[TD-13408]<test>: move example back for 2.4 (#10195)

* [TD-13408]<test>: add example back

for 2.4

* modify packaging script

examples/C#/.gitignore

+C#checker/bin/
+C#checker/obj/
+TDengineTest/bin/
+TDengineTest/obj/
+schemaless/bin/
+schemaless/obj/
+stmt/TDengineDriver.cs
+stmt/TaosBind.cs
+stmt/TaosMultiBind.cs
+stmt/bin/
+stmt/obj/
+taosdemo/bin/
+taosdemo/obj/

examples/C#/C#checker/C#checker.cs

+/*
+ * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
+ *
+ * This program is free software: you can use, redistribute, and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3
+ * or later ("AGPL"), as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+using System;
+using System.Text;
+using System.Collections.Generic;
+using System.Runtime.InteropServices;
+using System.Collections;
+
+namespace TDengineDriver
+{
+    class TDengineTest
+    {
+        //connect parameters
+        private string host;
+        private string configDir;
+        private string user;
+        private string password;
+        private short port = 0;
+
+        //sql parameters
+        private string dbName;
+        private string tbName;
+        private string precision;
+
+        private bool isInsertData;
+        private bool isQueryData;
+
+        private long tableCount;
+        private long totalRows;
+        private long batchRows;
+        private long beginTimestamp = 1551369600000L;
+
+        private IntPtr conn = IntPtr.Zero;
+        private long rowsInserted = 0;
+
+        static void Main(string[] args)
+        {
+            TDengineTest tester = new TDengineTest();
+            tester.ReadArgument(args);
+
+
+            tester.InitTDengine();
+            tester.ConnectTDengine();
+            tester.createDatabase();
+            tester.useDatabase();
+            tester.checkDropTable();
+            tester.createTable();
+            tester.checkInsert();
+            tester.checkSelect();
+            tester.checkDropTable();
+            tester.dropDatabase();
+            tester.CloseConnection();
+            tester.cleanup();
+
+
+        }
+
+        public long GetArgumentAsLong(String[] argv, String argName, int minVal, int maxVal, int defaultValue)
+        {
+            int argc = argv.Length;
+            for (int i = 0; i < argc; ++i)
+            {
+                if (argName != argv[i])
+                {
+                    continue;
+                }
+                if (i < argc - 1)
+                {
+                    String tmp = argv[i + 1];
+                    if (tmp[0] == '-')
+                    {
+                        Console.WriteLine("option {0:G} requires an argument", tmp);
+                        ExitProgram();
+                    }
+
+                    long tmpVal = Convert.ToInt64(tmp);
+                    if (tmpVal < minVal || tmpVal > maxVal)
+                    {
+                        Console.WriteLine("option {0:G} should in range [{1:G}, {2:G}]", argName, minVal, maxVal);
+                        ExitProgram();
+                    }
+
+                    return tmpVal;
+                }
+            }
+
+            return defaultValue;
+        }
+
+        public String GetArgumentAsString(String[] argv, String argName, String defaultValue)
+        {
+            int argc = argv.Length;
+            for (int i = 0; i < argc; ++i)
+            {
+                if (argName != argv[i])
+                {
+                    continue;
+                }
+                if (i < argc - 1)
+                {
+                    String tmp = argv[i + 1];
+                    if (tmp[0] == '-')
+                    {
+                        Console.WriteLine("option {0:G} requires an argument", tmp);
+                        ExitProgram();
+                    }
+                    return tmp;
+                }
+            }
+
+            return defaultValue;
+        }
+
+        public void PrintHelp(String[] argv)
+        {
+            for (int i = 0; i < argv.Length; ++i)
+            {
+                if ("--help" == argv[i])
+                {
+                    String indent = "    ";
+                    Console.WriteLine("taosTest is simple example to operate TDengine use C# Language.\n");
+                    Console.WriteLine("{0:G}{1:G}", indent, "-h");
+                    Console.WriteLine("{0:G}{1:G}{2:G}", indent, indent, "TDEngine server IP address to connect");
+                    Console.WriteLine("{0:G}{1:G}", indent, "-u");
+                    Console.WriteLine("{0:G}{1:G}{2:G}", indent, indent, "The TDEngine user name to use when connecting to the server, default is root");
+                    Console.WriteLine("{0:G}{1:G}", indent, "-p");
+                    Console.WriteLine("{0:G}{1:G}{2:G}", indent, indent, "The TDEngine user name to use when connecting to the server, default is taosdata");
+                    Console.WriteLine("{0:G}{1:G}", indent, "-d");
+                    Console.WriteLine("{0:G}{1:G}{2:G}", indent, indent, "Database used to create table or import data, default is db");
+                    Console.WriteLine("{0:G}{1:G}", indent, "-s");
+                    Console.WriteLine("{0:G}{1:G}{2:G}", indent, indent, "Super Tables used to create table, default is mt");
+                    Console.WriteLine("{0:G}{1:G}", indent, "-t");
+                    Console.WriteLine("{0:G}{1:G}{2:G}", indent, indent, "Table prefixs, default is t");
+                    Console.WriteLine("{0:G}{1:G}", indent, "-w");
+                    Console.WriteLine("{0:G}{1:G}{2:G}", indent, indent, "Whether to insert data");
+                    Console.WriteLine("{0:G}{1:G}", indent, "-r");
+                    Console.WriteLine("{0:G}{1:G}{2:G}", indent, indent, "Whether to query data");
+                    Console.WriteLine("{0:G}{1:G}", indent, "-n");
+                    Console.WriteLine("{0:G}{1:G}{2:G}", indent, indent, "How many Tables to create, default is 10");
+                    Console.WriteLine("{0:G}{1:G}", indent, "-b");
+                    Console.WriteLine("{0:G}{1:G}{2:G}", indent, indent, "How many rows per insert batch, default is 10");
+                    Console.WriteLine("{0:G}{1:G}", indent, "-i");
+                    Console.WriteLine("{0:G}{1:G}{2:G}", indent, indent, "How many rows to insert, default is 100");
+                    Console.WriteLine("{0:G}{1:G}", indent, "-c");
+                    Console.WriteLine("{0:G}{1:G}{2:G}", indent, indent, "Configuration directory");
+                    //
+                    Console.WriteLine("{0:G}{1:G}", indent, "-ps");
+                    Console.WriteLine("{0:G}{1:G}{2:G}", indent, indent, "Configurate db precision,default millisecond");
+                    ExitProgram();
+                }
+            }
+        }
+
+        public void ReadArgument(String[] argv)
+        {
+            PrintHelp(argv);
+            host = this.GetArgumentAsString(argv, "-h", "127.0.0.1");
+            user = this.GetArgumentAsString(argv, "-u", "root");
+            password = this.GetArgumentAsString(argv, "-p", "taosdata");
+            dbName = this.GetArgumentAsString(argv, "-d", "test");
+            tbName = this.GetArgumentAsString(argv, "-s", "weather");
+            precision = this.GetArgumentAsString(argv, "-ps", "ms");
+            isInsertData = this.GetArgumentAsLong(argv, "-w", 0, 1, 1) != 0;
+            isQueryData = this.GetArgumentAsLong(argv, "-r", 0, 1, 1) != 0;
+            tableCount = this.GetArgumentAsLong(argv, "-n", 1, 10000, 10);
+            batchRows = this.GetArgumentAsLong(argv, "-b", 1, 1000, 500);
+            totalRows = this.GetArgumentAsLong(argv, "-i", 1, 10000000, 10000);
+            configDir = this.GetArgumentAsString(argv, "-c", "C:/TDengine/cfg");
+        }
+
+        public void InitTDengine()
+        {
+            TDengine.Options((int)TDengineInitOption.TDDB_OPTION_CONFIGDIR, this.configDir);
+            TDengine.Options((int)TDengineInitOption.TDDB_OPTION_SHELL_ACTIVITY_TIMER, "60");
+            Console.WriteLine("init...");
+            TDengine.Init();
+            Console.WriteLine("get connection starting...");
+        }
+
+        public void ConnectTDengine()
+        {
+            string db = "";
+            this.conn = TDengine.Connect(this.host, this.user, this.password, db, this.port);
+            if (this.conn == IntPtr.Zero)
+            {
+                Console.WriteLine("connection failed: " + this.host);
+                ExitProgram();
+            }
+            else
+            {
+                Console.WriteLine("[ OK ] Connection established.");
+            }
+        }
+        public void createDatabase()
+        {
+            StringBuilder sql = new StringBuilder();
+            sql.Append("create database if not exists ").Append(this.dbName).Append(" precision '").Append(this.precision).Append("'");
+            execute(sql.ToString());
+        }
+        public void useDatabase()
+        {
+            StringBuilder sql = new StringBuilder();
+            sql.Append("use ").Append(this.dbName);
+            execute(sql.ToString());
+        }
+        public void checkSelect()
+        {
+            StringBuilder sql = new StringBuilder();
+            sql.Append("select * from ").Append(this.dbName).Append(".").Append(this.tbName);
+            ExecuteQuery(sql.ToString());
+        }
+        public void createTable()
+        {
+            StringBuilder sql = new StringBuilder();
+            sql.Append("create table if not exists ").Append(this.dbName).Append(".").Append(this.tbName).Append("(ts timestamp, temperature float, humidity int)");
+            execute(sql.ToString());
+        }
+        public void checkInsert()
+        {
+            StringBuilder sql = new StringBuilder();
+            sql.Append("insert into ").Append(this.dbName).Append(".").Append(this.tbName).Append("(ts, temperature, humidity) values(now, 20.5, 34)");
+            execute(sql.ToString());
+        }
+        public void checkDropTable()
+        {
+            StringBuilder sql = new StringBuilder();
+            sql.Append("drop table if exists ").Append(this.dbName).Append(".").Append(this.tbName).Append("");
+            execute(sql.ToString());
+        }
+        public void dropDatabase()
+        {
+            StringBuilder sql = new StringBuilder();
+            sql.Append("drop database if exists ").Append(this.dbName);
+            execute(sql.ToString());
+        }
+        public void execute(string sql)
+        {
+            DateTime dt1 = DateTime.Now;
+            IntPtr res = TDengine.Query(this.conn, sql.ToString());
+            DateTime dt2 = DateTime.Now;
+            TimeSpan span = dt2 - dt1;
+
+            if ((res == IntPtr.Zero) || (TDengine.ErrorNo(res) != 0))
+            {
+              Console.Write(sql.ToString() + " failure, ");
+              if (res != IntPtr.Zero) {
+                Console.Write("reason: " + TDengine.Error(res));
+              }
+              Console.WriteLine("");
+              ExitProgram();
+            }
+            else
+            {
+                Console.WriteLine(sql.ToString() + " success");
+            }
+            TDengine.FreeResult(res);
+        }
+
+        public void ExecuteQuery(string sql)
+        {
+
+            DateTime dt1 = DateTime.Now;
+            long queryRows = 0;
+            IntPtr res = TDengine.Query(conn, sql);
+            getPrecision(res);
+            if ((res == IntPtr.Zero) || (TDengine.ErrorNo(res) != 0))
+            {
+              Console.Write(sql.ToString() + " failure, ");
+              if (res != IntPtr.Zero) {
+                Console.Write("reason: " + TDengine.Error(res));
+              }
+              Console.WriteLine("");
+              ExitProgram();
+            }
+            DateTime dt2 = DateTime.Now;
+            TimeSpan span = dt2 - dt1;
+            Console.WriteLine("[OK] time cost: " + span.ToString() + "ms, execute statement ====> " + sql.ToString());
+            int fieldCount = TDengine.FieldCount(res);
+
+            List<TDengineMeta> metas = TDengine.FetchFields(res);
+            for (int j = 0; j < metas.Count; j++)
+            {
+                TDengineMeta meta = (TDengineMeta)metas[j];
+            }
+
+            IntPtr rowdata;
+            StringBuilder builder = new StringBuilder();
+            while ((rowdata = TDengine.FetchRows(res)) != IntPtr.Zero)
+            {
+                queryRows++;
+                for (int fields = 0; fields < fieldCount; ++fields)
+                {
+                    TDengineMeta meta = metas[fields];
+                    int offset = IntPtr.Size * fields;
+                    IntPtr data = Marshal.ReadIntPtr(rowdata, offset);
+
+                    builder.Append("---");
+
+                    if (data == IntPtr.Zero)
+                    {
+                        builder.Append("NULL");
+                        continue;
+                    }
+
+                    switch ((TDengineDataType)meta.type)
+                    {
+                        case TDengineDataType.TSDB_DATA_TYPE_BOOL:
+                            bool v1 = Marshal.ReadByte(data) == 0 ? false : true;
+                            builder.Append(v1);
+                            break;
+                        case TDengineDataType.TSDB_DATA_TYPE_TINYINT:
+                            byte v2 = Marshal.ReadByte(data);
+                            builder.Append(v2);
+                            break;
+                        case TDengineDataType.TSDB_DATA_TYPE_SMALLINT:
+                            short v3 = Marshal.ReadInt16(data);
+                            builder.Append(v3);
+                            break;
+                        case TDengineDataType.TSDB_DATA_TYPE_INT:
+                            int v4 = Marshal.ReadInt32(data);
+                            builder.Append(v4);
+                            break;
+                        case TDengineDataType.TSDB_DATA_TYPE_BIGINT:
+                            long v5 = Marshal.ReadInt64(data);
+                            builder.Append(v5);
+                            break;
+                        case TDengineDataType.TSDB_DATA_TYPE_FLOAT:
+                            float v6 = (float)Marshal.PtrToStructure(data, typeof(float));
+                            builder.Append(v6);
+                            break;
+                        case TDengineDataType.TSDB_DATA_TYPE_DOUBLE:
+                            double v7 = (double)Marshal.PtrToStructure(data, typeof(double));
+                            builder.Append(v7);
+                            break;
+                        case TDengineDataType.TSDB_DATA_TYPE_BINARY:
+                            string v8 = Marshal.PtrToStringAnsi(data);
+                            builder.Append(v8);
+                            break;
+                        case TDengineDataType.TSDB_DATA_TYPE_TIMESTAMP:
+                            long v9 = Marshal.ReadInt64(data);
+                            builder.Append(v9);
+                            break;
+                        case TDengineDataType.TSDB_DATA_TYPE_NCHAR:
+                            string v10 = Marshal.PtrToStringAnsi(data);
+                            builder.Append(v10);
+                            break;
+                    }
+                }
+                builder.Append("---");
+
+                if (queryRows <= 10)
+                {
+                    Console.WriteLine(builder.ToString());
+                }
+                builder.Clear();
+            }
+
+            if (TDengine.ErrorNo(res) != 0)
+            {
+                Console.Write("Query is not complete, Error {0:G}", TDengine.ErrorNo(res), TDengine.Error(res));
+            }
+            Console.WriteLine("");
+
+            TDengine.FreeResult(res);
+
+        }
+
+        public void CloseConnection()
+        {
+            if (this.conn != IntPtr.Zero)
+            {
+                TDengine.Close(this.conn);
+                Console.WriteLine("connection closed.");
+            }
+        }
+
+        static void ExitProgram()
+        {
+            System.Environment.Exit(0);
+        }
+
+        public void cleanup()
+        {
+            Console.WriteLine("clean up...");
+            System.Environment.Exit(0);
+        }
+        // method to get db precision
+        public void getPrecision(IntPtr res)
+        {
+            int psc=TDengine.ResultPrecision(res);
+            switch(psc)
+            {
+                case 0:
+                    Console.WriteLine("db：[{0:G}]'s precision is {1:G}",this.dbName,"millisecond");
+                    break;
+                case 1:
+                    Console.WriteLine("db：[{0:G}]'s precision is {1:G}",this.dbName,"microsecond");
+                    break;
+                case 2:
+                    Console.WriteLine("db：[{0:G}]'s precision is {1:G}",this.dbName,"nanosecond");
+                    break;
+            }
+
+        }
+    }
+}

