The following table lists all system variables applicable within mysqld.下表列出了mysqld中适用的所有系统变量。

The table lists command-line options (Cmd-line), options valid in configuration files (Option file), server system variables (System Var), and status variables (Status var) in one unified list, with an indication of where each option or variable is valid. 该表在一个统一列表中列出了命令行选项（Cmd-line）、配置文件中有效的选项（Option file）、服务器系统变量（System Var）和状态变量（Status Var），并指示每个选项或变量的有效位置。If a server option set on the command line or in an option file differs from the name of the corresponding system variable, the variable name is noted immediately below the corresponding option. 如果在命令行或选项文件中设置的服务器选项与相应系统变量的名称不同，则变量名称将在相应选项的正下方标注。The scope of the variable (Var Scope) is Global, Session, or both. 变量的作用域（Var scope）是全局、会话或两者兼有。Please see the corresponding item descriptions for details on setting and using the variables. Where appropriate, direct links to further information about the items are provided.有关设置和使用变量的详细信息，请参见相应的项目说明。在适当的情况下，提供有关这些项目的进一步信息的直接链接。

Notes:注：

1. This option is dynamic, but should be set only by server. 此选项是动态的，但只能由服务器设置。You should not set this variable manually.不应手动设置此变量。