http://keithlan.github.io/2015/07/17/22_performance_schema/
http://www.markleith.co.uk/
http://www.cnblogs.com/cchust/p/5022148.html?utm_source=tuicool&utm_medium=referral
MYSQL 是否支持 PERFORMANCE_SCHEMA 引擎
mysql> SELECT * FROM INFORMATION_SCHEMA.ENGINES ; +--------------------+---------+----------------------------------------------------------------+--------------+------+------------+ | ENGINE | SUPPORT | COMMENT | TRANSACTIONS | XA | SAVEPOINTS | +--------------------+---------+----------------------------------------------------------------+--------------+------+------------+ | PERFORMANCE_SCHEMA | YES | Performance Schema | NO | NO | NO | | MRG_MYISAM | YES | Collection of identical MyISAM tables | NO | NO | NO | | CSV | YES | CSV storage engine | NO | NO | NO | | BLACKHOLE | YES | /dev/null storage engine (anything you write to it disappears) | NO | NO | NO | | MyISAM | YES | MyISAM storage engine | NO | NO | NO | | MEMORY | YES | Hash based, stored in memory, useful for temporary tables | NO | NO | NO | | ARCHIVE | YES | Archive storage engine | NO | NO | NO | | InnoDB | DEFAULT | Supports transactions, row-level locking, and foreign keys | YES | YES | YES | | FEDERATED | NO | Federated MySQL storage engine | NULL | NULL | NULL | +--------------------+---------+----------------------------------------------------------------+--------------+------+------------+ 9 rows in set (0.00 sec)
mysql服务器起用 performance_schema
my.cnf文件中 [mysqld] performance_schema=ON
mysql> SHOW VARIABLES LIKE 'performance_schema'; +--------------------+-------+ | Variable_name | Value | +--------------------+-------+ | performance_schema | ON | +--------------------+-------+ 1 row in set (0.11 sec)
Performance Schema Instrument命名规则
最上层的instrument 组件
- idle
- stage
- statement
- wait
idle instrument 组件 idle event描述来自：socket_instances.STATE 列： Section 22.9.3.5, “The socket_instances Table”.
stage instrument 组件
组成形式： stage/code_area/stage_name ， code_area 一般是sql or myisam。 stage name 一般来自： SHOW PROCESSLIST，如：Sorting result ，Sending data
Statement instrument 组件 statement/abstract/* ： 一般都是早期的stage，在抽象sql都还没来得及解析的时候。 statement/com: SQL 命令操作 如：statement/com/Connect statement/sql： SQL语句操作 如：statement/sql/create_db
Wait Instrument 组件 wait/io ： IO 等待事件 wait/io/file ： 文件IO等待事件。等待文件操作完成的时间如：fwrite().但是物理IO有可能因为缓存的原因调用fwrite时不会写磁盘。 wait/io/socket： socket相关的IO等待 wait/io/table ： 表相关的IO等待。一般对于记录rows来说有fetch，insert，update，delete四种操作。 不像其他等待事件，table I/O 还包含了其他的等待事件。
比如：table io可能包含了文件IO和内存IO。因为读取table rows的时候，有可能会去从文件读取数据。 * wait/lock: * wait/lock/table ： 表操作的锁等待事件 * wait/synch: * wait/synch/cond ：condition就是线程与线程之间的信号。 * wait/synch/mutex ： mutex主要用来锁住一块共享资源。 * wait/synch/rwlock ： 读写锁
收集所有的事件:
instrument 和 consumer 都会被enable ， 所以一开始他们不会收集所有的事件。 为了让他们都enable 或者 enable event timing。
执行以下两条语句: mysql> UPDATE setup_instruments SET ENABLED = 'YES', TIMED = 'YES'; Query OK, 338 rows affected (0.12 sec)
mysql> UPDATE setup_consumers SET ENABLED = 'YES'; Query OK, 8 rows affected (0.00 sec)
events_waits_history & events_waits_history_long 记录了每个thread最近10条和10000条event。
SELECT EVENT_ID, EVENT_NAME, TIMER_WAIT FROM events_waits_history WHERE THREAD_ID =21 ORDER BY EVENT_ID;
summary 表提供了整个时间段的一些统计信息。他们统计事件的处理方式和之前都不一样。
如果想知道某个instrument 被执行的最频繁，或者发生的频率非常高，