examples/C#/C#checker/C#checker.csproj

+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net5.0</TargetFramework>
+    <RootNamespace>C_checker</RootNamespace>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="TDengine.Connector" Version="1.0.2" />
+  </ItemGroup>
+
+</Project>

examples/C#/TDengineTest/TDengineTest.csproj

+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net5.0</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="TDengine.Connector" Version="1.0.2" />
+  </ItemGroup>
+
+</Project>

examples/C#/schemaless/TDengineDriver.cs

+/*
+ * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
+ *
+ * This program is free software: you can use, redistribute, and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3
+ * or later ("AGPL"), as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+using System;
+using System.Collections.Generic;
+using System.Runtime.InteropServices;
+
+namespace TDengineDriver
+{
+    enum TDengineDataType
+    {
+        TSDB_DATA_TYPE_NULL = 0,     // 1 bytes
+        TSDB_DATA_TYPE_BOOL = 1,     // 1 bytes
+        TSDB_DATA_TYPE_TINYINT = 2,  // 1 bytes
+        TSDB_DATA_TYPE_SMALLINT = 3, // 2 bytes
+        TSDB_DATA_TYPE_INT = 4,      // 4 bytes
+        TSDB_DATA_TYPE_BIGINT = 5,   // 8 bytes
+        TSDB_DATA_TYPE_FLOAT = 6,    // 4 bytes
+        TSDB_DATA_TYPE_DOUBLE = 7,   // 8 bytes
+        TSDB_DATA_TYPE_BINARY = 8,   // string
+        TSDB_DATA_TYPE_TIMESTAMP = 9,// 8 bytes
+        TSDB_DATA_TYPE_NCHAR = 10,   // unicode string
+        TSDB_DATA_TYPE_UTINYINT = 11,// 1 byte
+        TSDB_DATA_TYPE_USMALLINT = 12,// 2 bytes
+        TSDB_DATA_TYPE_UINT = 13,    // 4 bytes
+        TSDB_DATA_TYPE_UBIGINT = 14   // 8 bytes
+    }
+
+    enum TDengineInitOption
+    {
+        TSDB_OPTION_LOCALE = 0,
+        TSDB_OPTION_CHARSET = 1,
+        TSDB_OPTION_TIMEZONE = 2,
+        TDDB_OPTION_CONFIGDIR = 3,
+        TDDB_OPTION_SHELL_ACTIVITY_TIMER = 4
+    }
+    enum TDengineSchemalessProtocol
+    {
+        TSDB_SML_UNKNOWN_PROTOCOL = 0,
+        TSDB_SML_LINE_PROTOCOL = 1,
+        TSDB_SML_TELNET_PROTOCOL = 2,
+        TSDB_SML_JSON_PROTOCOL = 3
+
+    }
+    enum TDengineSchemalessPrecision
+    {
+        TSDB_SML_TIMESTAMP_NOT_CONFIGURED = 0,
+        TSDB_SML_TIMESTAMP_HOURS = 1,
+        TSDB_SML_TIMESTAMP_MINUTES = 2,
+        TSDB_SML_TIMESTAMP_SECONDS = 3,
+        TSDB_SML_TIMESTAMP_MILLI_SECONDS = 4,
+        TSDB_SML_TIMESTAMP_MICRO_SECONDS = 5,
+        TSDB_SML_TIMESTAMP_NANO_SECONDS = 6
+    }
+
+    class TDengineMeta
+    {
+        public string name;
+        public short size;
+        public byte type;
+        public string TypeName()
+        {
+            switch ((TDengineDataType)type)
+            {
+                case TDengineDataType.TSDB_DATA_TYPE_BOOL:
+                    return "BOOL";
+                case TDengineDataType.TSDB_DATA_TYPE_TINYINT:
+                    return "TINYINT";
+                case TDengineDataType.TSDB_DATA_TYPE_SMALLINT:
+                    return "SMALLINT";
+                case TDengineDataType.TSDB_DATA_TYPE_INT:
+                    return "INT";
+                case TDengineDataType.TSDB_DATA_TYPE_BIGINT:
+                    return "BIGINT";
+                case TDengineDataType.TSDB_DATA_TYPE_UTINYINT:
+                    return "TINYINT UNSIGNED";
+                case TDengineDataType.TSDB_DATA_TYPE_USMALLINT:
+                    return "SMALLINT UNSIGNED";
+                case TDengineDataType.TSDB_DATA_TYPE_UINT:
+                    return "INT UNSIGNED";
+                case TDengineDataType.TSDB_DATA_TYPE_UBIGINT:
+                    return "BIGINT UNSIGNED";
+                case TDengineDataType.TSDB_DATA_TYPE_FLOAT:
+                    return "FLOAT";
+                case TDengineDataType.TSDB_DATA_TYPE_DOUBLE:
+                    return "DOUBLE";
+                case TDengineDataType.TSDB_DATA_TYPE_BINARY:
+                    return "STRING";
+                case TDengineDataType.TSDB_DATA_TYPE_TIMESTAMP:
+                    return "TIMESTAMP";
+                case TDengineDataType.TSDB_DATA_TYPE_NCHAR:
+                    return "NCHAR";
+                default:
+                    return "undefine";
+            }
+        }
+    }
+
+    class TDengine
+    {
+        public const int TSDB_CODE_SUCCESS = 0;
+
+        [DllImport("taos", EntryPoint = "taos_init", CallingConvention = CallingConvention.Cdecl)]
+        static extern public void Init();
+
+        [DllImport("taos", EntryPoint = "taos_cleanup", CallingConvention = CallingConvention.Cdecl)]
+        static extern public void Cleanup();
+
+        [DllImport("taos", EntryPoint = "taos_options", CallingConvention = CallingConvention.Cdecl)]
+        static extern public void Options(int option, string value);
+
+        [DllImport("taos", EntryPoint = "taos_connect", CallingConvention = CallingConvention.Cdecl)]
+        static extern public IntPtr Connect(string ip, string user, string password, string db, short port);
+
+        [DllImport("taos", EntryPoint = "taos_errstr", CallingConvention = CallingConvention.Cdecl)]
+        static extern private IntPtr taos_errstr(IntPtr res);
+        static public string Error(IntPtr res)
+        {
+            IntPtr errPtr = taos_errstr(res);
+            return Marshal.PtrToStringAnsi(errPtr);
+        }
+
+        [DllImport("taos", EntryPoint = "taos_errno", CallingConvention = CallingConvention.Cdecl)]
+        static extern public int ErrorNo(IntPtr res);
+
+        [DllImport("taos", EntryPoint = "taos_query", CallingConvention = CallingConvention.Cdecl)]
+        static extern public IntPtr Query(IntPtr conn, string sqlstr);
+
+        [DllImport("taos", EntryPoint = "taos_affected_rows", CallingConvention = CallingConvention.Cdecl)]
+        static extern public int AffectRows(IntPtr res);
+
+        [DllImport("taos", EntryPoint = "taos_field_count", CallingConvention = CallingConvention.Cdecl)]
+        static extern public int FieldCount(IntPtr res);
+
+        [DllImport("taos", EntryPoint = "taos_fetch_fields", CallingConvention = CallingConvention.Cdecl)]
+        static extern private IntPtr taos_fetch_fields(IntPtr res);
+        static public List<TDengineMeta> FetchFields(IntPtr res)
+        {
+            const int fieldSize = 68;
+
+            List<TDengineMeta> metas = new List<TDengineMeta>();
+            if (res == IntPtr.Zero)
+            {
+                return metas;
+            }
+
+            int fieldCount = FieldCount(res);
+            IntPtr fieldsPtr = taos_fetch_fields(res);
+
+            for (int i = 0; i < fieldCount; ++i)
+            {
+                int offset = i * fieldSize;
+
+                TDengineMeta meta = new TDengineMeta();
+                meta.name = Marshal.PtrToStringAnsi(fieldsPtr + offset);
+                meta.type = Marshal.ReadByte(fieldsPtr + offset + 65);
+                meta.size = Marshal.ReadInt16(fieldsPtr + offset + 66);
+                metas.Add(meta);
+            }
+
+            return metas;
+        }
+
+        [DllImport("taos", EntryPoint = "taos_fetch_row", CallingConvention = CallingConvention.Cdecl)]
+        static extern public IntPtr FetchRows(IntPtr res);
+
+        [DllImport("taos", EntryPoint = "taos_free_result", CallingConvention = CallingConvention.Cdecl)]
+        static extern public IntPtr FreeResult(IntPtr res);
+
+        [DllImport("taos", EntryPoint = "taos_close", CallingConvention = CallingConvention.Cdecl)]
+        static extern public int Close(IntPtr taos);
+
+        //get precision in  restultset
+        [DllImport("taos", EntryPoint = "taos_result_precision", CallingConvention = CallingConvention.Cdecl)]
+        static extern public int ResultPrecision(IntPtr taos);
+
+        //schemaless API 
+        [DllImport("taos",SetLastError = true, EntryPoint = "taos_schemaless_insert", CallingConvention = CallingConvention.Cdecl)]
+        static extern public IntPtr SchemalessInsert(IntPtr taos, string[] lines, int numLines, int protocol, int precision);
+    }
+}

examples/C#/schemaless/schemaless.csproj

+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net5.0</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="TDengine.Connector" Version="1.0.2" />
+  </ItemGroup>
+
+</Project>

