MySQL性能这块，其实都是DBA做的事情，一问DBA的朋友就会很快拿出一大堆工具就让你来使用，并且帮助你排查出很多问题。并不是每个公司都有DBA的，很多公司都是开发来弄的，如果业务量特别大并且上来的时候，我们可以招聘一个DBA，一般运维都会帮助来弄。
profile使用工具；
查看自己版本的是否开启了Profile， profiling=on是开启了这个profile功能，
mysql> select version();
+------------+
| version() |
+------------+
| 5.6.35-log |
+------------+
1 row in set (0.00 sec)
mysql> show variables like '%profil%';
+------------------------+-------+
| Variable_name | Value |
+------------------------+-------+
| have_profiling | YES |
| profiling | ON |
| profiling_history_size | 15 |
+------------------------+-------+
3 rows in set (0.01 sec)
Help profile 查看一下，profile的帮助，但是看一下，官方在这个时候会让你注意一下，profile会在5.7以后会废弃了，不用了，所以先查看一下自己的版本，估计好多公司都没用到5.7,还是老的版本。
mysql> help profile;
Name: 'SHOW PROFILE'
Description:
Syntax:
SHOW PROFILE [type [, type] ... ]
[FOR QUERY n]
[LIMIT row_count [OFFSET offset]]
type:
ALL --显示所有的开销信息
| BLOCK IO --显示块IO相关开销
| CONTEXT SWITCHES --上下文切换相关开销
| CPU --显示CPU相关开销信息
| IPC --显示发送和接收相关开销信息
| MEMORY --显示内存相关开销信息
| PAGE FAULTS --显示页面错误相关开销信息
| SOURCE --显示和Source_function，Source_file，Source_line相关的开销信息
| SWAPS --显示交换次数相关开销的信息
The SHOW PROFILE and SHOW PROFILES statements display profiling
information that indicates resource usage for statements executed
during the course of the current session.
*Note*: These statements are deprecated as of MySQL 5.6.7 and will be
removed in a future MySQL release. Use the Performance Schema instead;
see
ng.html.
Profiling is controlled by the profiling session variable, which has a
开启一下profiling功能；
mysql> set profile=1;
ERROR 1193 (HY000): Unknown system variable 'profile'
mysql> set profiling=1;
Query OK, 0 rows affected, 1 warning (0.00 sec)
mysql> show variables like '%profil%';
+------------------------+-------+
| Variable_name | Value |
+------------------------+-------+
| have_profiling | YES |
| profiling | ON |
| profiling_history_size | 15 |
+------------------------+-------+
3 rows in set (0.00 sec)
输入sql语句查看一下，profiles是否产生了。
mysql> SELECT count(*) from table where publishtime >='2017-01-01' and publishtime <='2017-08-30'
-> ;
+----------+
| count(*) |
+----------+
| 1317564 |
+----------+
1 row in set (2.46 sec)
mysql> show profiles;
+----------+------------+--------------------------------------------------------------------------------------------------------+
| Query_ID | Duration | Query |
+----------+------------+--------------------------------------------------------------------------------------------------------+
| 1 | 0.00109175 | show variables like '%profil%' |
| 2 | 2.46288425 | SELECT count(*) from table where publishtime >='2017-01-01' and publishtime <='2017-08-30' |
+----------+------------+--------------------------------------------------------------------------------------------------------+
2 rows in set, 1 warning (0.00 sec)
mysql>
获取指定的开销：
mysql> show profile for query 2;
+----------------------+----------+
| Status | Duration |
+----------------------+----------+
| starting | 0.000147 |
| checking permissions | 0.000023 |
| Opening tables | 0.000047 |
| init | 0.000081 |
| System lock | 0.000031 |
| optimizing | 0.000034 |
| statistics | 0.001650 |
| preparing | 0.000046 |
| executing | 0.000018 |
| Sending data | 2.460588 |
| end | 0.000041 |
| query end | 0.000019 |
| closing tables | 0.000022 |
| freeing items | 0.000055 |
| cleaning up | 0.000085 |
+----------------------+----------+
15 rows in set, 1 warning (0.00 sec)
可以看到Sending data ，这个还是比较耗时，这个是sending data 不是发送数据的意思，
是收集和发送集合的数据。
查看cpu的数据：
mysql> show profile cpu for query 2;
+----------------------+----------+----------+------------+
| Status | Duration | CPU_user | CPU_system |
+----------------------+----------+----------+------------+
| starting | 0.000147 | 0.000000 | 0.000000 |
| checking permissions | 0.000023 | 0.000000 | 0.000000 |
| Opening tables | 0.000047 | 0.000000 | 0.000000 |
| init | 0.000081 | 0.000000 | 0.000000 |
| System lock | 0.000031 | 0.000000 | 0.000000 |
| optimizing | 0.000034 | 0.000000 | 0.000000 |
| statistics | 0.001650 | 0.001000 | 0.001000 |
| preparing | 0.000046 | 0.000000 | 0.000000 |
| executing | 0.000018 | 0.000000 | 0.000000 |
| Sending data | 2.460588 | 2.464625 | 0.025996 |
| end | 0.000041 | 0.000000 | 0.000000 |
| query end | 0.000019 | 0.000000 | 0.000000 |
| closing tables | 0.000022 | 0.000000 | 0.000000 |
| freeing items | 0.000055 | 0.000000 | 0.000000 |
| cleaning up | 0.000085 | 0.000000 | 0.000000 |
+----------------------+----------+----------+------------+
15 rows in set, 1 warning (0.00 sec)
也是这个操作，
type:
ALL --显示所有的开销信息
| BLOCK IO --显示块IO相关开销
| CONTEXT SWITCHES --上下文切换相关开销
| CPU --显示CPU相关开销信息
| IPC --显示发送和接收相关开销信息
| MEMORY --显示内存相关开销信息
| PAGE FAULTS --显示页面错误相关开销信息
| SOURCE --显示和Source_function，Source_file，Source_line相关的开销信息
| SWAPS --显示交换次数相关开销的信息
这里边的可以任意特换就可以看到对应的参数的开销，自己试试看。