通过performance schema收集慢查询

Posted 2020-10-21 西橙

mysql5.6起performance schema自动开启，里面涉及记录 statement event的表

mysql> show tables like ‘%statement%‘;
+----------------------------------------------------+
| Tables_in_performance_schema (%statement%)         |
+----------------------------------------------------+
| events_statements_current                          |
| events_statements_history                          |
| events_statements_history_long                     |
| events_statements_summary_by_account_by_event_name |
| events_statements_summary_by_digest                |
| events_statements_summary_by_host_by_event_name    |
| events_statements_summary_by_program               |
| events_statements_summary_by_thread_by_event_name  |
| events_statements_summary_by_user_by_event_name    |
| events_statements_summary_global_by_event_name     |
| prepared_statements_instances                      |
+----------------------------------------------------+
11 rows in set (0.00 sec)

statement event 的设置 

详细参考官方文档：https://dev.mysql.com/doc/refman/5.6/en/performance-schema-statement-tables.ht

server端发生的所有的statement都会记录，当前未结束的会话发生的statement记录在表events_statements_current，已结束的会话线程发生的statement记录在events_statements_history，此表有大小限制，默认是100，达到限制会删除老的statement

设置记录哪些类型的statement，默认设置为所有的类型

mysql> SELECT * FROM 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   |
+---------------------------------------------+---------+-------+

关于对statement event相关表的设置，MySQL5.6 默认events_statements_history关闭，MySQL5.7开启

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

 

如果通过pmm来收集慢查询，其查询的是表events_statements_history_long，MySQL5.6需要启用此表

启用events_statements_history

UPDATE setup_consumers SET ENABLED = ‘NO‘
WHERE NAME LIKE ‘events_statements_history‘;