examples/C#/schemaless/schemalessSample.cs

+/*
+ * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
+ *
+ * This program is free software: you can use, redistribute, and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3
+ * or later ("AGPL"), as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+using System;
+using System.Text;
+using System.Collections.Generic;
+using System.Runtime.InteropServices;
+using System.Collections;
+
+namespace TDengineDriver
+{
+    class SchemalessSample
+    {
+        // connect parameters 
+        private string host = "127.0.0.1";
+        private string configDir = "C:/TDengine/cfg";
+        private string user = "root";
+        private string passwd = "taosdata";
+        private short port = 0;
+
+        private IntPtr conn = IntPtr.Zero;
+        private string dbName = "csharp";
+        private string dbPrecision = "ms";
+
+        static void Main(string[] args)
+        {
+            string[] lines = {
+                "stg,t1=3i64,t2=4f64,t3=\"t3\" c1=3i64,c3=L\"passit\",c2=false,c4=4f64 1626006833639000000",
+                "stg,t1=4i64,t3=\"t4\",t2=5f64,t4=5f64 c1=3i64,c3=L\"passitagin\",c2=true,c4=5f64,c5=5f64 1626006833641000000"
+            };
+            string[] jsonStr = {
+                "{"
+                   +"\"metric\": \"stb0_0\","
+                   +"\"timestamp\": 1626006833,"
+                   +"\"value\": 10,"
+                   +"\"tags\": {"
+                       +" \"t1\": true,"
+                       +"\"t2\": false,"
+                       +"\"t3\": 10,"
+                       +"\"t4\": \"123_abc_.!@#$%^&*:;,./?|+-=()[]{}<>\""
+                    +"}"
+                +"}"
+            };
+
+            SchemalessSample sample = new SchemalessSample();
+            sample.InitTDengine();
+            sample.ConnectTDengine();
+            sample.dropDatabase();
+            sample.createDatabase();
+            sample.useDatabase();
+            sample.schemalessInsert(lines, 2, (int)TDengineSchemalessProtocol.TSDB_SML_LINE_PROTOCOL, (int)TDengineSchemalessPrecision.TSDB_SML_TIMESTAMP_NANO_SECONDS);
+            sample.checkSelect("stg");
+            sample.schemalessInsert(jsonStr,1,(int)TDengineSchemalessProtocol.TSDB_SML_JSON_PROTOCOL,(int)TDengineSchemalessPrecision.TSDB_SML_TIMESTAMP_SECONDS);
+            sample.checkSelect("stb0_0");
+            sample.CloseConnection();
+            sample.cleanup();
+        }
+
+        public void InitTDengine()
+        {
+            TDengine.Options((int)TDengineInitOption.TDDB_OPTION_CONFIGDIR, this.configDir);
+            TDengine.Options((int)TDengineInitOption.TDDB_OPTION_SHELL_ACTIVITY_TIMER, "60");
+            Console.WriteLine("init...");
+            TDengine.Init();
+            Console.WriteLine("get connection starting...");
+        }
+
+        public void ConnectTDengine()
+        {
+            string db = "";
+            this.conn = TDengine.Connect(host, this.user, this.passwd, db, this.port);
+            if (this.conn == IntPtr.Zero)
+            {
+                Console.WriteLine("connection failed: " + this.host);
+                ExitProgram();
+            }
+            else
+            {
+                Console.WriteLine("[ OK ] Connection established.");
+            }
+        }
+        public void createDatabase()
+        {
+            StringBuilder sql = new StringBuilder();
+            sql.Append("create database if not exists ").Append(this.dbName).Append(" precision '").Append(this.dbPrecision).Append("'");
+            execute(sql.ToString());
+        }
+        public void useDatabase()
+        {
+            StringBuilder sql = new StringBuilder();
+            sql.Append("use ").Append(this.dbName);
+            execute(sql.ToString());
+        }
+        public void checkSelect(String tableName)
+        {
+            StringBuilder sql = new StringBuilder();
+            sql.Append("select * from ").Append(this.dbName).Append(".").Append(tableName);
+            ExecuteQuery(sql.ToString());
+        }
+
+        public void schemalessInsert(string[] sqlstr, int lineCnt, int protocol, int precision)
+        {
+
+            IntPtr res = TDengine.SchemalessInsert(this.conn, sqlstr, lineCnt, protocol, precision);
+
+            if (TDengine.ErrorNo(res) != 0)
+            {
+                Console.WriteLine("schemaless_insert failed:{0}", TDengine.Error(res));
+                Console.WriteLine("line string:{0}", sqlstr);
+                Console.WriteLine("");
+                ExitProgram();
+            }
+            else
+            {
+                Console.WriteLine("else");
+                Console.WriteLine("schemaless insert success:{0}", TDengine.ErrorNo(res));
+            }
+            DisplayRes(res);
+        }
+        public void dropDatabase()
+        {
+            StringBuilder sql = new StringBuilder();
+            sql.Append("drop database if exists ").Append(this.dbName);
+            execute(sql.ToString());
+        }
+        public void execute(string sql)
+        {
+            DateTime dt1 = DateTime.Now;
+
+            IntPtr res = TDengine.Query(this.conn, sql.ToString());
+
+            DateTime dt2 = DateTime.Now;
+            TimeSpan span = dt2 - dt1;
+            
+            if ((res == IntPtr.Zero) || (TDengine.ErrorNo(res) != 0))
+            {
+                Console.Write(sql.ToString() + " failure, ");
+                if (res != IntPtr.Zero)
+                {
+                    Console.Write("reason: " + TDengine.Error(res));
+                }
+                Console.WriteLine("");
+                ExitProgram();
+            }
+            else
+            {
+                Console.WriteLine(sql.ToString() + " success");
+            }
+            TDengine.FreeResult(res);
+        }
+        public void DisplayRes(IntPtr res)
+        {
+            long queryRows = 0;
+            int fieldCount = TDengine.FieldCount(res);
+
+            List<TDengineMeta> metas = TDengine.FetchFields(res);
+            for (int j = 0; j < metas.Count; j++)
+            {
+                TDengineMeta meta = (TDengineMeta)metas[j];
+            }
+
+            IntPtr rowdata;
+            StringBuilder builder = new StringBuilder();
+            while ((rowdata = TDengine.FetchRows(res)) != IntPtr.Zero)
+            {
+                queryRows++;
+                for (int fields = 0; fields < fieldCount; ++fields)
+                {
+                    TDengineMeta meta = metas[fields];
+                    int offset = IntPtr.Size * fields;
+                    IntPtr data = Marshal.ReadIntPtr(rowdata, offset);
+
+                    builder.Append("---");
+
+                    if (data == IntPtr.Zero)
+                    {
+                        builder.Append("NULL");
+                        continue;
+                    }
+
+                    switch ((TDengineDataType)meta.type)
+                    {
+                        case TDengineDataType.TSDB_DATA_TYPE_BOOL:
+                            bool v1 = Marshal.ReadByte(data) == 0 ? false : true;
+                            builder.Append(v1);
+                            break;
+                        case TDengineDataType.TSDB_DATA_TYPE_TINYINT:
+                            byte v2 = Marshal.ReadByte(data);
+                            builder.Append(v2);
+                            break;
+                        case TDengineDataType.TSDB_DATA_TYPE_SMALLINT:
+                            short v3 = Marshal.ReadInt16(data);
+                            builder.Append(v3);
+                            break;
+                        case TDengineDataType.TSDB_DATA_TYPE_INT:
+                            int v4 = Marshal.ReadInt32(data);
+                            builder.Append(v4);
+                            break;
+                        case TDengineDataType.TSDB_DATA_TYPE_BIGINT:
+                            long v5 = Marshal.ReadInt64(data);
+                            builder.Append(v5);
+                            break;
+                        case TDengineDataType.TSDB_DATA_TYPE_FLOAT:
+                            float v6 = (float)Marshal.PtrToStructure(data, typeof(float));
+                            builder.Append(v6);
+                            break;
+                        case TDengineDataType.TSDB_DATA_TYPE_DOUBLE:
+                            double v7 = (double)Marshal.PtrToStructure(data, typeof(double));
+                            builder.Append(v7);
+                            break;
+                        case TDengineDataType.TSDB_DATA_TYPE_BINARY:
+                            string v8 = Marshal.PtrToStringAnsi(data);
+                            builder.Append(v8);
+                            break;
+                        case TDengineDataType.TSDB_DATA_TYPE_TIMESTAMP:
+                            long v9 = Marshal.ReadInt64(data);
+                            builder.Append(v9);
+                            break;
+                        case TDengineDataType.TSDB_DATA_TYPE_NCHAR:
+                            string v10 = Marshal.PtrToStringAnsi(data);
+                            builder.Append(v10);
+                            break;
+                    }
+                }
+                builder.Append("---");
+
+                if (queryRows <= 10)
+                {
+                    Console.WriteLine(builder.ToString());
+                }
+                builder.Clear();
+            }
+
+            if (TDengine.ErrorNo(res) != 0)
+            {
+                Console.Write("Query is not complete, Error {0:G}", TDengine.ErrorNo(res), TDengine.Error(res));
+            }
+            Console.WriteLine("");
+
+            TDengine.FreeResult(res);
+
+        }
+        public void ExecuteQuery(string sql)
+        {
+
+            DateTime dt1 = DateTime.Now;
+
+            IntPtr res = TDengine.Query(conn, sql);
+
+            DateTime dt2 = DateTime.Now;
+            TimeSpan span = dt2 - dt1;
+
+            if ((res == IntPtr.Zero) || (TDengine.ErrorNo(res) != 0))
+            {
+                Console.Write(sql.ToString() + " failure, ");
+                if (res != IntPtr.Zero)
+                {
+                    Console.Write("reason: " + TDengine.Error(res));
+                }
+                Console.WriteLine("");
+                ExitProgram();
+            }
+
+            Console.WriteLine("[OK] time cost: " + span.ToString() + "ms, execute statement ====> " + sql.ToString());
+            DisplayRes(res);
+
+        }
+
+        public void CloseConnection()
+        {
+            if (this.conn != IntPtr.Zero)
+            {
+                TDengine.Close(this.conn);
+                Console.WriteLine("connection closed.");
+            }
+        }
+
+        static void ExitProgram()
+        {
+            System.Environment.Exit(0);
+        }
+
+        public void cleanup()
+        {
+            Console.WriteLine("clean up...");
+            System.Environment.Exit(0);
+        }
+        // method to get db precision
+    }
+}

examples/C#/stmt/stmt.csproj

+<Project Sdk="Microsoft.NET.Sdk">
+
+  <ItemGroup>
+    <PackageReference Include="TDengine.Connector" Version="1.0.2" />
+  </ItemGroup>
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net5.0</TargetFramework>
+  </PropertyGroup>
+
+</Project>

examples/C#/taosdemo/Dockerfile

+FROM tdengine/tdengine-beta:latest
+
+ENV DEBIAN_FRONTEND=noninteractive
+ARG MIRROR=archive.ubuntu.com
+RUN sed -Ei 's/\w+.ubuntu.com/'${MIRROR}'/' /etc/apt/sources.list && apt update && apt install mono-devel -y
+RUN apt-get install wget -y \
+  && wget https://packages.microsoft.com/config/ubuntu/18.04/packages-microsoft-prod.deb -O packages-microsoft-prod.deb \
+  && dpkg -i packages-microsoft-prod.deb \
+  && rm packages-microsoft-prod.deb \
+  && apt-get update && apt-get install -y dotnet-sdk-5.0
+COPY ./*.cs *.csproj /tmp/
+WORKDIR /tmp/
+RUN dotnet build -c Release && cp bin/Release/net5.0/taosdemo bin/Release/net5.0/taosdemo.* /usr/local/bin/ && rm -rf /tmp/*
+
+FROM tdengine/tdengine-beta:latest
+
+ENV DEBIAN_FRONTEND=noninteractive
+RUN apt-get update && apt-get install wget -y \
+  && wget https://packages.microsoft.com/config/ubuntu/18.04/packages-microsoft-prod.deb -O packages-microsoft-prod.deb \
+  && dpkg -i packages-microsoft-prod.deb \
+  && rm packages-microsoft-prod.deb \
+  && apt-get update && apt-get install -y dotnet-runtime-5.0
+COPY --from=0 /usr/local/bin/taosdemo* /usr/local/bin/
+CMD ["/usr/local/bin/taosdemo"]

examples/C#/taosdemo/README.md

+# C# Taosdemo
+
+## For Mono
+
+install build environment
+
+```sh
+yum/apt install mono-complete
+```
+
+build C# version taosdemo.
+
+```sh
+mcs -out:taosdemo *.cs
+./taosdemo --help
+```
+
+## For DotNet
+
+install dotnet environment.
+
+```sh
+wget https://packages.microsoft.com/config/ubuntu/18.04/packages-microsoft-prod.deb -O packages-microsoft-prod.deb \
+  && dpkg -i packages-microsoft-prod.deb \
+  && rm packages-microsoft-prod.deb \
+  && apt-get update && apt-get install -y dotnet-sdk-5.0
+```
+
+Build DotNet version taosdemo.
+
+```sh
+dotnet build -c Release
+./bin/Release/net5.0/taosdemo --help
+```
+
+## Usage
+
+```
+Usage: mono taosdemo.exe [OPTION...]
+
+        --help                   Show usage.
+
+        -h <hostname>            host, The host to connect to TDengine. Default is localhost.
+        -p <port>                port, The TCP/IP port number to use for the connection. Default is 0.
+        -u <username>            user, The user name to use when connecting to the server. Default is 'root'.
+        -P <password>            password, The password to use when connecting to the server. Default is 'taosdata'.
+        -d <dbname>              database, Destination database. Default is 'test'.
+        -a <replications>        replica, Set the replica parameters of the database, Default 1, min: 1, max: 5.
+        -m <table prefix>        table_prefix, Table prefix name. Default is 't'.
+        -M                       stable, Use super table.
+        -s <stable prefix>       stable_prefix, STable prefix name. Default is 'st'
+        -Q <DEFAULT | command>   query, Execute query command. set 'DEFAULT' means select * from each table
+        -T <number>              num_of_threads, The number of threads. Default is 10.
+        -r <number>              num_of_records_per_req, The number of records per request. Default is 1000.
+        -t <number>              num_of_tables, The number of tables. Default is 1.
+        -n <number>              num_of_records_per_table, The number of records per table. Default is 1.
+        -c <path>                config_directory, Configuration directory. Default is '/etc/taos/'.
+        -x                       flag, Insert only flag.
+        -O                       order, Insert mode--0: In order, 1: Out of order. Default is in order.
+        -R <number>              rate, Out of order data's rate--if order=1 Default 10, min: 0, max: 50.
+        -D <number>              Delete data methods 0: don't delete, 1: delete by table, 2: delete by stable, 3: delete by database.
+        -v                       Print verbose output
+        -g                       Print debug output
+        -y                       Skip read key for continous test, default is not skip
+```

