Merge branch 'develop' into feature/query

.lgtm.yml

+##########################################################################################
+# Customize file classifications.                                                        #
+# Results from files under any classifier will be excluded from LGTM                     #
+# statistics.                                                                            #
+##########################################################################################
+
+##########################################################################################
+# Use the `path_classifiers` block to define changes to the default classification of    #
+# files.                                                                                 #
+##########################################################################################
+
+path_classifiers:
+        # docs:
+    # Identify the top-level file called `generate_javadoc.py` as documentation-related.
+  test:
+    # Override LGTM's default classification of test files by excluding all files.
+    - exclude: /
+    # Classify all files in the top-level directories tests/ and testsuites/ as test code.
+    - tests
+      # - testsuites
+    # Classify all files with suffix `.test` as test code.
+    #        Note: use only forward slash / as a path separator.
+    #        Use ** to indicate an arbitrary parent path.
+    #        Use * to indicate any sequence of characters excluding /.
+    #        Always enclose the expression in double quotes if it includes *.
+    # - "**/*.test"
+    # Refine the classifications above by excluding files in test/util/.
+    # - exclude: test/util
+  # The default behavior is to tag all files created during the
+  # build as `generated`. Results are hidden for generated code. You can tag 
+  # further files as being generated by adding them to the `generated` section.
+  generated:
+    # Exclude all `*.c` files under the `ui/` directory from classification as 
+    # generated code.
+    # - exclude: ui/**/*.c
+    # By default, all files not checked into the repository are considered to be
+    # 'generated'.
+  # The default behavior is to tag library code as `library`. Results are hidden 
+  # for library code. You can tag further files as being library code by adding them
+  # to the `library` section.
+  library:
+    - exclude: deps/
+  # The default behavior is to tag template files as `template`. Results are hidden 
+  # for template files. You can tag further files as being template files by adding 
+  # them to the `template` section.
+  template:
+          #- exclude: path/to/template/code/**/*.c
+  # Define your own category, for example: 'some_custom_category'.
+  some_custom_category:
+    # Classify all files in the top-level directory tools/ (or the top-level file 
+    # called tools).
+    # - tools
+
+#########################################################################################
+# Use the `queries` block to change the default display of query results.               #
+#########################################################################################
+
+          # queries:
+  # Start by hiding the results of all queries.
+  #  - exclude: "*"
+  # Then include all queries tagged 'security' and 'correctness', and with a severity of
+  # 'error'.
+  #  - include:           
+  #      tags:
+  #        - "security"
+  #        - "correctness"           
+  #    severity: "error"
+  # Specifically hide the results of two queries.
+  # - exclude: cpp/use-of-goto
+    # - exclude: java/equals-on-unrelated-types
+  # Refine by including the `java/command-line-injection` query.
+  # - include: java/command-line-injection
+
+#########################################################################################
+# Define changes to the default code extraction process.                                #
+# Each block configures the extraction of a single language, and modifies actions in a  #
+# named step. Every named step includes automatic default actions,                      #
+# except for the 'prepare' step. The steps are performed in the following sequence:     #
+# prepare                                                                               #
+# after_prepare                                                                         #
+# configure (C/C++ only)                                                                #
+# python_setup (Python only)                                                            #
+# before_index                                                                          #
+# index                                                                                 #
+##########################################################################################
+
+#########################################################################################
+# Environment variables available to the steps:                                         #
+#########################################################################################
+
+# LGTM_SRC
+#   The root of the source tree.
+# LGTM_WORKSPACE
+#   An existing (initially empty) folder outside the source tree.
+#   Used for temporary download and setup commands.
+
+#########################################################################################
+# Use the extraction block to define changes to the default code extraction process     #
+# for one or more languages. The settings for each language are defined in a child      #
+# block, with one or more steps.                                                        #
+#########################################################################################
+
+extraction: 
+  # Define settings for C/C++ analysis
+  #####################################
+  cpp:
+    # The `prepare` step exists for customization on LGTM.com only.
+    prepare:
+    #   # The `packages` section is valid for LGTM.com only. It names Ubuntu packages to
+    #   # be installed.
+        packages:
+          - cmake
+    # Add an `after-prepare` step if you need to run commands after the prepare step.
+    # Each command should be listed on a separate line.
+    # This step is useful for C/C++ analysis where you want to prepare the environment
+    # for the `configure` step without changing the default behavior for that step. 
+    #    after_prepare:
+            #- export GNU_MAKE=make
+            #- export GIT=true
+    # The `configure` step generates build configuration files which the `index` step
+    # then uses to build the codebase.
+    configure:
+      command:
+        - mkdir build
+        - cd build
+        - cmake ..
+              # - ./prepare_deps
+    # Optional step. You should add a `before_index` step if you need to run commands
+    # before the `index` step.
+    # before_index:
+            # - export BOOST_DIR=$LGTM_SRC/boost
+            # - export GTEST_DIR=$LGTM_SRC/googletest
+            # - export HUNSPELL_DIR=$LGTM_SRC/hunspell
+            # - export CRYPTOPP_DIR=$LGTM_SRC/cryptopp
+    # The `index` step builds the code and extracts information during the build
+    # process.
+    index:
+      # Override the autobuild process by specifying a list of custom build commands
+      # to use instead. 
+      build_command:
+        - cd build
+        - make
+              # - $GNU_MAKE -j2 -s
+      # Specify that all project or solution files should be used for extraction.
+      # Default: false.
+      # all_solutions: true
+      # Specify a list of one or more project or solution files for extraction.
+      # Default: LGTM chooses the file closest to the root of the repository (this may
+      # fail if there are multiple candidates).
+      # solution: 
+      #  - myProject.sln
+      # Specify MSBuild settings
+      # msbuild:
+        # Specify a list of additional arguments to MSBuild. Default: empty.
+        # arguments: /p:Platform=x64 /p:Configuration=Release
+        # Specify the MSBuild configuration to use, for example, debug or release.
+        # Default: read from the solution file or files.
+        # configuration:
+        # Specify the platform to target, for example: x86, x64, or Any CPU.
+        # Default: read from the solution file or files.
+        # platform:
+        # Specify the MSBuild target. Default: rebuild.
+        # target:
+      # Specify whether or not to perform a NuGet restore for extraction. Default: true.
+      # nuget_restore: false
+      # Specify a version of Microsoft Visual Studio to use for MSBuild or any custom
+      # build commands (build_command). For example:
+      #    10 for Visual Studio 2010
+      #    12 for Visual Studio 2012
+      #    14 for Visual Studio 2015
+      #    15 for Visual Studio 2017
+      # Default: read from project files.
+      # vstools_version: 10
+
+  # Define settings for C# analysis
+  ##################################
+  #  csharp:
+    # The `prepare` step exists for customization on LGTM.com only.
+    # prepare:
+    #   packages:
+    #     - example_package
+    # Add an `after-prepare` step if you need to run commands after the `prepare` step.
+    # Each command should be listed on a separate line.
+    #  after_prepare:
+    #  - export PATH=$LGTM_WORKSPACE/tools:$PATH
+    # The `index` step builds the code and extracts information during the build
+    # process.
+    #index:
+      # Specify that all project or solution files should be used for extraction.
+      # Default: false.
+      #  all_solutions: true
+      # Specify a list of one or more project or solution files for extraction.
+      # Default: LGTM chooses the file closest to the root of the repository (this may
+      # fail if there are multiple candidates).
+      # solution: 
+      #  - myProject.sln
+      # Override the autobuild process by specifying a list of custom build commands
+      # to use instead. 
+      # build_command:
+      #  - ./example-compile-all.sh
+      # By default, LGTM analyzes the code by building it. You can override this,
+      # and tell LGTM not to build the code. Beware that this can lead
+      # to less accurate results.
+      # buildless: true
+      # Specify .NET Core settings.
+      # dotnet:
+        # Specify additional arguments to `dotnet build`.
+        # Default: empty.
+        # arguments: "example_arg"
+        # Specify the version of .NET Core SDK to use.
+        # Default: The version installed on the build machine.
+        # version: 2.1
+      # Specify MSBuild settings.
+      # msbuild:
+        # Specify a list of additional arguments to MSBuild. Default: empty.
+        # arguments: /P:WarningLevel=2
+        # Specify the MSBuild configuration to use, for example, debug or release.
+        # Default: read from the solution file or files.
+        # configuration: release
+        # Specify the platform to target, for example: x86, x64, or Any CPU.
+        # Default: read from the solution file or files.
+        # platform: x86
+        # Specify the MSBuild target. Default: rebuild.
+        # target: notest
+      # Specify whether or not to perform a NuGet restore for extraction. Default: true.
+      # nuget_restore: false
+      # Specify a version of Microsoft Visual Studio to use for MSBuild or any custom
+      # build commands (build_command). For example:
+      #    10 for Visual Studio 2010
+      #    12 for Visual Studio 2012
+      #    14 for Visual Studio 2015
+      #    15 for Visual Studio 2017
+      # Default: read from project files
+      # vstools_version: 10
+      # Specify additional options for the extractor,
+      # for example --fast to perform a faster extraction that produces a smaller 
+      # database.
+      # extractor: "--fast"
+
+  # Define settings for Go analysis
+  ##################################
+  #  go:
+    # The `prepare` step exists for customization on LGTM.com only.
+    # prepare:
+    #   packages:
+    #     - example_package
+    # Add an `after-prepare` step if you need to run commands after the `prepare` step.
+    # Each command should be listed on a separate line.
+    # after_prepare:
+    #  - export PATH=$LGTM_WORKSPACE/tools:$PATH
+    # The `index` step builds the code and extracts information during the build
+    # process.
+    # index:
+      # Override the autobuild process by specifying a list of custom build commands
+      # to use instead.
+      # build_command:
+              #  - ./compile-all.sh
+
+  # Define settings for Java analysis
+  ####################################
+  #  java:
+    # The `prepare` step exists for customization on LGTM.com only.
+    # prepare:
+    #   packages:
+    #     - example_package
+    # Add an `after-prepare` step if you need to run commands after the prepare step.
+    # Each command should be listed on a separate line.
+    # after_prepare:
+    # - export PATH=$LGTM_WORKSPACE/tools:$PATH
+    # The `index` step extracts information from the files in the codebase.
+    # index:
+      # Specify Gradle settings.
+      # gradle:
+        # Specify the required Gradle version.
+        # Default: determined automatically.
+        # version: 4.4
+      # Override the autobuild process by specifying a list of custom build commands
+      # to use instead. 
+      # build_command: ./compile-all.sh
+      # Specify the Java version required to build the project.
+      # java_version: 11
+      # Specify whether to extract Java .properties files
+      # Default: false
+      # properties_files: true
+      # Specify Maven settings.
+      # maven:
+        # Specify the path (absolute or relative) of a Maven settings file to use.
+        # Default: Maven uses a settings file in the default location, if it exists.
+        # settings_file: /opt/share/settings.xml
+        # Specify the path of a Maven toolchains file.
+        # Default: Maven uses a toolchains file in the default location, if it exists.
+        # toolchains_file: /opt/share/toolchains.xml
+        # Specify the required Maven version.
+        # Default: the Maven version is determined automatically, where feasible.
+        # version: 3.5.2
+      # Specify how XML files should be extracted:
+      #   all = extract all XML files.
+      #   default = only extract XML files named `AndroidManifest.xml`, `pom.xml`, and `web.xml`.
+      #   disabled = do not extract any XML files.
+      # xml_mode: all
+
+  # Define settings for JavaScript analysis
+  ##########################################
+  # javascript:
+    # The `prepare` step exists for customization on LGTM.com only.
+    # prepare:
+    #   packages:
+    #     - example_package
+    # Add an `after-prepare` step if you need to run commands after the prepare step.
+    # Each command should be listed on a separate line.
+    # after_prepare:
+    # - export PATH=$LGTM_WORKSPACE/tools:$PATH
+    # The `index` step extracts information from the files in the codebase.
+    # index:
+      # Specify a list of files and folders to extract.
+      # Default: The project root directory.
+      # include:
+              # - src/js
+      # Specify a list of files and folders to exclude from extraction.
+      # exclude:
+              # - thirdparty/lib
+      # You can add additional file types for LGTM to extract, by mapping file 
+      # extensions (including the leading dot) to file types. The usual 
+      # include/exclude patterns apply, so, for example, `.jsm` files under
+      # `thirdparty/lib` will not be extracted.
+      # filetypes:
+      # ".jsm": "js"
+      # ".tmpl": "html"
+      # Specify a list of glob patterns to include/exclude files from extraction; this 
+      # is applied on top of the include/exclude paths from above; patterns are 
+      # processed in the same way as for path classifiers above.
+      # Default: include all files with known extensions (such as .js, .ts and .html),
+      # but exclude files ending in `-min.js` or `.min.js` and folders named `node_modules`
+      # or `bower_components`
+      # filters:
+        # exclude any *.ts files anywhere.
+        # - exclude: "**/*.ts"
+        # but include *.ts files under src/js/typescript.
+        # - include: "src/js/typescript/**/*.ts"
+      # Specify how TypeScript files should be extracted:
+      #   none = exclude all TypeScript files.
+      #   basic = extract syntactic information from TypeScript files.
+      #   full = extract syntactic and type information from TypeScript files.
+      # Default: full.
+      # typescript: basic
+      # By default, LGTM doesn't extract any XML files. You can override this by 
+      # using the `xml_mode` property and setting it to `all`.
+      # xml_mode: all
+
+  # Define settings for Python analysis
+  ######################################
+  #  python:
+  #    # The `prepare` step exists for customization on LGTM.com only.
+  #    # prepare:
+  #    #   # The `packages` section is valid for LGTM.com only. It names packages to
+  #    #   # be installed.
+  #    #   packages: libpng-dev
+  #    # This step is useful for Python analysis where you want to prepare the 
+  #    # environment for the `python_setup` step without changing the default behavior 
+  #    # for that step.
+  #    after_prepare:
+  #      - export PATH=$LGTM_WORKSPACE/tools:$PATH
+  #      # This sets up the Python interpreter and virtual environment, ready for the 
+  #      # `index` step to extract the codebase.
+  #    python_setup:
+  #      # Specify packages that should NOT be installed despite being mentioned in the
+  #      # requirements.txt file.
+  #      # Default: no package marked for exclusion.
+  #      exclude_requirements:
+  #        - pywin32
+  #      # Specify a list of pip packages to install.
+  #      # If any of these packages cannot be installed, the extraction will fail.
+  #      requirements:
+  #        - Pillow
+  #      # Specify a list of requirements text files to use to set up the environment,
+  #      # or false for none. Default: any requirements.txt, test-requirements.txt,
+  #      # and similarly named files identified in the codebase are used.
+  #      requirements_files:
+  #        - required-packages.txt
+  #      # Specify a setup.py file to use to set up the environment, or false for none.
+  #      # Default: any setup.py files identified in the codebase are used in preference
+  #      # to any requirements text files.
+  #      setup_py: new-setup.py
+  #      # Override the version of the Python interpreter used for setup and extraction
+  #      # Default: Python 3.
+  #      version: 2
+  #    # Optional step. You should add a `before_index` step if you need to run commands
+  #    # before the `index` step.
+  #    before_index:
+  #      - antlr4 -Dlanguage=Python3 Grammar.g4
+  #    # The `index` step extracts information from the files in the codebase.
+  #    index:
+  #      # Specify a list of files and folders to exclude from extraction.
+  #      # Default: Git submodules and Subversion externals.
+  #      exclude:
+  #        - legacy-implementation
+  #        - thirdparty/libs
+  #      filters:
+  #       - exclude: "**/documentation/examples/snippets/*.py"
+  #       - include: "**/documentation/examples/test_application/*"
+  #      include:
+  #        - example/to/include

