组，称为 Meters。The server metrics are organised in groups, called Meters.

mysql> select * from performance_schema.setup_meters;
+------------------------+-----------+---------+-------------------------------------------+
| NAME                   | FREQUENCY | ENABLED | DESCRIPTION                               |
+------------------------+-----------+---------+-------------------------------------------+
| mysql.inno             |        10 | YES     | MySql InnoDB metrics                      |
| mysql.inno.buffer_pool |        10 | YES     | MySql InnoDB buffer pool metrics          |
| mysql.inno.data        |        10 | YES     | MySql InnoDB data metrics                 |
| mysql.x                |        10 | YES     | MySql X plugin metrics                    |
| mysql.x.stmt           |        10 | YES     | MySql X plugin statement statistics       |
| mysql.stats            |        10 | YES     | MySql core metrics                        |
| mysql.stats.com        |        10 | YES     | MySql command stats                       |
| mysql.stats.connection |        10 | YES     | MySql connection stats                    |
| mysql.stats.handler    |        10 | YES     | MySql handler stats                       |
| mysql.stats.ssl        |        10 | YES     | MySql TLS related stats                   |
| mysql.myisam           |        10 | YES     | MySql MyISAM storage engine stats         |
| mysql.perf_schema      |        10 | YES     | MySql performance_schema lost instruments |
+------------------------+-----------+---------+-------------------------------------------+
        

FREQUENCY 和 ENABLED可以编辑。例如，要更新 mysql.inno 指标的频率：FREQUENCY and ENABLED can be edited. For example, to update the frequency of the mysql.inno metrics:

       mysql>update performance_schema.setup_meters set FREQUENCY='30' where name = 'mysql.inno';
      

可以创建的仪表仪器的最大数量由performance_schema_max_meter_classes 设置。The maximum number of meter instruments which can be created is set by performance_schema_max_meter_classes.

仪表还可以通过命令行、服务器启动时或从配置文件进行配置。Meters can also be configured from the commandline, on server startup, or from a configuration file.

要启用或禁用仪表，或更改仪表频率，请使用以下命令行参数语法：To enable, or disable, a meter, or alter the meter frequency, use the following commandline parameter syntax:

        --performance-schema-meter='meterName=frequency:integer,enabled:ON|OFF'
      

下面的示例启用了mysql.inno仪表，并将频率设置为 50：The following example enables the mysql.inno meter and sets the frequency to 50:

        --performance-schema-meter='mysql.inno=frequency:50,enabled:ON'