examples/C#/taosdemo/taosdemo.csproj

+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net5.0</TargetFramework>
+    <GenerateAssemblyInfo>false</GenerateAssemblyInfo>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="TDengine.Connector" Version="1.0.2" />
+  </ItemGroup>
+
+</Project>

examples/JDBC/JDBCDemo/README-jdbc-windows.md

+# 如何在 windows环境下使用jdbc进行TDengine应用开发
+
+本文以windows环境为例，介绍java如何进行TDengine开发应用
+
+## 环境准备
+
+（1）安装jdk
+
+官网下载jdk-1.8，下载页面：https://www.oracle.com/java/technologies/javase/javase-jdk8-downloads.html
+
+安装，配置环境变量，把jdk加入到环境变量里。
+
+命令行内查看java的版本。
+
+```shell
+>java -version
+java version "1.8.0_131"
+Java(TM) SE Runtime Environment (build 1.8.0_131-b11)
+Java HotSpot(TM) 64-Bit Server VM (build 25.131-b11, mixed mode)
+```
+
+
+（2）安装配置maven
+
+官网下载maven，下载地址：http://maven.apache.org/download.cgi
+
+配置环境变量MAVEN_HOME，将MAVEN_HOME/bin添加到PATH
+
+命令行里查看maven的版本
+
+```shell
+>mvn --version
+Apache Maven 3.5.0 (ff8f5e7444045639af65f6095c62210b5713f426; 2017-04-04T03:39:06+08:00)
+Maven home: D:\apache-maven-3.5.0\bin\..
+Java version: 1.8.0_131, vendor: Oracle Corporation
+Java home: C:\Program Files\Java\jdk1.8.0_131\jre
+Default locale: zh_CN, platform encoding: GBK
+OS name: "windows 10", version: "10.0", arch: "amd64", family: "windows"
+```
+
+为了加快maven下载依赖的速度，可以为maven配置mirror，修改MAVEN_HOME\config\settings.xml文件
+
+```xml
+<settings xmlns="http://maven.apache.org/SETTINGS/1.0.0"
+          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+          xsi:schemaLocation="http://maven.apache.org/SETTINGS/1.0.0 http://maven.apache.org/xsd/settings-1.0.0.xsd">
+	<!-- 配置本地maven仓库的路径 -->
+    <localRepository>D:\apache-maven-localRepository</localRepository>
+    
+    <mirrors>
+        <!-- 配置阿里云Maven镜像仓库 -->
+		<mirror>
+			<id>alimaven</id>
+			<name>aliyun maven</name>
+			<url>http://maven.aliyun.com/nexus/content/groups/public/</url>
+			<mirrorOf>central</mirrorOf>
+		</mirror>
+    </mirrors>
+    
+    <profiles>
+        <!-- 配置jdk，maven会默认使用java1.8 -->
+        <profile>
+            <id>jdk-1.8</id>
+            <activation>
+                <activeByDefault>true</activeByDefault>
+                <jdk>1.8</jdk>
+            </activation>
+            <properties>
+                <maven.compiler.source>1.8</maven.compiler.source>
+                <maven.compiler.target>1.8</maven.compiler.target>
+                <maven.compiler.compilerVersion>1.8</maven.compiler.compilerVersion>
+            </properties>
+        </profile>
+    </profiles>
+</settings>
+```
+
+
+
+（3）在linux服务器上安装TDengine-server
+
+在taosdata官网下载TDengine-server，下载地址：https://www.taosdata.com/cn/all-downloads/
+
+在linux服务器上安装TDengine-server
+
+```shell
+# tar -zxvf package/TDengine-server-2.0.1.1-Linux-x64.tar.gz 
+# cd TDengine-server/
+# ./install.sh 
+```
+
+启动taosd
+
+```shell
+# systemctl start taosd
+```
+
+在server上用taos连接taosd
+
+```shell
+# taos
+taos> show dnodes;
+   id   |           end_point            | vnodes | cores  |     status     |   role   |       create_time       |
+==================================================================================================================
+      1 | td01:6030                      |      2 |      4 | ready          | any      | 2020-08-19 18:40:25.045 |
+Query OK, 1 row(s) in set (0.005765s)
+```
+
+如果可以正确连接到taosd实例，并打印出databases的信息，说明TDengine的server已经正确启动。这里查看server的hostname
+
+```shell
+# hostname -f
+td01
+```
+
+注意，如果安装TDengine后，使用默认的taos.cfg配置文件，taosd会使用当前server的hostname创建dnode实例。之后，在client也需要使用这个hostname来连接taosd。
+
+
+
+（4）在windows上安装TDengine-client
+
+在taosdata官网下载taos客户端，下载地址：
+https://www.taosdata.com/cn/all-downloads/
+下载后，双击exe安装。
+
+修改client的hosts文件（C:\Windows\System32\drivers\etc\hosts），将server的hostname和ip配置到client的hosts文件中
+
+```
+192.168.236.136	td01
+```
+
+配置完成后，在命令行内使用taos shell连接server端
+
+```shell
+C:\TDengine>taos -h td01
+Welcome to the TDengine shell from Linux, Client Version:2.0.1.1
+Copyright (c) 2017 by TAOS Data, Inc. All rights reserved.
+
+taos> show databases;
+              name              |      created_time       |   ntables   |   vgroups   | replica | quorum |  days  |    keep0,keep1,keep(D)     |  cache(MB)  |   blocks    |   minrows   |   maxrows   | wallevel |    fsync    | comp | precision |    status    |
+===================================================================================================================================================================================================================================================================
+ test                           | 2020-08-19 18:43:50.731 |           1 |           1 |       1 |      1 |      2 | 3650,3650,3650             |          16 |           6 |         100 |        4096 |        1 |        3000 |    2 | ms        | ready        |
+ log                            | 2020-08-19 18:40:28.064 |           4 |           1 |       1 |      1 |     10 | 30,30,30                   |           1 |           3 |         100 |        4096 |        1 |        3000 |    2 | us        | ready        |
+Query OK, 2 row(s) in set (0.068000s)
+```
+
+如果windows上的client能够正常连接，并打印database信息，说明client可以正常连接server了。
+
+
+
+## 应用开发
+
+（1）新建maven工程，在pom.xml中引入taos-jdbcdriver依赖。
+
+```xml
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>com.taosdata.demo</groupId>
+    <artifactId>JdbcDemo</artifactId>
+    <version>1.0-SNAPSHOT</version>
+
+    <dependencies>
+        <dependency>
+            <groupId>com.taosdata.jdbc</groupId>
+            <artifactId>taos-jdbcdriver</artifactId>
+            <version>2.0.8</version>
+        </dependency>
+    </dependencies>
+</project>
+```
+
+（2）使用jdbc查询TDengine数据库
+
+下面是示例代码：
+
+```java
+public class JdbcDemo {
+
+    public static void main(String[] args) throws Exception {
+        Connection conn = getConn();
+        Statement stmt = conn.createStatement();
+        // create database
+        stmt.executeUpdate("create database if not exists db");
+        // use database
+        stmt.executeUpdate("use db");
+        // create table
+        stmt.executeUpdate("create table if not exists tb (ts timestamp, temperature int, humidity float)");
+        // insert data
+        int affectedRows = stmt.executeUpdate("insert into tb values(now, 23, 10.3) (now + 1s, 20, 9.3)");
+        System.out.println("insert " + affectedRows + " rows.");
+        // query data
+        ResultSet resultSet = stmt.executeQuery("select * from tb");
+        Timestamp ts = null;
+        int temperature = 0;
+        float humidity = 0;
+        while(resultSet.next()){
+            ts = resultSet.getTimestamp(1);
+            temperature = resultSet.getInt(2);
+            humidity = resultSet.getFloat("humidity");
+            System.out.printf("%s, %d, %s\n", ts, temperature, humidity);
+        }
+    }
+
+    public static Connection getConn() throws Exception{
+        Class.forName("com.taosdata.jdbc.TSDBDriver");
+        String jdbcUrl = "jdbc:TAOS://td01:0/log?user=root&password=taosdata";
+        Properties connProps = new Properties();
+        connProps.setProperty(TSDBDriver.PROPERTY_KEY_CHARSET, "UTF-8");
+        connProps.setProperty(TSDBDriver.PROPERTY_KEY_LOCALE, "en_US.UTF-8");
+        connProps.setProperty(TSDBDriver.PROPERTY_KEY_TIME_ZONE, "UTC-8");
+        Connection conn = DriverManager.getConnection(jdbcUrl, connProps);
+        return conn;
+    }
+
+}
+```
+
+（3）测试jdbc访问tdengine的sever实例
+
+console输出：
+
+```
+insert 2 rows.
+2020-08-26 00:06:34.575, 23, 10.3
+2020-08-26 00:06:35.575, 20, 9.3
+```
+
+
+
+## 指南
+
+（1）如何设置主机名和hosts
+
+在server上查看hostname和fqdn
+```shell
+查看hostname
+# hostname
+taos-server
+
+查看fqdn
+# hostname -f
+taos-server
+```
+
+windows下hosts文件位于：
+C:\\Windows\System32\drivers\etc\hosts
+修改hosts文件，添加server的ip和hostname
+
+```s
+192.168.56.101  node5
+```
+
+（2）什么是fqdn？
+
+
+> 什么是FQDN？
+>
+> FQDN（Full qualified domain name）全限定域名，fqdn由2部分组成：hostname+domainname。
+>
+> 例如，一个邮件服务器的fqdn可能是：mymail.somecollege.edu，其中mymail是hostname（主机名），somcollege.edu是domainname（域名）。本例中，.edu是顶级域名，.somecollege是二级域名。
+>
+> 当连接服务器时，必须指定fqdn，然后，dns服务器通过查看dns表，将hostname解析为相应的ip地址。如果只指定hostname（不指定domainname），应用程序可能服务解析主机名。因为如果你试图访问不在本地的远程服务器时，本地的dns服务器和可能没有远程服务器的hostname列表。
+>
+> 参考：https://kb.iu.edu/d/aiuv

examples/JDBC/JDBCDemo/pom.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>com.taosdata.jdbc</groupId>
+    <artifactId>JDBCDemo</artifactId>
+    <version>SNAPSHOT</version>
+    <packaging>jar</packaging>
+
+    <properties>
+        <project.assembly.dir>src/main/resources/assembly</project.assembly.dir>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>com.taosdata.jdbc</groupId>
+            <artifactId>taos-jdbcdriver</artifactId>
+            <version>2.0.36</version>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-assembly-plugin</artifactId>
+                <version>3.3.0</version>
+                <executions>
+                    <!-- jdbcDemo -->
+                    <execution>
+                        <id>JdbcDemo</id>
+                        <configuration>
+                            <finalName>JdbcDemo</finalName>
+                            <archive>
+                                <manifest>
+                                    <mainClass>com.taosdata.example.JdbcDemo</mainClass>
+                                </manifest>
+                            </archive>
+                            <descriptorRefs>
+                                <descriptorRef>jar-with-dependencies</descriptorRef>
+                            </descriptorRefs>
+                        </configuration>
+                        <phase>package</phase>
+                        <goals>
+                            <goal>single</goal>
+                        </goals>
+                    </execution>
+
+                    <execution>
+                        <id>JdbcRestfulDemo</id>
+                        <configuration>
+                            <finalName>JdbcRestfulDemo</finalName>
+                            <archive>
+                                <manifest>
+                                    <mainClass>com.taosdata.example.JdbcRestfulDemo</mainClass>
+                                </manifest>
+                            </archive>
+                            <descriptorRefs>
+                                <descriptorRef>jar-with-dependencies</descriptorRef>
+                            </descriptorRefs>
+                        </configuration>
+                        <phase>package</phase>
+                        <goals>
+                            <goal>single</goal>
+                        </goals>
+                    </execution>
+
+                    <execution>
+                        <id>SubscribeDemo</id>
+                        <configuration>
+                            <finalName>SubscribeDemo</finalName>
+                            <archive>
+                                <manifest>
+                                    <mainClass>com.taosdata.example.SubscribeDemo</mainClass>
+                                </manifest>
+                            </archive>
+                            <descriptorRefs>
+                                <descriptorRef>jar-with-dependencies</descriptorRef>
+                            </descriptorRefs>
+                        </configuration>
+                        <phase>package</phase>
+                        <goals>
+                            <goal>single</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <source>8</source>
+                    <target>8</target>
+                    <encoding>UTF-8</encoding>
+                </configuration>
+            </plugin>
+
+        </plugins>
+    </build>
+
+</project>

