最开始用的 CLion，但电脑扛不住，最终换成 VSCode，世界瞬间清净了😁

macOS + CLion 版本看 这里

环境

  • macOS Big Sur 11.5.2
  • VSCode 1.59.1
  • MySQL 5.7.35

依赖

如果以下软件未安装或版本不符合，使用 brew 安装即可

  • CMake
  • g++
  • openssl 1.1

VSCode 插件

在 VSCode 应用商店搜索并安装以下插件

  • C/C++
  • C/C++ Clang Command Adapter
  • CodeLLDB
  • CMake Tools

下载源码

从官网下载携带 boost 版本源码

下载链接：https://dev.mysql.com/get/Downloads/MySQL-5.7/mysql-boost-5.7.35.tar.gz

也可以从 GitHub 上克隆代码，切换到指定 TAG 或分支。

解压源码：

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tar -zxf mysql-boost-5.7.35.tar.gz
cd mysql-5.7.35

Patch 源码

如果 MySQL <= 8.0.21，则需要执行以下脚本 Patch 源码：

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mv VERSION MYSQL_VERSION
sed -i '' 's|${CMAKE_SOURCE_DIR}/VERSION|${CMAKE_SOURCE_DIR}/MYSQL_VERSION|g' cmake/mysql_version.cmake

具体原因，可参考文章：MySQL 源码 —— 问题 expanded from macro MYSQL_VERSION_MAJOR

创建目录

编译、安装、数据、配置等都统一到 cmake-build-debug 目录，方便管理、不与其他冲突

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mkdir -p cmake-build-debug/{data,etc}

编译

有 2 种方式，命令行、CMake Tools

推荐 CMake Tools，因为后续 Debug 都在 VSCode 中，重新编译或切换编译目标也方便

CMake Tools

关于 CMake Tools 的详细配置和用法，参考官方文档：CMake Tools for Visual Studio Code documentation

配置

创建文件 .vscode/settings.json，并写入配置：

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{
    "cmake.buildBeforeRun": true,
    "cmake.buildDirectory": "${workspaceFolder}/cmake-build-debug/build",
    "cmake.configureSettings": {
        "WITH_DEBUG": "1",
        "CMAKE_INSTALL_PREFIX": "${workspaceFolder}/cmake-build-debug",
        "MYSQL_DATADIR": "${workspaceFolder}/cmake-build-debug/data",
        "SYSCONFDIR": "${workspaceFolder}/cmake-build-debug/etc",
        "MYSQL_TCP_PORT": "3307",
        "MYSQL_UNIX_ADDR": "${workspaceFolder}/cmake-build-debug/data/mysql-debug.sock",
        "WITH_BOOST": "${workspaceFolder}/boost",
        "DOWNLOAD_BOOST": "1",
        "DOWNLOAD_BOOST_TIMEOUT": "600"
    }
}

查看 > 命令面板，搜索CMake，找到CMake: Configure并回车运行： cmake-configure

等待配置完成，输出以下日志：

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[main] Configuring folder: mysql-5.7.35 
[proc] Executing command: /usr/local/bin/cmake --no-warn-unused-cli -DWITH_DEBUG:STRING=1 -DCMAKE_INSTALL_PREFIX:STRING=/path/to/mysql-5.7.35/cmake-build-debug -DMYSQL_DATADIR:STRING=/path/to/mysql-5.7.35/cmake-build-debug/data -DSYSCONFDIR:STRING=/path/to/mysql-5.7.35/cmake-build-debug/etc -DMYSQL_TCP_PORT:STRING=3307 -DMYSQL_UNIX_ADDR:STRING=/path/to/mysql-5.7.35/cmake-build-debug/data/mysql-debug.sock -DWITH_BOOST:STRING=/path/to/mysql-5.7.35/boost -DDOWNLOAD_BOOST:STRING=1 -DDOWNLOAD_BOOST_TIMEOUT:STRING=600 -DCMAKE_EXPORT_COMPILE_COMMANDS:BOOL=TRUE -DCMAKE_BUILD_TYPE:STRING=Debug -H/path/to/mysql-5.7.35 -B/path/to/mysql-5.7.35/cmake-build-debug/build -G "Unix Makefiles"

···中间日志省略···

[cmake] -- Configuring done
[cmake] -- Generating done
[cmake] -- Build files have been written to: /path/to/mysql-5.7.35/cmake-build-debug/build

编译

查看 > 命令面板，搜索CMake，找到CMake: Build Target并回车运行： 构建目标

查看 > 命令面板，搜索mysqld，找到mysqld EXECUTABLE并回车运行： 选择目标

然后，就开始编译了，最终输出日志：

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[main] Building folder: mysql-5.7.35 mysqld
[build] Starting build
[proc] Executing command: /usr/local/bin/cmake --build /path/to/mysql-5.7.35/cmake-build-debug/build --config Debug --target mysqld -j 6 --

···中间日志省略···

[build] [100%] Built target mysqld
[build] Build finished with exit code 0

命令行

切换到 cmake-build-debug 目录：

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cd cmake-build-debug

配置

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cmake .. \
-B./build \
-DWITH_DEBUG=1 \
-DCMAKE_INSTALL_PREFIX=. \
-DMYSQL_DATADIR=./data \
-DSYSCONFDIR=./etc \
-DMYSQL_TCP_PORT=3307 \
-DMYSQL_UNIX_ADDR=mysql-debug.sock \
-DWITH_BOOST=../boost \
-DDOWNLOAD_BOOST=1 \
-DDOWNLOAD_BOOST_TIMEOUT=60000

