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MySQL性能分析工具之PROFILE怎么用

小编给大家分享一下MySQL性能分析工具之PROFILE怎么用,相信大部分人都还不怎么了解,因此分享这篇文章给大家参考一下,希望大家阅读完这篇文章后大有收获,下面让我们一起去了解一下吧!

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分析SQL执行带来的开销是优化SQL的常用手段,在MySQL数据库中,可以通过配置profiling参数来启用SQL剖析。
它只能在session级别来设置,设置后影响当前session;当它开启后,后续执行的SQL语句都将记录其资源开销,诸如IO,上下文,CPU,MEMORY等。

实验环境:

  1. mysql> select version();

  2. +------------+

  3. | version() |

  4. +------------+

  5. | 5.7.17-log |

  6. +------------+

  7. 1 row in set (0.00 sec)

与profile相关的三个参数:

  1. mysql> show variables like '%profil%';

  2. +------------------------+-------+

  3. | Variable_name | Value |

  4. +------------------------+-------+

  5. | have_profiling | YES |                  ---用于控制是否由系统变量开启或禁用profiling

  6. | profiling | OFF |                       ---开启SQL语句剖析功能

  7. | profiling_history_size | 15 |           ---设置保留profiling的数目,缺省为15,范围为0至100,为0时将禁用profiling

  8. +------------------------+-------+

  9. 3 rows in set (0.01 sec)

开启profiling,有个警告,这个参数在以后会被删除,用information_scheam.PROFILING替代。

  1. mysql> set profiling=1;

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

  3. mysql> show warnings;
    +---------+------+----------------------------------------------------------------------+
    | Level   | Code | Message                                                              |
    +---------+------+----------------------------------------------------------------------+
    | Warning | 1287 | '@@profiling' is deprecated and will be removed in a future release. |
    +---------+------+----------------------------------------------------------------------+

执行一条sql测试一下:

  1. select * from oms3.customers where `type` = 1 AND `status` < 7 AND `isarea` = 6 AND `into_time`>='2016-12-01'AND `into_time`<='2017-01-02 23:59:59' order by score desc limit 40,20

sql执行很慢,执行完成之后查看:

  1. mysql> show profiles;

  2. +----------+--------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

  3. | Query_ID | Duration | Query |

  4. +----------+--------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

  5. | 7 | 0.00022275 | SELECT * FROM setup_actors |

  6. | 8 | 0.00016050 | SELECT DATABASE() |

  7. | 9 | 0.00032350 | show databases |

  8. | 10 | 0.00024050 | show tables |

  9. | 11 | 0.00019250 | SELECT * FROM setup_actors |

  10. | 12 | 0.00183950 | show variables like "profiling_hist%" |

  11. | 13 | 0.00192500 | show variables like '%profil%' |

  12. | 14 | 0.00011550 | show warnings |

  13. | 15 | 0.00044725 | help 'show profile' |

  14. | 16 | 0.00013875 | set profiling=1 |

  15. | 17 | 0.00011550 | show warnings |

  16. | 18 | 0.00025075 | select * from customers where `type` = 1 AND `status` < 7 AND `isarea` = 6 AND `into_time`>='2016-12-01'AND `into_time`<='2017-01-02 23:59:59' order by score desc limit 40,20 |

  17. | 19 | 333.19133875 | select * from oms3.customers where `type` = 1 AND `status` < 7 AND `isarea` = 6 AND `into_time`>='2016-12-01'AND `into_time`<='2017-01-02 23:59:59' order by score desc limit 40,20 |

  18. | 20 | 0.00011250 | show profilings |

  19. | 21 | 0.00010975 | show profilings |

  20. +----------+--------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

  21. 15 rows in set, 1 warning (0.00 sec)

  22. mysql> set @query_id=19;                ---上面显示是query_id为19

  23. Query OK, 0 rows affected (0.00 sec)

  24. mysql> select STATE,sum(duration) as Total_R,          ---用这条sql查询具体是哪里出问题,这条sql引用于《High Performance MySQL,Third Edition》

  25.     -> ROUND(

  26.     -> 100*SUM(DURATION)/

  27.     -> (SELECT SUM(DURATION) FROM INFORMATiON_SCHEMA.PROFILING WHERE QUERY_ID=@query_id),2) as Pct_R,

  28.     -> count(*) as calls,

  29.     -> sum(duration)/count(*) as "R/Call"

  30.     -> from information_schema.profiling

  31.     -> where query_id=@query_id

  32.     -> group by state

  33.     -> order by Total_R desc;

  34. +----------------------+------------+-------+-------+----------------+

  35. | STATE | Total_R | Pct_R | calls | R/Call |

  36. +----------------------+------------+-------+-------+----------------+

  37. | Sending data | 332.162424 | 99.69 | 1 | 332.1624240000 |         ---这个state基本占用了全部的资源,那么对这条sql的优化就着重于减少io上。

  38. | statistics | 1.027729 | 0.31 | 1 | 1.0277290000 |

  39. | Opening tables | 0.000519 | 0.00 | 1 | 0.0005190000 |

  40. | freeing items | 0.000157 | 0.00 | 1 | 0.0001570000 |

  41. | starting | 0.000147 | 0.00 | 1 | 0.0001470000 |

  42. | init | 0.000123 | 0.00 | 1 | 0.0001230000 |

  43. | logging slow query | 0.000096 | 0.00 | 1 | 0.0000960000 |

  44. | preparing | 0.000035 | 0.00 | 1 | 0.0000350000 |

  45. | cleaning up | 0.000019 | 0.00 | 1 | 0.0000190000 |

  46. | optimizing | 0.000016 | 0.00 | 1 | 0.0000160000 |

  47. | end | 0.000014 | 0.00 | 1 | 0.0000140000 |

  48. | System lock | 0.000014 | 0.00 | 1 | 0.0000140000 |

  49. | closing tables | 0.000013 | 0.00 | 1 | 0.0000130000 |

  50. | query end | 0.000013 | 0.00 | 1 | 0.0000130000 |

  51. | Sorting result | 0.000010 | 0.00 | 1 | 0.0000100000 |

  52. | checking permissions | 0.000009 | 0.00 | 1 | 0.0000090000 |

  53. | executing | 0.000003 | 0.00 | 1 | 0.0000030000 |

  54. +----------------------+------------+-------+-------+----------------+

  55. 17 rows in set, 18 warnings (0.00 sec)

其他用法:

  1. mysql> SHOW PROFILE CPU FOR QUERY 2;

  2. +----------------------+----------+----------+------------+

  3. | Status | Duration | CPU_user | CPU_system |

  4. +----------------------+----------+----------+------------+

  5. | checking permissions | 0.000040 | 0.000038 | 0.000002 |

  6. | creating table | 0.000056 | 0.000028 | 0.000028 |

  7. | After create | 0.011363 | 0.000217 | 0.001571 |

  8. | query end | 0.000375 | 0.000013 | 0.000028 |

  9. | freeing items | 0.000089 | 0.000010 | 0.000014 |

  10. | logging slow query | 0.000019 | 0.000009 | 0.000010 |

  11. | cleaning up | 0.000005 | 0.000003 | 0.000002 |

  12. +----------------------+----------+----------+------------+

更多用法详见:

help show profiles;

以上是“MySQL性能分析工具之PROFILE怎么用”这篇文章的所有内容,感谢各位的阅读!相信大家都有了一定的了解,希望分享的内容对大家有所帮助,如果还想学习更多知识,欢迎关注创新互联行业资讯频道!


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