MySQL Query Profiler

查看MySQL语法详细执行时间与CPU/记忆体使用量: MySQL Query Profiler?
MySQL的SQL语法调整主要都是使用EXPLAIN,但是这个并没办法知道详细的Ram(Memory)/CPU等使用量.?
于MySQL 5.0.37以上开始支援MySQL Query Profiler,可以查询到此SQL会执行多少时间,并看出CPU/Memory使用量,执行过程中System lock, Table lock花多少时间等等.?
MySQL Query Profile详细介绍可见: Using the New MySQL Query Profiler (2007.04.05发表)?
效能分析主要分下述三种(转载自上篇):?
? Bottleneck analysis - focuses on answering the questions: What is my database server waiting on; what is a user connection waiting on; what is a piece of SQL code waiting on??
? Workload analysis - examines the server and who is logged on to determine the resource usage and activity of each.?
? Ratio-based analysis - utilizes a number of rule-of-thumb ratios to gauge performance of a database, user connection, or piece of code.?
MySQL Query Profile使用方法
启动
? mysql> set profiling=1; #此命令于MySQL会于information_schema的database建立一个PROFILING的table来纪录.?
SQL profiles show?
? mysql> show profiles; #从启动之后所有语法及使用时间,含错误语法都会纪录.?
? ex: (root@localhost) [test]> show profiles; #注意Query_ID,下面执行时间统计等,都是依Query_ID在纪录
? +----------+------------+------------------------ ---+?
? | Query_ID | Duration | Query |?
? +----------+------------+------------------------ ---+?
? | 1 | 0.00090400 | show profile for query 1 |?
? | 2 | 0.00008700 | select * from users |?
? | 3 | 0.00183800 | show tables |?
? | 4 | 0.00027600 | mysql> show profiles |?
? +----------+------------+------------------------ ---+?

查询所有花费时间加总
? mysql> select sum(duration) from information_schema.profiling where query_id=1; # Query ID = 1?
? +---------------+?
? | sum(duration) |?
? +---------------+?
? | 0.000447 |?
? +---------------+?

查询各执行阶段花费多少时间
? mysql> show profile for query 1; # Query ID = 1?
? +--------------------+------------+?
? | Status | Duration |?
? +--------------------+------------+?
? | (initialization) | 0.00006300 |?
? | Opening tables | 0.00001400 |?
? | System lock | 0.00000600 |?
? | Table lock | 0.00001000 |?
? | init | 0.00002200 |?
? | optimizing | 0.00001100 |?
? | statistics | 0.00009300 |?
? | preparing | 0.00001700 |?
? | executing | 0.00000700 |?
? | Sending data | 0.00016800 |?
? | end | 0.00000700 |?
? | query end | 0.00000500 |?
? | freeing items | 0.00001200 |?
? | closing tables | 0.00000800 |?
? | logging slow query | 0.00000400 |?
? +--------------------+------------+?

查询各执行阶段花费的各种资源列表
? mysql> show profile cpu for query 1; # Query ID = 1?
? +--------------------------------+----------+---- ------+------------+?
? | Status | Duration | CPU_user | CPU_system |?
? +--------------------------------+----------+---- ------+------------+?
? | (initialization) | 0.000007 | 0 | 0 |?
? | checking query cache for query | 0.000071 | 0 | 0 |?
? | Opening tables | 0.000024 | 0 | 0 |?
? | System lock | 0.000014 | 0 | 0 |?
? | Table lock | 0.000055 | 0.001 | 0 |?
? | init | 0.000036 | 0 | 0 |?
? | optimizing | 0.000013 | 0 | 0 |?
? | statistics | 0.000021 | 0 | 0 |?
? | preparing | 0.00002 | 0 | 0 |?
? | executing | 0.00001 | 0 | 0 |?
? | Sending data | 0.015072 | 0.011998 | 0 |?
? | end | 0.000021 | 0 | 0 |?
? | query end | 0.000011 | 0 | 0 |?
? | storing result in query cache | 0.00001 | 0 | 0 |?
? | freeing items | 0.000018 | 0 | 0 |?
? | closing tables | 0.000019 | 0 | 0 |?
? | logging slow query | 0.000009 | 0 | 0 |?
? +--------------------------------+----------+---- ------+------------+?

? mysql> show profile IPC for query 1;?
? +--------------------------------+----------+---- -----------+-------------------+?
? | Status | Duration | Messages_sent | Messages_received |?
? +--------------------------------+----------+---- ------