MySQL5.6 PERFORMANCE_SCHEMA 说明
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：
1.
[mysqld]
2.
performance_schema=ON
查看是否开启：
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：
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。
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。
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：
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：
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：
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：
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：
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。
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）
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.
+-----------+-------------+
二：instance表
1，cond_instances：条件等待对象实例
表中记录了系统中使用的条件变量的对象，OBJECT_INSTANCE_BEGIN为对象的内存地址。
2，file_instances：文件实例
表中记录了系统中打开了文件的对象，包括ibdata文件，redo文件，binlog文件，用户的表文件等，open_count显示当前文件打开的数目，如果重来没有打开过，不会出现在表中。
01.
zjy@performance_schema 11:20:04>select * from file_instances limit 2,5;
02.
+---------------------------------+--------------------------------------+------------+
03.
| FILE_NAME | EVENT_NAME | OPEN_COUNT |
04.
+---------------------------------+--------------------------------------+------------+
05.
| /var/lib/mysql/mysql/plugin.frm | wait/io/file/sql/FRM | 0 |
06.
| /var/lib/mysql/mysql/plugin.MYI | wait/io/file/myisam/kfile | 1 |
07.
| /var/lib/mysql/mysql/plugin.MYD | wait/io/file/myisam/dfile | 1 |
08.
| /var/lib/mysql/ibdata1 | wait/io/file/innodb/innodb_data_file | 2 |
09.
| /var/lib/mysql/ib_logfile0 | wait/io/file/innodb/innodb_log_file | 2 |
10.
+---------------------------------+--------------------------------------+------------+
3，mutex_instances：互斥同步对象实例
表中记录了系统中使用互斥量对象的所有记录，其中name为：wait/synch/mutex/*。LOCKED_BY_THREAD_ID显示哪个线程正持有mutex，若没有线程持有，则为NULL。
4，rwlock_instances： 读写锁同步对象实例
表中记录了系统中使用读写锁对象的所有记录，其中name为 wait/synch/rwlock/*。WRITE_LOCKED_BY_THREAD_ID为正在持有该对象的thread_id，若没有线程持有，则为NULL。READ_LOCKED_BY_COUNT为记录了同时有多少个读者持有读锁。（通过 events_waits_current 表可以知道，哪个线程在等待锁；通过rwlock_instances知道哪个线程持有锁。rwlock_instances的缺陷是，只能记录持有写锁的线程，对于读锁则无能为力）。
5，socket_instances：活跃会话对象实例
表中记录了thread_id,socket_id,ip和port，其它表可以通过thread_id与socket_instance进行关联，获取IP-PORT信息，能够与应用对接起来。
event_name主要包含3类：
wait/io/socket/sql/server_unix_socket，服务端unix监听socket
wait/io/socket/sql/server_tcpip_socket，服务端tcp监听socket
wait/io/socket/sql/client_connection，客户端socket
三：Wait表
1，events_waits_current：记录了当前线程等待的事件
2，events_waits_history：记录了每个线程最近等待的10个事件
3，events_waits_history_long：记录了最近所有线程产生的10000个事件
表结构定义如下：
01.
CREATE TABLE `events_waits_current` (
02.
`THREAD_ID` bigint(20) unsigned NOT NULL COMMENT '线程ID',
03.
`EVENT_ID` bigint(20) unsigned NOT NULL COMMENT '当前线程的事件ID，和THREAD_ID确定唯一',
04.
`END_EVENT_ID` bigint(20) unsigned DEFAULT NULL COMMENT '当事件开始时，这一列被设置为NULL。当事件结束时，再更新为当前的事件ID',
05.
`EVENT_NAME` varchar(128) NOT NULL COMMENT '事件名称',
06.
`SOURCE` varchar(64) DEFAULT NULL COMMENT '该事件产生时的源码文件',
07.
`TIMER_START` bigint(20) unsigned DEFAULT NULL COMMENT '事件开始时间（皮秒）',
08.