可以通过排序 events_waits_summary_global_by_event_name表，根据 COUNT_STAR 或者 SUM_TIMER_WAIT列。
mysql> SELECT EVENT_NAME, COUNT_STAR FROM events_waits_summary_global_by_event_name ORDER BY COUNT_STAR DESC LIMIT 10; +--------------------------------------+------------+ | EVENT_NAME | COUNT_STAR | +--------------------------------------+------------+ | wait/io/file/sql/FRM | 1682 | | wait/io/file/innodb/innodb_data_file | 596 | | idle | 204 | | wait/io/file/sql/binlog | 170 | | wait/io/file/myisam/kfile | 110 | | wait/io/file/myisam/dfile | 90 | | wait/io/file/sql/binlog_index | 47 | | wait/io/file/innodb/innodb_log_file | 18 | | wait/io/file/sql/dbopt | 14 | | wait/io/file/sql/casetest | 10 | +--------------------------------------+------------+ 10 rows in set (0.31 sec)
mysql> SELECT EVENT_NAME, SUM_TIMER_WAIT FROM events_waits_summary_global_by_event_name ORDER BY SUM_TIMER_WAIT DESC LIMIT 10; +--------------------------------------+-------------------+ | EVENT_NAME | SUM_TIMER_WAIT | +--------------------------------------+-------------------+ | idle | 20173041031000000 | | wait/io/file/innodb/innodb_data_file | 666638377892 | | wait/io/file/sql/dbopt | 177140672226 | | wait/io/file/sql/FRM | 91152018924 | | wait/io/file/sql/binlog | 43352476474 | | wait/io/file/innodb/innodb_log_file | 35962857780 | | wait/io/file/sql/binlog_index | 20679496964 | | wait/io/file/myisam/kfile | 16840088732 | | wait/io/file/sql/ERRMSG | 8064330196 | | wait/io/file/myisam/dfile | 4785274304 | +--------------------------------------+-------------------+ 10 rows in set (0.03 sec)
setup表用来配置和显示监控信息的。 例如：什么样的timer 被使用，
请查询setup_timers
mysql> SELECT * FROM setup_timers; +-----------+-------------+ | NAME | TIMER_NAME | +-----------+-------------+ | idle | MICROSECOND | | wait | CYCLE | | stage | NANOSECOND | | statement | NANOSECOND | +-----------+-------------+ 4 rows in set (0.00 sec)
setup_instruments 列出了哪些event会被收集与监控：
mysql> SELECT * FROM setup_instruments limit 10; +-------------------------------------------------------+---------+-------+ | NAME | ENABLED | TIMED | +-------------------------------------------------------+---------+-------+ | wait/synch/mutex/sql/PAGE::lock | YES | YES | | wait/synch/mutex/sql/TC_LOG_MMAP::LOCK_sync | YES | YES | | wait/synch/mutex/sql/TC_LOG_MMAP::LOCK_active | YES | YES | | wait/synch/mutex/sql/TC_LOG_MMAP::LOCK_pool | YES | YES | | wait/synch/mutex/sql/LOCK_des_key_file | YES | YES | | wait/synch/mutex/sql/MYSQL_BIN_LOG::LOCK_commit | YES | YES | | wait/synch/mutex/sql/MYSQL_BIN_LOG::LOCK_commit_queue | YES | YES | | wait/synch/mutex/sql/MYSQL_BIN_LOG::LOCK_done | YES | YES | | wait/synch/mutex/sql/MYSQL_BIN_LOG::LOCK_flush_queue | YES | YES | | wait/synch/mutex/sql/MYSQL_BIN_LOG::LOCK_index | YES | YES | +-------------------------------------------------------+---------+-------+ 10 rows in set (0.00 sec)
哪些event是不是instrument，可以给enabled设置yes or no
mysql> UPDATE setup_instruments SET ENABLED = 'NO' WHERE NAME = 'wait/synch/mutex/sql/LOCK_mysql_create_db'; Query OK, 0 rows affected (0.01 sec) Rows matched: 0 Changed: 0 Warnings: 0
消费者:接收EVENTS 的表
performance schema 使用收集的events 来更新performance_schema 数据库的那些表，这些表扮演着事件信息消费者的角色。
setup_consumers 列出了可用的消费者 以及哪些是enabled.