README.md

@@ -83,12 +83,18 @@ sudo dnf install -y maven
 
 ## Get the source codes
 
-- github:
+First of all, you may clone the source codes from github:
 ```bash
 git clone https://github.com/taosdata/TDengine.git
 cd TDengine
 ```
 
+The connectors for go & grafana have been moved to separated repositories,
+so you should run this command in the TDengine directory to install them:
+```bash
+git submodule update --init --recursive
+```
+
 ## Build TDengine
 
 ### On Linux platform

documentation20/webdocs/markdowndocs/Evaluation-ch.md

@@ -11,7 +11,7 @@ TDengine的模块之一是时序数据库。但除此之外，为减少研发的
 * __全栈时序数据处理引擎__：将数据库、消息队列、缓存、流式计算等功能融为一体，应用无需再集成Kafka/Redis/HBase/Spark/HDFS等软件，大幅降低应用开发和维护的复杂度成本。 
 * __强大的分析功能__：无论是十年前还是一秒钟前的数据，指定时间范围即可查询。数据可在时间轴上或多个设备上进行聚合。即席查询可通过Shell, Python, R, Matlab随时进行。
 * __与第三方工具无缝连接__：不用一行代码，即可与Telegraf, Grafana, EMQ, Prometheus, Matlab, R等集成。后续将支持OPC, Hadoop, Spark等, BI工具也将无缝连接。
-* __零运维成本、零学习成本__：安装、集群一秒搞定，无需分库分表，实时备份。标准SQL，支持JDBC, RESTful, 支持Python/Java/C/C++/Go, 与MySQL相似，零学习成本。
+* __零运维成本、零学习成本__：安装集群简单快捷，无需分库分表，实时备份。类似标准SQL，支持RESTful, 支持Python/Java/C/C++/C#/Go/Node.js, 与MySQL相似，零学习成本。
 
 采用TDengine，可将典型的物联网、车联网、工业互联网大数据平台的总拥有成本大幅降低。但需要指出的是，因充分利用了物联网时序数据的特点，它无法用来处理网络爬虫、微博、微信、电商、ERP、CRM等通用型数据。
 

documentation20/webdocs/markdowndocs/Getting Started-ch.md

@@ -30,13 +30,13 @@ TDengine软件分为服务器、客户端和报警模块三部分，目前2.0版
 
 - TDengine-alert-2.0.0-Linux-x64.tar.gz (8.1M)
 
-目前，TDengine只支持在使用[`systemd`](https://en.wikipedia.org/wiki/Systemd)做进程服务管理的linux系统上安装。其他linux系统的支持正在开发中。用`which`命令来检测系统中是否存在`systemd`:
+目前，TDengine只支持在使用[`systemd`](https://en.wikipedia.org/wiki/Systemd)做进程服务管理的linux系统上安装。其他linux系统的支持正在开发中。用`which systemctl`命令来检测系统中是否存在`systemd`包:
 
 ```cmd
-which systemd
+which systemctl
 ```
 
-如果系统中不存在`systemd`命令，请考虑[通过源码安装](#通过源码安装)TDengine。
+如果系统中不存在`systemd`包，请考虑[通过源码安装](#通过源码安装)TDengine。
 
 具体的安装过程，请参见<a href="https://www.taosdata.com/blog/2019/08/09/566.html">TDengine多种安装包的安装和卸载</a>。
 

documentation20/webdocs/markdowndocs/Getting Started.md

@@ -16,13 +16,13 @@ Three different packages are provided, please pick up the one you like.
 <li><a id='tdengine-deb' style='color:var(--b2)'>TDengine DEB package (1.7M)</a></li>
 <li><a id='tdengine-tar' style='color:var(--b2)'>TDengine Tarball (3.0M)</a></li>
 </ul>
-For the time being, TDengine only supports installation on Linux systems using [`systemd`](https://en.wikipedia.org/wiki/Systemd) as the service manager. To check if your system has *systemd*, use the _which_ command.
+For the time being, TDengine only supports installation on Linux systems using [`systemd`](https://en.wikipedia.org/wiki/Systemd) as the service manager. To check if your system has *systemd* package, use the _which systemctl_ command.
 
 ```cmd
-which systemd
+which systemctl
 ```
 
-If the `systemd` command is not found, please [install from source code](#Install-from-Source). 
+If the `systemd` package is not found, please [install from source code](#Install-from-Source). 
 
