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
http://dev.mysql.com/doc/refman/5.6/en/performance-schema-query-profili
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。