examples/JDBC/JDBCDemo/readme.md

+# How to Run the JDBC Demo Code On Linux OS
+TDengine's JDBC demo project is organized in a Maven way so that users can easily compile, package and run the project. If you don't have Maven on your server, you may install it using
+```
+sudo apt-get install maven
+```
+
+## Install TDengine Client
+Make sure you have already installed a tdengine client on your current develop environment.
+Download the tdengine package on our website: ``https://www.taosdata.com/cn/all-downloads/`` and install the client.
+
+## Run jdbcDemo using mvn plugin
+run command:
+```
+mvn clean compile exec:java -Dexec.mainClass="com.taosdata.example.JdbcDemo"
+```
+
+and run with your customed args
+```
+mvn clean compile exec:java -Dexec.mainClass="com.taosdata.example.JdbcDemo" -Dexec.args="-host [HOSTNAME]"
+```
+
+## Compile the Demo Code and Run It
+To compile taos-jdbcdriver, go to the source directory ``TDengine/src/connector/jdbc`` and execute
+```
+mvn clean package -Dmaven.test.skip=true
+```
+
+To compile the demo project, go to the source directory ``TDengine/tests/examples/JDBC/JDBCDemo`` and execute
+```
+mvn clean package assembly:single
+```
+
+To run JDBCDemo.jar, go to ``TDengine/tests/examples/JDBC/JDBCDemo`` and execute
+```
+java -Djava.ext.dirs=../../../../src/connector/jdbc/target:$JAVA_HOME/jre/lib/ext -jar target/JDBCDemo-SNAPSHOT-jar-with-dependencies.jar -host [HOSTNAME]
+```
+

examples/JDBC/JDBCDemo/src/main/java/com/taosdata/example/BatchInsert.java

+package com.taosdata.example;
+
+import java.sql.*;
+import java.util.*;
+
+public class BatchInsert {
+
+    private static final String host = "127.0.0.1";    
+    private static final String user = "root";
+    private static final String password = "taosdata";
+
+
+    private static final String dbname = "test";
+    private static final String stbname = "stb";
+    private static final int tables= 100;
+    private static final int rows = 500;
+    private static final long ts = 1604877767000l;
+
+    private Connection conn;
+    
+    private void init() {
+        // final String url = "jdbc:TAOS://" + host + ":6030/?user=" + user + "&password=" + password;
+        final String url = "jdbc:TAOS-RS://" + host + ":6041/?user=" + user + "&password=" + password;
+        
+        // get connection
+        try {
+            Properties properties = new Properties();
+            properties.setProperty("charset", "UTF-8");
+            properties.setProperty("locale", "en_US.UTF-8");
+            properties.setProperty("timezone", "UTC-8");
+            System.out.println("get connection starting...");
+            conn = DriverManager.getConnection(url, properties);
+            if (conn != null){
+                System.out.println("[ OK ] Connection established.");
+            }
+            
+            Statement stmt = conn.createStatement();
+
+            stmt.execute("drop database if exists " + dbname);
+            stmt.execute("create database if not exists " + dbname);
+            stmt.execute("use " + dbname);
+            stmt.execute("create table " + dbname + "." + stbname + "(ts timestamp, col int) tags(id int)");
+
+        } catch (SQLException e) {
+            e.printStackTrace();
+        }
+    }
+
+    private String generateSql() {
+        StringBuilder sb = new StringBuilder();
+        Random rand = new Random();
+        sb.append("insert into ");
+        for (int i = 0; i < tables; i++) {
+            sb.append(dbname + ".tb" + i + " using " + dbname + "." + stbname + " tags(" + i +  ") values");
+            for (int j = 0; j < rows; j++) {
+                sb.append("(");
+                sb.append(ts + j);
+                sb.append(",");
+                sb.append(rand.nextInt(1000));
+                sb.append(") ");
+            }
+        }
+        return sb.toString();
+    }
+
+    private void executeQuery(String sql) {        
+        try (Statement stmt = conn.createStatement()) {
+            long start = System.currentTimeMillis();
+            stmt.execute(sql);
+            long end = System.currentTimeMillis();
+            
+            System.out.println("insert " + tables * rows + " records, cost " + (end - start)+ "ms");
+        } catch (SQLException ex) {
+            ex.printStackTrace();
+        }
+    }
+
+    public static void main(String[] args) {
+        BatchInsert bi = new BatchInsert();
+
+        String sql = bi.generateSql();
+        bi.init();
+        bi.executeQuery(sql);
+    }
+
+
+}

examples/JDBC/JDBCDemo/src/main/java/com/taosdata/example/ClientParameterSetting.java

+package com.taosdata.example;
+
+import com.taosdata.jdbc.TSDBDriver;
+
+import java.sql.*;
+import java.util.Properties;
+
+public class ClientParameterSetting {
+    private static final String host = "127.0.0.1";
+
+    public static void main(String[] args) throws SQLException {
+        setParameterInJdbcUrl();
+
+        setParameterInProperties();
+    }
+
+    private static void setParameterInJdbcUrl() throws SQLException {
+        String jdbcUrl = "jdbc:TAOS://" + host + ":6030/?debugFlag=135&asyncLog=0";
+
+        Connection connection = DriverManager.getConnection(jdbcUrl, "root", "taosdata");
+
+        printDatabase(connection);
+
+        connection.close();
+    }
+
+    private static void setParameterInProperties() throws SQLException {
+        String jdbcUrl = "jdbc:TAOS://" + host + ":6030/";
+        Properties properties = new Properties();
+        properties.setProperty("user", "root");
+        properties.setProperty("password", "taosdata");
+        properties.setProperty("debugFlag", "135");
+        properties.setProperty("asyncLog", "0");
+        properties.setProperty("maxSQLLength", "1048576");
+
+        try (Connection conn = DriverManager.getConnection(jdbcUrl, properties)) {
+            printDatabase(conn);
+        }
+    }
+
+    private static void printDatabase(Connection connection) throws SQLException {
+        try (Statement stmt = connection.createStatement()) {
+            ResultSet rs = stmt.executeQuery("show databases");
+
+            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();
+            }
+        }
+    }
+}

examples/JDBC/JDBCDemo/src/main/java/com/taosdata/example/JdbcDemo.java

+package com.taosdata.example;
+
+import java.sql.*;
+import java.util.Properties;
+
+public class JdbcDemo {
+    private static String host;
+    private static final String dbName = "test";
+    private static final String tbName = "weather";
+    private static final String user = "root";
+    private static final String password = "taosdata";
+
+    private Connection connection;
+
+    public static void main(String[] args) {
+        for (int i = 0; i < args.length; i++) {
+            if ("-host".equalsIgnoreCase(args[i]) && i < args.length - 1)
+                host = args[++i];
+        }
+        if (host == null) {
+            printHelp();
+        }
+        JdbcDemo demo = new JdbcDemo();
+        demo.init();
+        demo.createDatabase();
+        demo.useDatabase();
+        demo.dropTable();
+        demo.createTable();
+        demo.insert();
+        demo.select();
+        demo.dropTable();
+        demo.close();
+    }
+
+    private void init() {
+        final String url = "jdbc:TAOS://" + host + ":6030/?user=" + user + "&password=" + password;
+        // get connection
+        try {
+            Properties properties = new Properties();
+            properties.setProperty("charset", "UTF-8");
+            properties.setProperty("locale", "en_US.UTF-8");
+            properties.setProperty("timezone", "UTC-8");
+            System.out.println("get connection starting...");
+            connection = DriverManager.getConnection(url, properties);
+            if (connection != null)
+                System.out.println("[ OK ] Connection established.");
+        } catch (SQLException e) {
+            e.printStackTrace();
+        }
+    }
+
+    private void createDatabase() {
+        String sql = "create database if not exists " + dbName;
+        exuete(sql);
+    }
+
+    private void useDatabase() {
+        String sql = "use " + dbName;
+        exuete(sql);
+    }
+
+    private void dropTable() {
+        final String sql = "drop table if exists " + dbName + "." + tbName + "";
+        exuete(sql);
+    }
+
+    private void createTable() {
+        final String sql = "create table if not exists " + dbName + "." + tbName + " (ts timestamp, temperature float, humidity int)";
+        exuete(sql);
+    }
+
+    private void insert() {
+        final String sql = "insert into " + dbName + "." + tbName + " (ts, temperature, humidity) values(now, 20.5, 34)";
+        exuete(sql);
+    }
+
+    private void select() {
+        final String sql = "select * from " + dbName + "." + tbName;
+        executeQuery(sql);
+    }
+
+    private void close() {
+        try {
+            if (connection != null) {
+                this.connection.close();
+                System.out.println("connection closed.");
+            }
+        } catch (SQLException e) {
+            e.printStackTrace();
+        }
+    }
+
+    private void executeQuery(String sql) {
+        long start = System.currentTimeMillis();
+        try (Statement statement = connection.createStatement()) {
+            ResultSet resultSet = statement.executeQuery(sql);
+            long end = System.currentTimeMillis();
+            printSql(sql, true, (end - start));
+            printResult(resultSet);
+        } catch (SQLException e) {
+            long end = System.currentTimeMillis();
+            printSql(sql, false, (end - start));
+            e.printStackTrace();
+        }
+    }
+
+    private void printResult(ResultSet resultSet) throws SQLException {
+        ResultSetMetaData metaData = resultSet.getMetaData();
+        while (resultSet.next()) {
+            for (int i = 1; i <= metaData.getColumnCount(); i++) {
+                String columnLabel = metaData.getColumnLabel(i);
+                String value = resultSet.getString(i);
+                System.out.printf("%s: %s\t", columnLabel, value);
+            }
+            System.out.println();
+        }
+    }
+
+    private void printSql(String sql, boolean succeed, long cost) {
+        System.out.println("[ " + (succeed ? "OK" : "ERROR!") + " ] time cost: " + cost + " ms, execute statement ====> " + sql);
+    }
+
+    private void exuete(String sql) {
+        long start = System.currentTimeMillis();
+        try (Statement statement = connection.createStatement()) {
+            boolean execute = statement.execute(sql);
+            long end = System.currentTimeMillis();
+            printSql(sql, true, (end - start));
+        } catch (SQLException e) {
+            long end = System.currentTimeMillis();
+            printSql(sql, false, (end - start));
+            e.printStackTrace();
+        }
+    }
+
+    private static void printHelp() {
+        System.out.println("Usage: java -jar JDBCDemo.jar -host <hostname>");
+        System.exit(0);
+    }
+
+}

examples/JDBC/JDBCDemo/src/main/java/com/taosdata/example/JdbcRestfulDemo.java

+package com.taosdata.example;
+
+import java.sql.*;
+import java.util.Properties;
+
+public class JdbcRestfulDemo {
+    private static final String host = "localhost";
+    private static final String dbname = "test";
+    private static final String user = "root";
+    private static final String password = "taosdata";
+
+    public static void main(String[] args) {
+        try {
+            // use port 6041 in url when use JDBC-restful
+            String url = "jdbc:TAOS-RS://" + host + ":6041/?user=" + user + "&password=" + password;
+
+            Properties properties = new Properties();
+            properties.setProperty("charset", "UTF-8");
+            properties.setProperty("locale", "en_US.UTF-8");
+            properties.setProperty("timezone", "UTC-8");
+
+            Connection conn = DriverManager.getConnection(url, properties);
+            Statement stmt = conn.createStatement();
+
+            stmt.execute("drop database if exists " + dbname);
+            stmt.execute("create database if not exists " + dbname);
+            stmt.execute("use " + dbname);
+            stmt.execute("create table " + dbname + ".weather(ts timestamp, temperature float) tags(location nchar(64))");
+            stmt.executeUpdate("insert into t1 using " + dbname + ".weather tags('北京') values(now, 18.2)");
+            ResultSet rs = stmt.executeQuery("select * from " + dbname + ".weather");
+            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();
+            stmt.close();
+            conn.close();
+        } catch (SQLException e) {
+            e.printStackTrace();
+        }
+    }
+}

examples/JDBC/JDBCDemo/src/main/java/com/taosdata/example/ParameterBindingDemo.java

