to the end of resultSet
     public static final int ERROR_JNI_OUT_OF_MEMORY = 0x2359;   // JNI alloc memory failed
 
-    private static final HashSet<Integer> errorNumbers;
+    private static final Set<Integer> errorNumbers = new HashSet();
 
     static {
-        errorNumbers = new HashSet();
         errorNumbers.add(ERROR_CONNECTION_CLOSED);
         errorNumbers.add(ERROR_UNSUPPORTED_METHOD);
         errorNumbers.add(ERROR_INVALID_VARIABLE);
@@ -65,7 +65,6 @@ public class TSDBErrorNumbers {
         errorNumbers.add(ERROR_UNKNOWN_TAOS_TYPE_IN_TDENGINE);
         errorNumbers.add(ERROR_UNKNOWN_TIMESTAMP_PERCISION);
 
-        /*****************************************************/
         errorNumbers.add(ERROR_SUBSCRIBE_FAILED);
         errorNumbers.add(ERROR_UNSUPPORTED_ENCODING);
         errorNumbers.add(ERROR_JNI_TDENGINE_ERROR);
diff --git a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBJNIConnector.java b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBJNIConnector.java
index bc4d58785a..7f400fc1ee 100755
--- a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBJNIConnector.java
+++ b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBJNIConnector.java
@@ -29,14 +29,9 @@ import java.util.List;
 public class TSDBJNIConnector {
     private static volatile Boolean isInitialized = false;
 
-    private TaosInfo taosInfo = TaosInfo.getInstance();
-
-    // Connection pointer used in C
-    private long taos = TSDBConstants.JNI_NULL_POINTER;
-
-    // result set status in current connection
-    private boolean isResultsetClosed;
-
+    private final TaosInfo taosInfo = TaosInfo.getInstance();
+    private long taos = TSDBConstants.JNI_NULL_POINTER;     // Connection pointer used in C
+    private boolean isResultsetClosed;      // result set status in current connection
     private int affectedRows = -1;
 
     static {
@@ -96,11 +91,9 @@ public class TSDBJNIConnector {
 
     /**
      * Execute DML/DDL operation
-     *
-     * @throws SQLException
      */
     public long executeQuery(String sql) throws SQLException {
-        Long pSql = 0l;
+        long pSql = 0L;
         try {
             pSql = this.executeQueryImp(sql.getBytes(TaosGlobalConfig.getCharset()), this.taos);
             taosInfo.stmt_count_increment();
@@ -161,7 +154,7 @@ public class TSDBJNIConnector {
     private native long getResultSetImp(long connection, long pSql);
 
     public boolean isUpdateQuery(long pSql) {
-        return isUpdateQueryImp(this.taos, pSql) == 1 ? true : false;
+        return isUpdateQueryImp(this.taos, pSql) == 1;
     }
 
     private native long isUpdateQueryImp(long connection, long pSql);
@@ -195,7 +188,7 @@ public class TSDBJNIConnector {
      */
     public int getSchemaMetaData(long resultSet, List<ColumnMetaData> columnMetaData) {
         int ret = this.getSchemaMetaDataImp(this.taos, resultSet, columnMetaData);
-        columnMetaData.stream().forEach(column -> column.setColIndex(column.getColIndex() + 1));
+        columnMetaData.forEach(column -> column.setColIndex(column.getColIndex() + 1));
         return ret;
     }
 
@@ -218,8 +211,9 @@ public class TSDBJNIConnector {
 
     /**
      * Get Result Time Precision.
+     *
      * @return 0: ms, 1: us, 2: ns
-    */
+     */
     public int getResultTimePrecision(long sqlObj) {
         return this.getResultTimePrecisionImp(this.taos, sqlObj);
     }
@@ -228,8 +222,6 @@ public class TSDBJNIConnector {
 
     /**
      * Execute close operation from C to release connection pointer by JNI
-     *
-     * @throws SQLException
      */
     public void closeConnection() throws SQLException {
         int code = this.closeConnectionImp(this.taos);
@@ -268,8 +260,6 @@ public class TSDBJNIConnector {
 
     /**
      * Unsubscribe, close a subscription
-     *
-     * @param subscription
      */
     void unsubscribe(long subscription, boolean isKeep) {
         unsubscribeImp(subscription, isKeep);
@@ -282,13 +272,13 @@ public class TSDBJNIConnector {
      */
     public boolean validateCreateTableSql(String sql) {
         int res = validateCreateTableSqlImp(taos, sql.getBytes());
-        return res != 0 ? false : true;
+        return res == 0;
     }
 
     private native int validateCreateTableSqlImp(long connection, byte[] sqlBytes);
 
     public long prepareStmt(String sql) throws SQLException {
-        Long stmt;
+        long stmt;
         try {
             stmt = prepareStmtImp(sql.getBytes(), this.taos);
         } catch (Exception e) {
diff --git a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBPreparedStatement.java b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBPreparedStatement.java
index 1a007156e9..d9042fb729 100644
--- a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBPreparedStatement.java
+++ b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBPreparedStatement.java
@@ -62,8 +62,8 @@ public class TSDBPreparedStatement extends TSDBStatement implements PreparedStat
 
         if (parameterCnt > 1) {
             // the table name is also a parameter, so ignore it.
-            this.colData = new ArrayList<ColumnInfo>();
-            this.tableTags = new ArrayList<TableTagInfo>();
+            this.colData = new ArrayList<>();
+            this.tableTags = new ArrayList<>();
         }
     }
 
@@ -73,12 +73,16 @@ public class TSDBPreparedStatement extends TSDBStatement implements PreparedStat
     }
 
     /*
+     *
+     */
+
+    /**
      * Some of the SQLs sent by other popular frameworks or tools like Spark, contains syntax that cannot be parsed by
      * the TDengine client. Thus, some simple parsers/filters are intentionally added in this JDBC implementation in
      * order to process those supported SQLs.
      */
     private void preprocessSql() {
-        /***** For processing some of Spark SQLs*****/
+        /***For processing some of Spark SQLs*/
         // should replace it first
         this.rawSql = this.rawSql.replaceAll("or (.*) is null", "");
         this.rawSql = this.rawSql.replaceAll(" where ", " WHERE ");
@@ -125,7 +129,6 @@ public class TSDBPreparedStatement extends TSDBStatement implements PreparedStat
             }
             rawSql = rawSql.replace(matcher.group(1), tableFullName);
         }
-        /***** for inner queries *****/
     }
 
     @Override
@@ -519,12 +522,10 @@ public class TSDBPreparedStatement extends TSDBStatement implements PreparedStat
         }
     }
 
-    ;
-
     private static class TableTagInfo {
         private boolean isNull;
-        private Object value;
-        private int type;
+        private final Object value;
+        private final int type;
 
         public TableTagInfo(Object value, int type) {
             this.value = value;
@@ -538,8 +539,6 @@ public class TSDBPreparedStatement extends TSDBStatement implements PreparedStat
         }
     }
 
-    ;
-
     public void setTableName(String name) {
         this.tableName = name;
     }
@@ -627,7 +626,7 @@ public class TSDBPreparedStatement extends TSDBStatement implements PreparedStat
             this.colData.addAll(Collections.nCopies(this.parameters.length - 1 - this.tableTags.size(), null));
         }
 
-        ColumnInfo col = (ColumnInfo) this.colData.get(columnIndex);
+        ColumnInfo col = this.colData.get(columnIndex);
         if (col == null) {
             ColumnInfo p = new ColumnInfo();
             p.setType(type);
@@ -718,8 +717,7 @@ public class TSDBPreparedStatement extends TSDBStatement implements PreparedStat
             ByteBuffer isNullList = ByteBuffer.allocate(num * Integer.BYTES);
             isNullList.order(ByteOrder.LITTLE_ENDIAN);
 
-            for (int i = 0; i < num; ++i) {
-                TableTagInfo tag = this.tableTags.get(i);
+            for (TableTagInfo tag : this.tableTags) {
                 if (tag.isNull) {
                     typeList.put((byte) tag.type);
                     isNullList.putInt(1);
@@ -818,7 +816,7 @@ public class TSDBPreparedStatement extends TSDBStatement implements PreparedStat
                     typeList, lengthList, isNullList);
         }
 
-        ColumnInfo colInfo = (ColumnInfo) this.colData.get(0);
+        ColumnInfo colInfo = this.colData.get(0);
         if (colInfo == null) {
             throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_UNKNOWN, "column data not bind");
         }
@@ -954,7 +952,6 @@ public class TSDBPreparedStatement extends TSDBStatement implements PreparedStat
                     throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_UNKNOWN, "not support data types");
                 }
             }
-            ;
 
             connector.bindColumnDataArray(this.nativeStmtHandle, colDataList, lengthList, isNullList, col1.type, col1.bytes, rows, i);
         }
diff --git a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBResultSet.java b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBResultSet.java
index 59a64ad520..00a62206fc 100644
--- a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBResultSet.java
+++ b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBResultSet.java
@@ -339,11 +339,11 @@ public class TSDBResultSet extends AbstractResultSet implements ResultSet {
                 case TSDBConstants.TSDB_DATA_TYPE_SMALLINT:
                 case TSDBConstants.TSDB_DATA_TYPE_INT:
                 case TSDBConstants.TSDB_DATA_TYPE_BIGINT:
-                    res = new BigDecimal(Long.valueOf(this.rowData.getObject(columnIndex).toString()));
+                    res = new BigDecimal(Long.parseLong(this.rowData.getObject(columnIndex).toString()));
                     break;
                 case TSDBConstants.TSDB_DATA_TYPE_FLOAT:
                 case TSDBConstants.TSDB_DATA_TYPE_DOUBLE:
-                    res = new BigDecimal(Double.valueOf(this.rowData.getObject(columnIndex).toString()));
+                    res = BigDecimal.valueOf(Double.parseDouble(this.rowData.getObject(columnIndex).toString()));
                     break;
                 case TSDBConstants.TSDB_DATA_TYPE_TIMESTAMP:
                     return new BigDecimal(((Timestamp) this.rowData.getObject(columnIndex)).getTime());
diff --git a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBResultSetBlockData.java b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBResultSetBlockData.java
index 7b3be5d263..6211f61dc5 100644
--- a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBResultSetBlockData.java
+++ b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBResultSetBlockData.java
@@ -36,23 +36,20 @@ public class TSDBResultSetBlockData {
     private int rowIndex = 0;
 
     private List<ColumnMetaData> columnMetaDataList;
-    private ArrayList<Object> colData = null;
+    private ArrayList<Object> colData;
 
     public TSDBResultSetBlockData(List<ColumnMetaData> colMeta, int numOfCols) {
         this.columnMetaDataList = colMeta;
-        this.colData = new ArrayList<Object>(numOfCols);
+        this.colData = new ArrayList<>(numOfCols);
     }
 
     public TSDBResultSetBlockData() {
-        this.colData = new ArrayList<Object>();
+        this.colData = new ArrayList<>();
     }
 
     public void clear() {
         int size = this.colData.size();
-        if (this.colData != null) {
-            this.colData.clear();
-        }
-
+        this.colData.clear();
         setNumOfCols(size);
     }
 
@@ -69,7 +66,7 @@ public class TSDBResultSetBlockData {
     }
 
     public void setNumOfCols(int numOfCols) {
-        this.colData = new ArrayList<Object>(numOfCols);
+        this.colData = new ArrayList<>(numOfCols);
         this.colData.addAll(Collections.nCopies(numOfCols, null));
     }
 
@@ -166,15 +163,10 @@ public class TSDBResultSetBlockData {
         }
     }
 
-    
 
     /**
      * The original type may not be a string type, but will be converted to by
      * calling this method
-     *
-     * @param col column index
-     * @return
-     * @throws SQLException
      */
     public String getString(int col) throws SQLException {
         Object obj = get(col);
@@ -387,7 +379,7 @@ public class TSDBResultSetBlockData {
                     return null;
                 }
 
-                return (long) val;
+                return val;
             }
 
             case TSDBConstants.TSDB_DATA_TYPE_FLOAT: {
diff --git a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBResultSetMetaData.java b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBResultSetMetaData.java
index 48d4247392..6292673352 100644
--- a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBResultSetMetaData.java
+++ b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBResultSetMetaData.java
@@ -41,10 +41,7 @@ public class TSDBResultSetMetaData extends WrapperImpl implements ResultSetMetaD
     }
 
     public boolean isSearchable(int column) throws SQLException {
-        if (column == 1) {
-            return true;
-        }
-        return false;
+        return column == 1;
     }
 
     public boolean isCurrency(int column) throws SQLException {
diff --git a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBResultSetRowData.java b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBResultSetRowData.java
index e00ec1e758..b91fe88dfa 100644
--- a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBResultSetRowData.java
+++ b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBResultSetRowData.java
@@ -19,14 +19,13 @@ import com.taosdata.jdbc.utils.NullType;
 import java.math.BigDecimal;
 import java.sql.SQLException;
 import java.sql.Timestamp;
-import java.time.Instant;
 import java.util.ArrayList;
 import java.util.Collections;
 
 public class TSDBResultSetRowData {
 
     private ArrayList<Object> data;
-    private int colSize;
+    private final int colSize;
 
     public TSDBResultSetRowData(int colSize) {
         this.colSize = colSize;
@@ -390,27 +389,27 @@ public class TSDBResultSetRowData {
 
         switch (nativeType) {
             case TSDBConstants.TSDB_DATA_TYPE_UTINYINT: {
-                Byte value = new Byte(String.valueOf(obj));
+                byte value = new Byte(String.valueOf(obj));
                 if (value >= 0)
-                    return value.toString();
+                    return Byte.toString(value);
                 return Integer.toString(value & 0xff);
             }
             case TSDBConstants.TSDB_DATA_TYPE_USMALLINT: {
-                Short value = new Short(String.valueOf(obj));
+                short value = new Short(String.valueOf(obj));
                 if (value >= 0)
-                    return value.toString();
+                    return Short.toString(value);
                 return Integer.toString(value & 0xffff);
             }
             case TSDBConstants.TSDB_DATA_TYPE_UINT: {
-                Integer value = new Integer(String.valueOf(obj));
+                int value = new Integer(String.valueOf(obj));
                 if (value >= 0)
-                    return value.toString();
-                return Long.toString(value & 0xffffffffl);
+                    return Integer.toString(value);
+                return Long.toString(value & 0xffffffffL);
             }
             case TSDBConstants.TSDB_DATA_TYPE_UBIGINT: {
-                Long value = new Long(String.valueOf(obj));
+                long value = new Long(String.valueOf(obj));
                 if (value >= 0)
-                    return value.toString();
+                    return Long.toString(value);
                 long lowValue = value & 0x7fffffffffffffffL;
                 return BigDecimal.valueOf(lowValue).add(BigDecimal.valueOf(Long.MAX_VALUE)).add(BigDecimal.valueOf(1)).toString();
             }
@@ -432,25 +431,26 @@ public class TSDBResultSetRowData {
 
