性能模式（Performance Schema）对语句执行进行监控。语句事件发生在事件层次结构的高层。在事件层次结构中，等待事件（wait events）嵌套在阶段事件（stage events）中，阶段事件嵌套在语句事件（statement events）中，而语句事件又嵌套在事务事件（transaction events）中。The Performance Schema instruments statement execution. Statement events occur at a high level of the event hierarchy. Within the event hierarchy, wait events nest within stage events, which nest within statement events, which nest within transaction events.

这些表存储语句事件：These tables store statement events:

以下各节描述了语句事件表。同时，还有汇总表用于聚合语句事件的信息；请参见 第 29.12.20.3 节，“语句汇总表”。The following sections describe the statement event tables. There are also summary tables that aggregate information about statement events; see Section 29.12.20.3, “Statement Summary Tables”.

有关三个 events_statements_xxx 事件表之间关系的更多信息，请参见 第 29.9 节，“当前和历史事件的性能模式表”。For more information about the relationship between the three events_statements_xxx event tables, see Section 29.9, “Performance Schema Tables for Current and Historical Events”.

配置语句事件收集Configuring Statement Event Collection

要控制是否收集语句事件，请设置相关仪器和消费者的状态：To control whether to collect statement events, set the state of the relevant instruments and consumers:

语句工具默认是启用的，并且 events_statements_current、events_statements_history 和 statements_digest 语句消费者默认启用：The statement instruments are enabled by default, and the events_statements_current, events_statements_history, and statements_digest statement consumers are enabled by default:

mysql> SELECT NAME, ENABLED, TIMED
       FROM performance_schema.setup_instruments
       WHERE NAME LIKE 'statement/%';
+---------------------------------------------+---------+-------+
| NAME                                        | ENABLED | TIMED |
+---------------------------------------------+---------+-------+
| statement/sql/select                        | YES     | YES   |
| statement/sql/create_table                  | YES     | YES   |
| statement/sql/create_index                  | YES     | YES   |
...
| statement/sp/stmt                           | YES     | YES   |
| statement/sp/set                            | YES     | YES   |
| statement/sp/set_trigger_field              | YES     | YES   |
| statement/scheduler/event                   | YES     | YES   |
| statement/com/Sleep                         | YES     | YES   |
| statement/com/Quit                          | YES     | YES   |
| statement/com/Init DB                       | YES     | YES   |
...
| statement/abstract/Query                    | YES     | YES   |
| statement/abstract/new_packet               | YES     | YES   |
| statement/abstract/relay_log                | YES     | YES   |
+---------------------------------------------+---------+-------+

mysql> SELECT *
       FROM performance_schema.setup_consumers
       WHERE NAME LIKE '%statements%';
+--------------------------------+---------+
| NAME                           | ENABLED |
+--------------------------------+---------+
| events_statements_current      | YES     |
| events_statements_history      | YES     |
| events_statements_history_long | NO      |
| statements_digest              | YES     |
+--------------------------------+---------+

要在服务器启动时控制语句事件收集，请在您的 my.cnf 文件中使用如下行：To control statement event collection at server startup, use lines like these in your my.cnf file:

要在运行时控制语句事件收集，请更新 setup_instruments 和 setup_consumers 表：To control statement event collection at runtime, update the setup_instruments and setup_consumers tables:

要只收集特定的语句事件，请仅启用相应的语句工具。要仅为特定语句事件表收集语句事件，请启用语句工具，但只启用对应所需表的语句消费者。To collect only specific statement events, enable only the corresponding statement instruments. To collect statement events only for specific statement event tables, enable the statement instruments but only the statement consumers corresponding to the desired tables.

有关配置事件收集的更多信息，请参见第 29.3 节，“性能模式启动配置”，以及第 29.4 节，“性能模式运行时配置”。For additional information about configuring event collection, see Section 29.3, “Performance Schema Startup Configuration”, and Section 29.4, “Performance Schema Runtime Configuration”.

语句监控Statement Monitoring

语句监控从服务器看到线程上活动被请求的那一刻开始，到所有活动停止为止。通常，这意味着从服务器收到客户端的第一个数据包的时间，到服务器完成发送响应的时间。存储程序中的语句像其他语句一样受到监控。Statement monitoring begins from the moment the server sees that activity is requested on a thread, to the moment when all activity has ceased. Typically, this means from the time the server gets the first packet from the client to the time the server has finished sending the response. Statements within stored programs are monitored like other statements.