+package com.taosdata.example;
+
+import com.taosdata.jdbc.TSDBPreparedStatement;
+
+import java.sql.Connection;
+import java.sql.DriverManager;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.util.ArrayList;
+import java.util.Random;
+
+public class ParameterBindingDemo {
+
+    private static final String host = "127.0.0.1";
+    private static final Random random = new Random(System.currentTimeMillis());
+    private static final int BINARY_COLUMN_SIZE = 20;
+    private static final String[] schemaList = {
+            "create table stable1(ts timestamp, f1 tinyint, f2 smallint, f3 int, f4 bigint) tags(t1 tinyint, t2 smallint, t3 int, t4 bigint)",
+            "create table stable2(ts timestamp, f1 float, f2 double) tags(t1 float, t2 double)",
+            "create table stable3(ts timestamp, f1 bool) tags(t1 bool)",
+            "create table stable4(ts timestamp, f1 binary(" + BINARY_COLUMN_SIZE + ")) tags(t1 binary(" + BINARY_COLUMN_SIZE + "))",
+            "create table stable5(ts timestamp, f1 nchar(" + BINARY_COLUMN_SIZE + ")) tags(t1 nchar(" + BINARY_COLUMN_SIZE + "))"
+    };
+    private static final int numOfSubTable = 10, numOfRow = 10;
+
+    public static void main(String[] args) throws SQLException {
+
+        String jdbcUrl = "jdbc:TAOS://" + host + ":6030/";
+        Connection conn = DriverManager.getConnection(jdbcUrl, "root", "taosdata");
+
+        init(conn);
+
+        bindInteger(conn);
+
+        bindFloat(conn);
+
+        bindBoolean(conn);
+
+        bindBytes(conn);
+
+        bindString(conn);
+
+        conn.close();
+    }
+
+    private static void init(Connection conn) throws SQLException {
+        try (Statement stmt = conn.createStatement()) {
+            stmt.execute("drop database if exists test_parabind");
+            stmt.execute("create database if not exists test_parabind");
+            stmt.execute("use test_parabind");
+            for (int i = 0; i < schemaList.length; i++) {
+                stmt.execute(schemaList[i]);
+            }
+        }
+    }
+
+    private static void bindInteger(Connection conn) throws SQLException {
+        String sql = "insert into ? using stable1 tags(?,?,?,?) values(?,?,?,?,?)";
+
+        try (TSDBPreparedStatement pstmt = conn.prepareStatement(sql).unwrap(TSDBPreparedStatement.class)) {
+
+            for (int i = 1; i <= numOfSubTable; i++) {
+                // set table name
+                pstmt.setTableName("t1_" + i);
+                // set tags
+                pstmt.setTagByte(0, Byte.parseByte(Integer.toString(random.nextInt(Byte.MAX_VALUE))));
+                pstmt.setTagShort(1, Short.parseShort(Integer.toString(random.nextInt(Short.MAX_VALUE))));
+                pstmt.setTagInt(2, random.nextInt(Integer.MAX_VALUE));
+                pstmt.setTagLong(3, random.nextLong());
+                // set columns
+                ArrayList<Long> tsList = new ArrayList<>();
+                long current = System.currentTimeMillis();
+                for (int j = 0; j < numOfRow; j++)
+                    tsList.add(current + j);
+                pstmt.setTimestamp(0, tsList);
+
+                ArrayList<Byte> f1List = new ArrayList<>();
+                for (int j = 0; j < numOfRow; j++)
+                    f1List.add(Byte.parseByte(Integer.toString(random.nextInt(Byte.MAX_VALUE))));
+                pstmt.setByte(1, f1List);
+
+                ArrayList<Short> f2List = new ArrayList<>();
+                for (int j = 0; j < numOfRow; j++)
+                    f2List.add(Short.parseShort(Integer.toString(random.nextInt(Short.MAX_VALUE))));
+                pstmt.setShort(2, f2List);
+
+                ArrayList<Integer> f3List = new ArrayList<>();
+                for (int j = 0; j < numOfRow; j++)
+                    f3List.add(random.nextInt(Integer.MAX_VALUE));
+                pstmt.setInt(3, f3List);
+
+                ArrayList<Long> f4List = new ArrayList<>();
+                for (int j = 0; j < numOfRow; j++)
+                    f4List.add(random.nextLong());
+                pstmt.setLong(4, f4List);
+
+                // add column
+                pstmt.columnDataAddBatch();
+            }
+            // execute column
+            pstmt.columnDataExecuteBatch();
+        }
+
+    }
+
+    private static void bindFloat(Connection conn) throws SQLException {
+        String sql = "insert into ? using stable2 tags(?,?) values(?,?,?)";
+
+        TSDBPreparedStatement pstmt = conn.prepareStatement(sql).unwrap(TSDBPreparedStatement.class);
+
+        for (int i = 1; i <= numOfSubTable; i++) {
+            // set table name
+            pstmt.setTableName("t2_" + i);
+            // set tags
+            pstmt.setTagFloat(0, random.nextFloat());
+            pstmt.setTagDouble(1, random.nextDouble());
+            // set columns
+            ArrayList<Long> tsList = new ArrayList<>();
+            long current = System.currentTimeMillis();
+            for (int j = 0; j < numOfRow; j++)
+                tsList.add(current + j);
+            pstmt.setTimestamp(0, tsList);
+
+            ArrayList<Float> f1List = new ArrayList<>();
+            for (int j = 0; j < numOfRow; j++)
+                f1List.add(random.nextFloat());
+            pstmt.setFloat(1, f1List);
+
+            ArrayList<Double> f2List = new ArrayList<>();
+            for (int j = 0; j < numOfRow; j++)
+                f2List.add(random.nextDouble());
+            pstmt.setDouble(2, f2List);
+
+            // add column
+            pstmt.columnDataAddBatch();
+        }
+        // execute
+        pstmt.columnDataExecuteBatch();
+        // close if no try-with-catch statement is used
+        pstmt.close();
+    }
+
+    private static void bindBoolean(Connection conn) throws SQLException {
+        String sql = "insert into ? using stable3 tags(?) values(?,?)";
+
+        try (TSDBPreparedStatement pstmt = conn.prepareStatement(sql).unwrap(TSDBPreparedStatement.class)) {
+            for (int i = 1; i <= numOfSubTable; i++) {
+                // set table name
+                pstmt.setTableName("t3_" + i);
+                // set tags
+                pstmt.setTagBoolean(0, random.nextBoolean());
+                // set columns
+                ArrayList<Long> tsList = new ArrayList<>();
+                long current = System.currentTimeMillis();
+                for (int j = 0; j < numOfRow; j++)
+                    tsList.add(current + j);
+                pstmt.setTimestamp(0, tsList);
+
+                ArrayList<Boolean> f1List = new ArrayList<>();
+                for (int j = 0; j < numOfRow; j++)
+                    f1List.add(random.nextBoolean());
+                pstmt.setBoolean(1, f1List);
+
+                // add column
+                pstmt.columnDataAddBatch();
+            }
+            // execute
+            pstmt.columnDataExecuteBatch();
+        }
+    }
+
+    private static void bindBytes(Connection conn) throws SQLException {
+        String sql = "insert into ? using stable4 tags(?) values(?,?)";
+
+        try (TSDBPreparedStatement pstmt = conn.prepareStatement(sql).unwrap(TSDBPreparedStatement.class)) {
+
+            for (int i = 1; i <= numOfSubTable; i++) {
+                // set table name
+                pstmt.setTableName("t4_" + i);
+                // set tags
+                pstmt.setTagString(0, new String("abc"));
+
+                // set columns
+                ArrayList<Long> tsList = new ArrayList<>();
+                long current = System.currentTimeMillis();
+                for (int j = 0; j < numOfRow; j++)
+                    tsList.add(current + j);
+                pstmt.setTimestamp(0, tsList);
+
+                ArrayList<String> f1List = new ArrayList<>();
+                for (int j = 0; j < numOfRow; j++) {
+                    f1List.add(new String("abc"));
+                }
+                pstmt.setString(1, f1List, BINARY_COLUMN_SIZE);
+
+                // add column
+                pstmt.columnDataAddBatch();
+            }
+            // execute
+            pstmt.columnDataExecuteBatch();
+        }
+    }
+
+    private static void bindString(Connection conn) throws SQLException {
+        String sql = "insert into ? using stable5 tags(?) values(?,?)";
+
+        try (TSDBPreparedStatement pstmt = conn.prepareStatement(sql).unwrap(TSDBPreparedStatement.class)) {
+
+            for (int i = 1; i <= numOfSubTable; i++) {
+                // set table name
+                pstmt.setTableName("t5_" + i);
+                // set tags
+                pstmt.setTagNString(0, "北京-abc");
+
+                // set columns
+                ArrayList<Long> tsList = new ArrayList<>();
+                long current = System.currentTimeMillis();
+                for (int j = 0; j < numOfRow; j++)
+                    tsList.add(current + j);
+                pstmt.setTimestamp(0, tsList);
+
+                ArrayList<String> f1List = new ArrayList<>();
+                for (int j = 0; j < numOfRow; j++) {
+                    f1List.add("北京-abc");
+                }
+                pstmt.setNString(1, f1List, BINARY_COLUMN_SIZE);
+
+                // add column
+                pstmt.columnDataAddBatch();
+            }
+            // execute
+            pstmt.columnDataExecuteBatch();
+        }
+    }
+
+
+}

examples/JDBC/JDBCDemo/src/main/java/com/taosdata/example/SubscribeDemo.java

+package com.taosdata.example;
+
+import com.taosdata.jdbc.TSDBConnection;
+import com.taosdata.jdbc.TSDBDriver;
+import com.taosdata.jdbc.TSDBResultSet;
+import com.taosdata.jdbc.TSDBSubscribe;
+
+import java.sql.DriverManager;
+import java.sql.ResultSetMetaData;
+import java.util.Properties;
+import java.util.concurrent.TimeUnit;
+
+public class SubscribeDemo {
+    private static final String usage = "java -jar SubscribeDemo.jar -host <hostname> -database <database name> -topic <topic> -sql <sql>";
+
+    public static void main(String[] args) {
+        // parse args from command line
+        String host = "", database = "", topic = "", sql = "";
+        for (int i = 0; i < args.length; i++) {
+            if ("-host".equalsIgnoreCase(args[i]) && i < args.length - 1) {
+                host = args[++i];
+            }
+            if ("-database".equalsIgnoreCase(args[i]) && i < args.length - 1) {
+                database = args[++i];
+            }
+            if ("-topic".equalsIgnoreCase(args[i]) && i < args.length - 1) {
+                topic = args[++i];
+            }
+            if ("-sql".equalsIgnoreCase(args[i]) && i < args.length - 1) {
+                sql = args[++i];
+            }
+        }
+        if (host.isEmpty() || database.isEmpty() || topic.isEmpty() || sql.isEmpty()) {
+            System.out.println(usage);
+            return;
+        }
+
+        try {
+            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");
+            final String url = "jdbc:TAOS://" + host + ":6030/" + database + "?user=root&password=taosdata";
+            // get TSDBConnection
+            TSDBConnection connection = (TSDBConnection) DriverManager.getConnection(url, properties);
+            // create TSDBSubscribe
+            TSDBSubscribe sub = connection.subscribe(topic, sql, false);
+
+            int total = 0;
+            while (true) {
+                TSDBResultSet rs = sub.consume();
+                int count = 0;
+                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();
+                    count++;
+                }
+                total += count;
+//                System.out.printf("%d rows consumed, total %d\n", count, total);
+                if (total >= 10)
+                    break;
+                TimeUnit.SECONDS.sleep(1);
+            }
+            sub.close(false);
+            connection.close();
+        } catch (Exception e) {
+            System.out.println("host: " + host + ", database: " + database + ", topic: " + topic + ", sql: " + sql);
+            e.printStackTrace();
+        }
+    }
+}
\ No newline at end of file

examples/JDBC/SpringJdbcTemplate/.gitignore

+HELP.md
+target/
+.mvn/
+!**/src/main/**
+!**/src/test/**
+
+### STS ###
+.apt_generated
+.classpath
+.factorypath
+.project
+.settings
+.springBeans
+.sts4-cache
+
+### IntelliJ IDEA ###
+.idea
+*.iws
+*.iml
+*.ipr
+
+### NetBeans ###
+/nbproject/private/
+/nbbuild/
+/dist/
+/nbdist/
+/.nb-gradle/
+build/
+
+### VS Code ###
+.vscode/

examples/JDBC/SpringJdbcTemplate/pom.xml

+<?xml version="1.0" encoding="UTF-8"?>
+
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>com.taosdata.jdbc</groupId>
+    <artifactId>SpringJdbcTemplate</artifactId>
+    <version>1.0-SNAPSHOT</version>
+
+    <name>SpringJdbcTemplate</name>
+    <url>http://www.taosdata.com</url>
+
+    <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <maven.compiler.source>1.8</maven.compiler.source>
+        <maven.compiler.target>1.8</maven.compiler.target>
+    </properties>
+
+    <dependencies>
+
+        <dependency>
+            <groupId>org.springframework</groupId>
+            <artifactId>spring-context</artifactId>
+            <version>5.2.8.RELEASE</version>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springframework</groupId>
+            <artifactId>spring-jdbc</artifactId>
+            <version>5.1.9.RELEASE</version>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springframework</groupId>
+            <artifactId>spring-test</artifactId>
+            <version>5.1.9.RELEASE</version>
+        </dependency>
+
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>4.13.1</version>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>com.taosdata.jdbc</groupId>
+            <artifactId>taos-jdbcdriver</artifactId>
+            <version>2.0.18</version>
+        </dependency>
+
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>3.8.0</version>
+                <configuration>
+                    <source>1.8</source>
+                    <target>1.8</target>
+                </configuration>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-assembly-plugin</artifactId>
+                <version>3.1.0</version>
+                <configuration>
+                    <archive>
+                        <manifest>
+                            <mainClass>com.taosdata.example.jdbcTemplate.App</mainClass>
+                        </manifest>
+                    </archive>
+                    <descriptorRefs>
+                        <descriptorRef>jar-with-dependencies</descriptorRef>
+                    </descriptorRefs>
+                </configuration>
+                <executions>
+                    <execution>
+                        <id>make-assembly</id>
+                        <phase>package</phase>
+                        <goals>
+                            <goal>single</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+</project>

examples/JDBC/SpringJdbcTemplate/readme.md

+
+## TDengine Spring JDBC Template Demo
+
+`Spring JDBC Template` 简化了原生 JDBC Connection 获取释放等操作，使得操作数据库更加方便。
+
+### 配置
+
+修改 `src/main/resources/applicationContext.xml` 文件中 TDengine 的配置信息：
+
+```xml
+<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
+    <property name="driverClassName" value="com.taosdata.jdbc.TSDBDriver"></property>
+    <property name="url" value="jdbc:TAOS://127.0.0.1:6030/log"></property>
+    <property name="username" value="root"></property>
+    <property name="password" value="taosdata"></property>
+</bean>
+
+<bean id = "jdbcTemplate"  class="org.springframework.jdbc.core.JdbcTemplate" >
+    <property name="dataSource" ref = "dataSource" ></property>
+</bean>
+```
+
+### 打包运行
+
+进入 `TDengine/tests/examples/JDBC/SpringJdbcTemplate` 目录下，执行以下命令可以生成可执行 jar 包。
+```shell
+mvn clean package
+```
+打包成功之后，进入 `target/` 目录下，执行以下命令就可运行测试：
+```shell
+java -jar SpringJdbcTemplate-1.0-SNAPSHOT-jar-with-dependencies.jar 
+```
\ No newline at end of file

examples/JDBC/SpringJdbcTemplate/src/main/java/com/taosdata/example/jdbcTemplate/App.java