     /**
      * !!! this method is invoked by JNI method and the index start from 0 in C implementations
+     *
      * @param precision 0 : ms, 1 : us, 2 : ns
      */
     public void setTimestamp(int col, long ts, int precision) {
-        long milliseconds = 0;
-        int fracNanoseconds = 0;
+        long milliseconds;
+        int fracNanoseconds;
         switch (precision) {
             case 0: {
                 milliseconds = ts;
-                fracNanoseconds = (int)(ts*1_000_000%1_000_000_000);
+                fracNanoseconds = (int) (ts * 1_000_000 % 1_000_000_000);
                 break;
             }
             case 1: {
-                milliseconds = ts/1_000;
-                fracNanoseconds = (int)(ts*1_000%1_000_000_000);
+                milliseconds = ts / 1_000;
+                fracNanoseconds = (int) (ts * 1_000 % 1_000_000_000);
                 break;
             }
             case 2: {
-                milliseconds = ts/1_000_000;
-                fracNanoseconds = (int)(ts%1_000_000_000);
+                milliseconds = ts / 1_000_000;
+                fracNanoseconds = (int) (ts % 1_000_000_000);
                 break;
             }
             default: {
@@ -467,12 +467,10 @@ public class TSDBResultSetRowData {
         Object obj = data.get(col - 1);
         if (obj == null)
             return null;
-        switch (nativeType) {
-            case TSDBConstants.TSDB_DATA_TYPE_BIGINT:
-                return new Timestamp((Long) obj);
-            default:
-                return (Timestamp) obj;
+        if (nativeType == TSDBConstants.TSDB_DATA_TYPE_BIGINT) {
+            return new Timestamp((Long) obj);
         }
+        return (Timestamp) obj;
     }
 
     public Object getObject(int col) {
diff --git a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBSubscribe.java b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBSubscribe.java
index c5fd497ca3..d74f7755b2 100644
--- a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBSubscribe.java
+++ b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBSubscribe.java
@@ -47,9 +47,6 @@ public class TSDBSubscribe {
 
     /**
      * close subscription
-     *
-     * @param keepProgress
-     * @throws SQLException
      */
     public void close(boolean keepProgress) throws SQLException {
         if (this.connecter.isClosed())
diff --git a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/rs/enums/TimestampFormat.java b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/enums/TimestampFormat.java
similarity index 65%
rename from src/connector/jdbc/src/main/java/com/taosdata/jdbc/rs/enums/TimestampFormat.java
rename to src/connector/jdbc/src/main/java/com/taosdata/jdbc/enums/TimestampFormat.java
index edc429857e..5ff0774639 100644
--- a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/rs/enums/TimestampFormat.java
+++ b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/enums/TimestampFormat.java
@@ -1,4 +1,4 @@
-package com.taosdata.jdbc.rs.enums;
+package com.taosdata.jdbc.enums;
 
 public enum TimestampFormat {
     STRING,
diff --git a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/rs/RestfulConnection.java b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/rs/RestfulConnection.java
index d6a02b7e3a..12a0ab57e2 100644
--- a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/rs/RestfulConnection.java
+++ b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/rs/RestfulConnection.java
@@ -16,7 +16,7 @@ public class RestfulConnection extends AbstractConnection {
     private final String host;
     private final int port;
     private final String url;
-    private volatile String database;
+    private final String database;
     private final String token;
     /******************************************************/
     private boolean isClosed;
diff --git a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/rs/RestfulPreparedStatement.java b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/rs/RestfulPreparedStatement.java
index 16272f4289..1eaddce1d6 100644
--- a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/rs/RestfulPreparedStatement.java
+++ b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/rs/RestfulPreparedStatement.java
@@ -13,7 +13,7 @@ import java.util.Calendar;
 
 public class RestfulPreparedStatement extends RestfulStatement implements PreparedStatement {
 
-    private ParameterMetaData parameterMetaData;
+    private final ParameterMetaData parameterMetaData;
     private final String rawSql;
     private Object[] parameters;
     private boolean isPrepared;
diff --git a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/rs/RestfulResultSet.java b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/rs/RestfulResultSet.java
index 13850f0b80..d435062ef6 100644
--- a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/rs/RestfulResultSet.java
+++ b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/rs/RestfulResultSet.java
@@ -7,7 +7,7 @@ import com.google.common.primitives.Longs;
 import com.google.common.primitives.Shorts;
 import com.taosdata.jdbc.*;
 import com.taosdata.jdbc.enums.TimestampPrecision;
-import com.taosdata.jdbc.rs.enums.TimestampFormat;
+import com.taosdata.jdbc.enums.TimestampFormat;
 import com.taosdata.jdbc.utils.Utils;
 
 import java.math.BigDecimal;
@@ -17,19 +17,20 @@ import java.time.ZoneOffset;
 import java.time.format.DateTimeParseException;
 import java.util.ArrayList;
 import java.util.Calendar;
+import java.util.List;
 
 public class RestfulResultSet extends AbstractResultSet implements ResultSet {
-    private volatile boolean isClosed;
-    private int pos = -1;
 
-    private final String database;
     private final Statement statement;
     // data
-    private final ArrayList<ArrayList<Object>> resultSet = new ArrayList<>();
+    private final List<List<Object>> resultSet = new ArrayList<>();
     // meta
-    private ArrayList<String> columnNames = new ArrayList<>();
-    private ArrayList<Field> columns = new ArrayList<>();
-    private RestfulResultSetMetaData metaData;
+    private final List<String> columnNames = new ArrayList<>();
+    private final List<Field> columns = new ArrayList<>();
+    private final RestfulResultSetMetaData metaData;
+
+    private volatile boolean isClosed;
+    private int pos = -1;
 
     /**
      * 由一个result的Json构造结果集，对应执行show databases, show tables等这些语句，返回结果集，但无法获取结果集对应的meta，统一当成String处理
@@ -37,35 +38,30 @@ public class RestfulResultSet extends AbstractResultSet implements ResultSet {
      * @param resultJson: 包含data信息的结果集，有sql返回的结果集
      ***/
     public RestfulResultSet(String database, Statement statement, JSONObject resultJson) throws SQLException {
-        this.database = database;
         this.statement = statement;
 
+        // get head
+        JSONArray head = resultJson.getJSONArray("head");
         // get column metadata
         JSONArray columnMeta = resultJson.getJSONArray("column_meta");
         // get row data
         JSONArray data = resultJson.getJSONArray("data");
-        if (data == null || data.isEmpty()) {
-            columnNames.clear();
-            columns.clear();
-            this.resultSet.clear();
-            this.metaData = new RestfulResultSetMetaData(this.database, null, this);
-            return;
-        }
-        // get head
-        JSONArray head = resultJson.getJSONArray("head");
         // get rows
         Integer rows = resultJson.getInteger("rows");
+
         // parse column_meta
         if (columnMeta != null) {
             parseColumnMeta_new(columnMeta);
         } else {
             parseColumnMeta_old(head, data, rows);
         }
-        this.metaData = new RestfulResultSetMetaData(this.database, columns, this);
+        this.metaData = new RestfulResultSetMetaData(database, columns, this);
+
+        if (data == null || data.isEmpty())
+            return;
         // parse row data
-        resultSet.clear();
         for (int rowIndex = 0; rowIndex < data.size(); rowIndex++) {
-            ArrayList row = new ArrayList();
+            List<Object> row = new ArrayList();
             JSONArray jsonRow = data.getJSONArray(rowIndex);
             for (int colIndex = 0; colIndex < this.metaData.getColumnCount(); colIndex++) {
                 row.add(parseColumnData(jsonRow, colIndex, columns.get(colIndex).taos_type));
@@ -174,8 +170,8 @@ public class RestfulResultSet extends AbstractResultSet implements ResultSet {
                 //TODO: this implementation has bug if the timestamp bigger than 9999_9999_9999_9
                 if (value < 1_0000_0000_0000_0L)
                     return new Timestamp(value);
-                long epochSec = value / 1000_000l;
-                long nanoAdjustment = value % 1000_000l * 1000l;
+                long epochSec = value / 1000_000L;
+                long nanoAdjustment = value % 1000_000L * 1000L;
                 return Timestamp.from(Instant.ofEpochSecond(epochSec, nanoAdjustment));
             }
             case UTC: {
@@ -244,10 +240,7 @@ public class RestfulResultSet extends AbstractResultSet implements ResultSet {
         if (isClosed())
             throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_RESULTSET_CLOSED);
         pos++;
-        if (pos <= resultSet.size() - 1) {
-            return true;
-        }
-        return false;
+        return pos <= resultSet.size() - 1;
     }
 
     @Override
@@ -257,13 +250,6 @@ public class RestfulResultSet extends AbstractResultSet implements ResultSet {
         }
     }
 
-//    @Override
-//    public boolean wasNull() throws SQLException {
-//        if (isClosed())
-//            throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_RESULTSET_CLOSED);
-//        return resultSet.isEmpty();
-//    }
-
     @Override
     public String getString(int columnIndex) throws SQLException {
         checkAvailability(columnIndex, resultSet.get(pos).size());
@@ -288,7 +274,7 @@ public class RestfulResultSet extends AbstractResultSet implements ResultSet {
         wasNull = false;
         if (value instanceof Boolean)
             return (boolean) value;
-        return Boolean.valueOf(value.toString());
+        return Boolean.parseBoolean(value.toString());
     }
 
     @Override
@@ -443,9 +429,7 @@ public class RestfulResultSet extends AbstractResultSet implements ResultSet {
             return null;
         if (value instanceof Timestamp)
             return new Date(((Timestamp) value).getTime());
-        Date date = null;
-        date = Utils.parseDate(value.toString());
-        return date;
+        return Utils.parseDate(value.toString());
     }
 
     @Override
@@ -460,8 +444,7 @@ public class RestfulResultSet extends AbstractResultSet implements ResultSet {
         Time time = null;
         try {
             time = Utils.parseTime(value.toString());
-        } catch (DateTimeParseException e) {
-            time = null;
+        } catch (DateTimeParseException ignored) {
         }
         return time;
     }
@@ -525,9 +508,9 @@ public class RestfulResultSet extends AbstractResultSet implements ResultSet {
             return null;
 
         if (value instanceof Long || value instanceof Integer || value instanceof Short || value instanceof Byte)
-            return new BigDecimal(Long.valueOf(value.toString()));
+            return new BigDecimal(Long.parseLong(value.toString()));
         if (value instanceof Double || value instanceof Float)
-            return new BigDecimal(Double.valueOf(value.toString()));
+            return BigDecimal.valueOf(Double.parseDouble(value.toString()));
         if (value instanceof Timestamp)
             return new BigDecimal(((Timestamp) value).getTime());
         BigDecimal ret;
@@ -637,36 +620,6 @@ public class RestfulResultSet extends AbstractResultSet implements ResultSet {
         if (isClosed())
             throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_RESULTSET_CLOSED);
 
-//        if (this.resultSet.size() == 0)
-//            return false;
-//
-//        if (row == 0) {
-//            beforeFirst();
-//            return false;
-//        } else if (row == 1) {
-//            return first();
-//        } else if (row == -1) {
-//            return last();
-//        } else if (row > this.resultSet.size()) {
-//            afterLast();
-//            return false;
-//        } else {
-//            if (row < 0) {
-//                // adjust to reflect after end of result set
-//                int newRowPosition = this.resultSet.size() + row + 1;
-//                if (newRowPosition <= 0) {
-//                    beforeFirst();
-//                    return false;
-//                } else {
-//                    return absolute(newRowPosition);
-//                }
-//            } else {
-//                row--; // adjust for index difference
-//                this.pos = row;
-//                return true;
-//            }
-//        }
-
         throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_UNSUPPORTED_METHOD);
     }
 
@@ -710,5 +663,4 @@ public class RestfulResultSet extends AbstractResultSet implements ResultSet {
         return isClosed;
     }
 
-
-}
+}
\ No newline at end of file
diff --git a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/rs/RestfulResultSetMetaData.java b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/rs/RestfulResultSetMetaData.java
index a185abb709..148f77974f 100644
--- a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/rs/RestfulResultSetMetaData.java
+++ b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/rs/RestfulResultSetMetaData.java
@@ -7,20 +7,17 @@ import java.sql.ResultSetMetaData;
 import java.sql.SQLException;
 import java.sql.Timestamp;
 import java.sql.Types;
-import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 
 public class RestfulResultSetMetaData extends WrapperImpl implements ResultSetMetaData {
 
     private final String database;
-    private List<RestfulResultSet.Field> fields;
-    private final RestfulResultSet resultSet;
+    private final List<RestfulResultSet.Field> fields;
 
-    public RestfulResultSetMetaData(String database, ArrayList<RestfulResultSet.Field> fields, RestfulResultSet resultSet) {
+    public RestfulResultSetMetaData(String database, List<RestfulResultSet.Field> fields, RestfulResultSet resultSet) {
         this.database = database;
         this.fields = fields == null ? Collections.emptyList() : fields;
-        this.resultSet = resultSet;
     }
 
     public List<RestfulResultSet.Field> getFields() {
@@ -141,8 +138,8 @@ public class RestfulResultSetMetaData extends WrapperImpl implements ResultSetMe
 
     @Override
     public String getColumnTypeName(int column) throws SQLException {
-        int taos_type = fields.get(column - 1).taos_type;
-        return TSDBConstants.taosType2JdbcTypeName(taos_type);
+        int taosType = fields.get(column - 1).taos_type;
+        return TSDBConstants.taosType2JdbcTypeName(taosType);
     }
 
     @Override
diff --git a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/rs/RestfulStatement.java b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/rs/RestfulStatement.java
index e9d193f6b4..f8acd8f061 100644
--- a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/rs/RestfulStatement.java
+++ b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/rs/RestfulStatement.java
@@ -35,10 +35,6 @@ public class RestfulStatement extends AbstractStatement {
         if (!SqlSyntaxValidator.isValidForExecuteQuery(sql))
             throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_INVALID_FOR_EXECUTE_QUERY, "not a valid sql for executeQuery: " + sql);
 