 ### Running TDengine
 

documentation20/webdocs/markdowndocs/Queries-ch.md

@@ -29,23 +29,9 @@ Query OK, 2 row(s) in set (0.001100s)
 具体的查询语法请看<a href="https://www.taosdata.com/cn/documentation20/taos-sql/">TAOS SQL </a>。
 
 ## 多表聚合查询
+物联网场景中，往往同一个类型的数据采集点有多个。TDengine采用超级表(STable)的概念来描述某一个类型的数据采集点，一张普通的表来描述一个具体的数据采集点。同时TDengine使用标签来描述数据采集点的静态属性，一个具体的数据采集点有具体的标签值。通过指定标签的过滤条件，TDengine提供了一高效的方法将超级表(某一类型的数据采集点)所属的子表进行聚合查询。对普通表的聚合函数以及绝大部分操作都适用于超级表，语法完全一样。
 
-TDengine对每个数据采集点单独建表，但在实际应用中经常需要对不同的采集点数据进行聚合。为高效的进行聚合操作，TDengine引入超级表（STable）的概念。超级表用来代表一特定类型的数据采集点，它是包含多张表的表集合，集合里每张表的模式（schema）完全一致，但每张表都带有自己的静态标签，标签可以多个，可以随时增加、删除和修改。
-
-应用可通过指定标签的过滤条件，对一个STable下的全部或部分表进行聚合或统计操作，这样大大简化应用的开发。其具体流程如下图所示：
-
-<center> <img src="../assets/stable.png"> </center>
-
-<center> 多表聚合查询原理图  </center>
-
-1：应用将一个查询条件发往系统；2: taosc将超级表的名字发往 Meta Node（管理节点)；3：管理节点将超级表所拥有的 vnode 列表发回 taosc；4：taosc将计算的请求连同标签过滤条件发往这些vnode对应的多个数据节点；5：每个vnode先在内存里查找出自己节点里符合标签过滤条件的表的集合，然后扫描存储的时序数据，完成相应的聚合计算，将结果返回给taosc；6：taosc将多个数据节点返回的结果做最后的聚合，将其返回给应用。
-
-由于TDengine在vnode内将标签数据与时序数据分离存储，通过先在内存里过滤标签数据，将需要扫描的数据集大幅减少，大幅提升聚合计算速度。同时，由于数据分布在多个vnode/dnode，聚合计算操作在多个vnode里并发进行，又进一步提升了聚合的速度。
-
-对普通表的聚合函数以及绝大部分操作都适用于超级表，语法完全一样，细节请看 TAOS SQL。
-
-比如：在TAOS Shell，查找所有智能电表采集的电压平均值，并按照location分组
-
+**示例1**：在TAOS Shell，查找北京所有智能电表采集的电压平均值，并按照location分组
 ```mysql
 taos> SELECT AVG(voltage) FROM meters GROUP BY location;
        avg(voltage)        |            location            |
@@ -55,6 +41,18 @@ taos> SELECT AVG(voltage) FROM meters GROUP BY location;
 Query OK, 2 row(s) in set (0.002136s)
 ```
 
+**示例2**：在TAOS shell, 查找groupId为2的所有智能电表过去24小时的记录条数，电流的最大值
+
+```mysql
+taos> SELECT count(*), max(current) FROM meters where groupId = 2 and ts > now - 24h;
+     cunt(*)  |    max(current)  |
+==================================
+            5 |             13.4 |
+Query OK, 1 row(s) in set (0.002136s)
+```
+
+TDengine仅容许对属于同一个超级表的表之间进行聚合查询，不同超级表之间的聚合查询不支持。在<a href="https://www.taosdata.com/cn/documentation20/taos-sql/">TAOS SQL </a>一章，查询类操作都会注明是否支持超级表。
+
 ## 降采样查询、插值
 
 物联网场景里，经常需要通过降采样（down sampling）将采集的数据按时间段进行聚合。TDengine 提供了一个简便的关键词 interval 让按照时间窗口的查询操作变得极为简单。比如，将智能电表 d1001 采集的电流值每10秒钟求和
@@ -66,9 +64,9 @@ taos> SELECT sum(current) FROM d1001 INTERVAL(10s);
  2018-10-03 14:38:10.000 |              24.900000572 |
 Query OK, 2 row(s) in set (0.000883s)
 ```
-降采样操作也适用于超级表，比如：将所有智能电表采集的电流值每秒钟求和
+降采样操作也适用于超级表，比如：将北京所有智能电表采集的电流值每秒钟求和
 ```mysql
-taos> SELECT SUM(current) FROM meters INTERVAL(1s);
+taos> SELECT SUM(current) FROM meters where location like "Beijing%" INTERVAL(1s);
            ts            |       sum(current)        |
 ======================================================
  2018-10-03 14:38:04.000 |              10.199999809 |

documentation20/webdocs/markdowndocs/TAOS SQL-ch.md

@@ -124,7 +124,8 @@ TDengine缺省的时间戳是毫秒精度，但通过修改配置参数enableMic
     说明：
     1) 表的第一个字段必须是TIMESTAMP，并且系统自动将其设为主键；
     2) 表名最大长度为193；
-    3) 表的每行长度不能超过16k个字符;     
+    3) 表的每行长度不能超过16k个字符;
+    4) 子表名只能由字母、数字和下划线组成，且不能以数字开头
     5) 使用数据类型binary或nchar，需指定其最长的字节数，如binary(20)，表示20字节；
 
 - **删除数据表**

documentation20/webdocs/markdowndocs/architecture-ch.md

@@ -65,24 +65,24 @@ TDengine 的设计是基于单个硬件、软件系统不可靠，基于任何
 TDengine 分布式架构的逻辑结构图如下：
 <center> <img src="../assets/structure.png"> </center>
 <center> 图 1 TDengine架构示意图  </center>
-一个完整的 TDengine 系统是运行在一到多个物理节点上的，逻辑上，它包含数据节点(dnode)、TDengine客户端(taosc)以及应用(app)。系统中存在一到多个数据节点，这些数据节点组成一个集群(cluster)。应用通过taosc的API与TDengine集群进行互动。下面对每个逻辑单元进行简要介绍。
+一个完整的 TDengine 系统是运行在一到多个物理节点上的，逻辑上，它包含数据节点(dnode)、TDengine应用驱动(taosc)以及应用(app)。系统中存在一到多个数据节点，这些数据节点组成一个集群(cluster)。应用通过taosc的API与TDengine集群进行互动。下面对每个逻辑单元进行简要介绍。
 
-**物理节点(pnode):** pnode是一独立运行、拥有自己的计算、存储和网络能力的计算机，可以是安装有OS的物理机、虚拟机或容器。物理节点由其配置的 FQDN(Fully Qualified Domain Name)来标识。TDengine完全依赖FQDN来进行网络通讯，如果不了解FQDN，请看博文《[一篇文章说清楚TDengine的FQDN](https://www.taosdata.com/blog/2020/09/11/1824.html)》。
+**物理节点(pnode):** pnode是一独立运行、拥有自己的计算、存储和网络能力的计算机，可以是安装有OS的物理机、虚拟机或Docker容器。物理节点由其配置的 FQDN(Fully Qualified Domain Name)来标识。TDengine完全依赖FQDN来进行网络通讯，如果不了解FQDN，请看博文《[一篇文章说清楚TDengine的FQDN](https://www.taosdata.com/blog/2020/09/11/1824.html)》。
 
 **数据节点(dnode):** dnode 是 TDengine 服务器侧执行代码 taosd 在物理节点上的一个运行实例，一个工作的系统必须有至少一个数据节点。dnode包含零到多个逻辑的虚拟节点(VNODE)，零或者至多一个逻辑的管理节点(mnode)。dnode在系统中的唯一标识由实例的End Point (EP )决定。EP是dnode所在物理节点的FQDN (Fully Qualified Domain Name)和系统所配置的网络端口号(Port)的组合。通过配置不同的端口，一个物理节点(一台物理机、虚拟机或容器）可以运行多个实例，或有多个数据节点。
 
-**虚拟节点(vnode)**: 为更好的支持数据分片、负载均衡，防止数据过热或倾斜，数据节点被虚拟化成多个虚拟节点(vnode，图中V2, V3, V4等)。每个 vnode 都是一个相对独立的工作单元，是时序数据存储的基本单元，具有独立的运行线程、内存空间与持久化存储的路径。一个 vnode 包含一定数量的表（数据采集点）。当创建一张新表时，系统会检查是否需要创建新的 vnode。一个数据节点上能创建的 vnode 的数量取决于该数据节点所在物理节点的硬件资源。一个 vnode 只属于一个DB，但一个DB可以有多个 vnode。一个 vnode 除存储的时序数据外，也保存有所包含的表的SCHEMA、标签值等。一个虚拟节点由所属的数据节点的EP，以及所属的VGroup ID在系统内唯一标识，由管理节点创建并管理。
+**虚拟节点(vnode)**: 为更好的支持数据分片、负载均衡，防止数据过热或倾斜，数据节点被虚拟化成多个虚拟节点(vnode，图中V2, V3, V4等)。每个 vnode 都是一个相对独立的工作单元，是时序数据存储的基本单元，具有独立的运行线程、内存空间与持久化存储的路径。一个 vnode 包含一定数量的表（数据采集点）。当创建一张新表时，系统会检查是否需要创建新的 vnode。一个数据节点上能创建的 vnode 的数量取决于该数据节点所在物理节点的硬件资源。一个 vnode 只属于一个DB，但一个DB可以有多个 vnode。一个 vnode 除存储的时序数据外，也保存有所包含的表的schema、标签值等。一个虚拟节点由所属的数据节点的EP，以及所属的VGroup ID在系统内唯一标识，由管理节点创建并管理。
 
 **管理节点(mnode):** 一个虚拟的逻辑单元，负责所有数据节点运行状态的监控和维护，以及节点之间的负载均衡(图中M)。同时，管理节点也负责元数据(包括用户、数据库、表、静态标签等)的存储和管理，因此也称为 Meta Node。TDengine 集群中可配置多个(最多不超过5个) mnode，它们自动构建成为一个虚拟管理节点组(图中M0, M1, M2)。mnode 间采用 master/slave 的机制进行管理，而且采取强一致方式进行数据同步, 任何数据更新操作只能在 Master 上进行。mnode 集群的创建由系统自动完成，无需人工干预。每个dnode上至多有一个mnode，由所属的数据节点的EP来唯一标识。每个dnode通过内部消息交互自动获取整个集群中所有 mnode 所在的 dnode 的EP。
 
