打开profiling,默认是没开启的.
mysql> set profiling=1;
执行要分析的SQL语句
mysql> select count(1) from wechat_employee,Employee;
显示profiles表
mysql> show profiles;
查询结果：
+----------+------------+-----------------------------------------------+ | Query_ID | Duration | Query | +----------+------------+-----------------------------------------------+ | 1 | 0.00072975 | select count(1) from wechat_employee,Employee | | 2 | 0.00028450 | set profiling=1 | | 3 | 0.00324875 | select count(1) from wechat_employee,Employee | +----------+------------+-----------------------------------------------+
查询详细信息：
show profile cpu,block io for query 3;
结果：
+--------------------------------+----------+----------+------------+--------------+---------------+ | Status | Duration | CPU_user | CPU_system | Block_ops_in | Block_ops_out | +--------------------------------+----------+----------+------------+--------------+---------------+ | starting | 0.000041 | 0.000000 | 0.000000 | 0 | 0 | | Waiting for query cache lock | 0.000073 | 0.000000 | 0.000000 | 0 | 0 | | checking query cache for query | 0.000025 | 0.000000 | 0.000000 | 0 | 0 | | checking privileges on cached | 0.000023 | 0.000000 | 0.000000 | 0 | 0 | | checking permissions | 0.000018 | 0.000000 | 0.000000 | 0 | 0 | | checking permissions | 0.000012 | 0.000000 | 0.000000 | 0 | 0 | | sending cached result to clien | 0.003009 | 0.000000 | 0.004000 | 0 | 0 | | logging slow query | 0.000032 | 0.000000 | 0.000000 | 0 | 0 | | cleaning up | 0.000018 | 0.000000 | 0.000000 | 0 | 0 | +--------------------------------+----------+----------+------------+--------------+---------------+ 9 rows in set (0.00 sec)
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