-        if (SqlSyntaxValidator.isDatabaseUnspecifiedQuery(sql)) {
-            return executeOneQuery(sql);
-        }
-
         return executeOneQuery(sql);
     }
 
@@ -50,9 +46,6 @@ public class RestfulStatement extends AbstractStatement {
             throw TSDBError.createSQLException(TSDBErrorNumbers.ERROR_INVALID_FOR_EXECUTE_UPDATE, "not a valid sql for executeUpdate: " + sql);
 
         final String url = "http://" + conn.getHost() + ":" + conn.getPort() + "/rest/sql";
-        if (SqlSyntaxValidator.isDatabaseUnspecifiedUpdate(sql)) {
-            return executeOneUpdate(url, sql);
-        }
 
         return executeOneUpdate(url, sql);
     }
diff --git a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/utils/HttpClientPoolUtil.java b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/utils/HttpClientPoolUtil.java
index ff27bdbdad..715b051b74 100644
--- a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/utils/HttpClientPoolUtil.java
+++ b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/utils/HttpClientPoolUtil.java
@@ -27,19 +27,18 @@ public class HttpClientPoolUtil {
     private static final int DEFAULT_MAX_TOTAL = 1000;
     private static final int DEFAULT_HTTP_KEEP_TIME = 15000;
 
-    private static PoolingHttpClientConnectionManager connectionManager;
     private static CloseableHttpClient httpClient;
 
     private static synchronized void initPools() {
         if (httpClient == null) {
-            connectionManager = new PoolingHttpClientConnectionManager();
+            PoolingHttpClientConnectionManager connectionManager = new PoolingHttpClientConnectionManager();
             connectionManager.setDefaultMaxPerRoute(DEFAULT_MAX_PER_ROUTE);
             connectionManager.setMaxTotal(DEFAULT_MAX_TOTAL);
             httpClient = HttpClients.custom().setKeepAliveStrategy(DEFAULT_KEEP_ALIVE_STRATEGY).setConnectionManager(connectionManager).build();
         }
     }
 
-    private static ConnectionKeepAliveStrategy DEFAULT_KEEP_ALIVE_STRATEGY = (response, context) -> {
+    private static final ConnectionKeepAliveStrategy DEFAULT_KEEP_ALIVE_STRATEGY = (response, context) -> {
         HeaderElementIterator it = new BasicHeaderElementIterator(response.headerIterator(HTTP.CONN_KEEP_ALIVE));
         int keepTime = DEFAULT_HTTP_KEEP_TIME * 1000;
         while (it.hasNext()) {
diff --git a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/utils/SqlSyntaxValidator.java b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/utils/SqlSyntaxValidator.java
index 251ca2af01..15faa41a27 100644
--- a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/utils/SqlSyntaxValidator.java
+++ b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/utils/SqlSyntaxValidator.java
@@ -14,10 +14,6 @@
  *****************************************************************************/
 package com.taosdata.jdbc.utils;
 
-import com.taosdata.jdbc.TSDBConnection;
-
-import java.sql.Connection;
-
 public class SqlSyntaxValidator {
 
     private static final String[] SQL = {"select", "insert", "import", "create", "use", "alter", "drop", "set", "show", "describe"};
@@ -26,12 +22,6 @@ public class SqlSyntaxValidator {
 
     private static final String[] databaseUnspecifiedShow = {"databases", "dnodes", "mnodes", "variables"};
 
-    private TSDBConnection tsdbConnection;
-
-    public SqlSyntaxValidator(Connection connection) {
-        this.tsdbConnection = (TSDBConnection) connection;
-    }
-
     public static boolean isValidForExecuteUpdate(String sql) {
         for (String prefix : updateSQL) {
             if (sql.trim().toLowerCase().startsWith(prefix))
diff --git a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/utils/Utils.java b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/utils/Utils.java
index 4c92d27a28..e3179bd317 100644
--- a/src/connector/jdbc/src/main/java/com/taosdata/jdbc/utils/Utils.java
+++ b/src/connector/jdbc/src/main/java/com/taosdata/jdbc/utils/Utils.java
@@ -6,6 +6,7 @@ import com.google.common.collect.TreeRangeSet;
 import com.taosdata.jdbc.enums.TimestampPrecision;
 
 import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
 import java.sql.Date;
 import java.sql.Time;
 import java.sql.Timestamp;
@@ -160,7 +161,7 @@ public class Utils {
             String paraStr;
             if (para != null) {
                 if (para instanceof byte[]) {
-                    paraStr = new String((byte[]) para, Charset.forName("UTF-8"));
+                    paraStr = new String((byte[]) para, StandardCharsets.UTF_8);
                 } else {
                     paraStr = para.toString();
                 }
diff --git a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/StatementTest.java b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/StatementTest.java
deleted file mode 100644
index 73ceafa729..0000000000
--- a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/StatementTest.java
+++ /dev/null
@@ -1,108 +0,0 @@
-package com.taosdata.jdbc;
-
-import org.junit.AfterClass;
-import org.junit.Assert;
-import org.junit.BeforeClass;
-import org.junit.Test;
-
-import java.sql.*;
-import java.util.Properties;
-
-public class StatementTest {
-    static Connection connection = null;
-    static Statement statement = null;
-    static String dbName = "test";
-    static String tName = "t0";
-    static String host = "localhost";
-
-    @BeforeClass
-    public static void createConnection() throws SQLException {
-        try {
-            Class.forName("com.taosdata.jdbc.TSDBDriver");
-            Properties properties = new Properties();
-            properties.setProperty(TSDBDriver.PROPERTY_KEY_CHARSET, "UTF-8");
-            properties.setProperty(TSDBDriver.PROPERTY_KEY_LOCALE, "en_US.UTF-8");
-            properties.setProperty(TSDBDriver.PROPERTY_KEY_TIME_ZONE, "UTC-8");
-            connection = DriverManager.getConnection("jdbc:TAOS://" + host + ":0/?user=root&password=taosdata", properties);
-            statement = connection.createStatement();
-            statement.executeUpdate("drop database if exists " + dbName);
-
-        } catch (ClassNotFoundException e) {
-            return;
-        }
-    }
-
-    @Test
-    public void testCase() {
-        try {
-            ResultSet rs = statement.executeQuery("show databases");
-            ResultSetMetaData metaData = rs.getMetaData();
-            while (rs.next()) {
-                for (int i = 1; i <= metaData.getColumnCount(); i++) {
-                    System.out.print(metaData.getColumnLabel(i) + ":" + rs.getString(i) + "\t");
-                }
-                System.out.println();
-            }
-        } catch (SQLException e) {
-            e.printStackTrace();
-        }
-    }
-
-    @Test
-    public void createTableAndQuery() throws SQLException {
-        long ts = System.currentTimeMillis();
-
-        statement.executeUpdate("create database if not exists " + dbName);
-        statement.executeUpdate("create table if not exists " + dbName + "." + tName + "(ts timestamp, k1 int)");
-        statement.executeUpdate("insert into " + dbName + "." + tName + " values (" + ts + ", 1)");
-        statement.execute("select * from " + dbName + "." + tName);
-        ResultSet resultSet = statement.getResultSet();
-        Assert.assertNotNull(resultSet);
-
-        boolean isClosed = statement.isClosed();
-        Assert.assertEquals(false, isClosed);
-    }
-
-    @Test(expected = SQLException.class)
-    public void testUnsupport() throws SQLException {
-        Assert.assertNotNull(statement.unwrap(TSDBStatement.class));
-        Assert.assertTrue(statement.isWrapperFor(TSDBStatement.class));
-
-        statement.getMaxFieldSize();
-        statement.setMaxFieldSize(0);
-        statement.setEscapeProcessing(true);
-        statement.cancel();
-        statement.getWarnings();
-        statement.clearWarnings();
-        statement.setCursorName(null);
-        statement.getMoreResults();
-        statement.setFetchDirection(0);
-        statement.getFetchDirection();
-        statement.getResultSetConcurrency();
-        statement.getResultSetType();
-        statement.getConnection();
-        statement.getMoreResults();
-        statement.getGeneratedKeys();
-        statement.executeUpdate(null, 0);
-        statement.executeUpdate(null, new int[]{0});
-        statement.executeUpdate(null, new String[]{"str1", "str2"});
-        statement.getResultSetHoldability();
-        statement.setPoolable(true);
-        statement.isPoolable();
-        statement.closeOnCompletion();
-        statement.isCloseOnCompletion();
-    }
-
-    @AfterClass
-    public static void close() {
-        try {
-            statement.execute("drop database if exists " + dbName);
-            if (statement != null)
-                statement.close();
-            if (connection != null)
-                connection.close();
-        } catch (SQLException e) {
-            e.printStackTrace();
-        }
-    }
-}
diff --git a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/TSDBConnectionTest.java b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/TSDBConnectionTest.java
index dc6d0d322a..30c6d99a40 100644
--- a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/TSDBConnectionTest.java
+++ b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/TSDBConnectionTest.java
@@ -380,14 +380,15 @@ public class TSDBConnectionTest {
         conn.abort(null);
     }
 
-    @Test(expected = SQLFeatureNotSupportedException.class)
+    @Test
     public void setNetworkTimeout() throws SQLException {
         conn.setNetworkTimeout(null, 1000);
     }
 
-    @Test(expected = SQLFeatureNotSupportedException.class)
+    @Test
     public void getNetworkTimeout() throws SQLException {
-        conn.getNetworkTimeout();
+        int networkTimeout = conn.getNetworkTimeout();
+        Assert.assertEquals(0, networkTimeout);
     }
 
     @Test
diff --git a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/TSDBStatementTest.java b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/TSDBStatementTest.java
index 51535bc886..c1dfa42511 100644
--- a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/TSDBStatementTest.java
+++ b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/TSDBStatementTest.java
@@ -14,24 +14,6 @@ public class TSDBStatementTest {
     private static Connection conn;
     private static Statement stmt;
 
-    @Test
-    public void executeQuery() {
-        try {
-            ResultSet rs = stmt.executeQuery("show databases");
-            Assert.assertNotNull(rs);
-            ResultSetMetaData meta = rs.getMetaData();
-            while (rs.next()) {
-                for (int i = 1; i <= meta.getColumnCount(); i++) {
-                    System.out.print(meta.getColumnLabel(i) + ": " + rs.getString(i) + "\t");
-                }
-                System.out.println();
-            }
-            rs.close();
-        } catch (SQLException e) {
-            e.printStackTrace();
-        }
-    }
-
     @Test
     public void executeUpdate() {
         final String dbName = ("test_" + UUID.randomUUID()).replace("-", "_").substring(0, 32);
@@ -173,10 +155,6 @@ public class TSDBStatementTest {
             Assert.assertEquals(3, meta.getColumnCount());
             int count = 0;
             while (rs.next()) {
-                for (int i = 1; i <= meta.getColumnCount(); i++) {
-                    System.out.print(meta.getColumnLabel(i) + ": " + rs.getString(i) + "\t");
-                }
-                System.out.println();
                 count++;
             }
             Assert.assertEquals(1, count);
diff --git a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/AppMemoryLeakTest.java b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/AppMemoryLeakTest.java
index 19bc5f713f..4f37183e71 100644
--- a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/AppMemoryLeakTest.java
+++ b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/AppMemoryLeakTest.java
@@ -1,5 +1,6 @@
 package com.taosdata.jdbc.cases;
 
+import org.junit.Assert;
 import org.junit.Test;
 
 import java.sql.Connection;
@@ -12,21 +13,19 @@ public class AppMemoryLeakTest {
     @Test(expected = SQLException.class)
     public void testCreateTooManyConnection() throws ClassNotFoundException, SQLException {
         Class.forName("com.taosdata.jdbc.TSDBDriver");
-        int conCnt = 0;
         while (true) {
             Connection conn = DriverManager.getConnection("jdbc:TAOS://localhost:6030/?user=root&password=taosdata");
-            System.out.println(conCnt++ + " : " + conn);
+            Assert.assertNotNull(conn);
         }
     }
 
     @Test(expected = Exception.class)
     public void testCreateTooManyStatement() throws ClassNotFoundException, SQLException {
         Class.forName("com.taosdata.jdbc.TSDBDriver");
-        int stmtCnt = 0;
         Connection conn = DriverManager.getConnection("jdbc:TAOS://localhost:6030/?user=root&password=taosdata");
         while (true) {
             Statement stmt = conn.createStatement();
-            System.out.println(++stmtCnt + " : " + stmt);
+            Assert.assertNotNull(stmt);
         }
     }
 
diff --git a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/rs/AuthenticationTest.java b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/AuthenticationTest.java
similarity index 98%
rename from src/connector/jdbc/src/test/java/com/taosdata/jdbc/rs/AuthenticationTest.java
rename to src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/AuthenticationTest.java
index a6fb6cfda0..6702de9bdb 100644
--- a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/rs/AuthenticationTest.java
+++ b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/AuthenticationTest.java
@@ -1,4 +1,4 @@
-package com.taosdata.jdbc.rs;
+package com.taosdata.jdbc.cases;
 
 import org.junit.Before;
 import org.junit.Test;
diff --git a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/BatchInsertTest.java b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/BatchInsertTest.java
index e2541e8109..e175d6d114 100644
--- a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/BatchInsertTest.java
+++ b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/BatchInsertTest.java
@@ -60,7 +60,6 @@ public class BatchInsertTest {
             final int index = i;
             executorService.execute(() -> {
                 try {
-                    long startTime = System.currentTimeMillis();
                     Statement statement = connection.createStatement(); // get statement
                     StringBuilder sb = new StringBuilder();
                     sb.append("INSERT INTO " + tablePrefix + index + " VALUES");
@@ -73,8 +72,6 @@ public class BatchInsertTest {
                     }
                     statement.addBatch(sb.toString());
                     statement.executeBatch();
-                    long endTime = System.currentTimeMillis();
-                    System.out.println("Thread " + index + " takes " + (endTime - startTime) + " microseconds");
                     connection.commit();
                     statement.close();
                 } catch (Exception e) {
diff --git a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/ConnectMultiTaosdByRestfulWithDifferentTokenTest.java b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/ConnectMultiTaosdByRestfulWithDifferentTokenTest.java
index 7f2d367dce..31893527af 100644
--- a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/ConnectMultiTaosdByRestfulWithDifferentTokenTest.java
+++ b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/ConnectMultiTaosdByRestfulWithDifferentTokenTest.java
@@ -31,9 +31,6 @@ public class ConnectMultiTaosdByRestfulWithDifferentTokenTest {
             ResultSet rs = stmt.executeQuery("select server_status()");
             ResultSetMetaData meta = rs.getMetaData();
             while (rs.next()) {
-                for (int i = 1; i <= meta.getColumnCount(); i++) {
-                    System.out.println(meta.getColumnLabel(i) + ": " + rs.getString(i));
-                }
             }
         } catch (SQLException e) {
             e.printStackTrace();
diff --git a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/DatetimeBefore1970Test.java b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/DatetimeBefore1970Test.java
index f97e555ad1..14c7698548 100644
--- a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/DatetimeBefore1970Test.java
+++ b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/DatetimeBefore1970Test.java
@@ -1,64 +1,76 @@
 package com.taosdata.jdbc.cases;
 
 import com.taosdata.jdbc.utils.TimestampUtil;
-import org.junit.AfterClass;
-import org.junit.BeforeClass;
-import org.junit.Test;
+import org.junit.*;
 
 import java.sql.*;
 
 public class DatetimeBefore1970Test {
 
-    private static Connection conn;
+    private static final String host = "127.0.0.1";
+    private Connection conn;
 