当性能架构对请求（服务器命令或 SQL 语句）进行检测时，它使用的检测器名称按阶段从更一般（或“抽象””）到更具体的顺序，直到达到最终的检测器名称。When the Performance Schema instruments a request (server command or SQL statement), it uses instrument names that proceed in stages from more general (or “abstract”) to more specific until it arrives at a final instrument name.

最终的检测器名称对应于服务器命令和 SQL 语句：Final instrument names correspond to server commands and SQL statements:

一些最终的工具名称是特定于错误处理的：Some final instrument names are specific to error handling:

请求可以来自以下任一来源：A request can be obtained from any of these sources:

请求的详细信息最初是未知的，性能模式从抽象到具体的仪器名称，顺序取决于请求的来源。The details for a request are not initially known and the Performance Schema proceeds from abstract to specific instrument names in a sequence that depends on the source of the request.

对于来自客户端的请求：For a request received from a client:

对于从副本的中继日志中读取为语句的请求：For a request read as a statement from the relay log on a replica:

上述描述仅适用于基于语句的复制。对于基于行的复制，在副本处理行更改时进行的表 I/O 可以被监控，但中继日志中的行事件不会以单独语句的形式出现。The preceding description applies only for statement-based replication. For row-based replication, table I/O done on the replica as it processes row changes can be instrumented, but row events in the relay log do not appear as discrete statements.

对于从事件调度器接收到的请求：For a request received from the Event Scheduler:

事件执行使用名称 statement/scheduler/event 进行监控。这是最终名称。The event execution is instrumented using the name statement/scheduler/event. This is the final name.

在事件主体中执行的语句使用 statement/sql/* 名称进行检测，而不使用任何前置的抽象检测。事件是一个存储程序，而存储程序在执行前会在内存中预编译。因此，在运行时不会进行解析，并且每条语句的类型在执行时已知。Statements executed within the event body are instrumented using statement/sql/* names, without use of any preceding abstract instrument. An event is a stored program, and stored programs are precompiled in memory before execution. Consequently, there is no parsing at runtime and the type of each statement is known by the time it executes.

在事件体内执行的语句是子语句。例如，如果一个事件执行了一个 INSERT 语句，那么事件本身的执行是父操作，使用 statement/scheduler/event 仪表化，而 INSERT 是子操作，使用 statement/sql/insert 仪表化。父/子关系存在于各自独立的仪表化操作 之间。这不同于发生在单个仪表化操作 内部 的抽象到最终仪表名称的细化序列。Statements executed within the event body are child statements. For example, if an event executes an INSERT statement, execution of the event itself is the parent, instrumented using statement/scheduler/event, and the INSERT is the child, instrumented using statement/sql/insert. The parent/child relationship holds between separate instrumented operations. This differs from the sequence of refinement that occurs within a single instrumented operation, from abstract to final instrument names.

For statistics to be collected for statements, it is not sufficient to enable only the final statement/sql/* instruments used for individual statement types. The abstract statement/abstract/* instruments must be enabled as well. This should not normally be an issue because all statement instruments are enabled by default. However, an application that enables or disables statement instruments selectively must take into account that disabling abstract instruments also disables statistics collection for the individual statement instruments. For example, to collect statistics for INSERT statements, statement/sql/insert must be enabled, but also statement/abstract/new_packet以及statement/abstract/Query. Similarly, for replicated statements to be instrumented, statement/abstract/relay_log must be enabled.For statistics to be collected for statements, it is not sufficient to enable only the final statement/sql/* instruments used for individual statement types. The abstract statement/abstract/* instruments must be enabled as well. This should not normally be an issue because all statement instruments are enabled by default. However, an application that enables or disables statement instruments selectively must take into account that disabling abstract instruments also disables statistics collection for the individual statement instruments. For example, to collect statistics for INSERT statements, statement/sql/insert must be enabled, but also statement/abstract/new_packet and statement/abstract/Query. Similarly, for replicated statements to be instrumented, statement/abstract/relay_log must be enabled.

抽象工具如 statement/abstract/Query 的统计数据不会被汇总，因为没有任何语句会被归类为以抽象工具作为最终语句名称。No statistics are aggregated for abstract instruments such as statement/abstract/Query because no statement is ever classified with an abstract instrument as the final statement name.