记一次SQL查询执行分析

查询t_system_user表所有数据
SELECT * FROM t_system_user;

找出执行上面SQL执行的ID
show profiles;

查看SQL执行每一步消耗的时间(下面表格内容是具体执行步骤)
show profile for query [ID]（show profile for query 33）

status	Duration
starting	2.1E-5
checking permissions	4E-6
checking permissions	3E-6
Opening tables	0.000199
init	5E-6
System lock	4E-6
optimizing	2E-6
statistics	9E-6
preparing	6E-6
executing	7E-6
Opening tables	7E-6
checking permissions	2.6E-5
checking permissions	7E-6
checking permissions	5E-6
checking permissions	5E-6
checking permissions	6E-6
checking permissions	5E-6
checking permissions	5E-6
checking permissions	9E-6
Sending data	4.4E-5
end	3E-6
query end	4E-6
closing tables	2E-6
removing tmp table	3E-5
closing tables	3E-6
freeing items	4.8E-5
cleaning up	1.4E-5