     @Test
     public void test() {
         try (Statement stmt = conn.createStatement()) {
+            // given
             stmt.executeUpdate("insert into weather(ts) values('1969-12-31 23:59:59.999')");
             stmt.executeUpdate("insert into weather(ts) values('1970-01-01 00:00:00.000')");
             stmt.executeUpdate("insert into weather(ts) values('1970-01-01 08:00:00.000')");
             stmt.executeUpdate("insert into weather(ts) values('1970-01-01 07:59:59.999')");
+            ResultSet rs = stmt.executeQuery("select * from weather order by ts asc");
+            ResultSetMetaData metaData = rs.getMetaData();
+            Assert.assertEquals(2, metaData.getColumnCount());
+
+            // when
+            rs.next();
+            // then
+            Timestamp ts = rs.getTimestamp("ts");
+            Assert.assertEquals("1969-12-31 23:59:59.999", TimestampUtil.longToDatetime(ts.getTime()));
+
+            // when
+            rs.next();
+            // then
+            ts = rs.getTimestamp("ts");
+            Assert.assertEquals("1970-01-01 00:00:00.000", TimestampUtil.longToDatetime(ts.getTime()));
+
+            // when
+            rs.next();
+            // then
+            ts = rs.getTimestamp("ts");
+            Assert.assertEquals("1970-01-01 08:00:00.000", TimestampUtil.longToDatetime(ts.getTime()));
+
+            // when
+            rs.next();
+            // then
+            ts = rs.getTimestamp("ts");
+            Assert.assertEquals("1970-01-01 07:59:59.999", TimestampUtil.longToDatetime(ts.getTime()));
 
-            ResultSet rs = stmt.executeQuery("select * from weather");
-            while (rs.next()) {
-                Timestamp ts = rs.getTimestamp("ts");
-                System.out.println("long: " + ts.getTime() + ", string: " + TimestampUtil.longToDatetime(ts.getTime()));
-            }
         } catch (SQLException e) {
             e.printStackTrace();
         }
     }
 
-    public static void main(String[] args) {
-        System.out.println("timestamp: " + Long.MAX_VALUE + ", string: " + TimestampUtil.longToDatetime(Long.MAX_VALUE));
-        System.out.println("timestamp: " + Long.MIN_VALUE + ", string: " + TimestampUtil.longToDatetime(Long.MIN_VALUE));
-        System.out.println("timestamp: " + 0 + ", string: " + TimestampUtil.longToDatetime(0));
-        System.out.println("timestamp: " + -1 + ", string: " + TimestampUtil.longToDatetime(-1));
-        String datetime = "1970-01-01 00:00:00.000";
-        System.out.println("timestamp: " + TimestampUtil.datetimeToLong(datetime) + ", string: " + datetime);
-        datetime = "1969-12-31 23:59:59.999";
-        System.out.println("timestamp: " + TimestampUtil.datetimeToLong(datetime) + ", string: " + datetime);
-    }
-
-    @BeforeClass
-    public static void beforeClass() {
+    @Before
+    public void before() {
         try {
-            Class.forName("com.taosdata.jdbc.TSDBDriver");
-            conn = DriverManager.getConnection("jdbc:TAOS://127.0.0.1:6030/?user=root&password=taosdata");
+            conn = DriverManager.getConnection("jdbc:TAOS://" + host + ":6030/?user=root&password=taosdata");
             Statement stmt = conn.createStatement();
             stmt.execute("drop database if exists test_timestamp");
             stmt.execute("create database if not exists test_timestamp keep 36500");
             stmt.execute("use test_timestamp");
             stmt.execute("create table weather(ts timestamp,f1 float)");
             stmt.close();
-        } catch (ClassNotFoundException | SQLException e) {
+        } catch (SQLException e) {
             e.printStackTrace();
         }
     }
 
-    @AfterClass
-    public static void afterClass() {
+    @After
+    public void after() {
         try {
+            Statement stmt = conn.createStatement();
+            stmt.execute("drop database if exists test_timestamp");
             if (conn != null)
                 conn.close();
         } catch (SQLException e) {
diff --git a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/ImportTest.java b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/ImportTest.java
index d7603312a0..bc11c7f34e 100644
--- a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/ImportTest.java
+++ b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/ImportTest.java
@@ -20,7 +20,6 @@ public class ImportTest {
     @BeforeClass
     public static void before() {
         try {
-            Class.forName("com.taosdata.jdbc.TSDBDriver");
             Properties properties = new Properties();
             properties.setProperty(TSDBDriver.PROPERTY_KEY_CHARSET, "UTF-8");
             properties.setProperty(TSDBDriver.PROPERTY_KEY_LOCALE, "en_US.UTF-8");
@@ -33,8 +32,6 @@ public class ImportTest {
             stmt.close();
 
             ts = System.currentTimeMillis();
-        } catch (ClassNotFoundException e) {
-            e.printStackTrace();
         } catch (SQLException e) {
             e.printStackTrace();
         }
@@ -47,7 +44,6 @@ public class ImportTest {
             for (int i = 0; i < 50; i++) {
                 ts++;
                 int row = stmt.executeUpdate("import into " + dbName + "." + tName + " values (" + ts + ", " + (100 + i) + ", " + i + ")");
-                System.out.println("import into " + dbName + "." + tName + " values (" + ts + ", " + (100 + i) + ", " + i + ")\t" + row);
                 assertEquals(1, row);
             }
         }
@@ -84,7 +80,6 @@ public class ImportTest {
                 long t = (++ts) + a;
                 sqlBuilder.append("(").append(t).append(",").append((100 + i)).append(",").append(i).append(") ");
             }
-            System.out.println(sqlBuilder.toString());
             int rows = stmt.executeUpdate(sqlBuilder.toString());
             assertEquals(50, rows);
         } catch (SQLException e) {
diff --git a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/MicroSecondPrecisionJNITest.java b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/MicroSecondPrecisionJNITest.java
index 54e4273ea3..eb8f134227 100644
--- a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/MicroSecondPrecisionJNITest.java
+++ b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/MicroSecondPrecisionJNITest.java
@@ -41,7 +41,6 @@ public class MicroSecondPrecisionJNITest {
             rs.next();
 
             Timestamp timestamp = rs.getTimestamp(1);
-            System.out.println(timestamp);
             long ts = timestamp.getTime();
             Assert.assertEquals(timestamp1, ts);
             int nanos = timestamp.getNanos();
diff --git a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/MultiThreadsWithSameStatmentTest.java b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/MultiThreadsWithSameStatementTest.java
similarity index 84%
rename from src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/MultiThreadsWithSameStatmentTest.java
rename to src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/MultiThreadsWithSameStatementTest.java
index 5cb76cc0cb..da6853d2fa 100644
--- a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/MultiThreadsWithSameStatmentTest.java
+++ b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/MultiThreadsWithSameStatementTest.java
@@ -7,7 +7,7 @@ import org.junit.Test;
 import java.sql.*;
 import java.util.concurrent.TimeUnit;
 
-public class MultiThreadsWithSameStatmentTest {
+public class MultiThreadsWithSameStatementTest {
 
 
     private class Service {
@@ -16,12 +16,11 @@ public class MultiThreadsWithSameStatmentTest {
 
         public Service() {
             try {
-                Class.forName("com.taosdata.jdbc.TSDBDriver");
                 conn = DriverManager.getConnection("jdbc:TAOS://localhost:6030/?user=root&password=taosdata");
                 stmt = conn.createStatement();
                 stmt.execute("create database if not exists jdbctest");
                 stmt.executeUpdate("create table if not exists jdbctest.weather (ts timestamp, f1 int)");
-            } catch (ClassNotFoundException | SQLException e) {
+            } catch (SQLException e) {
                 e.printStackTrace();
             }
         }
@@ -48,10 +47,6 @@ public class MultiThreadsWithSameStatmentTest {
                 ResultSet resultSet = service.stmt.executeQuery("select * from jdbctest.weather");
                 while (resultSet.next()) {
                     ResultSetMetaData metaData = resultSet.getMetaData();
-                    for (int i = 1; i <= metaData.getColumnCount(); i++) {
-                        System.out.print(metaData.getColumnLabel(i) + ": " + resultSet.getString(i));
-                    }
-                    System.out.println();
                 }
                 resultSet.close();
                 service.release();
diff --git a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/NullValueInResultSetJNITest.java b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/NullValueInResultSetJNITest.java
index 076125a752..ae0241bf31 100644
--- a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/NullValueInResultSetJNITest.java
+++ b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/NullValueInResultSetJNITest.java
@@ -17,11 +17,6 @@ public class NullValueInResultSetJNITest {
             ResultSet rs = stmt.executeQuery("select * from weather");
             ResultSetMetaData meta = rs.getMetaData();
             while (rs.next()) {
-                for (int i = 1; i <= meta.getColumnCount(); i++) {
-                    Object value = rs.getObject(i);
-                    System.out.print(meta.getColumnLabel(i) + ": " + value + "\t");
-                }
-                System.out.println();
             }
 
         } catch (SQLException e) {
diff --git a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/NullValueInResultSetRestfulTest.java b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/NullValueInResultSetRestfulTest.java
index ea6e36ec1d..7fbb30a524 100644
--- a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/NullValueInResultSetRestfulTest.java
+++ b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/NullValueInResultSetRestfulTest.java
@@ -19,9 +19,7 @@ public class NullValueInResultSetRestfulTest {
             while (rs.next()) {
                 for (int i = 1; i <= meta.getColumnCount(); i++) {
                     Object value = rs.getObject(i);
-                    System.out.print(meta.getColumnLabel(i) + ": " + value + "\t");
                 }
-                System.out.println();
             }
 
         } catch (SQLException e) {
diff --git a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/QueryDataTest.java b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/QueryDataTest.java
index d0ba113b7a..535e56f7d7 100644
--- a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/QueryDataTest.java
+++ b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/QueryDataTest.java
@@ -21,7 +21,6 @@ public class QueryDataTest {
     @Before
     public void createDatabase() {
         try {
-            Class.forName("com.taosdata.jdbc.TSDBDriver");
             Properties properties = new Properties();
             properties.setProperty(TSDBDriver.PROPERTY_KEY_CHARSET, "UTF-8");
             properties.setProperty(TSDBDriver.PROPERTY_KEY_LOCALE, "en_US.UTF-8");
@@ -36,7 +35,7 @@ public class QueryDataTest {
             String createTableSql = "create table " + stbName + "(ts timestamp, name binary(64))";
             statement.executeUpdate(createTableSql);
 
-        } catch (ClassNotFoundException | SQLException e) {
+        } catch (SQLException e) {
             return;
         }
     }
@@ -44,7 +43,6 @@ public class QueryDataTest {
     @Test
     public void testQueryBinaryData() throws SQLException {
         String insertSql = "insert into " + stbName + " values(now, 'taosdata')";
-        System.out.println(insertSql);
         statement.executeUpdate(insertSql);
 
         String querySql = "select * from " + stbName;
@@ -52,7 +50,6 @@ public class QueryDataTest {
 
         while (rs.next()) {
             String name = rs.getString(2);
-            System.out.println("name = " + name);
             assertEquals("taosdata", name);
         }
         rs.close();
diff --git a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/ResultSetMetaShouldNotBeNullRestfulTest.java b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/ResultSetMetaShouldNotBeNullRestfulTest.java
index f6d6bb2556..be27b13507 100644
--- a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/ResultSetMetaShouldNotBeNullRestfulTest.java
+++ b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/ResultSetMetaShouldNotBeNullRestfulTest.java
@@ -31,7 +31,7 @@ public class ResultSetMetaShouldNotBeNullRestfulTest {
 
         // then
         Assert.assertNotNull(metaData);
-        Assert.assertEquals(0, columnCount);
+        Assert.assertEquals(2, columnCount);
     }
 
     @Test
@@ -53,7 +53,7 @@ public class ResultSetMetaShouldNotBeNullRestfulTest {
         // then
         Assert.assertEquals(true, execute);
         Assert.assertNotNull(metaData);
-        Assert.assertEquals(0, columnCount);
+        Assert.assertEquals(2, columnCount);
     }
 
