打开profiling,默认是没开启的.
mysql> set profiling=1;运行要分析的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 |
+----------+------------+-----------------------------------------------+
查询具体信息：
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)