MYSQL的profiling功能要在Mysql版本5.0.37以上才能使用。
查看profile是否开启
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mysql> show variables like '%profil%';
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+------------------------+-------+
| Variable_name | Value |
+------------------------+-------+
| profiling | OFF | --开启SQL语句剖析功能
| 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
+------------------------+-------+
2 rows in set (0.00 sec)
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基于会话级别开启
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mysql> set profiling = 1; --关闭则用set profiling = off
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Query OK, 0 rows affected (0.00 sec)
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mysql> select distinct d.account,a.server_id from tab_appserver_user a
-> inner join tab_department_parent b on a.key_id = b.parent_id
-> inner join tab_department_member c on b.department_id = c.department_id and c.state=1
-> and c.isdefault=1 inner join tab_user_info d on c.user_id = d.user_id and d.state=1
-> where a.type=1
-> union
-> select distinct b.account,a.server_id from tab_appserver_user a
-> inner join tab_user_info b on a.key_id = b.user_id and b.state=1
-> where a.type=0;
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查看是否设置生效：
默认是0，设置成功是1
运行SQL语句：
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mysql> select * FROM hx_line WHERE id = '1455023';
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查看profiles
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+----------+------------+---------------------------------------------+
| Query_ID | Duration | Query |
+----------+------------+---------------------------------------------+
| 1 | 0.00036150 | select * FROM hx_line WHERE id = '1455023' |
+----------+------------+---------------------------------------------+
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查看具体某条的profile
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mysql> show profile FOR QUERY 1;
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+--------------------------------+----------+
| Status | Duration |
+--------------------------------+----------+
| starting | 0.000013 |
| Waiting for query cache lock | 0.000014 |
| checking query cache for query | 0.000038 |
| checking permissions | 0.000006 |
| Opening tables | 0.000013 |
| System lock | 0.000009 |
| Waiting for query cache lock | 0.000024 |
| init | 0.000060 |
| optimizing | 0.000014 |
| statistics | 0.000046 |
| preparing | 0.000017 |
| executing | 0.000004 |
| Sending data | 0.000081 |
| end | 0.000005 |
| query end | 0.000004 |
| closing tables | 0.000008 |
| freeing items | 0.000009 |
| Waiting for query cache lock | 0.000003 |
| freeing items | 0.000013 |
| Waiting for query cache lock | 0.000003 |
| freeing items | 0.000003 |
| storing result in query cache | 0.000005 |
| logging slow query | 0.000003 |
| cleaning up | 0.000004 |
+--------------------------------+----------+
24 rows
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