     @Before
diff --git a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/SelectTest.java b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/SelectTest.java
index 38c8cbb98c..0022ceaf21 100644
--- a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/SelectTest.java
+++ b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/SelectTest.java
@@ -19,7 +19,6 @@ public class SelectTest {
     @Before
     public void createDatabaseAndTable() {
         try {
-            Class.forName("com.taosdata.jdbc.TSDBDriver");
             Properties properties = new Properties();
             properties.setProperty(TSDBDriver.PROPERTY_KEY_CHARSET, "UTF-8");
             properties.setProperty(TSDBDriver.PROPERTY_KEY_LOCALE, "en_US.UTF-8");
@@ -31,8 +30,6 @@ public class SelectTest {
             stmt.execute("create database if not exists " + dbName);
             stmt.execute("create table if not exists " + dbName + "." + tName + " (ts timestamp, k int, v int)");
             stmt.close();
-        } catch (ClassNotFoundException e) {
-            return;
         } catch (SQLException e) {
             e.printStackTrace();
         }
@@ -47,7 +44,6 @@ public class SelectTest {
             for (int i = 0; i < 50; i++) {
                 ts++;
                 int row = stmt.executeUpdate("insert into " + dbName + "." + tName + " values (" + ts + ", " + (100 + i) + ", " + i + ")");
-                System.out.println("insert into " + dbName + "." + tName + " values (" + ts + ", " + (100 + i) + ", " + i + ")\t" + row);
                 assertEquals(1, row);
             }
 
diff --git a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/StableTest.java b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/StableTest.java
index 4575cb73a0..332c171c38 100644
--- a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/StableTest.java
+++ b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/cases/StableTest.java
@@ -23,7 +23,6 @@ public class StableTest {
     @BeforeClass
     public static void createDatabase() {
         try {
-            Class.forName("com.taosdata.jdbc.TSDBDriver");
             Properties properties = new Properties();
             properties.setProperty(TSDBDriver.PROPERTY_KEY_CHARSET, "UTF-8");
             properties.setProperty(TSDBDriver.PROPERTY_KEY_LOCALE, "en_US.UTF-8");
@@ -34,8 +33,6 @@ public class StableTest {
             statement.execute("create database if not exists " + dbName);
             statement.execute("use " + dbName);
             statement.close();
-        } catch (ClassNotFoundException e) {
-            return;
         } catch (SQLException e) {
             e.printStackTrace();
         }
@@ -68,9 +65,6 @@ public class StableTest {
             String sql = "describe " + stbName;
             ResultSet rs = stmt.executeQuery(sql);
             while (rs.next()) {
-                for (int i = 1; i <= rs.getMetaData().getColumnCount(); i++) {
-                    System.out.println(i + ":" + rs.getString(i));
-                }
                 num++;
             }
             rs.close();
@@ -86,9 +80,6 @@ public class StableTest {
         try (Statement stmt = connection.createStatement()) {
             ResultSet rs = stmt.executeQuery("describe t1");
             while (rs.next()) {
-                for (int i = 1; i <= rs.getMetaData().getColumnCount(); i++) {
-                    System.out.printf("%d: %s\n", i, rs.getString(i));
-                }
                 num++;
             }
             rs.close();
diff --git a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/rs/RestfulDriverTest.java b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/rs/RestfulDriverTest.java
index e239aa068b..c2f732c869 100644
--- a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/rs/RestfulDriverTest.java
+++ b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/rs/RestfulDriverTest.java
@@ -8,11 +8,6 @@ import java.sql.*;
 public class RestfulDriverTest {
     private static final String host = "127.0.0.1";
 
-    @Test
-    public void connect() {
-
-    }
-
     @Test
     public void acceptsURL() throws SQLException {
         Driver driver = new RestfulDriver();
@@ -27,9 +22,7 @@ public class RestfulDriverTest {
         Driver driver = new RestfulDriver();
         final String url = "";
         DriverPropertyInfo[] propertyInfo = driver.getPropertyInfo(url, null);
-        for (DriverPropertyInfo prop : propertyInfo) {
-            System.out.println(prop);
-        }
+        Assert.assertNotNull(propertyInfo);
     }
 
     @Test
diff --git a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/rs/RestfulJDBCTest.java b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/rs/RestfulJDBCTest.java
index c8bb69d827..b07dae8003 100644
--- a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/rs/RestfulJDBCTest.java
+++ b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/rs/RestfulJDBCTest.java
@@ -10,132 +10,151 @@ import java.util.Random;
 public class RestfulJDBCTest {
 
     private static final String host = "127.0.0.1";
-    private static Connection connection;
-    private Random random = new Random(System.currentTimeMillis());
+    private final Random random = new Random(System.currentTimeMillis());
+    private Connection connection;
 
-    /**
-     * select * from log.log
-     **/
     @Test
     public void testCase001() {
-        try {
-            Statement statement = connection.createStatement();
-            ResultSet resultSet = statement.executeQuery("select * from log.log");
-            ResultSetMetaData metaData = resultSet.getMetaData();
-            while (resultSet.next()) {
-                for (int i = 1; i <= metaData.getColumnCount(); i++) {
-                    String column = metaData.getColumnLabel(i);
-                    String value = resultSet.getString(i);
-                    System.out.print(column + ":" + value + "\t");
-                }
-                System.out.println();
-            }
-            statement.close();
-        } catch (SQLException e) {
-            e.printStackTrace();
-        }
+        // given
+        String sql = "drop database if exists restful_test";
+        // when
+        boolean execute = execute(connection, sql);
+        // then
+        Assert.assertFalse(execute);
+
+        // given
+        sql = "create database if not exists restful_test";
+        // when
+        execute = execute(connection, sql);
+        // then
+        Assert.assertFalse(execute);
+
+        // given
+        sql = "use restful_test";
+        // when
+        execute = execute(connection, sql);
+        // then
+        Assert.assertFalse(execute);
     }
 
-    /**
-     * create database
-     */
     @Test
     public void testCase002() {
-        try (Statement stmt = connection.createStatement()) {
-            stmt.execute("drop database if exists restful_test");
-            stmt.execute("create database if not exists restful_test");
-            stmt.execute("use restful_test");
-        } catch (SQLException e) {
-            e.printStackTrace();
-        }
-    }
-
-    /**
-     * create super table
-     ***/
-    @Test
-    public void testCase003() {
-        try (Statement stmt = connection.createStatement()) {
-            stmt.execute("create table weather(ts timestamp, temperature float, humidity int) tags(location nchar(64), groupId int)");
-        } catch (SQLException e) {
-            e.printStackTrace();
-        }
+        // given
+        String sql = "create table weather(ts timestamp, temperature float, humidity int) tags(location nchar(64), groupId int)";
+        // when
+        boolean execute = execute(connection, sql);
+        // then
+        Assert.assertFalse(execute);
     }
 
     @Test
     public void testCase004() {
-        try (Statement stmt = connection.createStatement()) {
-            for (int i = 1; i <= 100; i++) {
-                stmt.execute("create table t" + i + " using weather tags('beijing', '" + i + "')");
-            }
-        } catch (SQLException e) {
-            e.printStackTrace();
+        for (int i = 1; i <= 100; i++) {
+            // given
+            String sql = "create table t" + i + " using weather tags('beijing', '" + i + "')";
+            // when
+            boolean execute = execute(connection, sql);
+            // then
+            Assert.assertFalse(execute);
         }
     }
 
-
     @Test
     public void testCase005() {
-        try (Statement stmt = connection.createStatement()) {
-            int rows = 0;
-            for (int i = 0; i < 10; i++) {
-                for (int j = 1; j <= 100; j++) {
-                    long currentTimeMillis = System.currentTimeMillis();
-                    int affectRows = stmt.executeUpdate("insert into t" + j + " values(" + currentTimeMillis + "," + (random.nextFloat() * 50) + "," + random.nextInt(100) + ")");
-                    Assert.assertEquals(1, affectRows);
-                    rows += affectRows;
-                }
+        int rows = 0;
+        for (int i = 0; i < 10; i++) {
+            for (int j = 1; j <= 100; j++) {
+
+                // given
+                long currentTimeMillis = System.currentTimeMillis();
+                String sql = "insert into t" + j + " values(" + currentTimeMillis + "," + (random.nextFloat() * 50) + "," + random.nextInt(100) + ")";
+                // when
+                int affectRows = executeUpdate(connection, sql);
+                // then
+                Assert.assertEquals(1, affectRows);
+
+                rows += affectRows;
             }
-            Assert.assertEquals(1000, rows);
-        } catch (SQLException e) {
-            e.printStackTrace();
         }
+        Assert.assertEquals(1000, rows);
     }
 
     @Test
-    public void testCase006() {
-        try (Statement stmt = connection.createStatement()) {
-            ResultSet rs = stmt.executeQuery("select * from weather");
-            while (rs.next()) {
-                System.out.print("ts: " + rs.getTimestamp("ts"));
-                System.out.print(", temperature: " + rs.getString("temperature"));
-                System.out.print(", humidity: " + rs.getString("humidity"));
-                System.out.println(", location: " + rs.getString("location"));
-            }
-        } catch (SQLException e) {
-            e.printStackTrace();
+    public void testCase006() throws SQLException {
+        // given
+        String sql = "select * from weather";
+        // when
+        ResultSet rs = executeQuery(connection, sql);
+        ResultSetMetaData meta = rs.getMetaData();
+
+        // then
+        Assert.assertEquals(5, meta.getColumnCount());
+
+        while (rs.next()) {
+            Assert.assertNotNull(rs.getTimestamp("ts"));
+            Assert.assertNotNull(rs.getFloat("temperature"));
+            Assert.assertNotNull(rs.getInt("humidity"));
+            Assert.assertNotNull(rs.getString("location"));
         }
     }
 
     @Test
     public void testCase007() {
+        // given
+        String sql = "drop database restful_test";
+
+        // when
+        boolean execute = execute(connection, sql);
+
+        // then
+        Assert.assertFalse(execute);
+    }
+
+    private int executeUpdate(Connection connection, String sql) {
         try (Statement stmt = connection.createStatement()) {
-            ResultSet rs = stmt.executeQuery("select * from weather");
-            ResultSetMetaData meta = rs.getMetaData();
-            while (rs.next()) {
-                int columnCount = meta.getColumnCount();
-                for (int i = 1; i <= columnCount; i++) {
-                    String columnLabel = meta.getColumnLabel(i);
-                    String value = rs.getString(i);
-                    System.out.print(columnLabel + ": " + value + "\t");
-                }
-                System.out.println();
-            }
+            return stmt.executeUpdate(sql);
+        } catch (SQLException e) {
+            e.printStackTrace();
+        }
+        return 0;
+    }
+
+    private boolean execute(Connection connection, String sql) {
+        try (Statement stmt = connection.createStatement()) {
+            return stmt.execute(sql);
+        } catch (SQLException e) {
+            e.printStackTrace();
+        }
+        return false;
+    }
+
+
+    private ResultSet executeQuery(Connection connection, String sql) {
+        try (Statement statement = connection.createStatement()) {
+            return statement.executeQuery(sql);
+        } catch (SQLException e) {
+            e.printStackTrace();
+        }
+        return null;
+    }
+
+    @Before
+    public void before() {
+        try {
+            connection = DriverManager.getConnection("jdbc:TAOS-RS://" + host + ":6041/restful_test?user=root&password=taosdata");
         } catch (SQLException e) {
             e.printStackTrace();
         }
     }
 
-    @BeforeClass
-    public static void before() throws ClassNotFoundException, SQLException {
-        Class.forName("com.taosdata.jdbc.rs.RestfulDriver");
-        connection = DriverManager.getConnection("jdbc:TAOS-RS://" + host + ":6041/restful_test?user=root&password=taosdata");
-    }
-
-    @AfterClass
-    public static void after() throws SQLException {
-        if (connection != null)
-            connection.close();
+    @After
+    public void after() {
+        try {
+            if (connection != null)
+                connection.close();
+        } catch (SQLException e) {
+            e.printStackTrace();
+        }
     }
 
 }
diff --git a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/rs/RestfulPreparedStatementTest.java b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/rs/RestfulPreparedStatementTest.java
index ee457ff412..244e8afd11 100644
--- a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/rs/RestfulPreparedStatementTest.java
+++ b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/rs/RestfulPreparedStatementTest.java
@@ -27,12 +27,9 @@ public class RestfulPreparedStatementTest {
         ResultSet rs = pstmt_select.executeQuery();
         Assert.assertNotNull(rs);
         ResultSetMetaData meta = rs.getMetaData();
-        while (rs.next()) {
-            for (int i = 1; i <= meta.getColumnCount(); i++) {
-                System.out.print(meta.getColumnLabel(i) + ": " + rs.getString(i) + "\t");
-            }
-            System.out.println();
-        }
+        int columnCount = meta.getColumnCount();
+        Assert.assertEquals(10, columnCount);
+        Assert.assertNotNull(rs);
     }
 
     @Test
@@ -373,18 +370,19 @@ public class RestfulPreparedStatementTest {
     @BeforeClass
     public static void beforeClass() {
         try {
-            Class.forName("com.taosdata.jdbc.rs.RestfulDriver");
             conn = DriverManager.getConnection("jdbc:TAOS-RS://" + host + ":6041/?user=root&password=taosdata");
-            try (Statement stmt = conn.createStatement()) {
-                stmt.execute("drop database if exists test_pstmt");
-                stmt.execute("create database if not exists test_pstmt");
-                stmt.execute("use test_pstmt");
-                stmt.execute("create table weather(ts timestamp, f1 int, f2 bigint, f3 float, f4 double, f5 smallint, f6 tinyint, f7 bool, f8 binary(64), f9 nchar(64)) tags(loc nchar(64))");
-                stmt.execute("create table t1 using weather tags('beijing')");
-            }
+
+            Statement stmt = conn.createStatement();
+            stmt.execute("drop database if exists test_pstmt");
+            stmt.execute("create database if not exists test_pstmt");
+            stmt.execute("use test_pstmt");
+            stmt.execute("create table weather(ts timestamp, f1 int, f2 bigint, f3 float, f4 double, f5 smallint, f6 tinyint, f7 bool, f8 binary(64), f9 nchar(64)) tags(loc nchar(64))");
+            stmt.execute("create table t1 using weather tags('beijing')");
+            stmt.close();
+
             pstmt_insert = conn.prepareStatement(sql_insert);
             pstmt_select = conn.prepareStatement(sql_select);
-        } catch (ClassNotFoundException | SQLException e) {
+        } catch (SQLException e) {
             e.printStackTrace();
         }
     }
diff --git a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/rs/RestfulStatementTest.java b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/rs/RestfulStatementTest.java
index 1be32b502d..a7b3ceb9d3 100644
--- a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/rs/RestfulStatementTest.java
+++ b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/rs/RestfulStatementTest.java
@@ -12,6 +12,7 @@ import java.util.UUID;
 
 public class RestfulStatementTest {
     private static final String host = "127.0.0.1";
+
     private static Connection conn;
     private static Statement stmt;
 