+package com.taosdata.example.jdbcTemplate;
+
+
+import com.taosdata.example.jdbcTemplate.dao.ExecuteAsStatement;
+import com.taosdata.example.jdbcTemplate.dao.WeatherDao;
+import com.taosdata.example.jdbcTemplate.domain.Weather;
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.support.ClassPathXmlApplicationContext;
+
+import java.sql.Timestamp;
+import java.util.Date;
+import java.util.List;
+import java.util.Random;
+
+public class App {
+
+    private static Random random = new Random(System.currentTimeMillis());
+
+    public static void main(String[] args) {
+
+        ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml");
+
+        ExecuteAsStatement executor = ctx.getBean(ExecuteAsStatement.class);
+        // drop database
+        executor.doExecute("drop database if exists test");
+        // create database
+        executor.doExecute("create database if not exists test");
+        //use database
+        executor.doExecute("use test");
+        // create table
+        executor.doExecute("create table if not exists test.weather (ts timestamp, temperature int, humidity float)");
+
+        WeatherDao weatherDao = ctx.getBean(WeatherDao.class);
+        Weather weather = new Weather(new Timestamp(new Date().getTime()), random.nextFloat() * 50.0f, random.nextInt(100));
+        // insert rows
+        int affectedRows = weatherDao.add(weather);
+        System.out.println("insert success " + affectedRows + " rows.");
+
+        // query for list
+        int limit = 10, offset = 0;
+        List<Weather> weatherList = weatherDao.queryForList(limit, offset);
+        for (Weather w : weatherList) {
+            System.out.println(w);
+        }
+
+    }
+
+}

examples/JDBC/SpringJdbcTemplate/src/main/java/com/taosdata/example/jdbcTemplate/dao/ExecuteAsStatement.java

+package com.taosdata.example.jdbcTemplate.dao;
+
+public interface ExecuteAsStatement{
+
+    void doExecute(String sql);
+}

examples/JDBC/SpringJdbcTemplate/src/main/java/com/taosdata/example/jdbcTemplate/dao/ExecuteAsStatementImpl.java

+package com.taosdata.example.jdbcTemplate.dao;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.jdbc.core.JdbcTemplate;
+import org.springframework.stereotype.Repository;
+
+
+@Repository
+public class ExecuteAsStatementImpl implements ExecuteAsStatement {
+
+    @Autowired
+    private JdbcTemplate jdbcTemplate;
+
+    @Override
+    public void doExecute(String sql) {
+        jdbcTemplate.execute(sql);
+    }
+}

examples/JDBC/SpringJdbcTemplate/src/main/java/com/taosdata/example/jdbcTemplate/dao/WeatherDao.java

+package com.taosdata.example.jdbcTemplate.dao;
+
+import com.taosdata.example.jdbcTemplate.domain.Weather;
+
+import java.util.List;
+
+public interface WeatherDao {
+
+
+    int add(Weather weather);
+
+    int[] batchInsert(List<Weather> weatherList);
+
+    List<Weather> queryForList(int limit, int offset);
+
+    int count();
+}

examples/JDBC/SpringJdbcTemplate/src/main/java/com/taosdata/example/jdbcTemplate/dao/WeatherDaoImpl.java

+package com.taosdata.example.jdbcTemplate.dao;
+
+import com.taosdata.example.jdbcTemplate.domain.Weather;
+import com.taosdata.example.jdbcTemplate.dao.WeatherDao;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.jdbc.core.BatchPreparedStatementSetter;
+import org.springframework.jdbc.core.JdbcTemplate;
+import org.springframework.stereotype.Repository;
+
+import java.sql.PreparedStatement;
+import java.sql.SQLException;
+import java.sql.Timestamp;
+import java.util.List;
+
+@Repository
+public class WeatherDaoImpl implements WeatherDao {
+
+    @Autowired
+    private JdbcTemplate jdbcTemplate;
+
+    @Override
+    public int add(Weather weather) {
+        return jdbcTemplate.update(
+                "insert into test.weather(ts, temperature, humidity) VALUES(?,?,?)",
+                weather.getTs(), weather.getTemperature(), weather.getHumidity()
+        );
+    }
+
+    @Override
+    public int[] batchInsert(List<Weather> weatherList) {
+        return jdbcTemplate.batchUpdate("insert into test.weather(ts, temperature, humidity) values( ?, ?, ?)", new BatchPreparedStatementSetter() {
+            @Override
+            public void setValues(PreparedStatement ps, int i) throws SQLException {
+                ps.setTimestamp(1, weatherList.get(i).getTs());
+                ps.setFloat(2, weatherList.get(i).getTemperature());
+                ps.setInt(3, weatherList.get(i).getHumidity());
+            }
+
+            @Override
+            public int getBatchSize() {
+                return weatherList.size();
+            }
+        });
+    }
+
+    @Override
+    public List<Weather> queryForList(int limit, int offset) {
+        return jdbcTemplate.query("select * from test.weather limit ? offset ?", (rs, rowNum) -> {
+            Timestamp ts = rs.getTimestamp("ts");
+            float temperature = rs.getFloat("temperature");
+            int humidity = rs.getInt("humidity");
+            return new Weather(ts, temperature, humidity);
+        }, limit, offset);
+    }
+
+    @Override
+    public int count() {
+        return jdbcTemplate.queryForObject("select count(*) from test.weather", Integer.class);
+    }
+}

examples/JDBC/SpringJdbcTemplate/src/main/java/com/taosdata/example/jdbcTemplate/domain/Weather.java

+package com.taosdata.example.jdbcTemplate.domain;
+
+import java.sql.Timestamp;
+
+public class Weather {
+
+    private Timestamp ts;
+    private float temperature;
+    private int humidity;
+
+    public Weather() {
+    }
+
+    public Weather(Timestamp ts, float temperature, int humidity) {
+        this.ts = ts;
+        this.temperature = temperature;
+        this.humidity = humidity;
+    }
+
+    @Override
+    public String toString() {
+        return "Weather{" +
+                "ts=" + ts +
+                ", temperature=" + temperature +
+                ", humidity=" + humidity +
+                '}';
+    }
+
+    public Timestamp getTs() {
+        return ts;
+    }
+
+    public void setTs(Timestamp ts) {
+        this.ts = ts;
+    }
+
+    public float getTemperature() {
+        return temperature;
+    }
+
+    public void setTemperature(float temperature) {
+        this.temperature = temperature;
+    }
+
+    public int getHumidity() {
+        return humidity;
+    }
+
+    public void setHumidity(int humidity) {
+        this.humidity = humidity;
+    }
+
+
+}

examples/JDBC/SpringJdbcTemplate/src/main/resources/applicationContext.xml

+<?xml version="1.0" encoding="utf-8"?>
+<beans xmlns="http://www.springframework.org/schema/beans"
+       xmlns:context="http://www.springframework.org/schema/context"
+       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:tx="http://www.springframework.org/schema/tx"
+       xsi:schemaLocation="
+	http://www.springframework.org/schema/beans
+	http://www.springframework.org/schema/beans/spring-beans.xsd
+	http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd"
+       default-autowire="byName">
+
+    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
+        <property name="driverClassName" value="com.taosdata.jdbc.TSDBDriver"></property>
+        <property name="url" value="jdbc:TAOS://127.0.0.1:6030/"></property>
+        <property name="username" value="root"></property>
+        <property name="password" value="taosdata"></property>
+    </bean>
+
+
+    <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
+        <property name="dataSource" ref="dataSource"></property>
+    </bean>
+
+    <context:component-scan base-package="com.taosdata.example.jdbcTemplate"/>
+
+</beans>

examples/JDBC/SpringJdbcTemplate/src/test/java/com/taosdata/example/jdbcTemplate/BatcherInsertTest.java

+package com.taosdata.example.jdbcTemplate;
+
+
+import com.taosdata.example.jdbcTemplate.dao.ExecuteAsStatement;
+import com.taosdata.example.jdbcTemplate.dao.WeatherDao;
+import com.taosdata.example.jdbcTemplate.domain.Weather;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+
+import java.sql.Timestamp;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Random;
+
+import static org.junit.Assert.assertEquals;
+
+@RunWith(SpringJUnit4ClassRunner.class)
+@ContextConfiguration({"classpath:applicationContext.xml"})
+public class BatcherInsertTest {
+
+
+    @Autowired
+    private WeatherDao weatherDao;
+    @Autowired
+    private ExecuteAsStatement executor;
+
+    private static final int numOfRecordsPerTable = 1000;
+    private static long ts = 1496732686000l;
+    private static Random random = new Random(System.currentTimeMillis());
+
+    @Before
+    public void before() {
+        // drop database
+        executor.doExecute("drop database if exists test");
+        // create database
+        executor.doExecute("create database if not exists test");
+        //use database
+        executor.doExecute("use test");
+        // create table
+        executor.doExecute("create table if not exists test.weather (ts timestamp, temperature int, humidity float)");
+    }
+
+    @Test
+    public void batchInsert() {
+        List<Weather> weatherList = new ArrayList<>();
+        for (int i = 0; i < numOfRecordsPerTable; i++) {
+            ts += 1000;
+            Weather weather = new Weather(new Timestamp(ts), random.nextFloat() * 50.0f, random.nextInt(100));
+            weatherList.add(weather);
+        }
+        long start = System.currentTimeMillis();
+        weatherDao.batchInsert(weatherList);
+        long end = System.currentTimeMillis();
+        System.out.println("batch insert(" + numOfRecordsPerTable + " rows) time cost ==========> " + (end - start) + " ms");
+
+        int count = weatherDao.count();
+        assertEquals(count, numOfRecordsPerTable);
+    }
+
+}

examples/JDBC/connectionPools/README-cn.md

+这个example中，我们适配了java常见的连接池:
+* HikariCP（默认）
+* druid
+* dbcp
+* c3p0
+
+### 说明
+ConnectionPoolDemo的程序逻辑：
+1. 创建到host的connection连接池
+2. 创建名称为pool_test的database，创建表超级weather，创建tableSize个子表
+3. 总共插入totalNumber条数据。
+
+### 如何运行这个例子：
+
+```shell script
+mvn clean package assembly:single
+java -jar target/connectionPools-1.0-SNAPSHOT-jar-with-dependencies.jar -host 127.0.0.1
+```
+使用mvn运行ConnectionPoolDemo的main方法，可以指定参数
+```shell script
+Usage: 
+java -jar target/connectionPools-1.0-SNAPSHOT-jar-with-dependencies.jar
+-host : hostname
+-poolType <c3p0| dbcp| druid| hikari>
+-poolSize <poolSize>
+-tableSize <tableSize>
+-batchSize : 每条Insert SQL中values的数量
+-sleep : 每次插入任务提交后的
+```
+
+### 日志
+使用log4j，将日志和错误分别输出到了debug.log和error.log中
\ No newline at end of file