 **虚拟节点组(VGroup):** 不同数据节点上的 vnode 可以组成一个虚拟节点组(vnode group)来保证系统的高可靠。虚拟节点组内采取master/slave的方式进行管理。写操作只能在 master vnode 上进行，系统采用异步复制的方式将数据同步到 slave vnode，这样确保了一份数据在多个物理节点上有拷贝。一个 vgroup 里虚拟节点个数就是数据的副本数。如果一个DB的副本数为N，系统必须有至少N个数据节点。副本数在创建DB时通过参数 replica 可以指定，缺省为1。使用 TDengine 的多副本特性，可以不再需要昂贵的磁盘阵列等存储设备，就可以获得同样的数据高可靠性。虚拟节点组由管理节点创建、管理，并且由管理节点分配一个系统唯一的ID，VGroup ID。如果两个虚拟节点的vnode group ID相同，说明他们属于同一个组，数据互为备份。虚拟节点组里虚拟节点的个数是可以动态改变的，容许只有一个，也就是没有数据复制。VGroup ID是永远不变的，即使一个虚拟节点组被删除，它的ID也不会被收回重复利用。
 
-**TAOSC:** taosc是TDengine给应用提供的驱动程序(driver)，负责处理应用与集群的接口交互，内嵌于JDBC、ODBC driver中，或者C、Python、Go语言连接库里。应用都是通过taosc而不是直接连接集群中的数据节点与整个集群进行交互的。这个模块负责获取并缓存元数据；将插入、查询等请求转发到正确的数据节点；在把结果返回给应用时，还需要负责最后一级的聚合、排序、过滤等操作。对于JDBC, ODBC, C/C++接口而言，这个模块是在应用所处的物理节点上运行，但消耗的资源很小。同时，为支持全分布式的RESTful接口，taosc在TDengine集群的每个dnode上都有一运行实例。
+**TAOSC:** taosc是TDengine给应用提供的驱动程序(driver)，负责处理应用与集群的接口交互，提供C/C++语言原生接口，内嵌于JDBC、C#、Python、Go、Node.js语言连接库里。应用都是通过taosc而不是直接连接集群中的数据节点与整个集群进行交互的。这个模块负责获取并缓存元数据；将插入、查询等请求转发到正确的数据节点；在把结果返回给应用时，还需要负责最后一级的聚合、排序、过滤等操作。对于JDBC, C/C++/C#/Python/Go/Node.js接口而言，这个模块是在应用所处的物理节点上运行。同时，为支持全分布式的RESTful接口，taosc在TDengine集群的每个dnode上都有一运行实例。
 
 ### 节点之间的通讯
-**通讯方式：**TDengine系统的各个节点之间的通讯是通过TCP/UDP进行的。因为考虑到物联网场景，数据写入的包一般不大，因此TDengine 除采用TCP做传输之外，还采用UDP方式，因为UDP 更加高效，而且不受连接数的限制。TDengine实现了自己的超时、重传、确认等机制，以确保UDP的可靠传输。对于数据量不到15K的数据包，采取UDP的方式进行传输，超过15K的，或者是查询类的操作，自动采取TCP的方式进行传输。同时，TDengine根据配置和数据包，会自动对数据进行压缩/解压缩，数字签名/认证等处理。对于数据节点之间的数据复制，只采用TCP方式进行数据传输。
+**通讯方式：**TDengine系统的各个数据节点之间，以及应用驱动与各数据节点之间的通讯是通过TCP/UDP进行的。因为考虑到物联网场景，数据写入的包一般不大，因此TDengine 除采用TCP做传输之外，还采用UDP方式，因为UDP 更加高效，而且不受连接数的限制。TDengine实现了自己的超时、重传、确认等机制，以确保UDP的可靠传输。对于数据量不到15K的数据包，采取UDP的方式进行传输，超过15K的，或者是查询类的操作，自动采取TCP的方式进行传输。同时，TDengine根据配置和数据包，会自动对数据进行压缩/解压缩，数字签名/认证等处理。对于数据节点之间的数据复制，只采用TCP方式进行数据传输。
 
-**FQDN配置**：一个数据节点有一个或多个FQDN，可以在系统配置文件taos.cfg通过参数“fqdn"进行指定，如果没有指定，系统将自动获取FQDN。如果节点没有配置FQDN，可以直接将该节点的配置参数fqdn设置为它的IP地址。但不建议使用IP，因为IP地址可变，一旦变化，将让集群无法正常工作。一个数据节点的EP(End Point)由FQDN + Port组成。采用FQDN，需要保证DNS服务正常工作，或者在节点以及应用所在的节点配置好hosts文件。
+**FQDN配置**：一个数据节点有一个或多个FQDN，可以在系统配置文件taos.cfg通过参数“fqdn"进行指定，如果没有指定，系统将自动获取计算机的hostname作为其FQDN。如果节点没有配置FQDN，可以直接将该节点的配置参数fqdn设置为它的IP地址。但不建议使用IP，因为IP地址可变，一旦变化，将让集群无法正常工作。一个数据节点的EP(End Point)由FQDN + Port组成。采用FQDN，需要保证DNS服务正常工作，或者在节点以及应用所在的节点配置好hosts文件。
 
 **端口配置：**一个数据节点对外的端口由TDengine的系统配置参数serverPort决定，对集群内部通讯的端口是serverPort+5。集群内数据节点之间的数据复制操作还占有一个TCP端口，是serverPort+10. 为支持多线程高效的处理UDP数据，每个对内和对外的UDP连接，都需要占用5个连续的端口。因此一个数据节点总的端口范围为serverPort到serverPort + 10，总共11个TCP/UDP端口。使用时，需要确保防火墙将这些端口打开。每个数据节点可以配置不同的serverPort。
 
@@ -153,6 +153,7 @@ TDengine除vnode分片之外，还对时序数据按照时间段进行分区。
 当新的数据节点被添加进集群，因为新的计算和存储被添加进来，系统也将自动启动负载均衡流程。
 
 负载均衡过程无需任何人工干预，应用也无需重启，将自动连接新的节点，完全透明。
+**提示：负载均衡由参数balance控制，决定开启/关闭自动负载均衡。**
 
 ## 数据写入与复制流程
 如果一个数据库有N个副本，那一个虚拟节点组就有N个虚拟节点，但是只有一个是Master，其他都是slave。当应用将新的记录写入系统时，只有Master vnode能接受写的请求。如果slave vnode收到写的请求，系统将通知taosc需要重新定向。
@@ -192,7 +193,8 @@ Master Vnode遵循下面的写入流程：
 
 理论上，只要是异步复制，就无法保证100%不丢失。但是这个窗口极小，mater与slave要同时发生故障，而且发生在刚给应用确认写入成功之后。
 
-注：异地容灾、IDC无中断迁移，仅仅企业版支持
+注：异地容灾、IDC无中断迁移，仅仅企业版支持。
+**提示：该功能暂未提供**
 
 ### 主从选择
 Vnode会保持一个数据版本号(Version)，对内存数据进行持久化存储时，对该版本号也进行持久化存储。每个数据更新操作，无论是采集的时序数据还是元数据，这个版本号将增一。
@@ -259,6 +261,7 @@ dataDir /mnt/disk6/taos 2
 挂载的盘也可以是非本地的网络盘，只要系统能访问即可。
 
 注：多级存储功能仅企业版支持
+**提示：该功能暂未提供**
 
 ## 数据查询
 TDengine提供了多种多样针对表和超级表的查询处理功能，除了常规的聚合查询之外，还提供针对时序数据的窗口查询、统计聚合等功能。TDengine的查询处理需要客户端、vnode, mnode节点协同完成。
@@ -289,11 +292,18 @@ select count(*) from d1001 interval(1h) fill(prev);
 针对d1001设备采集数据统计每小时记录数，如果某一个小时不存在数据，这返回之前一个小时的统计数据。TDengine提供前向插值(prev)、线性插值(linear)、NULL值填充(NULL)、特定值填充(value)。
 
 ### 多表聚合查询
-多表聚合查询与单表查询的整体流程相同，但是存在如下的差异：
-
-- 由于多表可能分布在不同的节点(dnode)，因此多表的聚合查询需要首先获得表所在的全部数据节点的信息，并且同时向相关的dnode发出查询请求。
-- 每个vnode的计算获得的中间结果(partial results)需要进行第二阶段的聚合才能形成最终结果，第二阶段的聚合过程在客户端完成。
-- 由于表标签信息存储在vnode中，因此针对标签信息的查询也需要vnode完成。客户端将标签的过滤表达式封装在查询请求结构体中发送给vnode，由vnode的查询执行线程从中抽取出标签查询条件，然后执行查询。标签查询与过滤是在针对表的查询之前完成。标签查询完成以后，将符合条件的表纳入到接下来的查询处理流程中。
+TDengine对每个数据采集点单独建表，但在实际应用中经常需要对不同的采集点数据进行聚合。为高效的进行聚合操作，TDengine引入超级表（STable）的概念。超级表用来代表一特定类型的数据采集点，它是包含多张表的表集合，集合里每张表的模式（schema）完全一致，但每张表都带有自己的静态标签，标签可以多个，可以随时增加、删除和修改。 应用可通过指定标签的过滤条件，对一个STable下的全部或部分表进行聚合或统计操作，这样大大简化应用的开发。其具体流程如下图所示：
+<center> <img src="../assets/multi_tables.png">  </center>
+
+<center> 图 5 多表聚合查询原理图  </center>
+1：应用将一个查询条件发往系统；
+2: taosc将超级表的名字发往 Meta Node（管理节点)；
+3：管理节点将超级表所拥有的 vnode 列表发回 taosc；
+4：taosc将计算的请求连同标签过滤条件发往这些vnode对应的多个数据节点；
+5：每个vnode先在内存里查找出自己节点里符合标签过滤条件的表的集合，然后扫描存储的时序数据，完成相应的聚合计算，将结果返回给taosc；
+6：taosc将多个数据节点返回的结果做最后的聚合，将其返回给应用。 
+
+由于TDengine在vnode内将标签数据与时序数据分离存储，通过在内存里过滤标签数据，先找到需要参与聚合操作的表的集合，将需要扫描的数据集大幅减少，大幅提升聚合计算速度。同时，由于数据分布在多个vnode/dnode，聚合计算操作在多个vnode里并发进行，又进一步提升了聚合的速度。 对普通表的聚合函数以及绝大部分操作都适用于超级表，语法完全一样，细节请看 TAOS SQL。
 