@@ -21,11 +22,11 @@ public class RestfulStatementTest {
             ResultSet rs = stmt.executeQuery("show databases");
             Assert.assertNotNull(rs);
             ResultSetMetaData meta = rs.getMetaData();
+            int columnCount = meta.getColumnCount();
+            Assert.assertTrue(columnCount > 1);
             while (rs.next()) {
-                for (int i = 1; i <= meta.getColumnCount(); i++) {
-                    System.out.print(meta.getColumnLabel(i) + ": " + rs.getString(i) + "\t");
-                }
-                System.out.println();
+                Assert.assertEquals("name", meta.getColumnLabel(1));
+                Assert.assertNotNull(rs.getString("name"));
             }
             rs.close();
         } catch (SQLException e) {
@@ -174,10 +175,10 @@ public class RestfulStatementTest {
             Assert.assertEquals(3, meta.getColumnCount());
             int count = 0;
             while (rs.next()) {
-                for (int i = 1; i <= meta.getColumnCount(); i++) {
-                    System.out.print(meta.getColumnLabel(i) + ": " + rs.getString(i) + "\t");
-                }
-                System.out.println();
+                Assert.assertEquals("ts", meta.getColumnLabel(1));
+                Assert.assertNotNull(rs.getTimestamp(1));
+                Assert.assertEquals("temperature", meta.getColumnLabel(2));
+                Assert.assertEquals(22.33, rs.getFloat(2), 0.001f);
                 count++;
             }
             Assert.assertEquals(1, count);
@@ -388,15 +389,12 @@ public class RestfulStatementTest {
     @BeforeClass
     public static void beforeClass() {
         try {
-            Class.forName("com.taosdata.jdbc.rs.RestfulDriver");
             Properties properties = new Properties();
             properties.setProperty(TSDBDriver.PROPERTY_KEY_CHARSET, "UTF-8");
             properties.setProperty(TSDBDriver.PROPERTY_KEY_LOCALE, "en_US.UTF-8");
             properties.setProperty(TSDBDriver.PROPERTY_KEY_TIME_ZONE, "UTC-8");
             conn = DriverManager.getConnection("jdbc:TAOS-RS://" + host + ":6041/?user=root&password=taosdata", properties);
             stmt = conn.createStatement();
-        } catch (ClassNotFoundException e) {
-            e.printStackTrace();
         } catch (SQLException e) {
             e.printStackTrace();
         }
diff --git a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/rs/SQLTest.java b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/rs/SQLTest.java
index 4ad9826384..6b88de258d 100644
--- a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/rs/SQLTest.java
+++ b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/rs/SQLTest.java
@@ -1,342 +1,586 @@
 package com.taosdata.jdbc.rs;
 
-import com.taosdata.jdbc.utils.SQLExecutor;
-import org.junit.AfterClass;
-import org.junit.BeforeClass;
-import org.junit.FixMethodOrder;
-import org.junit.Test;
+import org.junit.*;
 import org.junit.runners.MethodSorters;
 
 import java.sql.*;
 
 @FixMethodOrder(MethodSorters.NAME_ASCENDING)
 public class SQLTest {
+
     private static final String host = "127.0.0.1";
     private static Connection connection;
 
     @Test
     public void testCase001() {
+        // given
         String sql = "create database if not exists restful_test";
-        SQLExecutor.execute(connection, sql);
+
+        // when
+        boolean execute = execute(connection, sql);
+
+        // then
+        Assert.assertFalse(execute);
     }
 
     @Test
     public void testCase002() {
+        // given
         String sql = "use restful_test";
-        SQLExecutor.execute(connection, sql);
+
+        // when
+        boolean execute = execute(connection, sql);
+
+        // then
+        Assert.assertFalse(execute);
     }
 
     @Test
     public void testCase003() {
+        // given
         String sql = "show databases";
-        SQLExecutor.executeWithResult(connection, sql);
+
+        // when
+        boolean execute = execute(connection, sql);
+
+        // then
+        Assert.assertTrue(execute);
     }
 
     @Test
     public void testCase004() {
+        // given
         String sql = "show tables";
-        SQLExecutor.executeWithResult(connection, sql);
+
+        // when
+        boolean execute = execute(connection, sql);
+
+        // then
+        Assert.assertTrue(execute);
     }
 
     @Test
     public void testCase005() {
+        // given
         String sql = "show stables";
-        SQLExecutor.executeWithResult(connection, sql);
+
+        // when
+        boolean execute = execute(connection, sql);
+
+        // then
+        Assert.assertTrue(execute);
     }
 
     @Test
     public void testCase006() {
+        // given
         String sql = "show dnodes";
-        SQLExecutor.executeWithResult(connection, sql);
+
+        // when
+        boolean execute = execute(connection, sql);
+
+        // then
+        Assert.assertTrue(execute);
     }
 
     @Test
     public void testCase007() {
+        // given
         String sql = "show vgroups";
-        SQLExecutor.executeWithResult(connection, sql);
+
+        // when
+        boolean execute = execute(connection, sql);
+
+        // then
+        Assert.assertTrue(execute);
     }
 
     @Test
     public void testCase008() {
+        // given
         String sql = "drop table if exists restful_test.weather";
-        SQLExecutor.execute(connection, sql);
+
+        // when
+        boolean execute = execute(connection, sql);
+
+        // then
+        Assert.assertFalse(execute);
     }
 
     @Test
     public void testCase009() {
+        // given
         String sql = "create table if not exists restful_test.weather(ts timestamp, temperature float) tags(location nchar(64))";
-        SQLExecutor.execute(connection, sql);
+
+        // when
+        boolean execute = execute(connection, sql);
+
+        // then
+        Assert.assertFalse(execute);
     }
 
     @Test
     public void testCase010() {
+        // given
         String sql = "create table t1 using restful_test.weather tags('北京')";
-        SQLExecutor.execute(connection, sql);
+
+        // when
+        boolean execute = execute(connection, sql);
+
+        // then
+        Assert.assertFalse(execute);
     }
 
     @Test
     public void testCase011() {
+        // given
         String sql = "insert into restful_test.t1 values(now, 22.22)";
-        SQLExecutor.executeUpdate(connection, sql);
+
+        // when
+        boolean execute = execute(connection, sql);
+
+        // then
+        Assert.assertFalse(execute);
     }
 
     @Test
     public void testCase012() {
+        // given
         String sql = "insert into restful_test.t1 values('2020-01-01 00:00:00.000', 22.22)";
-        SQLExecutor.executeUpdate(connection, sql);
+
+        // when
+        boolean execute = execute(connection, sql);
+
+        // then
+        Assert.assertFalse(execute);
     }
 
     @Test
     public void testCase013() {
+        // given
         String sql = "insert into restful_test.t1 values('2020-01-01 00:01:00.000', 22.22),('2020-01-01 00:02:00.000', 22.22)";
-        SQLExecutor.executeUpdate(connection, sql);
+
+        // when
+        boolean execute = execute(connection, sql);
+
+        // then
+        Assert.assertFalse(execute);
     }
 
     @Test
     public void testCase014() {
+        // given
         String sql = "insert into restful_test.t2 using weather tags('上海') values('2020-01-01 00:03:00.000', 22.22)";
-        SQLExecutor.executeUpdate(connection, sql);
+
+        // when
+        boolean execute = execute(connection, sql);
+
+        // then
+        Assert.assertFalse(execute);
     }
 
     @Test
     public void testCase015() {
+        // given
         String sql = "insert into restful_test.t2 using weather tags('上海') values('2020-01-01 00:01:00.000', 22.22),('2020-01-01 00:02:00.000', 22.22)";
-        SQLExecutor.executeUpdate(connection, sql);
+
+        // when
+        boolean execute = execute(connection, sql);
+
+        // then
+        Assert.assertFalse(execute);
     }
 
     @Test
     public void testCase016() {
+        // given
         String sql = "insert into t1 values('2020-01-01 01:0:00.000', 22.22),('2020-01-01 02:00:00.000', 22.22) t2 values('2020-01-01 01:0:00.000', 33.33),('2020-01-01 02:00:00.000', 33.33)";
-        SQLExecutor.executeUpdate(connection, sql);
+
+        // when
+        boolean execute = execute(connection, sql);
+
+        // then
+        Assert.assertFalse(execute);
     }
 
     @Test
     public void testCase017() {
+        // given
         String sql = "Insert into t3 using weather tags('广东') values('2020-01-01 01:0:00.000', 22.22),('2020-01-01 02:00:00.000', 22.22) t4 using weather tags('天津') values('2020-01-01 01:0:00.000', 33.33),('2020-01-01 02:00:00.000', 33.33)";
-        SQLExecutor.executeUpdate(connection, sql);
+
+        // when
+        boolean execute = execute(connection, sql);
+
+        // then
+        Assert.assertFalse(execute);
     }
 
     @Test
     public void testCase018() {
+        // given
         String sql = "select * from restful_test.t1";
-        SQLExecutor.executeQuery(connection, sql);
+        // when
+        boolean execute = execute(connection, sql);
+        // then
+        Assert.assertTrue(execute);
     }
 
     @Test
     public void testCase019() {
+        // given
         String sql = "select * from restful_test.weather";
-        SQLExecutor.executeQuery(connection, sql);
+        // when
+        boolean execute = execute(connection, sql);
+        // then
+        Assert.assertTrue(execute);
     }
 
     @Test
     public void testCase020() {
+        // given
         String sql = "select ts, temperature from restful_test.t1";
-        SQLExecutor.executeQuery(connection, sql);
+        // when
+        boolean execute = execute(connection, sql);
+        // then
+        Assert.assertTrue(execute);
     }
 
     @Test
     public void testCase021() {
+        // given
         String sql = "select ts, temperature from restful_test.weather";
-        SQLExecutor.executeQuery(connection, sql);
+        // when
+        boolean execute = execute(connection, sql);
+        // then
+        Assert.assertTrue(execute);
     }
 
     @Test
     public void testCase022() {
+        // given
         String sql = "select temperature, ts from restful_test.t1";
-        SQLExecutor.executeQuery(connection, sql);
+        // when
+        boolean execute = execute(connection, sql);
+        // then
+        Assert.assertTrue(execute);
     }
 
     @Test
     public void testCase023() {
+        // given
         String sql = "select temperature, ts from restful_test.weather";
-        SQLExecutor.executeQuery(connection, sql);
+        // when
+        boolean execute = execute(connection, sql);
+        // then
+        Assert.assertTrue(execute);
     }
 
     @Test
     public void testCase024() {
+        // given
         String sql = "import into restful_test.t5 using weather tags('石家庄') values('2020-01-01 00:01:00.000', 22.22)";
-        SQLExecutor.executeUpdate(connection, sql);
+        // when
+        int affectedRows = executeUpdate(connection, sql);
+        // then
+        Assert.assertEquals(1, affectedRows);
     }
 
     @Test
     public void testCase025() {
+        // given
         String sql = "import into restful_test.t6 using weather tags('沈阳') values('2020-01-01 00:01:00.000', 22.22),('2020-01-01 00:02:00.000', 22.22)";
-        SQLExecutor.executeUpdate(connection, sql);
+        // when
+        int affectedRows = executeUpdate(connection, sql);
+        // then
+        Assert.assertEquals(2, affectedRows);
     }
 
     @Test
     public void testCase026() {
+        // given
         String sql = "import into restful_test.t7 using weather tags('长沙') values('2020-01-01 00:01:00.000', 22.22) restful_test.t8 using weather tags('吉林') values('2020-01-01 00:01:00.000', 22.22)";
-        SQLExecutor.executeUpdate(connection, sql);
+
+        // when
+        int affectedRows = executeUpdate(connection, sql);
+        // then
+        Assert.assertEquals(2, affectedRows);
     }
 
     @Test
     public void testCase027() {
+        // given
         String sql = "import into restful_test.t9 using weather tags('武汉') values('2020-01-01 00:01:00.000', 22.22) ,('2020-01-02 00:01:00.000', 22.22) restful_test.t10 using weather tags('哈尔滨') values('2020-01-01 00:01:00.000', 22.22),('2020-01-02 00:01:00.000', 22.22)";
-        SQLExecutor.executeUpdate(connection, sql);
+        // when
+        int affectedRows = executeUpdate(connection, sql);
+        // then
+        Assert.assertEquals(4, affectedRows);
     }
 
     @Test
     public void testCase028() {
+        // given
         String sql = "select location, temperature, ts from restful_test.weather where temperature > 1";
-        SQLExecutor.executeQuery(connection, sql);
+        // when
+        ResultSet rs = executeQuery(connection, sql);
+        // then
+        Assert.assertNotNull(rs);
     }
 
     @Test
     public void testCase029() {
         String sql = "select location, temperature, ts from restful_test.weather where temperature < 1";
-        SQLExecutor.executeQuery(connection, sql);
+        // when
+        ResultSet rs = executeQuery(connection, sql);
+        // then
+        Assert.assertNotNull(rs);
     }
 
     @Test
     public void testCase030() {
         String sql = "select location, temperature, ts from restful_test.weather where ts  > now";
-        SQLExecutor.executeQuery(connection, sql);
+        // when
+        ResultSet rs = executeQuery(connection, sql);
+        // then
+        Assert.assertNotNull(rs);
     }
 
     @Test
     public void testCase031() {
         String sql = "select location, temperature, ts from restful_test.weather where ts  < now";
-        SQLExecutor.executeQuery(connection, sql);
+        // when
+        ResultSet rs = executeQuery(connection, sql);
+        // then
+        Assert.assertNotNull(rs);
     }
 
     @Test
     public void testCase032() {
         String sql = "select count(*) from restful_test.weather";
-        SQLExecutor.executeQuery(connection, sql);
+        // when
+        ResultSet rs = executeQuery(connection, sql);
+        // then
+        Assert.assertNotNull(rs);
     }
 
     @Test
     public void testCase033() {
         String sql = "select first(*) from restful_test.weather";
-        SQLExecutor.executeQuery(connection, sql);
+        // when
+        ResultSet rs = executeQuery(connection, sql);
+        // then
+        Assert.assertNotNull(rs);
     }
 
     @Test
     public void testCase034() {
         String sql = "select last(*) from restful_test.weather";
-        SQLExecutor.executeQuery(connection, sql);
+        // when
+        ResultSet rs = executeQuery(connection, sql);
+        // then
+        Assert.assertNotNull(rs);
     }
 
     @Test
     public void testCase035() {
         String sql = "select last_row(*) from restful_test.weather";
-        SQLExecutor.executeQuery(connection, sql);
+        // when
+        ResultSet rs = executeQuery(connection, sql);
+        // then
+        Assert.assertNotNull(rs);
     }
 
