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 |

• +--------------------------------+----------+---- -----------+-------------------+

• | (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 | 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 | 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 |

• +--------------------------------+----------+---- -----------+-------------------+其它属性列表• ALL - displays all information

• BLOCK IO - displays counts for block input and output operations

• CONTEXT SWITCHES - displays counts for voluntary and involuntary context switches

• IPC - displays counts for messages sent and received

• MEMORY - is not currently implemented

• PAGE FAULTS - displays counts for major and minor page faults

• SOURCE - displays the names of functions from the source code, together with the name and line number of the file in which the function occurs

• SWAPS - displays swap counts设定Profiling存的Size

• mysql> show variables where variable_name='profiling_history_size'; #预设是15关闭• mysql> set profiling=0;