`TIMER_END` bigint(20) unsigned DEFAULT NULL COMMENT '事件结束结束时间（皮秒）',
09.
`TIMER_WAIT` bigint(20) unsigned DEFAULT NULL COMMENT '事件等待时间（皮秒）',
10.
`SPINS` int(10) unsigned DEFAULT NULL COMMENT '',
11.
`OBJECT_SCHEMA` varchar(64) DEFAULT NULL COMMENT '库名',
12.
`OBJECT_NAME` varchar(512) DEFAULT NULL COMMENT '文件名、表名、IP:SOCK值',
13.
`OBJECT_TYPE` varchar(64) DEFAULT NULL COMMENT 'FILE、TABLE、TEMPORARY TABLE',
14.
`INDEX_NAME` varchar(64) DEFAULT NULL COMMENT '索引名',
15.
`OBJECT_INSTANCE_BEGIN` bigint(20) unsigned NOT NULL COMMENT '内存地址',
16.
`NESTING_EVENT_ID` bigint(20) unsigned DEFAULT NULL COMMENT '该事件对应的父事件ID',
17.
`NESTING_EVENT_TYPE` enum('STATEMENT','STAGE','WAIT') DEFAULT NULL COMMENT '父事件类型(STATEMENT, STAGE, WAIT)',
18.
`OPERATION` varchar(32) NOT NULL COMMENT '操作类型（lock, read, write）',
19.
`NUMBER_OF_BYTES` bigint(20) DEFAULT NULL COMMENT '',
20.
`FLAGS` int(10) unsigned DEFAULT NULL COMMENT '标记'
21.
) ENGINE=PERFORMANCE_SCHEMA DEFAULT CHARSET=utf8
四：Stage 表
1，events_stages_current：记录了当前线程所处的执行阶段
2，events_stages_history：记录了当前线程所处的执行阶段10条历史记录
3，events_stages_history_long：记录了当前线程所处的执行阶段10000条历史记录
表结构定义如下：
01.
CREATE TABLE `events_stages_current` (
02.
`THREAD_ID` bigint(20) unsigned NOT NULL COMMENT '线程ID',
03.
`EVENT_ID` bigint(20) unsigned NOT NULL COMMENT '事件ID',
04.
`END_EVENT_ID` bigint(20) unsigned DEFAULT NULL COMMENT '结束事件ID',
05.
`EVENT_NAME` varchar(128) NOT NULL COMMENT '事件名称',
06.
`SOURCE` varchar(64) DEFAULT NULL COMMENT '源码位置',
07.
`TIMER_START` bigint(20) unsigned DEFAULT NULL COMMENT '事件开始时间（皮秒）',
08.
`TIMER_END` bigint(20) unsigned DEFAULT NULL COMMENT '事件结束结束时间（皮秒）',
09.
`TIMER_WAIT` bigint(20) unsigned DEFAULT NULL COMMENT '事件等待时间（皮秒）',
10.
`NESTING_EVENT_ID` bigint(20) unsigned DEFAULT NULL COMMENT '该事件对应的父事件ID',
11.
`NESTING_EVENT_TYPE` enum('STATEMENT','STAGE','WAIT') DEFAULT NULL COMMENT '父事件类型(STATEMENT, STAGE, WAIT)'
12.
) ENGINE=PERFORMANCE_SCHEMA DEFAULT CHARSET=utf8
五：Statement 表
1，events_statements_current：通过 thread_id+event_id可以唯一确定一条记录。Statments表只记录最顶层的请求，SQL语句或是COMMAND，每条语句一行。event_name形式为statement/sql/*，或statement/com/*
2，events_statements_history
3，events_statements_history_long
表结构定义如下：
01.
CREATE TABLE `events_statements_current` (
02.
`THREAD_ID` bigint(20) unsigned NOT NULL COMMENT '线程ID',
03.
`EVENT_ID` bigint(20) unsigned NOT NULL COMMENT '事件ID',
04.
`END_EVENT_ID` bigint(20) unsigned DEFAULT NULL COMMENT '结束事件ID',
05.