     @Test
     public void testCase036() {
         String sql = "select ts, ts as primary_key from restful_test.weather";
-        SQLExecutor.executeQuery(connection, sql);
+        // when
+        ResultSet rs = executeQuery(connection, sql);
+        // then
+        Assert.assertNotNull(rs);
     }
 
 
     @Test
     public void testCase037() {
         String sql = "select database()";
-        SQLExecutor.execute(connection, "use restful_test");
-        SQLExecutor.executeQuery(connection, sql);
+        // when
+        ResultSet rs = executeQuery(connection, sql);
+        // then
+        Assert.assertNotNull(rs);
     }
 
     @Test
     public void testCase038() {
         String sql = "select client_version()";
-        SQLExecutor.executeQuery(connection, sql);
+        // when
+        ResultSet rs = executeQuery(connection, sql);
+        // then
+        Assert.assertNotNull(rs);
     }
 
     @Test
     public void testCase039() {
         String sql = "select server_status()";
-        SQLExecutor.executeQuery(connection, sql);
+        // when
+        ResultSet rs = executeQuery(connection, sql);
+        // then
+        Assert.assertNotNull(rs);
     }
 
     @Test
     public void testCase040() {
         String sql = "select server_status() as status";
-        SQLExecutor.executeQuery(connection, sql);
+        // when
+        ResultSet rs = executeQuery(connection, sql);
+        // then
+        Assert.assertNotNull(rs);
     }
 
     @Test
     public void testCase041() {
         String sql = "select tbname, location from restful_test.weather";
-        SQLExecutor.executeQuery(connection, sql);
+        // when
+        ResultSet rs = executeQuery(connection, sql);
+        // then
+        Assert.assertNotNull(rs);
     }
 
     @Test
     public void testCase042() {
         String sql = "select count(tbname) from restful_test.weather";
-        SQLExecutor.executeQuery(connection, sql);
+        // when
+        ResultSet rs = executeQuery(connection, sql);
+        // then
+        Assert.assertNotNull(rs);
     }
 
     @Test
     public void testCase043() {
         String sql = "select * from restful_test.weather where ts < now - 1h";
-        SQLExecutor.executeQuery(connection, sql);
+        // when
+        ResultSet rs = executeQuery(connection, sql);
+        // then
+        Assert.assertNotNull(rs);
     }
 
     @Test
     public void testCase044() {
         String sql = "select * from restful_test.weather where ts < now - 1h and location like '%'";
-        SQLExecutor.executeQuery(connection, sql);
+        // when
+        ResultSet rs = executeQuery(connection, sql);
+        // then
+        Assert.assertNotNull(rs);
     }
 
     @Test
     public void testCase045() {
         String sql = "select * from restful_test.weather where ts < now - 1h order by ts";
-        SQLExecutor.executeQuery(connection, sql);
+        // when
+        ResultSet rs = executeQuery(connection, sql);
+        // then
+        Assert.assertNotNull(rs);
     }
 
     @Test
     public void testCase046() {
         String sql = "select last(*) from restful_test.weather where ts < now - 1h group by tbname order by tbname";
-        SQLExecutor.executeQuery(connection, sql);
+        // when
+        ResultSet rs = executeQuery(connection, sql);
+        // then
+        Assert.assertNotNull(rs);
     }
 
     @Test
     public void testCase047() {
         String sql = "select * from restful_test.weather limit 2";
-        SQLExecutor.executeQuery(connection, sql);
+        // when
+        ResultSet rs = executeQuery(connection, sql);
+        // then
+        Assert.assertNotNull(rs);
     }
 
     @Test
     public void testCase048() {
         String sql = "select * from restful_test.weather limit 2 offset 5";
-        SQLExecutor.executeQuery(connection, sql);
+        // when
+        ResultSet rs = executeQuery(connection, sql);
+        // then
+        Assert.assertNotNull(rs);
     }
 
     @Test
     public void testCase049() {
         String sql = "select * from restful_test.t1, restful_test.t3 where t1.ts = t3.ts ";
-        SQLExecutor.executeQuery(connection, sql);
+        // when
+        ResultSet rs = executeQuery(connection, sql);
+        // then
+        Assert.assertNotNull(rs);
     }
 
     @Test
     public void testCase050() {
         String sql = "select * from restful_test.t1, restful_test.t3 where t1.ts = t3.ts and t1.location = t3.location";
-        SQLExecutor.executeQuery(connection, sql);
+        // when
+        ResultSet rs = executeQuery(connection, sql);
+        // then
+        Assert.assertNotNull(rs);
     }
 
     @Test
     public void testCase051() {
         String sql = "select * from restful_test.t1 tt, restful_test.t3 yy where tt.ts = yy.ts";
-        SQLExecutor.executeQuery(connection, sql);
+        // when
+        ResultSet rs = executeQuery(connection, sql);
+        // then
+        Assert.assertNotNull(rs);
     }
 
     @Test
     public void testCase052() {
         String sql = "select server_status()";
-        SQLExecutor.executeQuery(connection, sql);
+        // when
+        ResultSet rs = executeQuery(connection, sql);
+        // then
+        Assert.assertNotNull(rs);
     }
 
     @Test
     public void testCase053() {
         String sql = "select avg(cpu_taosd), avg(cpu_system), max(cpu_cores), avg(mem_taosd), avg(mem_system), max(mem_total), avg(disk_used), max(disk_total), avg(band_speed), avg(io_read), avg(io_write), sum(req_http), sum(req_select), sum(req_insert) from log.dn1 where ts> now - 60m and ts<= now interval(1m) fill(value, 0)";
-        SQLExecutor.executeQuery(connection, sql);
+        // when
+        ResultSet rs = executeQuery(connection, sql);
+        // then
+        Assert.assertNotNull(rs);
+    }
+
+    private boolean execute(Connection connection, String sql) {
+        try (Statement statement = connection.createStatement()) {
+            return statement.execute(sql);
+        } catch (SQLException e) {
+            e.printStackTrace();
+        }
+        return false;
+    }
+
+    private ResultSet executeQuery(Connection connection, String sql) {
+        try (Statement statement = connection.createStatement()) {
+            return statement.executeQuery(sql);
+        } catch (SQLException e) {
+            e.printStackTrace();
+        }
+        return null;
+    }
+
+    private int executeUpdate(Connection connection, String sql) {
+        try (Statement statement = connection.createStatement()) {
+            return statement.executeUpdate(sql);
+        } catch (SQLException e) {
+            e.printStackTrace();
+        }
+        return 0;
     }
 
     @BeforeClass
-    public static void before() throws ClassNotFoundException, SQLException {
-        Class.forName("com.taosdata.jdbc.rs.RestfulDriver");
+    public static void before() throws SQLException {
         connection = DriverManager.getConnection("jdbc:TAOS-RS://" + host + ":6041/restful_test?user=root&password=taosdata");
     }
 
diff --git a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/utils/SQLExecutor.java b/src/connector/jdbc/src/test/java/com/taosdata/jdbc/utils/SQLExecutor.java
deleted file mode 100644
index bf034bf458..0000000000
--- a/src/connector/jdbc/src/test/java/com/taosdata/jdbc/utils/SQLExecutor.java
+++ /dev/null
@@ -1,74 +0,0 @@
-package com.taosdata.jdbc.utils;
-
-import java.sql.*;
-
-public class SQLExecutor {
-
-    // insert, import
-    public static void executeUpdate(Connection connection, String sql) {
-        try (Statement statement = connection.createStatement()) {
-            long start = System.currentTimeMillis();
-            int affectedRows = statement.executeUpdate(sql);
-            long end = System.currentTimeMillis();
-            System.out.println("[ affected rows : " + affectedRows + " ] time cost: " + (end - start) + " ms, execute statement ====> " + sql);
-        } catch (SQLException e) {
-            e.printStackTrace();
-        }
-    }
-
-    // show databases, show tables, show stables
-    public static void executeWithResult(Connection connection, String sql) {
-        try (Statement statement = connection.createStatement()) {
-            statement.execute(sql);
-            ResultSet resultSet = statement.getResultSet();
-            printResult(resultSet);
-        } catch (SQLException e) {
-            e.printStackTrace();
-        }
-    }
-
-    // use database, create database, create table, drop table...
-    public static void execute(Connection connection, String sql) {
-        try (Statement statement = connection.createStatement()) {
-            long start = System.currentTimeMillis();
-            boolean execute = statement.execute(sql);
-            long end = System.currentTimeMillis();
-            printSql(sql, execute, (end - start));
-        } catch (SQLException e) {
-            System.out.println("ERROR execute SQL ===> " + sql);
-            e.printStackTrace();
-        }
-    }
-
-    // select
-    public static void executeQuery(Connection connection, String sql) {
-        try (Statement statement = connection.createStatement()) {
-            long start = System.currentTimeMillis();
-            ResultSet resultSet = statement.executeQuery(sql);
-            long end = System.currentTimeMillis();
-            printSql(sql, true, (end - start));
-            printResult(resultSet);
-        } catch (SQLException e) {
-            System.out.println("ERROR execute SQL ===> " + sql);
-            e.printStackTrace();
-        }
-    }
-
-    private static void printSql(String sql, boolean succeed, long cost) {
-        System.out.println("[ " + (succeed ? "OK" : "ERROR!") + " ] time cost: " + cost + " ms, execute statement ====> " + sql);
-    }
-
-    private static void printResult(ResultSet resultSet) throws SQLException {
-        ResultSetMetaData metaData = resultSet.getMetaData();
-        while (resultSet.next()) {
-            StringBuilder sb = new StringBuilder();
-            for (int i = 1; i <= metaData.getColumnCount(); i++) {
-                String columnLabel = metaData.getColumnLabel(i);
-                String value = resultSet.getString(i);
-                sb.append(columnLabel + ": " + value + "\t");
-            }
-            System.out.println(sb.toString());
-        }
-    }
-
-}
diff --git a/src/kit/taosdemo/taosdemo.c b/src/kit/taosdemo/taosdemo.c
index b2ac11b2ca..ec4c6d8773 100644
--- a/src/kit/taosdemo/taosdemo.c
+++ b/src/kit/taosdemo/taosdemo.c
@@ -4408,14 +4408,12 @@ static bool getMetaFromQueryJsonFile(cJSON* root) {
 
         cJSON* resubAfterConsume =
             cJSON_GetObjectItem(specifiedQuery, "resubAfterConsume");
+        g_queryInfo.specifiedQueryInfo.resubAfterConsume[j] = -1;
         if ((resubAfterConsume)
                 && (resubAfterConsume->type == cJSON_Number)
                 && (resubAfterConsume->valueint >= 0)) {
             g_queryInfo.specifiedQueryInfo.resubAfterConsume[j]
                 = resubAfterConsume->valueint;
-        } else if (!resubAfterConsume) {
-            // default value is -1, which mean do not resub
-            g_queryInfo.specifiedQueryInfo.resubAfterConsume[j] = -1;
         }
 
         cJSON *result = cJSON_GetObjectItem(sql, "result");
@@ -4572,14 +4570,12 @@ static bool getMetaFromQueryJsonFile(cJSON* root) {
 
     cJSON* superResubAfterConsume =
             cJSON_GetObjectItem(superQuery, "resubAfterConsume");
+    g_queryInfo.superQueryInfo.resubAfterConsume = -1;
     if ((superResubAfterConsume)
             && (superResubAfterConsume->type == cJSON_Number)
             && (superResubAfterConsume->valueint >= 0)) {
         g_queryInfo.superQueryInfo.resubAfterConsume =
             superResubAfterConsume->valueint;
-    } else if (!superResubAfterConsume) {
-        // default value is -1, which mean do not resub
-        g_queryInfo.superQueryInfo.resubAfterConsume = -1;
     }
 
     // supert table sqls
@@ -7222,151 +7218,159 @@ static TAOS_SUB* subscribeImpl(
   }
 
   if (tsub == NULL) {
-    printf("failed to create subscription. topic:%s, sql:%s\n", topic, sql);
-    return NULL;
+      errorPrint("failed to create subscription. topic:%s, sql:%s\n", topic, sql);
+      return NULL;
   }
 
   return tsub;
 }
 
 static void *superSubscribe(void *sarg) {
-  threadInfo *pThreadInfo = (threadInfo *)sarg;
-  char subSqlstr[MAX_QUERY_SQL_LENGTH];
-  TAOS_SUB*    tsub[MAX_QUERY_SQL_COUNT] = {0};
-  uint64_t tsubSeq;
+    threadInfo *pThreadInfo = (threadInfo *)sarg;
+    char subSqlstr[MAX_QUERY_SQL_LENGTH];
+    TAOS_SUB*    tsub[MAX_QUERY_SQL_COUNT] = {0};
+    uint64_t tsubSeq;
 
-  if (pThreadInfo->ntables > MAX_QUERY_SQL_COUNT) {
-      errorPrint("The table number(%"PRId64") of the thread is more than max query sql count: %d\n",
-              pThreadInfo->ntables,
-              MAX_QUERY_SQL_COUNT);
-      exit(-1);
-  }
-
-  if (pThreadInfo->taos == NULL) {
-    pThreadInfo->taos = taos_connect(g_queryInfo.host,
-          g_queryInfo.user,
-          g_queryInfo.password,
-          g_queryInfo.dbName,
-          g_queryInfo.port);
-    if (pThreadInfo->taos == NULL) {
-      errorPrint("[%d] Failed to connect to TDengine, reason:%s\n",
-            pThreadInfo->threadID, taos_errstr(NULL));
-      return NULL;
+    if (pThreadInfo->ntables > MAX_QUERY_SQL_COUNT) {
+        errorPrint("The table number(%"PRId64") of the thread is more than max query sql count: %d\n",
+                pThreadInfo->ntables, MAX_QUERY_SQL_COUNT);
+        exit(-1);
     }
-  }
 
-  char sqlStr[MAX_TB_NAME_SIZE*2];
-  sprintf(sqlStr, "use %s", g_queryInfo.dbName);
-  if (0 != queryDbExec(pThreadInfo->taos, sqlStr, NO_INSERT_TYPE, false)) {
-    taos_close(pThreadInfo->taos);
-    errorPrint( "use database %s failed!\n\n",
-                g_queryInfo.dbName);
-    return NULL;
-  }
+    if (pThreadInfo->taos == NULL) {
+        pThreadInfo->taos = taos_connect(g_queryInfo.host,
+                g_queryInfo.user,
+                g_queryInfo.password,
+                g_queryInfo.dbName,
+                g_queryInfo.port);
+        if (pThreadInfo->taos == NULL) {
+            errorPrint("[%d] Failed to connect to TDengine, reason:%s\n",
+                    pThreadInfo->threadID, taos_errstr(NULL));
+            return NULL;
+        }
+    }
 