examples/JDBC/connectionPools/pom.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <properties>
+     <maven.compiler.source>1.8</maven.compiler.source>
+     <maven.compiler.target>1.8</maven.compiler.target>
+    </properties>
+
+    <groupId>com.taosdata.demo</groupId>
+    <artifactId>connectionPools</artifactId>
+    <version>1.0-SNAPSHOT</version>
+
+    <dependencies>
+        <!-- taos -->
+        <dependency>
+            <groupId>com.taosdata.jdbc</groupId>
+            <artifactId>taos-jdbcdriver</artifactId>
+            <version>2.0.34</version>
+        </dependency>
+        <!-- druid -->
+        <dependency>
+            <groupId>com.alibaba</groupId>
+            <artifactId>druid</artifactId>
+            <version>1.1.17</version>
+        </dependency>
+        <!-- HikariCP -->
+        <dependency>
+            <groupId>com.zaxxer</groupId>
+            <artifactId>HikariCP</artifactId>
+            <version>3.2.0</version>
+        </dependency>
+        <!-- dbcp Connection Pool -->
+        <dependency>
+            <groupId>commons-pool</groupId>
+            <artifactId>commons-pool</artifactId>
+            <version>1.5.4</version>
+        </dependency>
+        <dependency>
+            <groupId>commons-dbcp</groupId>
+            <artifactId>commons-dbcp</artifactId>
+            <version>1.4</version>
+        </dependency>
+        <!-- c3p0 -->
+        <dependency>
+            <groupId>com.mchange</groupId>
+            <artifactId>c3p0</artifactId>
+            <version>0.9.5.4</version>
+        </dependency>
+        <!-- log4j -->
+        <dependency>
+            <groupId>org.apache.logging.log4j</groupId>
+            <artifactId>log4j-core</artifactId>
+            <version>2.17.0</version>
+        </dependency>
+        <!-- proxool -->
+        <dependency>
+            <groupId>com.cloudhopper.proxool</groupId>
+            <artifactId>proxool</artifactId>
+            <version>0.9.1</version>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-assembly-plugin</artifactId>
+                <version>3.3.0</version>
+                <executions>
+                    <execution>
+                        <id>ConnectionPoolDemo</id>
+                        <configuration>
+                            <finalName>ConnectionPoolDemo</finalName>
+                            <archive>
+                                <manifest>
+                                    <mainClass>com.taosdata.example.ConnectionPoolDemo</mainClass>
+                                </manifest>
+                            </archive>
+                            <descriptorRefs>
+                                <descriptorRef>jar-with-dependencies</descriptorRef>
+                            </descriptorRefs>
+                        </configuration>
+                        <phase>package</phase>
+                        <goals>
+                            <goal>single</goal>
+                        </goals>
+                    </execution>
+
+                    <execution>
+                        <id>ProxoolDemo</id>
+                        <configuration>
+                            <finalName>ProxoolDemo</finalName>
+                            <archive>
+                                <manifest>
+                                    <mainClass>com.taosdata.example.ProxoolDemo</mainClass>
+                                </manifest>
+                            </archive>
+                            <descriptorRefs>
+                                <descriptorRef>jar-with-dependencies</descriptorRef>
+                            </descriptorRefs>
+                        </configuration>
+                        <phase>package</phase>
+                        <goals>
+                            <goal>single</goal>
+                        </goals>
+                    </execution>
+
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+
+</project>

examples/JDBC/connectionPools/src/main/java/com/taosdata/example/ConnectionPoolDemo.java

+package com.taosdata.example;
+
+import com.taosdata.example.common.InsertTask;
+import com.taosdata.example.pool.C3p0Builder;
+import com.taosdata.example.pool.DbcpBuilder;
+import com.taosdata.example.pool.DruidPoolBuilder;
+import com.taosdata.example.pool.HikariCpBuilder;
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.LogManager;
+
+import javax.sql.DataSource;
+import java.sql.Connection;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+
+public class ConnectionPoolDemo {
+
+    private static Logger logger = LogManager.getLogger(DruidPoolBuilder.class);
+    private static final String dbName = "pool_test";
+
+    private static String poolType = "hikari";
+    private static long totalSize = 1_000_000l;
+    private static long tableSize = 1;
+    private static long batchSize = 1;
+
+    private static int poolSize = 50;
+    private static int threadCount = 50;
+    private static int sleep = 0;
+
+    public static void main(String[] args) {
+        String host = null;
+        for (int i = 0; i < args.length; i++) {
+            if ("-host".equalsIgnoreCase(args[i]) && i < args.length - 1) {
+                host = args[++i];
+            }
+            if ("-poolType".equalsIgnoreCase(args[i]) && i < args.length - 1) {
+                poolType = args[++i];
+            }
+            if ("-recordNumber".equalsIgnoreCase(args[i]) && i < args.length - 1) {
+                totalSize = Long.parseLong(args[++i]);
+            }
+            if ("-tableNumber".equalsIgnoreCase(args[i]) && i < args.length - 1) {
+                tableSize = Long.parseLong(args[++i]);
+            }
+            if ("-batchNumber".equalsIgnoreCase(args[i]) && i < args.length - 1) {
+                batchSize = Long.parseLong(args[++i]);
+            }
+
+        }
+        if (host == null) {
+            System.out.println("Usage: java -jar XXX.jar -host <hostname> " +
+                    "-poolType <c3p0| dbcp| druid| hikari>" +
+                    "-recordNumber <number> " +
+                    "-tableNumber <number> " +
+                    "-batchNumber <number> " +
+                    "-sleep <number> "
+            );
+            return;
+        }
+
+        DataSource dataSource;
+        switch (poolType) {
+            case "c3p0":
+                dataSource = C3p0Builder.getDataSource(host, poolSize);
+                break;
+            case "dbcp":
+                dataSource = DbcpBuilder.getDataSource(host, poolSize);
+                break;
+            case "druid":
+                dataSource = DruidPoolBuilder.getDataSource(host, poolSize);
+                break;
+            case "hikari":
+            default:
+                dataSource = HikariCpBuilder.getDataSource(host, poolSize);
+                poolType = "hikari";
+        }
+
+        logger.info(">>>>>>>>>>>>>> connection pool Type: " + poolType);
+        init(dataSource);
+
+//        try {
+//            Connection connection = dataSource.getConnection();
+//            Statement statement = connection.createStatement();
+//            String sql = "insert into " + dbName + ".t_1 values('2020-01-01 00:00:00.000',12.12,111)";
+//            int affectRows = statement.executeUpdate(sql);
+//            System.out.println("affectRows >>> " + affectRows);
+//            affectRows = statement.executeUpdate(sql);
+//            System.out.println("affectRows >>> " + affectRows);
+//            statement.close();
+//            connection.close();
+//        } catch (SQLException e) {
+//            e.printStackTrace();
+//        }
+
+        ExecutorService executor = Executors.newFixedThreadPool(threadCount);
+        for (long i = 0; i < totalSize / tableSize / batchSize; i++) {
+            executor.execute(new InsertTask(dataSource, dbName, tableSize, batchSize));
+            // sleep few seconds
+            try {
+                if (sleep > 0)
+                    TimeUnit.MILLISECONDS.sleep(sleep);
+            } catch (InterruptedException e) {
+                e.printStackTrace();
+            }
+        }
+        executor.shutdown();
+
+    }
+
+    private static void init(DataSource dataSource) {
+        try (Connection conn = dataSource.getConnection()) {
+            execute(conn, "drop database if exists " + dbName + "");
+            execute(conn, "create database if not exists " + dbName + "");
+            execute(conn, "use " + dbName + "");
+            execute(conn, "create table weather(ts timestamp, temperature float, humidity int) tags(location nchar(64), groupId int)");
+            for (int tb_ind = 1; tb_ind <= tableSize; tb_ind++) {
+                execute(conn, "create table t_" + tb_ind + " using weather tags('beijing'," + (tb_ind + 1) + ")");
+            }
+            logger.info(">>>>>>>>>>>>>>>>>>>>>>>>>>>> init finished.");
+        } catch (SQLException e) {
+            e.printStackTrace();
+        }
+    }
+
+    private static void execute(Connection con, String sql) {
+        try (Statement stmt = con.createStatement()) {
+            stmt.executeUpdate(sql);
+            logger.info("SQL >>> " + sql);
+        } catch (SQLException e) {
+            e.printStackTrace();
+        }
+    }
+
+}

examples/JDBC/connectionPools/src/main/java/com/taosdata/example/ProxoolDemo.java

+package com.taosdata.example;
+
+import org.logicalcobwebs.proxool.ProxoolException;
+import org.logicalcobwebs.proxool.configuration.JAXPConfigurator;
+
+import java.sql.*;
+
+public class ProxoolDemo {
+
+
+    public static void main(String[] args) {
+
+        String xml = parseConfigurationXml(args);
+        if (xml == null) {
+            printHelp();
+            System.exit(0);
+        }
+
+        try {
+            JAXPConfigurator.configure(xml, false);
+            Class.forName("org.logicalcobwebs.proxool.ProxoolDriver");
+            Connection connection = DriverManager.getConnection("proxool.ds");
+
+            Statement stmt = connection.createStatement();
+
+            ResultSet rs = stmt.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));
+                }
+                System.out.println();
+            }
+
+            stmt.close();
+
+        } catch (ClassNotFoundException | SQLException | ProxoolException e) {
+            e.printStackTrace();
+        }
+    }
+
+    private static String parseConfigurationXml(String[] args) {
+        String host = null;
+        for (int i = 0; i < args.length; i++) {
+            if ("--xml".equalsIgnoreCase(args[i]) && i < args.length - 1) {
+                host = args[++i];
+            }
+        }
+        return host;
+    }
+
+    private static void printHelp() {
+        System.out.println("Usage: java -jar ProxoolDemo.jar --xml [xml]");
+    }
+
+}

examples/JDBC/connectionPools/src/main/java/com/taosdata/example/common/InsertTask.java

+package com.taosdata.example.common;
+
+import org.apache.logging.log4j.Logger;
+import org.apache.logging.log4j.LogManager;
+
+import javax.sql.DataSource;
+import java.sql.Connection;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.util.Random;
+
+public class InsertTask implements Runnable {
+    private final Random random = new Random(System.currentTimeMillis());
+    private static final Logger logger = LogManager.getLogger(InsertTask.class);
+
+    private final DataSource ds;
+    private final String dbName;
+    private final long tableSize;
+    private final long batchSize;
+
+    public InsertTask(DataSource ds, String dbName, long tableSize, long batchSize) {
+        this.ds = ds;
+        this.dbName = dbName;
+        this.tableSize = tableSize;
+        this.batchSize = batchSize;
+    }
+
+    @Override
+    public void run() {
+        int affectedRows = 0;
+        long start = System.currentTimeMillis();
+        try (Connection conn = ds.getConnection(); Statement stmt = conn.createStatement()) {
+            for (int tb_index = 1; tb_index <= tableSize; tb_index++) {
+                StringBuilder sb = new StringBuilder();
+                sb.append("insert into ").append(dbName).append(".t_").append(tb_index).append("(ts, temperature, humidity) values ");
+                for (int i = 0; i < batchSize; i++) {
+                    sb.append("(").append(start + i).append(", ").append(random.nextFloat() * 30).append(", ").append(random.nextInt(70)).append(") ");
+                }
+                logger.info("SQL >>> " + sb.toString());
+                affectedRows += stmt.executeUpdate(sb.toString());
+            }
+        } catch (SQLException e) {
+            e.printStackTrace();
+        }
+        logger.info(">>> affectedRows:" + affectedRows + "  TimeCost:" + (System.currentTimeMillis() - start) + " ms");
+    }
+}

examples/JDBC/connectionPools/src/main/java/com/taosdata/example/pool/C3p0Builder.java

+package com.taosdata.example.pool;
+
+import com.mchange.v2.c3p0.ComboPooledDataSource;
+
+import javax.sql.DataSource;
+import java.beans.PropertyVetoException;
+
+public class C3p0Builder {
+
+    public static DataSource getDataSource(String host, int poolSize) {
+        ComboPooledDataSource ds = new ComboPooledDataSource();
+
+        try {
+            ds.setDriverClass("com.taosdata.jdbc.TSDBDriver");
+        } catch (PropertyVetoException e) {
+            e.printStackTrace();
+        }
+        ds.setJdbcUrl("jdbc:TAOS://" + host + ":6030");
+        ds.setUser("root");
+        ds.setPassword("taosdata");
+
+        ds.setMinPoolSize(poolSize);
+        ds.setMaxPoolSize(poolSize);
+        ds.setAcquireIncrement(5);
+        return ds;
+    }
+}

examples/JDBC/connectionPools/src/main/java/com/taosdata/example/pool/DbcpBuilder.java

+package com.taosdata.example.pool;
+
+import org.apache.commons.dbcp.BasicDataSource;
+
+import javax.sql.DataSource;
+
+public class DbcpBuilder {
+
+    public static DataSource getDataSource(String host, int poolSize) {
+        BasicDataSource ds = new BasicDataSource();
+        ds.setDriverClassName("com.taosdata.jdbc.TSDBDriver");
+        ds.setUrl("jdbc:TAOS://" + host + ":6030");
+        ds.setUsername("root");
+        ds.setPassword("taosdata");
+
+        ds.setMaxActive(poolSize);
+        ds.setMinIdle(poolSize);
+        ds.setInitialSize(poolSize);
+        return ds;
+    }
+}

examples/JDBC/connectionPools/src/main/java/com/taosdata/example/pool/DruidPoolBuilder.java

+package com.taosdata.example.pool;
+
+import com.alibaba.druid.pool.DruidDataSource;
+
+import javax.sql.DataSource;
+
+public class DruidPoolBuilder {
+
+    public static DataSource getDataSource(String host, int poolSize) {
+        final String url = "jdbc:TAOS://" + host + ":6030";
+
+        DruidDataSource dataSource = new DruidDataSource();
+        // jdbc properties
+        dataSource.setDriverClassName("com.taosdata.jdbc.TSDBDriver");
+        dataSource.setUrl(url);
+        dataSource.setUsername("root");
+        dataSource.setPassword("taosdata");
+        // pool configurations
+        dataSource.setInitialSize(poolSize);
+        dataSource.setMinIdle(poolSize);
+        dataSource.setMaxActive(poolSize);
+        dataSource.setMaxWait(30000);
+        dataSource.setValidationQuery("select server_status()");
+        return dataSource;
+    }
+
+}