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《Mysql必读mysql显示SQL语句执行时间的实例详解》要点：
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导读：本节内容：显示SQL语句执行时间MySQL 的 SQL 语法调整主要使用 EXPLAIN,不过该命令无法获取详细的 Ram(Memory)/CPU 等使用量.于 My...
本节内容：
显示SQL语句执行时间MYSQL教程
MySQL 的 SQL 语法调整主要使用 EXPLAIN,不过该命令无法获取详细的 Ram(Memory)/CPU 等使用量.MYSQL教程
于 MySQL 5.0.37 以上开始支持 MySQL Query Profiler,可以查詢到此 SQL执行多长时间,并 並看出 CPU/Memory 使用量,执行过程中 System lock,Table lock 花多少时间等.MYSQL教程
效能分析主要分下述三种:
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?MYSQL教程
Workload analysis - examines the server and who is logged on to determine the resource usage and activity of each.MYSQL教程
Ratio-based analysis - utilizes a number of rule-of-thumb ratios to gauge performance of a database,user connection,or piece of code.MYSQL教程
MySQL Query Profile 使用方法MYSQL教程
启动：
mysql> set profiling=1; # 此命令于 MySQL 会于 information_schema 的 database 建立一个 PROFILING 的 table 来记录.MYSQL教程
SQL profiles show
mysql> show profiles; # 从启动之后所有语法及使用时间,含错误语法都会记录.
例如:MYSQL教程
(root@jbxue.com) [test]> show profiles; # 注意 Query_ID,下面执行时间统计等,都是依 Query_ID 在记录
+----------+------------+---------------------------+
| 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????? |
+----------+------------+---------------------------+
1,查询所有花费时间加总
?MYSQL教程
mysql> select sum(duration) from information_schema.profiling where query_id=1; # Query ID = 1
+---------------+
| sum(duration) |
+---------------+
|????? 0.000447 |
+---------------+
2,查询各执行阶段花费多少时间
?MYSQL教程
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 |
+--------------------+------------+
3,查询各执行阶段花费的各种资源列表
?MYSQL教程
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教程
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 |
+--------------------------------+----------+---------------+-------------------+MYSQL教程
4,其它属性列表
?MYSQL教程
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
5,设定 Profiling 存的 Size：
?MYSQL教程
mysql> show variables where variable_name='profiling_history_size'; # 预设是 15笔
关闭：
?MYSQL教程
mysql> set profiling=0;编程之家PHP培训学院每天发布《Mysql必读mysql显示SQL语句执行时间的实例详解》等实战技能，PHP、MYSQL、LINUX、APP、JS,CSS全面培养人才。 （编辑：李大同）
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