mysql> SELECT * FROM setup_consumers; +--------------------------------+---------+ | NAME | ENABLED | +--------------------------------+---------+ | events_stages_current | YES | | events_stages_history | YES | | events_stages_history_long | YES | | events_statements_current | YES | | events_statements_history | YES | | events_statements_history_long | YES | | events_waits_current | YES | | events_waits_history | YES | | events_waits_history_long | YES | | global_instrumentation | YES | | thread_instrumentation | YES | | statements_digest | YES |
http://www.javacoder.cn/?p=332
MySQL在5.6版本中包含了一个强大的特性——performance-schema
合理的使用这个数据库中的表，能为我们解决一些瓶颈问题提供帮助，但是在我使用的5.6.21版本中，已经包含了52张表，后续还有可能会持续增加，所以搞清楚各个表之间的关系很重要。
mysql> show tables like '%setup%'; +----------------------------------------+ | Tables_in_performance_schema (%setup%) | +----------------------------------------+ | setup_actors | | setup_consumers | | setup_instruments | | setup_objects | | setup_timers | +----------------------------------------+ 5 rows in set (0.01 sec)
1)setup_instruments [测量仪器]
使用performance-schema诊断问题的过程类似于医生给病人看病的过程。"setup_instruments"犹如医生能够使用的测量仪器（比如温度计，CT，X光等），在MySQL的官方文档中，使用“instrument”一词来表示，这应该也是这个表的名称的来源。这个表的每一行代表一个"instrument","instrument"在MySQL的源码中表示为一段为了测量相应指标的代码。这张表的三个字段分别为“name enabled timed”,enabled表示是否启用该"instrument", "timed"表示是否对其进行定量的耗时分析。
mysql> SELECT * FROM setup_instruments limit 10; +-------------------------------------------------------+---------+-------+ | NAME | ENABLED | TIMED | +-------------------------------------------------------+---------+-------+ | wait/synch/mutex/sql/PAGE::lock | YES | YES | | wait/synch/mutex/sql/TC_LOG_MMAP::LOCK_sync | YES | YES | | wait/synch/mutex/sql/TC_LOG_MMAP::LOCK_active | YES | YES | | wait/synch/mutex/sql/TC_LOG_MMAP::LOCK_pool | YES | YES | | wait/synch/mutex/sql/LOCK_des_key_file | YES | YES | | wait/synch/mutex/sql/MYSQL_BIN_LOG::LOCK_commit | YES | YES | | wait/synch/mutex/sql/MYSQL_BIN_LOG::LOCK_commit_queue | YES | YES | | wait/synch/mutex/sql/MYSQL_BIN_LOG::LOCK_done | YES | YES | | wait/synch/mutex/sql/MYSQL_BIN_LOG::LOCK_flush_queue | YES | YES | | wait/synch/mutex/sql/MYSQL_BIN_LOG::LOCK_index | YES | YES | +-------------------------------------------------------+---------+-------+ 10 rows in set (0.01 sec)
2）setup_objects
setup_objects类似某类病人(精神病，男科，妇科等)，在MySQL中指table, 表示哪些表需要“instrument”,该表的默认值为：
mysql> SELECT * FROM setup_objects limit 10; +-------------+--------------------+-------------+---------+-------+ | OBJECT_TYPE | OBJECT_SCHEMA | OBJECT_NAME | ENABLED | TIMED | +-------------+--------------------+-------------+---------+-------+ | TABLE | mysql | % | NO | NO | | TABLE | performance_schema | % | NO | NO | | TABLE | information_schema | % | NO | NO | | TABLE | % | % | YES | YES | +-------------+--------------------+-------------+---------+-------+ 4 rows in set (0.00 sec)
表示出了系统表“mysql performance_schema information_schema”外，都需要对其进行“instrument”操作。
3）threads
"threads“类似于某个病人，在MySQL中的某个线程，这个表有一个非常重要的字段”INSTRUMENTED“，表示是否需要对该线程进行”instrument“,这个字段由”setup_actors“表中的内容决定。setup_actors的默认内容如下
mysql> SELECT THREAD_ID,NAME,TYPE,INSTRUMENTED,role FROM threads limit 10; +-----------+---------------------------------+------------+--------------+------+ | THREAD_ID | NAME | TYPE | INSTRUMENTED | role | +-----------+---------------------------------+------------+--------------+------+ | 1 | thread/sql/main | BACKGROUND | YES | NULL | | 2 | thread/innodb/io_handler_thread | BACKGROUND | YES | NULL | | 3 | thread/innodb/io_handler_thread | BACKGROUND | YES | NULL | | 4 | thread/innodb/io_handler_thread | BACKGROUND | YES | NULL | | 5 | thread/innodb/io_handler_thread | BACKGROUND | YES | NULL | | 6 | thread/innodb/io_handler_thread | BACKGROUND | YES | NULL | | 7 | thread/innodb/io_handler_thread | BACKGROUND | YES | NULL | | 8 | thread/innodb/io_handler_thread | BACKGROUND | YES | NULL | | 11 | thread/innodb/io_handler_thread | BACKGROUND | YES | NULL | | 9 | thread/innodb/io_handler_thread | BACKGROUND | YES | NULL | +-----------+---------------------------------+------------+--------------+------+ 10 rows in set (0.01 sec)
线程分前台线程和后台线程，后台线程指MySQL为了完成任务二自己开启的线程，这样的线程的setup_objects.INSTRUMENTED字段默认为true。
前台线程值用户操作而开启的线程。这时如果当前用户匹配setup_actors中的某个记录，那么setup_objects.INSTRUMENTED=true.