编译

  • -j 3 表示3个线程，提高速度

  • --build build 表示构建build目录，此处与-B./build保持一致

  • --target mysqld 表示只构建mysqld

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cmake --build build --target mysqld -j 3

Tips: make 命令会编译所有目标

初始化数据库

以下步骤切换到 cmake-build-debug 目录下执行：

  • MySQL 配置文件
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cat > etc/my.cnf <<EOF
[mysqld]
port=3307
socket=mysql.sock
innodb_file_per_table=1
EOF

修改 port 和 socket 是为了避免与本机数据库冲突。

  • 初始化数据库
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# 不携带配置文件，因为CMake时指定了SYSCONFDIR
build/sql/mysqld --initialize-insecure

# 也可携带文件路径
build/sql/mysqld --defaults-file=etc/my.cnf --initialize-insecure

配置调试参数

创建文件 .vscode/launch.json，并写入配置：

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{
    // 使用 IntelliSense 了解相关属性。 
    // 悬停以查看现有属性的描述。
    // 欲了解更多信息，请访问: https://go.microsoft.com/fwlink/?linkid=830387
    "version": "0.2.0",
    "configurations": [
        {
            "type": "lldb",
            "request": "launch",
            "name": "Debug mysqld",
            "program": "${workspaceFolder}/cmake-build-debug/build/sql/mysqld",
            "args": [
                "--defaults-file=${workspaceFolder}/cmake-build-debug/etc/my.cnf"
            ],
            "cwd": "${workspaceFolder}"
        },
        {
            "type": "lldb",
            "request": "launch",
            "name": "Debug mysql",
            "program": "${workspaceFolder}/cmake-build-debug/build/client/mysql",
            "args": [
                "-uroot",
                "-P3307",
                "-h127.0.0.1"
            ],
            "cwd": "${workspaceFolder}"
        }
    ]
}

启动调试

启动 mysqld

左侧导航栏 > 运行与调试，选择 Debug mysqld，开始调试。 选择mysqld调试

终端中会输出 mysqld 服务器的启动日志：

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[Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use amp server option (see documentation for more details).
[Note] --secure-file-priv is set to NULL. Operations related to importing and exporting data 
[Note] /path/to/mysql-5.7.35/cmake-build-debug/build/sql/mysqld (mysqld ess 70489 ...
[ERROR] Can't find error-message file '/path/to/mysql-5.7.35/cmake-build-debug/shareage file location and 'lc-messages-dir' configuration directive.
[Warning] Setting lower_case_table_names=2 because file system for /path/to/data/ is case insensitive
[Note] InnoDB: !!!!!!!! UNIV_DEBUG switched on !!!!!!!!!
[Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
[Note] InnoDB: Uses event mutexes
[Note] InnoDB: GCC builtin __atomic_thread_fence() is used for memory barrier
[Note] InnoDB: Compressed tables use zlib 1.2.11
[Note] InnoDB: Number of pools: 1
[Note] InnoDB: Using CPU crc32 instructions
[Note] InnoDB: Initializing buffer pool, total size = 128M, instances = 1, chunk size = 128M
[Note] InnoDB: Completed initialization of buffer pool
[Note] InnoDB: Highest supported file format is Barracuda.
[Note] InnoDB: Log scan progressed past the checkpoint lsn 2748488
[Note] InnoDB: Doing recovery: scanned up to log sequence number 2748497
[Note] InnoDB: Database was not shutdown normally!
[Note] InnoDB: Starting crash recovery.
[Note] InnoDB: Removed temporary tablespace data file: "ibtmp1"
[Note] InnoDB: Creating shared tablespace for temporary tables
[Note] InnoDB: Setting file './ibtmp1' size to 12 MB. Physically writing the file full; 
[Note] InnoDB: File './ibtmp1' size is now 12 MB.
[Note] InnoDB: 96 redo rollback segment(s) found. 96 redo rollback segment(s) are active.
[Note] InnoDB: 32 non-redo rollback segment(s) are active.
[Note] InnoDB: Waiting for purge to start
[Note] InnoDB: 5.7.35 started; log sequence number 2748497
[Note] InnoDB: Loading buffer pool(s) from /path/to/mysql-5.7.35/cmake-build-debug/
[Note] Plugin 'FEDERATED' is disabled.
[Note] InnoDB: Buffer pool(s) load completed at 210826 21:45:37
[Note] Found ca.pem, server-cert.pem and server-key.pem in data directory. Trying to enable 
[Note] Skipping generation of SSL certificates as certificate files are present in data 
[Warning] 
[Warning] 
[Warning] CA certificate ca.pem is self signed.
[Note] Skipping generation of RSA key pair as key files are present in data directory.
[Note] Server hostname (bind-address): '*'; port: 3307
[Note] IPv6 is available.
[Note]   - '::' resolves to '::';
[Note] Server socket created on IP: '::'.
[Note] Event Scheduler: Loaded 0 events
[Note]

连接数据库

以同样的方式，先编译 mysql，然后启动 mysql 客户端，连接到刚刚启动的服务端 mysqld： 选择mysql连接服务端

这样就可以在一个窗口下，既 Debug 源码，也能看到输出。

当然，也可以通过其他 mysql 客户端，或 Navicat 连接：

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mysql -uroot -P3307 -h127.0.0.1

Debug 界面

debug-window

小技巧

代码蒙灰

C/C++ 扩展有个 C_Cpp.dimInactiveRegions 参数，控制非活动区域代码变灰。 C_Cpp.dimInactiveRegions

参考资料