-  char topic[32] = {0};
-  for (uint64_t i = pThreadInfo->start_table_from;
-          i <= pThreadInfo->end_table_to; i++) {
-
-      tsubSeq = i - pThreadInfo->start_table_from;
-      verbosePrint("%s() LN%d, [%d], start=%"PRId64" end=%"PRId64" i=%"PRIu64"\n",
-              __func__, __LINE__,
-              pThreadInfo->threadID,
-              pThreadInfo->start_table_from,
-              pThreadInfo->end_table_to, i);
-      sprintf(topic, "taosdemo-subscribe-%"PRIu64"-%"PRIu64"",
-              i, pThreadInfo->querySeq);
-      memset(subSqlstr, 0, sizeof(subSqlstr));
-      replaceChildTblName(
-              g_queryInfo.superQueryInfo.sql[pThreadInfo->querySeq],
-              subSqlstr, i);
-      if (g_queryInfo.superQueryInfo.result[pThreadInfo->querySeq][0] != 0) {
-        sprintf(pThreadInfo->filePath, "%s-%d",
-                g_queryInfo.superQueryInfo.result[pThreadInfo->querySeq],
-                pThreadInfo->threadID);
-      }
-
-      debugPrint("%s() LN%d, [%d] subSqlstr: %s\n",
-              __func__, __LINE__, pThreadInfo->threadID, subSqlstr);
-      tsub[tsubSeq] = subscribeImpl(
-              STABLE_CLASS,
-              pThreadInfo, subSqlstr, topic,
-              g_queryInfo.superQueryInfo.subscribeRestart,
-              g_queryInfo.superQueryInfo.subscribeInterval);
-      if (NULL == tsub[tsubSeq]) {
+    char sqlStr[MAX_TB_NAME_SIZE*2];
+    sprintf(sqlStr, "use %s", g_queryInfo.dbName);
+    if (0 != queryDbExec(pThreadInfo->taos, sqlStr, NO_INSERT_TYPE, false)) {
         taos_close(pThreadInfo->taos);
+        errorPrint( "use database %s failed!\n\n",
+                g_queryInfo.dbName);
         return NULL;
-      }
-  }
+    }
 
-  // start loop to consume result
-  int consumed[MAX_QUERY_SQL_COUNT];
-  for (int i = 0; i < MAX_QUERY_SQL_COUNT; i++) {
-    consumed[i] = 0;
-  }
-  TAOS_RES* res = NULL;
+    char topic[32] = {0};
+    for (uint64_t i = pThreadInfo->start_table_from;
+            i <= pThreadInfo->end_table_to; i++) {
+        tsubSeq = i - pThreadInfo->start_table_from;
+        verbosePrint("%s() LN%d, [%d], start=%"PRId64" end=%"PRId64" i=%"PRIu64"\n",
+                __func__, __LINE__,
+                pThreadInfo->threadID,
+                pThreadInfo->start_table_from,
+                pThreadInfo->end_table_to, i);
+        sprintf(topic, "taosdemo-subscribe-%"PRIu64"-%"PRIu64"",
+                i, pThreadInfo->querySeq);
+        memset(subSqlstr, 0, sizeof(subSqlstr));
+        replaceChildTblName(
+                g_queryInfo.superQueryInfo.sql[pThreadInfo->querySeq],
+                subSqlstr, i);
+        if (g_queryInfo.superQueryInfo.result[pThreadInfo->querySeq][0] != 0) {
+            sprintf(pThreadInfo->filePath, "%s-%d",
+                    g_queryInfo.superQueryInfo.result[pThreadInfo->querySeq],
+                    pThreadInfo->threadID);
+        }
 
-  uint64_t st = 0, et = 0;
+        debugPrint("%s() LN%d, [%d] subSqlstr: %s\n",
+                __func__, __LINE__, pThreadInfo->threadID, subSqlstr);
+        tsub[tsubSeq] = subscribeImpl(
+                STABLE_CLASS,
+                pThreadInfo, subSqlstr, topic,
+                g_queryInfo.superQueryInfo.subscribeRestart,
+                g_queryInfo.superQueryInfo.subscribeInterval);
+        if (NULL == tsub[tsubSeq]) {
+            taos_close(pThreadInfo->taos);
+            return NULL;
+        }
+    }
 
-  while ((g_queryInfo.superQueryInfo.endAfterConsume == -1)
-          || (g_queryInfo.superQueryInfo.endAfterConsume <
-              consumed[pThreadInfo->end_table_to - pThreadInfo->start_table_from])) {
+    // start loop to consume result
+    int consumed[MAX_QUERY_SQL_COUNT];
+    for (int i = 0; i < MAX_QUERY_SQL_COUNT; i++) {
+        consumed[i] = 0;
+    }
+    TAOS_RES* res = NULL;
+
+    uint64_t st = 0, et = 0;
+
+    while ((g_queryInfo.superQueryInfo.endAfterConsume == -1)
+            || (g_queryInfo.superQueryInfo.endAfterConsume >
+                consumed[pThreadInfo->end_table_to
+                - pThreadInfo->start_table_from])) {
+
+        verbosePrint("super endAfterConsume: %d, consumed: %d\n",
+                g_queryInfo.superQueryInfo.endAfterConsume,
+                consumed[pThreadInfo->end_table_to
+                - pThreadInfo->start_table_from]);
+        for (uint64_t i = pThreadInfo->start_table_from;
+                i <= pThreadInfo->end_table_to; i++) {
+            tsubSeq = i - pThreadInfo->start_table_from;
+            if (ASYNC_MODE == g_queryInfo.superQueryInfo.asyncMode) {
+                continue;
+            }
+
+            st = taosGetTimestampMs();
+            performancePrint("st: %"PRIu64" et: %"PRIu64" st-et: %"PRIu64"\n", st, et, (st - et));
+            res = taos_consume(tsub[tsubSeq]);
+            et = taosGetTimestampMs();
+            performancePrint("st: %"PRIu64" et: %"PRIu64" delta: %"PRIu64"\n", st, et, (et - st));
+
+            if (res) {
+                if (g_queryInfo.superQueryInfo.result[pThreadInfo->querySeq][0] != 0) {
+                    sprintf(pThreadInfo->filePath, "%s-%d",
+                            g_queryInfo.superQueryInfo.result[pThreadInfo->querySeq],
+                            pThreadInfo->threadID);
+                    fetchResult(res, pThreadInfo);
+                }
+                consumed[tsubSeq] ++;
+
+                if ((g_queryInfo.superQueryInfo.resubAfterConsume != -1)
+                        && (consumed[tsubSeq] >=
+                            g_queryInfo.superQueryInfo.resubAfterConsume)) {
+                    verbosePrint("%s() LN%d, keepProgress:%d, resub super table query: %"PRIu64"\n",
+                            __func__, __LINE__,
+                            g_queryInfo.superQueryInfo.subscribeKeepProgress,
+                            pThreadInfo->querySeq);
+                    taos_unsubscribe(tsub[tsubSeq],
+                            g_queryInfo.superQueryInfo.subscribeKeepProgress);
+                    consumed[tsubSeq]= 0;
+                    tsub[tsubSeq] = subscribeImpl(
+                            STABLE_CLASS,
+                            pThreadInfo, subSqlstr, topic,
+                            g_queryInfo.superQueryInfo.subscribeRestart,
+                            g_queryInfo.superQueryInfo.subscribeInterval
+                            );
+                    if (NULL == tsub[tsubSeq]) {
+                        taos_close(pThreadInfo->taos);
+                        return NULL;
+                    }
+                }
+            }
+        }
+    }
+    verbosePrint("%s() LN%d, super endAfterConsume: %d, consumed: %d\n",
+            __func__, __LINE__,
+            g_queryInfo.superQueryInfo.endAfterConsume,
+            consumed[pThreadInfo->end_table_to - pThreadInfo->start_table_from]);
+    taos_free_result(res);
 
     for (uint64_t i = pThreadInfo->start_table_from;
             i <= pThreadInfo->end_table_to; i++) {
-      tsubSeq = i - pThreadInfo->start_table_from;
-      if (ASYNC_MODE == g_queryInfo.superQueryInfo.asyncMode) {
-          continue;
-      }
-
-      st = taosGetTimestampMs();
-      performancePrint("st: %"PRIu64" et: %"PRIu64" st-et: %"PRIu64"\n", st, et, (st - et));
-      res = taos_consume(tsub[tsubSeq]);
-      et = taosGetTimestampMs();
-      performancePrint("st: %"PRIu64" et: %"PRIu64" delta: %"PRIu64"\n", st, et, (et - st));
-
-      if (res) {
-          if (g_queryInfo.superQueryInfo.result[pThreadInfo->querySeq][0] != 0) {
-              sprintf(pThreadInfo->filePath, "%s-%d",
-                      g_queryInfo.superQueryInfo.result[pThreadInfo->querySeq],
-                      pThreadInfo->threadID);
-              fetchResult(res, pThreadInfo);
-          }
-          consumed[tsubSeq] ++;
-
-          if ((g_queryInfo.superQueryInfo.resubAfterConsume != -1)
-                  && (consumed[tsubSeq] >=
-                      g_queryInfo.superQueryInfo.resubAfterConsume)) {
-              printf("keepProgress:%d, resub super table query: %"PRIu64"\n",
-                      g_queryInfo.superQueryInfo.subscribeKeepProgress,
-                      pThreadInfo->querySeq);
-              taos_unsubscribe(tsub[tsubSeq],
-                    g_queryInfo.superQueryInfo.subscribeKeepProgress);
-              consumed[tsubSeq]= 0;
-              tsub[tsubSeq] = subscribeImpl(
-                      STABLE_CLASS,
-                      pThreadInfo, subSqlstr, topic,
-                      g_queryInfo.superQueryInfo.subscribeRestart,
-                      g_queryInfo.superQueryInfo.subscribeInterval
-                      );
-              if (NULL == tsub[tsubSeq]) {
-                  taos_close(pThreadInfo->taos);
-                  return NULL;
-              }
-          }
-      }
+        tsubSeq = i - pThreadInfo->start_table_from;
+        taos_unsubscribe(tsub[tsubSeq], 0);
     }
-  }
-  taos_free_result(res);
 
-  for (uint64_t i = pThreadInfo->start_table_from;
-          i <= pThreadInfo->end_table_to; i++) {
-    tsubSeq = i - pThreadInfo->start_table_from;
-    taos_unsubscribe(tsub[tsubSeq], 0);
-  }
-
-  taos_close(pThreadInfo->taos);
-  return NULL;
+    taos_close(pThreadInfo->taos);
+    return NULL;
 }
 
 static void *specifiedSubscribe(void *sarg) {
@@ -7420,8 +7424,13 @@ static void *specifiedSubscribe(void *sarg) {
           || (g_queryInfo.specifiedQueryInfo.consumed[pThreadInfo->threadID] <
               g_queryInfo.specifiedQueryInfo.endAfterConsume[pThreadInfo->querySeq])) {
 
+      printf("consumed[%d]: %d, endAfterConsum[%"PRId64"]: %d\n",
+              pThreadInfo->threadID,
+              g_queryInfo.specifiedQueryInfo.consumed[pThreadInfo->threadID],
+              pThreadInfo->querySeq,
+              g_queryInfo.specifiedQueryInfo.endAfterConsume[pThreadInfo->querySeq]);
       if (ASYNC_MODE == g_queryInfo.specifiedQueryInfo.asyncMode) {
-        continue;
+          continue;
       }
 
       g_queryInfo.specifiedQueryInfo.res[pThreadInfo->threadID] = taos_consume(
diff --git a/tests/pytest/fulltest.sh b/tests/pytest/fulltest.sh
index c66ccc5477..88c5909863 100755
--- a/tests/pytest/fulltest.sh
+++ b/tests/pytest/fulltest.sh
@@ -150,6 +150,7 @@ python3 ./test.py -f import_merge/importCSV.py
 #======================p2-start===============
 # tools
 python3 test.py -f tools/taosdumpTest.py
+python3 test.py -f tools/taosdumpTest2.py
 
 python3 test.py -f tools/taosdemoTest.py
 python3 test.py -f tools/taosdemoTestWithoutMetric.py
diff --git a/tests/pytest/util/taosdemoCfg.py b/tests/pytest/util/taosdemoCfg.py
index 5071e915a5..d211f86b81 100644
--- a/tests/pytest/util/taosdemoCfg.py
+++ b/tests/pytest/util/taosdemoCfg.py
@@ -25,6 +25,21 @@ from multiprocessing import cpu_count
 
 # TODO: fully test the function. Handle exceptions.
 #       Handle json format not accepted by taosdemo
+
+### How to use TaosdemoCfg:
+#   Before you start: 
+#       Make sure you understand how is taosdemo's JSON file structured. Because the python used does
+#       not support directory in directory for self objects, the config is being tear to different parts.
+#       Please make sure you understand which directory represent which part of which type of the file 
+#       This module will reassemble the parts when creating the JSON file.
+#
+#   Basic use example
+#   step 1:use self.append_sql_stb() to append the insert/query/subscribe directory into the module
+#       you can append many insert/query/subscribe directory, but pay attention about taosdemo's limit
+#   step 2:use alter function to alter the specific config 
+#   step 3:use the generation function to generate the files
+#
+#   step 1 and step 2 can be replaced with using import functions
 class TDTaosdemoCfg:
     def __init__(self):
         self.insert_cfg = {
@@ -264,7 +279,7 @@ class TDTaosdemoCfg:
         elif key == "super_table_query":
             self.query_cfg["super_table_query"] = self.stable_query
         else:
-            self.table_query[key] = value
+            self.query_cfg[key] = value
 
     def alter_sub_cfg(self, key, value):
         if key == "specified_table_query":
@@ -272,7 +287,7 @@ class TDTaosdemoCfg:
         elif key == "super_table_query":
             self.sub_cfg["super_table_query"] = self.stable_sub
         else:
-            self.table_query[key] = value
+            self.sub_cfg[key] = value
 
     def alter_sub_stb(self, key, value):
         if key == "sqls":