MySQL5.6PERFORMANCE_SCHEMA说明_MySQL

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发布时间：2016-05-27 13:45:09

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背景：

MySQL 5.5开始新增一个数据库：PERFORMANCE_SCHEMA，主要用于收集数据库服务器性能参数。并且库里表的存储引擎均为PERFORMANCE_SCHEMA，而用户是不能创建存储引擎为PERFORMANCE_SCHEMA的表。MySQL5.5默认是关闭的，需要手动开启，在配置文件里添加：

view sourceprint?1.[mysqld]2.performance_schema=ON

查看是否开启：

view
 sourceprint?
1.
mysql>show
 variables like 
'performance_schema'
;
2.
+--------------------+-------+
3.
|
 Variable_name      | Value |
4.
+--------------------+-------+
5.
|
 performance_schema | 
ON
    |
6.
+--------------------+-------+

从MySQL5.6开始，默认打开，本文就从MySQL5.6来说明，在数据库使用当中PERFORMANCE_SCHEMA的一些比较常用的功能。具体的信息可以查看官方文档。

相关表信息：

一：配置（setup）表：

view
 sourceprint?
01.
zjy
@performance_schema 
10
:
16
:
56
>show
 tables like 
'%setup%'
;
02.
+----------------------------------------+
03.
|
 Tables_in_performance_schema (%setup%) |
04.
+----------------------------------------+
05.
|
 setup_actors                           |
06.
|
 setup_consumers                        |
07.
|
 setup_instruments                      |
08.
|
 setup_objects                          |
09.
|
 setup_timers                           |
10.
+----------------------------------------+

1，setup_actors：配置用户纬度的监控，默认监控所有用户。

view
 sourceprint?
1.
zjy
@performance_schema 
10
:
19
:
11
>select
 * from setup_actors;
2.
+------+------+------+
3.
|
 HOST | USER | ROLE |
4.
+------+------+------+
5.
|
 %    | %    | %    |
6.
+------+------+------+

2，setup_consumers：配置events的消费者类型，即收集的events写入到哪些统计表中。

view
 sourceprint?
01.
zjy@:
 performance_schema 
10
:
23
:
35
>select
 * from setup_consumers;
02.
+--------------------------------+---------+
03.
|
 NAME                           | ENABLED |
04.
+--------------------------------+---------+
05.
|
 events_stages_current          | NO      |
06.
|
 events_stages_history          | NO      |
07.
|
 events_stages_history_long     | NO      |
08.
|
 events_statements_current      | YES     |
09.
|
 events_statements_history      | NO      |
10.
|
 events_statements_history_long | NO      |
11.
|
 events_waits_current           | NO      |
12.
|
 events_waits_history           | NO      |
13.
|
 events_waits_history_long      | NO      |
14.
|
 global_instrumentation         | YES     |
15.
|
 thread_instrumentation         | YES     |
16.
|
 statements_digest              | YES     |
17.
+--------------------------------+---------+

这里需要说明的是需要查看哪个就更新其ENABLED列为YES。如：

view
 sourceprint?
1.
zjy
@performance_schema 
10
:
25
:
02
>update
 setup_consumers set ENABLED=
'YES' 
where
 NAME in (
'events_stages_current'
,
'events_waits_current'
);
2.
Query
 OK, 
2 
rows
 affected (
0.00 
sec)

更新完后立即生效，但是服务器重启之后又会变回默认值，要永久生效需要在配置文件里添加：

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view
 sourceprint?
1.
[mysqld]
2.
#performance_schema
3.
performance_schema_consumer_events_waits_current=on
4.
performance_schema_consumer_events_stages_current=on
5.
performance_schema_consumer_events_statements_current=on
6.
performance_schema_consumer_events_waits_history=on
7.
performance_schema_consumer_events_stages_history=on
8.
performance_schema_consumer_events_statements_history=on

