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    如何使用Performance Schema查看Profiling[ mysql数据库 ]

    mysql数据库 时间:2024-11-26 22:17:28

    作者:文/会员上传

    简介:

    SHOW PROFILE可以用来MySQL执行语句时候所使用的资源(诸如IO,上下文切换,CPU,Memory等等),但是从MySQL 5.6.7开始此特性将被移除,而使用Performance Schema代替,如下:setup_actors

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    SHOW PROFILE可以用来MySQL执行语句时候所使用的资源(诸如IO,上下文切换,CPU,Memory等等),但是从MySQL 5.6.7开始此特性将被移除,而使用Performance Schema代替,如下:


    setup_actors 配置

    MySQL 5.7.8, 可以通过setup_actors表来配置host, user, or account的信息被收集,如下:
    #默认情况下setup_actors 的配置是允许监控和收集所有前台线程的历史事件信息

    >SELECT * FROMperformance_schema.setup_actors;
    +------+------+------+---------+---------+
    | HOST | USER | ROLE | ENABLED | HISTORY |
    +------+------+------+---------+---------+
    | % | % | %| YES | YES |
    +------+------+------+---------+---------+
    1 row in set (0.03 sec)


    #修改默认的配置,关闭对所有前台线程的监控和收集。并且插入新的行为指定的用户开启监控和收集信息

    mysql>UPDATE performance_schema.setup_actors SET ENABLED = 'NO', HISTORY = 'NO'
    -> WHERE HOST = '%' AND USER = '%';
    mysql> INSERT INTO performance_schema.setup_actors(HOST,USER,ROLE,ENABLED,HISTORY)
    -> VALUES('localhost','test_user','%','YES','YES');

    #修改后的配置如下:
    mysql> SELECT * FROM performance_schema.setup_actors;
    +-----------+-----------+------+---------+---------+
    | HOST | USER | ROLE | ENABLED | HISTORY |
    +-----------+-----------+------+---------+---------+
    | % | % | % | NO | NO |
    | localhost | test_user | % | YES | YES |
    +-----------+-----------+------+---------+---------+
    #只监控和收集test_user@localhost用户相关的事件信息

    Query Profiling Using Performance Schema下文简单尝试下使用Performance Schema来查询profile相关信息,使用方法如下1.开启setup_instruments表中statement和stage instrumentation相关配置,其中有些可能默认已经开启

    mysql> UPDATE performance_schema.setup_instruments SET ENABLED = 'YES', TIMED = 'YES'
    -> WHERE NAME LIKE '%statement/%';
    mysql> UPDATE performance_schema.setup_instruments SET ENABLED = 'YES', TIMED = 'YES'
    -> WHERE NAME LIKE '%stage/%';

    2.开启events_statements_* and events_stages_*相关消费(consumers),有些项目已经默认开启

    mysql> UPDATE performance_schema.setup_consumers SET ENABLED = 'YES'
    -> WHERE NAME LIKE '%events_statements_%';
    mysql> UPDATE performance_schema.setup_consumers SET ENABLED = 'YES'
    -> WHERE NAME LIKE '%events_stages_%';

    3.为了与show profile的结果做对比,开启profiling功能

    mysql >set profiling=1;

    Query OK, 0 rows affected, 1 warning (0.00 sec)

    mysql >show warnings; #此处,也可以看到此特性将被移除的警告

    +---------+------+----------------------------------------------------------------------+

    | Level | Code | Message |

    +---------+------+----------------------------------------------------------------------+

    | Warning | 1287 | '@@profiling' is deprecated and will be removed in a future release. |

    +---------+------+----------------------------------------------------------------------+

    1 row in set (0.00 sec)

    4.执行SQL语句

    mysql >select * from t;

    +----+------+

    | 9 | 15 |

    | 10 | 15 |

    | 2 | 20 |

    | 3 | 20 |

    | 8 | 25 |

    +----+------+

    5 rows in set (0.00 sec)5 rows in set (0.00 sec)

    5.查看profiling结果

    mysql>show profiles;
    +----------+------------+-----------------+
    | Query_ID | Duration | Query |
    +----------+------------+-----------------+
    | 1 | 0.00010150 | show warnings |
    | 2 | 0.00032075 | select * from t |
    +----------+------------+-----------------+
    2 rows in set, 1 warning (0.00 sec)

    mysql>show profile for query 2;
    +----------------------+----------+
    | Status | Duration |
    +----------------------+----------+
    | starting | 0.000038 |
    | checking permissions | 0.000009 |
    | Opening tables | 0.000048|
    | init | 0.000022 |
    | System lock | 0.000012 |
    | optimizing | 0.000007 |
    | statistics | 0.000016 |
    | preparing | 0.000015 |
    | executing | 0.000005 |
    | Sending data | 0.000063 |
    | end | 0.000008 |
    | query end | 0.000009 |
    | closing tables | 0.000013 |
    | freeing items | 0.000012 |
    | cleaning up | 0.000050 |
    +----------------------+----------+
    15 rows in set, 1 warning (0.00 sec)

    6.查找刚才执行SQL的EVENT_ID,这步骤类似于show profiles查看query id.通过查询表events_statements_history_long获得对应的EVENT_ID

    注:此处只为了说明问题,可能还查询到很多其他的SQL,但是我们自己知道我们执行的SQL是哪条,其他的SQL此处都被省略了

    7.通过查询events_stages_history_long表(NESTING_EVENT_ID=EVENT_ID)获得最终结果

    mysql>SELECT event_name AS Stage, TRUNCATE(TIMER_WAIT/1000000000000,6) AS Duration

    >FROM performance_schema.events_stages_history_long WHERE NESTING_EVENT_ID=79;
    +--------------------------------+----------+
    | Stage | Duration |
    +--------------------------------+----------+
    | stage/sql/init | 0.000048 |
    | stage/sql/checking permissions | 0.000008 |
    | stage/sql/Opening tables | 0.000051 |
    | stage/sql/init | 0.000019 |
    | stage/sql/System lock | 0.000012 |
    | stage/sql/optimizing | 0.000006 |
    | stage/sql/statistics | 0.000016 |
    | stage/sql/preparing | 0.000015 |
    | stage/sql/executing | 0.000004 |
    | stage/sql/Sending data | 0.000066 |
    | stage/sql/end | 0.000005 |
    | stage/sql/query end | 0.000008 |
    | stage/sql/closing tables | 0.000013 |
    | stage/sql/freeing items | 0.000011 |
    | stage/sql/cleaning up | 0.000001 |
    +--------------------------------+----------+
    15 rows in set (0.01 sec)

    如上,实现了通过Performance Schema来查询profileing相关信息,最终能看到的选项跟show profile显示的选项几乎一样,只是各项的值好像不太一致。

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