 ### 预计算
 为有效提升查询处理的性能，针对物联网数据的不可更改的特点，在数据块头部记录该数据块中存储数据的统计信息：包括最大值、最小值、和。我们称之为预计算单元。如果查询处理涉及整个数据块的全部数据，直接使用预计算结果，完全不需要读取数据块的内容。由于预计算数据量远小于磁盘上存储的数据块数据的大小，对于磁盘IO为瓶颈的查询处理，使用预计算结果可以极大地减小读取IO压力，加速查询处理的流程。预计算机制与Postgre SQL的索引BRIN（block range index）有异曲同工之妙。

documentation20/webdocs/markdowndocs/cluster-ch.md

@@ -8,7 +8,7 @@ TDengine的集群管理极其简单，除添加和删除节点需要人工干预
 
 ## 准备工作
 
-**第零步**：如果没有部署DNS服务，请规划集群所有物理节点的FQDN，然后按照《[一篇文章说清楚TDengine的FQDN](https://www.taosdata.com/blog/2020/09/11/1824.html)》里的步骤，将所有集群物理节点的IP与FQDN的对应关系添加好。
+**第零步**：规划集群所有物理节点的FQDN，将规划好的FQDN分别添加到每个物理节点的/etc/hostname；修改每个物理节点的/etc/hosts，将所有集群物理节点的IP与FQDN的对应添加好。【如部署了DNS，请联系网络管理员在DNS上做好相关配置】
 
 **第一步**：如果搭建集群的物理节点中，存有之前的测试数据、装过1.X的版本，或者装过其他版本的TDengine，请先将其删除，并清空所有数据，具体步骤请参考博客[《TDengine多种安装包的安装和卸载》](https://www.taosdata.com/blog/2019/08/09/566.html ) 
 **注意1：**因为FQDN的信息会写进文件，如果之前没有配置或者更改FQDN，且启动了TDengine。请一定在确保数据无用或者备份的前提下，清理一下之前的数据（rm -rf /var/lib/taos/）；
@@ -16,9 +16,9 @@ TDengine的集群管理极其简单，除添加和删除节点需要人工干预
 
 **第二步**：建议关闭所有物理节点的防火墙，至少保证端口：6030 - 6042的TCP和UDP端口都是开放的。**强烈建议**先关闭防火墙，集群搭建完毕之后，再来配置端口；
 
-**第三步**：在所有节点安装TDengine，且版本必须是一致的，**但不要启动taosd**。安装时，提示输入是否要加入一个已经存在的TDengine集群时，第一个物理节点直接回车创建新集群，后续物理节点则输入该集群任何一个在线的物理节点的FQDN:端口号(默认6030)；
+**第三步**：在所有物理节点安装TDengine，且版本必须是一致的，**但不要启动taosd**。安装时，提示输入是否要加入一个已经存在的TDengine集群时，第一个物理节点直接回车创建新集群，后续物理节点则输入该集群任何一个在线的物理节点的FQDN:端口号(默认6030)；
 
-**第四步**：检查所有数据节点，以及应用所在物理节点的网络设置：
+**第四步**：检查所有数据节点，以及应用程序所在物理节点的网络设置：
 
 1. 每个物理节点上执行命令`hostname -f`，查看和确认所有节点的hostname是不相同的(应用驱动所在节点无需做此项检查)；
 2. 每个物理节点上执行`ping host`, 其中host是其他物理节点的hostname, 看能否ping通其它物理节点; 如果不能ping通，需要检查网络设置, 或/etc/hosts文件(Windows系统默认路径为C:\Windows\system32\drivers\etc\hosts)，或DNS的配置。如果无法ping通，是无法组成集群的；

documentation20/webdocs/markdowndocs/insert-ch.md

@@ -22,7 +22,7 @@ INSERT INTO d1001 VALUES (1538548685000, 10.3, 219, 0.31) (1538548695000, 12.6,
 
 **Tips:** 
 
-- 要提高写入效率，需要批量写入。一批写入的记录条数越多，插入效率就越高。但一条记录不能超过16K，一条SQL语句总长度不能超过64K（可通过参数maxSQLLength配置，最大可配置为8M）。
+- 要提高写入效率，需要批量写入。一批写入的记录条数越多，插入效率就越高。但一条记录不能超过16K，一条SQL语句总长度不能超过64K（可通过参数maxSQLLength配置，最大可配置为1M）。
 - TDengine支持多线程同时写入，要进一步提高写入速度，一个客户端需要打开20个以上的线程同时写。但线程数达到一定数量后，无法再提高，甚至还会下降，因为线程切频繁切换，带来额外开销。
 - 对同一张表，如果新插入记录的时间戳已经存在，新记录将被直接抛弃，也就是说，在一张表里，时间戳必须是唯一的。如果应用自动生成记录，很有可能生成的时间戳是一样的，这样，成功插入的记录条数会小于应用插入的记录条数。
 - 写入的数据的时间戳必须大于当前时间减去配置参数keep的时间。如果keep配置为3650天，那么无法写入比3650天还老的数据。写入数据的时间戳也不能大于当前时间加配置参数days。如果days配置为2，那么无法写入比当前时间还晚2天的数据。

go @ 8c58c512

-Subproject commit 567b7b12f3fd2775c718d284beffc8c38dd6c219
+Subproject commit 8c58c512b6acda8bcdfa48fdc7140227b5221766

src/dnode/src/dnodeMgmt.c

@@ -468,8 +468,24 @@ void dnodeUpdateMnodeEpSetForPeer(SRpcEpSet *pEpSet) {
 
     if (!mnodeIsRunning()) {
       if (strcmp(pEpSet->fqdn[i], tsLocalFqdn) == 0 && pEpSet->port[i] == tsServerPort) {
-        dInfo("mnode index:%d %s:%u should work as master", i, pEpSet->fqdn[i], pEpSet->port[i]);
-        sdbUpdateSync();
+        dInfo("mnode index:%d %s:%u should work as mnode", i, pEpSet->fqdn[i], pEpSet->port[i]);
+        bool find = false;
+        for (int i = 0; i < tsDMnodeInfos.nodeNum; ++i) {
+          if (tsDMnodeInfos.nodeInfos[i].nodeId == dnodeGetDnodeId()) {
+            dInfo("localEp found in mnode infos");
+            find = true;
+            break;
+          }
+        }
+
+        if (!find) {
+          dInfo("localEp not found in mnode infos, will set into mnode infos");
+          tstrncpy(tsDMnodeInfos.nodeInfos[tsDMnodeInfos.nodeNum].nodeEp, tsLocalEp, TSDB_EP_LEN);
+          tsDMnodeInfos.nodeInfos[tsDMnodeInfos.nodeNum].nodeId = dnodeGetDnodeId();
+          tsDMnodeInfos.nodeNum++;
+        }
+
+        dnodeStartMnode();
       }
     }
   }

src/dnode/src/dnodeModule.c

@@ -146,19 +146,16 @@ void dnodeProcessModuleStatus(uint32_t moduleStatus) {
   }
 }
 
-bool dnodeCheckMnodeStarting() {
-  if (tsModuleStatus & (1 << TSDB_MOD_MNODE)) return false;
-
-  SDMMnodeInfos *mnodes = dnodeGetMnodeInfos();
-  for (int32_t i = 0; i < mnodes->nodeNum; ++i) {
-    SDMMnodeInfo *node = &mnodes->nodeInfos[i];
-    if (node->nodeId == dnodeGetDnodeId()) {
-      uint32_t moduleStatus = tsModuleStatus | (1 << TSDB_MOD_MNODE);
-      dInfo("start mnode module, module status:%d, new status:%d", tsModuleStatus, moduleStatus);
-      dnodeProcessModuleStatus(moduleStatus);
-      return true;
-    }
+bool dnodeStartMnode() {
+  if (tsModuleStatus & (1 << TSDB_MOD_MNODE)) {
+    dDebug("mnode module is already started, module status:%d", tsModuleStatus);
+    return false;
   }
 
-  return false;
+  uint32_t moduleStatus = tsModuleStatus | (1 << TSDB_MOD_MNODE);
+  dInfo("start mnode module, module status:%d, new status:%d", tsModuleStatus, moduleStatus);
+  dnodeProcessModuleStatus(moduleStatus);
+
+  sdbUpdateSync();
+  return true;
 }

src/dnode/src/dnodeVRead.c

@@ -187,6 +187,7 @@ void dnodeSendRpcReadRsp(void *pVnode, SReadMsg *pRead, int32_t code) {
 }
 
 void dnodeDispatchNonRspMsg(void *pVnode, SReadMsg *pRead, int32_t code) {
+  rpcFreeCont(pRead->rpcMsg.pCont);
   vnodeRelease(pVnode);
   return;
 }

src/inc/dnode.h

@@ -43,7 +43,7 @@ void    dnodeGetMnodeEpSetForPeer(void *epSet);
 void    dnodeGetMnodeEpSetForShell(void *epSet);
 void *  dnodeGetMnodeInfos();
 int32_t dnodeGetDnodeId();
-bool    dnodeCheckMnodeStarting();
+bool    dnodeStartMnode();
 
 void  dnodeAddClientRspHandle(uint8_t msgType, void (*fp)(SRpcMsg *rpcMsg));
 void  dnodeSendMsgToDnode(SRpcEpSet *epSet, SRpcMsg *rpcMsg);

src/mnode/src/mnodeSdb.c

@@ -91,7 +91,6 @@ typedef struct {
 } SSdbWriteWorkerPool;
 
 extern void *     tsMnodeTmr;
-static void *     tsUpdateSyncTmr;
 static SSdbObject tsSdbObj = {0};
 static taos_qset  tsSdbWriteQset;
 static taos_qall  tsSdbWriteQall;
@@ -298,16 +297,12 @@ static void sdbConfirmForward(void *ahandle, void *param, int32_t code) {
   taosFreeQitem(pOper);
 }
 
-static void sdbUpdateSyncTmrFp(void *param, void *tmrId) { sdbUpdateSync(); }
-
 void sdbUpdateSync() {
   if (!mnodeIsRunning()) {
     mDebug("mnode not start yet, update sync info later");
-    if (dnodeCheckMnodeStarting()) {
-      taosTmrReset(sdbUpdateSyncTmrFp, 1000, NULL, tsMnodeTmr, &tsUpdateSyncTmr);
-    }
     return;
   }
+
   mDebug("update sync info in sdb");
 