threads表的另一个功能是可以代替"show processlist"指令和"information_schema.processlist"表的功能，其不用获取同步的mutex对象，不会又那么重的额外消耗(overhead).
4)setup_consumers
setup_consumers表类似于各种诊断报告是否需要记录的配置，这个表的默认配置为：select * from setup_consumers;
mysql> select * from setup_consumers; +--------------------------------+---------+ | NAME | ENABLED | +--------------------------------+---------+ | events_stages_current | YES | | events_stages_history | YES | | events_stages_history_long | YES | | events_statements_current | YES | | events_statements_history | YES | | events_statements_history_long | YES | | events_waits_current | YES | | events_waits_history | YES | | events_waits_history_long | YES | | global_instrumentation | YES | | thread_instrumentation | YES | | statements_digest | YES | +--------------------------------+---------+ 12 rows in set (0.00 sec)
5）setup_actors
mysql> select * from setup_actors ; +------+------+------+ | HOST | USER | ROLE | +------+------+------+ | % | % | % | +------+------+------+ 1 row in set (0.16 sec)
6)setup_timers
mysql> select * from setup_timers ; +-----------+-------------+ | NAME | TIMER_NAME | +-----------+-------------+ | idle | MICROSECOND | | wait | CYCLE | | stage | NANOSECOND | | statement | NANOSECOND | +-----------+-------------+ 4 rows in set (0.00 sec)
这个表的各个记录还存在层级关系，只有当上级的配置启用时才会考虑下级的配置。
层级关系为：
global_instrumentation
|----thread_instrumentation
| |----events_waits_current
| | |-events_waits_history
| | |-events_waits_history_long
| |----events_stages_current
| | |-events_stages_history
| | |-events_stages_history_long
| |----events_statements_current
| |-events_statements_history
| |-events_statements_history_long
|-----statements_digest
当global_instrumentation启用时，"thread_instrumentation"和"statements_digest"的配置才有可能生效。其他的配置类推。
只有当"setup_instruments"，"setup_objects",”setup_consumers“和"threads"都某一项测量指标都启用时才能收集到它的信息。
结束语
对于”statement, stages, waits“这三类统计信息，除了setup_consumers中配置的名称，还有summary版本的统计信息（summary_by_host_by_event_name, summary_by_user_event_name, summary_global_by_event_name）等按照各个维度的统计信息，外加file_instance, mutext_instance, rwlock_instance, table_io_waits_summary_by_index_usage, table_io_waits_summary_by_table,table_lock_waits_summary_by_table,外加一些杂项信息。
由于这些都是基础信息，网上有一个叫做ps_helper的项目，它提供了一些视图，存储过程来简化performence_schema数据库的使用，
MySQL官方的GUI工具——MySQL Workbench就含义ps_helper的安装向导入下图，
安装完后会新增一个名为"sys"的数据库，里面会包含一些视图和存储过程，具体的内容可以查看官方文档。
一些不错的资料：
ps_helper官方
MySQL Performance_Schema官网
Using-MySQL-5.6-Performance-Schema-To-Troubleshoot-Typical-Workload-Bottlenecks.pdf