即在这些表的前面加上：performance_schema_consumer_xxx。表setup_consumers里面的值有个层级关系：

view
 sourceprint?
1.
global_instrumentation

 > 
thread_instrumentation
 = 
statements_digest
 > events_stages_
current
 = events_statements_current = events_waits_current > events_stages_
history
 = events_statements_history = events_waits_history
 > events_stages_
history_long
 = events_statements_history_long = events_waits_history_long

只有上一层次的为YES，才会继续检查该本层为YES or NO。global_instrumentation是最高级别consumer，如果它设置为NO，则所有的consumer都会忽略。其中history和history_long存的是current表的历史记录条数，history表记录了每个线程最近等待的10个事件，而history_long表则记录了最近所有线程产生的10000个事件，这里的10和10000都是可以配置的。这三个表表结构相同，history和history_long表数据都来源于current表。长度通过控制参数：

view
 sourceprint?
01.
zjy
@performance_schema 
11
:
10
:
03
>show
 variables like 
'performance_schema%history%size'
;
02.
+--------------------------------------------------------+-------+
03.
|
 Variable_name                                          | Value |
04.
+--------------------------------------------------------+-------+
05.
|
 performance_schema_events_stages_history_long_size     | 
10000 
|
06.
|
 performance_schema_events_stages_history_size          | 
10    
|
07.
|
 performance_schema_events_statements_history_long_size | 
10000 
|
08.
|
 performance_schema_events_statements_history_size      | 
10    
|
09.
|
 performance_schema_events_waits_history_long_size      | 
10000 
|
10.
|
 performance_schema_events_waits_history_size           | 
10    
|
11.
+--------------------------------------------------------+-------+
3，setup_instruments：配置具体的instrument，主要包含4大类：idle、stage/xxx、statement/xxx、wait/xxx：
view
 sourceprint?
01.
zjy
@performance_schema 
10
:
56
:
35
>select
 name,count(*) from setup_instruments group by LEFT(name,
5
);
02.
+---------------------------------+----------+
03.
|
 name                            | count(*) |
04.
+---------------------------------+----------+
05.
|
 idle                            |        
1 
|
06.
|
 stage/sql/After create          |      
111 
|
07.
|
 statement/sql/select            |      
179 
|
08.
|
 wait/synch/mutex/sql/PAGE::lock |      
296 
|
09.
+---------------------------------+----------+

idle表示socket空闲的时间，stage类表示语句的每个执行阶段的统计，statement类统计语句维度的信息，wait类统计各种等待事件，比如IO，mutux，spin_lock,condition等。

4，setup_objects：配置监控对象，默认对mysql，performance_schema和information_schema中的表都不监控，而其它DB的所有表都监控。

view
 sourceprint?
01.
zjy
@performance_schema 
11
:
00
:
18
>select
 * from setup_objects;
02.
+-------------+--------------------+-------------+---------+-------+
03.
|
 OBJECT_TYPE | OBJECT_SCHEMA      | OBJECT_NAME | ENABLED | TIMED |
04.
+-------------+--------------------+-------------+---------+-------+
05.
|
 TABLE       | mysql              | %           | NO      | NO    |
06.
|
 TABLE       | performance_schema | %           | NO      | NO    |
07.
|
 TABLE       | information_schema | %           | NO      | NO    |
08.
|
 TABLE       | %                  | %           | 
YES
     | 
YES
   |
09.
+-------------+--------------------+-------------+---------+-------+

5，setup_timers：配置每种类型指令的统计时间单位。MICROSECOND表示统计单位是微妙，CYCLE表示统计单位是时钟周期，时间度量与CPU的主频有关，NANOSECOND表示统计单位是纳秒。但无论采用哪种度量单位，最终统计表中统计的时间都会装换到皮秒。（1秒＝1000000000000皮秒）

view
 sourceprint?
01.
zjy
@performance_schema 
11
:
05
:
12
>select
 * from setup_timers;
02.
+-----------+-------------+
03.
|
 NAME      | TIMER_NAME  |
04.
+-----------+-------------+
05.
|
 idle      | MICROSECOND |
06.
|
 wait      | CYCLE       |
07.
|
 stage     | NANOSECOND  |
08.
|
 statement | NANOSECOND  |
09.
+-----------+-------------+