   SSyncCfg syncCfg = {0};

src/rpc/src/rpcMain.c

@@ -195,7 +195,7 @@ static void  rpcSendMsgToPeer(SRpcConn *pConn, void *data, int dataLen);
 static void  rpcSendReqHead(SRpcConn *pConn);
 
 static void *rpcProcessMsgFromPeer(SRecvInfo *pRecv);
-static void  rpcProcessIncomingMsg(SRpcConn *pConn, SRpcHead *pHead);
+static void  rpcProcessIncomingMsg(SRpcConn *pConn, SRpcHead *pHead, SRpcReqContext *pContext);
 static void  rpcProcessConnError(void *param, void *id);
 static void  rpcProcessRetryTimer(void *, void *);
 static void  rpcProcessIdleTimer(void *param, void *tmrId);
@@ -323,7 +323,7 @@ void *rpcMallocCont(int contLen) {
     tError("failed to malloc msg, size:%d", size);
     return NULL;
   } else {
-    tDebug("malloc msg: %p", start);
+    tTrace("malloc mem: %p", start);
   }
 
   return start + sizeof(SRpcReqContext) + sizeof(SRpcHead);
@@ -333,7 +333,7 @@ void rpcFreeCont(void *cont) {
   if (cont) {
     char *temp = ((char *)cont) - sizeof(SRpcHead) - sizeof(SRpcReqContext);
     free(temp);
-    tDebug("free mem: %p", temp);
+    tTrace("free mem: %p", temp);
   }
 }
 
@@ -553,7 +553,7 @@ static void rpcFreeMsg(void *msg) {
   if ( msg ) {
     char *temp = (char *)msg - sizeof(SRpcReqContext);
     free(temp);
-    tDebug("free msg: %p", temp);
+    tTrace("free mem: %p", temp);
   }
 }
 
@@ -819,9 +819,18 @@ static int rpcProcessReqHead(SRpcConn *pConn, SRpcHead *pHead) {
       return TSDB_CODE_RPC_LAST_SESSION_NOT_FINISHED;
     }
 
+    if (rpcContLenFromMsg(pHead->msgLen) <= 0) {
+      tDebug("%s, message body is empty, ignore", pConn->info);
+      return TSDB_CODE_RPC_APP_ERROR;
+    }
+
     pConn->inTranId = pHead->tranId;
     pConn->inType = pHead->msgType;
 
+    // start the progress timer to monitor the response from server app
+    if (pConn->connType != RPC_CONN_TCPS) 
+      pConn->pTimer = taosTmrStart(rpcProcessProgressTimer, tsProgressTimer, pConn, pConn->pRpc->tmrCtrl);
+ 
     return 0;
 }
 
@@ -881,17 +890,32 @@ static int rpcProcessRspHead(SRpcConn *pConn, SRpcHead *pHead) {
   pConn->outType = 0;
   pConn->pReqMsg = NULL;
   pConn->reqMsgLen = 0;
+  SRpcReqContext *pContext = pConn->pContext;
+
+  if (pHead->code == TSDB_CODE_RPC_REDIRECT) { 
+    if (rpcContLenFromMsg(pHead->msgLen) < sizeof(SRpcEpSet)) {
+      // if EpSet is not included in the msg, treat it as NOT_READY
+      pHead->code = TSDB_CODE_RPC_NOT_READY; 
+    } else {
+      pContext->redirect++;
+      if (pContext->redirect > TSDB_MAX_REPLICA) {
+        pHead->code = TSDB_CODE_RPC_NETWORK_UNAVAIL; 
+        tWarn("%s, too many redirects, quit", pConn->info);
+      }
+    }
+  } 
 
   return TSDB_CODE_SUCCESS;
 }
 
-static SRpcConn *rpcProcessMsgHead(SRpcInfo *pRpc, SRecvInfo *pRecv) {
+static SRpcConn *rpcProcessMsgHead(SRpcInfo *pRpc, SRecvInfo *pRecv, SRpcReqContext **ppContext) {
   int32_t    sid;
   SRpcConn  *pConn = NULL;
 
   SRpcHead *pHead = (SRpcHead *)pRecv->msg;
 
   sid = htonl(pHead->destId);
+  *ppContext = NULL;
 
   if (pHead->msgType >= TSDB_MSG_TYPE_MAX || pHead->msgType <= 0) {
     tDebug("%s sid:%d, invalid message type:%d", pRpc->label, sid, pHead->msgType);
@@ -945,6 +969,7 @@ static SRpcConn *rpcProcessMsgHead(SRpcInfo *pRpc, SRecvInfo *pRecv) {
         pConn->pIdleTimer = taosTmrStart(rpcProcessIdleTimer, tsRpcTimer*2, pConn, pRpc->tmrCtrl);
     } else {
       terrno = rpcProcessRspHead(pConn, pHead);
+      *ppContext = pConn->pContext;
     }
   }
 
@@ -1009,7 +1034,8 @@ static void *rpcProcessMsgFromPeer(SRecvInfo *pRecv) {
   }
 
   terrno = 0;
-  pConn = rpcProcessMsgHead(pRpc, pRecv);
+  SRpcReqContext *pContext;
+  pConn = rpcProcessMsgHead(pRpc, pRecv, &pContext);
 
   if (pHead->msgType >= 1 && pHead->msgType < TSDB_MSG_TYPE_MAX) {
     tDebug("%s %p %p, %s received from 0x%x:%hu, parse code:0x%x len:%d sig:0x%08x:0x%08x:%d code:0x%x", pRpc->label,
@@ -1029,7 +1055,7 @@ static void *rpcProcessMsgFromPeer(SRecvInfo *pRecv) {
         tDebug("%s %p %p, %s is sent with error code:0x%x", pRpc->label, pConn, (void *)pHead->ahandle, taosMsg[pHead->msgType+1], code);
       } 
     } else { // msg is passed to app only parsing is ok 
-      rpcProcessIncomingMsg(pConn, pHead);
+      rpcProcessIncomingMsg(pConn, pHead, pContext);
     }
   }
 
@@ -1060,7 +1086,7 @@ static void rpcNotifyClient(SRpcReqContext *pContext, SRpcMsg *pMsg) {
   rpcFreeCont(pContext->pCont); 
 }
 
-static void rpcProcessIncomingMsg(SRpcConn *pConn, SRpcHead *pHead) {
+static void rpcProcessIncomingMsg(SRpcConn *pConn, SRpcHead *pHead, SRpcReqContext *pContext) {
 
   SRpcInfo *pRpc = pConn->pRpc;
   SRpcMsg   rpcMsg;
@@ -1070,29 +1096,18 @@ static void rpcProcessIncomingMsg(SRpcConn *pConn, SRpcHead *pHead) {
   rpcMsg.pCont = pHead->content;
   rpcMsg.msgType = pHead->msgType;
   rpcMsg.code = pHead->code; 
-  rpcMsg.ahandle = pConn->ahandle;
    
   if ( rpcIsReq(pHead->msgType) ) {
-    if (rpcMsg.contLen > 0) {
-      rpcMsg.handle = pConn;
-      rpcAddRef(pRpc);  // add the refCount for requests
+    rpcMsg.ahandle = pConn->ahandle;
+    rpcMsg.handle = pConn;
+    rpcAddRef(pRpc);  // add the refCount for requests
 
-      // start the progress timer to monitor the response from server app
-      if (pConn->connType != RPC_CONN_TCPS) 
-        pConn->pTimer = taosTmrStart(rpcProcessProgressTimer, tsProgressTimer, pConn, pRpc->tmrCtrl);
- 
-      // notify the server app
-      (*(pRpc->cfp))(&rpcMsg, NULL);
-    } else {
-      tDebug("%s, message body is empty, ignore", pConn->info);
-      rpcFreeCont(rpcMsg.pCont);
-    }
+    // notify the server app
+    (*(pRpc->cfp))(&rpcMsg, NULL);
   } else {
     // it's a response
-    SRpcReqContext *pContext = pConn->pContext;
     rpcMsg.handle = pContext;
-    pConn->pContext = NULL;
-    pConn->pReqMsg = NULL;
+    rpcMsg.ahandle = pContext->ahandle;
 
     // for UDP, port may be changed by server, the port in epSet shall be used for cache
     if (pHead->code != TSDB_CODE_RPC_TOO_SLOW) {
@@ -1101,19 +1116,6 @@ static void rpcProcessIncomingMsg(SRpcConn *pConn, SRpcHead *pHead) {
       rpcCloseConn(pConn);
     }
 
-    if (pHead->code == TSDB_CODE_RPC_REDIRECT) { 
-      if (rpcMsg.contLen < sizeof(SRpcEpSet)) {
-        // if EpSet is not included in the msg, treat it as NOT_READY
-        pHead->code = TSDB_CODE_RPC_NOT_READY; 
-      } else {
-        pContext->redirect++;
-        if (pContext->redirect > TSDB_MAX_REPLICA) {
-          pHead->code = TSDB_CODE_RPC_NETWORK_UNAVAIL; 
-          tWarn("%s, too many redirects, quit", pConn->info);
-        }
-      }
-    }
-
     if (pHead->code == TSDB_CODE_RPC_REDIRECT) {
       pContext->numOfTry = 0;
       SRpcEpSet *pEpSet = (SRpcEpSet*)pHead->content;
@@ -1445,7 +1447,7 @@ static SRpcHead *rpcDecompressRpcMsg(SRpcHead *pHead) {
       pNewHead->msgLen = rpcMsgLenFromCont(origLen);
       rpcFreeMsg(pHead); // free the compressed message buffer
       pHead = pNewHead; 
-      //tTrace("decompress rpc msg, compLen:%d, after:%d", compLen, contLen);
+      tTrace("decomp malloc mem: %p", temp);
     } else {
       tError("failed to allocate memory to decompress msg, contLen:%d", contLen);
     }

src/rpc/src/rpcTcp.c

@@ -62,7 +62,7 @@ typedef struct {
   char        label[TSDB_LABEL_LEN];
   int         numOfThreads;
   void *      shandle;
-  SThreadObj *pThreadObj;
+  SThreadObj **pThreadObj;
   pthread_t   thread;
 } SServerObj;
 
@@ -90,7 +90,7 @@ void *taosInitTcpServer(uint32_t ip, uint16_t port, char *label, int numOfThread
   tstrncpy(pServerObj->label, label, sizeof(pServerObj->label));
   pServerObj->numOfThreads = numOfThreads;
 
-  pServerObj->pThreadObj = (SThreadObj *)calloc(sizeof(SThreadObj), numOfThreads);
+  pServerObj->pThreadObj = (SThreadObj **)calloc(sizeof(SThreadObj *), numOfThreads);
   if (pServerObj->pThreadObj == NULL) {
     tError("TCP:%s no enough memory", label);
     terrno = TAOS_SYSTEM_ERROR(errno); 
@@ -104,19 +104,28 @@ void *taosInitTcpServer(uint32_t ip, uint16_t port, char *label, int numOfThread
   pthread_attr_setdetachstate(&thattr, PTHREAD_CREATE_JOINABLE);
 
   // initialize parameters in case it may encounter error later 
-  pThreadObj = pServerObj->pThreadObj;
   for (int i = 0; i < numOfThreads; ++i) {
+    pThreadObj = (SThreadObj *)calloc(sizeof(SThreadObj), 1);
+    if (pThreadObj == NULL) {
+      tError("TCP:%s no enough memory", label);
+      terrno = TAOS_SYSTEM_ERROR(errno); 
+      for (int j=0; j<i; ++j) free(pServerObj->pThreadObj[j]);
+      free(pServerObj->pThreadObj);
+      free(pServerObj);
+      return NULL;
+    }
+      
+    pServerObj->pThreadObj[i] = pThreadObj;
     pThreadObj->pollFd = -1;
     taosResetPthread(&pThreadObj->thread);
     pThreadObj->processData = fp;
     tstrncpy(pThreadObj->label, label, sizeof(pThreadObj->label));
     pThreadObj->shandle = shandle;
-    pThreadObj++;
   }
 
   // initialize mutex, thread, fd which may fail
-  pThreadObj = pServerObj->pThreadObj;
   for (int i = 0; i < numOfThreads; ++i) {
+    pThreadObj = pServerObj->pThreadObj[i];
     code = pthread_mutex_init(&(pThreadObj->mutex), NULL);
     if (code < 0) {
       tError("%s failed to init TCP process data mutex(%s)", label, strerror(errno));
@@ -137,7 +146,6 @@ void *taosInitTcpServer(uint32_t ip, uint16_t port, char *label, int numOfThread
     }
 
     pThreadObj->threadId = i;
-    pThreadObj++;
   }
 
   pServerObj->fd = taosOpenTcpServerSocket(pServerObj->ip, pServerObj->port);
@@ -166,6 +174,11 @@ static void taosStopTcpThread(SThreadObj* pThreadObj) {
   pThreadObj->stop = true;
   eventfd_t fd = -1;
 
+  if (taosComparePthread(pThreadObj->thread, pthread_self())) {
+    pthread_detach(pthread_self());
+    return;
+  }
+
   if (taosCheckPthreadValid(pThreadObj->thread) && pThreadObj->pollFd >= 0) {
     // signal the thread to stop, try graceful method first,
     // and use pthread_cancel when failed
@@ -183,15 +196,11 @@ static void taosStopTcpThread(SThreadObj* pThreadObj) {
     }
   }
 
-  if (taosCheckPthreadValid(pThreadObj->thread)) pthread_join(pThreadObj->thread, NULL);
-  if (pThreadObj->pollFd >=0) taosCloseSocket(pThreadObj->pollFd);
-  if (fd != -1) taosCloseSocket(fd);
-
-  while (pThreadObj->pHead) {
-    SFdObj *pFdObj = pThreadObj->pHead;
-    pThreadObj->pHead = pFdObj->next;
-    taosFreeFdObj(pFdObj);
+  if (taosCheckPthreadValid(pThreadObj->thread) && pThreadObj->pollFd >= 0) {
+     pthread_join(pThreadObj->thread, NULL);
   }
+
+  if (fd != -1) taosCloseSocket(fd);
 }
 
 void taosStopTcpServer(void *handle) {
@@ -199,7 +208,14 @@ void taosStopTcpServer(void *handle) {
 
   if (pServerObj == NULL) return;
   if(pServerObj->fd >=0) shutdown(pServerObj->fd, SHUT_RD);
-  if (taosCheckPthreadValid(pServerObj->thread)) pthread_join(pServerObj->thread, NULL);
+
+  if (taosCheckPthreadValid(pServerObj->thread)) {
+    if (taosComparePthread(pServerObj->thread, pthread_self())) {
+      pthread_detach(pthread_self());
+    } else {
+      pthread_join(pServerObj->thread, NULL);
+    }
+  }
 
   tDebug("%s TCP server is stopped", pServerObj->label);
 }
@@ -210,9 +226,8 @@ void taosCleanUpTcpServer(void *handle) {
   if (pServerObj == NULL) return;
 
   for (int i = 0; i < pServerObj->numOfThreads; ++i) {
-    pThreadObj = pServerObj->pThreadObj + i;
+    pThreadObj = pServerObj->pThreadObj[i];
     taosStopTcpThread(pThreadObj);
-    pthread_mutex_destroy(&(pThreadObj->mutex));
   }
 
   tDebug("%s TCP server is cleaned up", pServerObj->label);
@@ -249,7 +264,7 @@ static void *taosAcceptTcpConnection(void *arg) {
     taosSetSockOpt(connFd, SOL_SOCKET, SO_RCVTIMEO, &to, sizeof(to));
 
     // pick up the thread to handle this connection
-    pThreadObj = pServerObj->pThreadObj + threadId;
+    pThreadObj = pServerObj->pThreadObj[threadId];
 
     SFdObj *pFdObj = taosMallocFdObj(pThreadObj, connFd);
     if (pFdObj) {
@@ -327,10 +342,8 @@ void taosCleanUpTcpClient(void *chandle) {
   SThreadObj *pThreadObj = chandle;
   if (pThreadObj == NULL) return;
 
+  tDebug ("%s TCP client will be cleaned up", pThreadObj->label);
   taosStopTcpThread(pThreadObj);
-  tDebug ("%s TCP client is cleaned up", pThreadObj->label);
-
-  taosTFree(pThreadObj);
 }
 
 void *taosOpenTcpClientConnection(void *shandle, void *thandle, uint32_t ip, uint16_t port) {
@@ -365,7 +378,7 @@ void *taosOpenTcpClientConnection(void *shandle, void *thandle, uint32_t ip, uin
 
 void taosCloseTcpConnection(void *chandle) {
   SFdObj *pFdObj = chandle;
-  if (pFdObj == NULL) return;
+  if (pFdObj == NULL || pFdObj->signature != pFdObj) return;
 
   SThreadObj *pThreadObj = pFdObj->pThreadObj;
   tDebug("%s %p TCP connection will be closed, FD:%p", pThreadObj->label, pFdObj->thandle, pFdObj); 
@@ -378,7 +391,7 @@ void taosCloseTcpConnection(void *chandle) {
 int taosSendTcpData(uint32_t ip, uint16_t port, void *data, int len, void *chandle) {
   SFdObj *pFdObj = chandle;
 
-  if (chandle == NULL) return -1;
+  if (pFdObj == NULL || pFdObj->signature != pFdObj) return -1;
 
   return taosWriteMsg(pFdObj->fd, data, len);
 }
@@ -425,7 +438,7 @@ static int taosReadTcpData(SFdObj *pFdObj, SRecvInfo *pInfo) {
     tError("%s %p TCP malloc(size:%d) fail", pThreadObj->label, pFdObj->thandle, msgLen);
     return -1;
   } else {
-    tDebug("TCP malloc mem: %p", buffer);
+    tTrace("TCP malloc mem: %p", buffer);
   }
 
   msg = buffer + tsRpcOverhead;
@@ -503,8 +516,22 @@ static void *taosProcessTcpData(void *param) {
       pFdObj->thandle = (*(pThreadObj->processData))(&recvInfo);
       if (pFdObj->thandle == NULL) taosFreeFdObj(pFdObj);
     }
+
+    if (pThreadObj->stop) break; 
+  }
+
+  if (pThreadObj->pollFd >=0) taosCloseSocket(pThreadObj->pollFd);
+
+  while (pThreadObj->pHead) {
+    SFdObj *pFdObj = pThreadObj->pHead;
+    pThreadObj->pHead = pFdObj->next;
+    taosFreeFdObj(pFdObj);
   }
 
+  pthread_mutex_destroy(&(pThreadObj->mutex));
+  tDebug("%s TCP thread exits ...", pThreadObj->label);
+  taosTFree(pThreadObj);
+
   return NULL;
 }
 

src/rpc/src/rpcUdp.c

@@ -214,7 +214,7 @@ static void *taosRecvUdpData(void *param) {
       tError("%s failed to allocate memory, size:%" PRId64, pConn->label, (int64_t)dataLen);
       continue;
     } else {
-      tDebug("UDP malloc mem: %p", tmsg);
+      tTrace("UDP malloc mem: %p", tmsg);
     }
 
     tmsg += tsRpcOverhead;  // overhead for SRpcReqContext

src/sync/src/taosTcpPool.c

@@ -219,7 +219,10 @@ static void *taosProcessTcpData(void *param) {
           continue;
         }
       }
+
     }
+
+    if (pThread->stop) break;
   }
 
   uDebug("%p TCP epoll thread exits", pThread);
@@ -321,5 +324,5 @@ static void taosStopPoolThread(SThreadObj *pThread) {
   }
 
   pthread_join(thread, NULL);
-  taosClose(fd);
+  if (fd >= 0) taosClose(fd);
 }

tests/examples/JDBC/calciteDemo/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.example.calcite</groupId>
+    <artifactId>calciteDemo</artifactId>
+    <version>1.0-SNAPSHOT</version>
+
+    <dependencies>
+        <!-- slf4j -->
+        <dependency>
+            <groupId>org.slf4j</groupId>
+            <artifactId>slf4j-simple</artifactId>
+            <version>1.7.25</version>
+            <scope>compile</scope>
+        </dependency>
+        <!-- calcite -->
+        <dependency>
+            <groupId>org.apache.calcite</groupId>
+            <artifactId>calcite-core</artifactId>
+            <version>1.23.0</version>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-dbcp2</artifactId>
+            <version>2.7.0</version>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.calcite.avatica</groupId>
+            <artifactId>avatica-core</artifactId>
+            <version>1.17.0</version>
+        </dependency>
+
+        <!-- mysql -->
+        <dependency>
+            <groupId>mysql</groupId>
+            <artifactId>mysql-connector-java</artifactId>
+            <version>5.1.47</version>
+        </dependency>
+
+        <!-- tdengine -->
+        <dependency>
+            <groupId>com.taosdata.jdbc</groupId>
+            <artifactId>taos-jdbcdriver</artifactId>
+            <version>2.0.7</version>
+        </dependency>
+
+    </dependencies>
+
+
+</project>
\ No newline at end of file

tests/examples/JDBC/calciteDemo/src/main/java/com/taosdata/example/calcite/CalciteDemo.java

+package com.taosdata.example.calcite;
+
+import org.apache.calcite.adapter.jdbc.JdbcSchema;
+import org.apache.calcite.jdbc.CalciteConnection;
+import org.apache.calcite.schema.Schema;
+import org.apache.calcite.schema.SchemaPlus;
+import org.apache.calcite.sql.parser.SqlParseException;
+import org.apache.commons.dbcp2.BasicDataSource;
+
+import java.sql.*;
+import java.util.Properties;
+
+public class CalciteDemo {
+
+    private static String url_taos = "jdbc:TAOS://192.168.236.135:6030/test";
+    private static String url_mysql = "jdbc:mysql://master:3306/test?useSSL=false&useUnicode=true&characterEncoding=UTF-8";
+
+    public static void main(String[] args) throws SqlParseException, ClassNotFoundException, SQLException {
+        Class.forName("org.apache.calcite.jdbc.Driver");
+        Properties info = new Properties();
+        info.setProperty("caseSensitive", "false");
+
+        Connection connection = DriverManager.getConnection("jdbc:calcite:", info);
+        CalciteConnection calciteConnection = connection.unwrap(CalciteConnection.class);
+
+        SchemaPlus rootSchema = calciteConnection.getRootSchema();
+
+        //这里hdb是在tdengine中创建的数据库名
+        Schema schema = mysqlTest(rootSchema);
+//        Schema schema = tdengineTest(rootSchema);
+
+        //创建新的schema自动映射到原来的hdb数据库
+        rootSchema.add("test", schema);
+
+        Statement stmt = calciteConnection.createStatement();
+        //查询schema test中的表，表名是tdengine中的表
+        ResultSet rs = stmt.executeQuery("select * from test.t");
+        ResultSetMetaData metaData = rs.getMetaData();
+        while (rs.next()) {
+            for (int i = 1; i <= metaData.getColumnCount(); i++) {
+                System.out.println(metaData.getColumnLabel(i) + " : " + rs.getString(i));
+            }
+        }
+    }
+
+
+    private static Schema tdengineTest(SchemaPlus rootSchema) throws ClassNotFoundException {
+        Class.forName("com.taosdata.jdbc.TSDBDriver");
+        BasicDataSource dataSource = new BasicDataSource();
+        dataSource.setUrl(url_taos);
+        dataSource.setUsername("root");
+        dataSource.setPassword("taosdata");
+
+        return JdbcSchema.create(rootSchema, "test", dataSource, "hdb", null);
+    }
+
+    private static Schema mysqlTest(SchemaPlus rootSchema) throws ClassNotFoundException {
+        Class.forName("com.mysql.jdbc.Driver");
+        BasicDataSource dataSource = new BasicDataSource();
+        dataSource.setUrl(url_mysql);
+        dataSource.setUsername("root");
+        dataSource.setPassword("123456");
+
+        //Schema schema = JdbcSchema.create(rootSchema, "test", dataSource, "hdb", null);
+        return JdbcSchema.create(rootSchema, "test", dataSource, "test", null);
+    }
+}

tests/examples/JDBC/calciteDemo/src/main/resources/log4j.properties

+log4j.rootLogger=info,stdout
+
+#console
+log4j.appender.stdout=org.apache.log4j.ConsoleAppender 
+log4j.appender.stdout.layout=org.apache.log4j.PatternLayout 
+log4j.appender.stdout.layout.ConversionPattern= [%d{yyyy-MM-dd HH:mm:ss a}]:%p %l%m%n
\ No newline at end of file

tests/pytest/concurrent_inquiry.py

+###################################################################
+#           Copyright (c) 2016 by TAOS Technologies, Inc.
+#                     All rights reserved.
+#
+#  This file is proprietary and confidential to TAOS Technologies.
+#  No part of this file may be reproduced, stored, transmitted,
+#  disclosed or used in any form or by any means other than as
+#  expressly provided by the written permission from Jianhui Tao
+#
+###################################################################
+
+# -*- coding: utf-8 -*-
+import threading
+import taos
+
+import json
+import time
+import random
+# query sql
+query_sql = [
+# first supertable
+"select count(*) from test.meters where c1 > 50;",
+"select count(*) from test.meters where c2 >= 50 and c2 < 100;",
+"select count(*) from test.meters where c3 != 5;",
+"select count(*) from test.meters where t3 > 2;",
+"select count(*) from test.meters where ts <> '2020-05-13 10:00:00.002';",
+"select count(*) from test.meters where t7 like 'fi%';",
+"select count(*) from test.meters where t7 like '_econd';",
+"select count(*) from test.meters interval(1n) order by ts desc;",
+"select first(*)  from test.meters;",
+"select last(*)  from test.meters;",
+"select last_row(*)  from test.meters;",
+"select twa(c1) from test.t1 where ts > 1500000001000  and ts < 1500000101000" ,
+"select avg(c1) from test.meters;",
+"select bottom(c1, 2) from test.t1;",
+"select diff(c1) from test.t1;",
+"select leastsquares(c1, 1, 1) from test.t1  ;",
+"select max(c1) from test.meters;",
+"select min(c1) from test.meters;",
+"select c1 + c2 * c3 + c1 / c5 + c4 + c2 from test.t1;",
+"select percentile(c1, 50) from test.t1;",
+"select spread(c1) from test.t1  ;",
+"select stddev(c1) from test.t1;",
+"select sum(c1) from test.meters;",
+"select top(c1, 2) from test.meters;"
+"select twa(c6) from test.t1 where ts > 1500000001000  and ts < 1500000101000" ,
+"select avg(c6) from test.meters;",
+"select bottom(c6, 2) from test.t1;",
+"select diff(c6) from test.t1;",
+"select leastsquares(c6, 1, 1) from test.t1  ;",
+"select max(c6) from test.meters;",
+"select min(c6) from test.meters;",
+"select c6 + c2 * c3 + c6 / c5 + c4 + c2 from test.t1;",
+"select percentile(c6, 50) from test.t1;",
+"select spread(c6) from test.t1  ;",
+"select stddev(c6) from test.t1;",
+"select sum(c6) from test.meters;",
+"select top(c6, 2) from test.meters;",
+# second supertable
+"select count(*) from test.meters1 where c1 > 50;",
+"select count(*) from test.meters1 where c2 >= 50 and c2 < 100;",
+"select count(*) from test.meters1 where c3 != 5;",
+"select count(*) from test.meters1 where t3 > 2;",
+"select count(*) from test.meters1 where ts <> '2020-05-13 10:00:00.002';",
+"select count(*) from test.meters1 where t7 like 'fi%';",
+"select count(*) from test.meters1 where t7 like '_econd';",
+"select count(*) from test.meters1 interval(1n) order by ts desc;",
+"select first(*)  from test.meters1;",
+"select last(*)  from test.meters1;",
+"select last_row(*)  from test.meters1;",
+"select twa(c1) from test.m1 where ts > 1500000001000  and ts < 1500000101000" ,
+"select avg(c1) from test.meters1;",
+"select bottom(c1, 2) from test.m1;",
+"select diff(c1) from test.m1;",
+"select leastsquares(c1, 1, 1) from test.m1  ;",
+"select max(c1) from test.meters1;",
+"select min(c1) from test.meters1;",
+"select c1 + c2 * c3 + c1 / c5 + c3 + c2 from test.m1;",
+"select percentile(c1, 50) from test.m1;",
+"select spread(c1) from test.m1  ;",
+"select stddev(c1) from test.m1;",
+"select sum(c1) from test.meters1;",
+"select top(c1, 2) from test.meters1;",
+"select twa(c6) from test.m1 where ts > 1500000001000  and ts < 1500000101000" ,
+"select avg(c6) from test.meters1;",
+"select bottom(c6, 2) from test.m1;",
+"select diff(c6) from test.m1;",
+"select leastsquares(c6, 1, 1) from test.m1  ;",
+"select max(c6) from test.meters1;",
+"select min(c6) from test.meters1;",
+"select c6 + c2 * c3 + c6 / c5 + c3 + c2 from test.m1;",
+"select percentile(c6, 50) from test.m1;",
+"select spread(c6) from test.m1  ;",
+"select stddev(c6) from test.m1;",
+"select sum(c6) from test.meters1;",
+"select top(c6, 2) from test.meters1;"
+]
+
+class ConcurrentInquiry:
+    def initConnection(self):  
+        self.numOfTherads = 50
+        self.ts=1500000001000
+        
+
+    def query_thread(self,threadID):
+        host = "10.211.55.14"
+        user = "root"
+        password = "taosdata"
+        conn = taos.connect(
+            host,
+            user,
+            password,
+            )
+        cl = conn.cursor()
+        
+        print("Thread %d: starting" % threadID)
+        
+        while True:
+            ran_query_sql=query_sql
+            random.shuffle(ran_query_sql)
+            for i in ran_query_sql:
+                print("Thread %d : %s"% (threadID,i))
+                try:
+                    cl.execute(i)
+                    cl.fetchall
+                except Exception as e:
+                    print(
+                "Failure thread%d, sql: %s,exception: %s" %
+                (threadID, str(i),str(e)))
+                    
+                
+            print("Thread %d: finishing" % threadID)
+          
+        
+
+    def run(self):
+       
+        threads = []
+        for i in range(50):
+            thread = threading.Thread(target=self.query_thread, args=(i,))
+            threads.append(thread)
+            thread.start()  
+        
+q = ConcurrentInquiry()
+q.initConnection()
+q.run()

tests/script/general/http/restful_full.sim

@@ -119,7 +119,7 @@ endi
 
 system_content curl -H 'Authorization: Taosd /KfeAzX/f9na8qdtNZmtONryp201ma04bEl8LcvLUd7a8qdtNZmtONryp201ma04'  -d '  used1' 127.0.0.1:7111/rest/sql
 print 17-> $system_content
-if $system_content != @{"status":"error","code":534,"desc":"Syntax errr in SQL"}@ then
+if $system_content != @{"status":"error","code":534,"desc":"Syntax error in SQL"}@ then
   return -1
 endi
 

tests/script/unique/mnode/mgmt23.sim

@@ -65,7 +65,7 @@ endi
 
 print ============== step4
 sql drop dnode $hostname2
-sleep 16000
+sleep 10000
 
 sql show mnodes
 $dnode1Role = $data2_1