`EVENT_NAME` varchar(128) NOT NULL COMMENT '事件名称',
06.
`SOURCE` varchar(64) DEFAULT NULL COMMENT '源码位置',
07.
`TIMER_START` bigint(20) unsigned DEFAULT NULL COMMENT '事件开始时间（皮秒）',
08.
`TIMER_END` bigint(20) unsigned DEFAULT NULL COMMENT '事件结束结束时间（皮秒）',
09.
`TIMER_WAIT` bigint(20) unsigned DEFAULT NULL COMMENT '事件等待时间（皮秒）',
10.
`LOCK_TIME` bigint(20) unsigned NOT NULL COMMENT '锁时间',
11.
`SQL_TEXT` longtext COMMENT '记录SQL语句',
12.
`DIGEST` varchar(32) DEFAULT NULL COMMENT '对SQL_TEXT做MD5产生的32位字符串',
13.
`DIGEST_TEXT` longtext COMMENT '将语句中值部分用问号代替，用于SQL语句归类',
14.
`CURRENT_SCHEMA` varchar(64) DEFAULT NULL COMMENT '默认的数据库名',
15.
`OBJECT_TYPE` varchar(64) DEFAULT NULL COMMENT '保留字段',
16.
`OBJECT_SCHEMA` varchar(64) DEFAULT NULL COMMENT '保留字段',
17.
`OBJECT_NAME` varchar(64) DEFAULT NULL COMMENT '保留字段',
18.
`OBJECT_INSTANCE_BEGIN` bigint(20) unsigned DEFAULT NULL COMMENT '内存地址',
19.
`MYSQL_ERRNO` int(11) DEFAULT NULL COMMENT '',
20.
`RETURNED_SQLSTATE` varchar(5) DEFAULT NULL COMMENT '',
21.
`MESSAGE_TEXT` varchar(128) DEFAULT NULL COMMENT '信息',
22.
`ERRORS` bigint(20) unsigned NOT NULL COMMENT '错误数目',
23.
`WARNINGS` bigint(20) unsigned NOT NULL COMMENT '警告数目',
24.
`ROWS_AFFECTED` bigint(20) unsigned NOT NULL COMMENT '影响的数目',
25.
`ROWS_SENT` bigint(20) unsigned NOT NULL COMMENT '返回的记录数',
26.
`ROWS_EXAMINED` bigint(20) unsigned NOT NULL COMMENT '读取扫描的记录数目',
27.
`CREATED_TMP_DISK_TABLES` bigint(20) unsigned NOT NULL COMMENT '创建磁盘临时表数目',
28.
`CREATED_TMP_TABLES` bigint(20) unsigned NOT NULL COMMENT '创建临时表数目',
29.
`SELECT_FULL_JOIN` bigint(20) unsigned NOT NULL COMMENT 'join时，第一个表为全表扫描的数目',
30.
`SELECT_FULL_RANGE_JOIN` bigint(20) unsigned NOT NULL COMMENT '引用表采用range方式扫描的数目',
31.
`SELECT_RANGE` bigint(20) unsigned NOT NULL COMMENT 'join时，第一个表采用range方式扫描的数目',
32.
`SELECT_RANGE_CHECK` bigint(20) unsigned NOT NULL COMMENT '',
33.
`SELECT_SCAN` bigint(20) unsigned NOT NULL COMMENT 'join时，第一个表位全表扫描的数目',
34.
`SORT_MERGE_PASSES` bigint(20) unsigned NOT NULL COMMENT '',
35.
`SORT_RANGE` bigint(20) unsigned NOT NULL COMMENT '范围排序数目',
36.
`SORT_ROWS` bigint(20) unsigned NOT NULL COMMENT '排序的记录数目',
37.
`SORT_SCAN` bigint(20) unsigned NOT NULL COMMENT '全表排序数目',
38.
`NO_INDEX_USED` bigint(20) unsigned NOT NULL COMMENT '没有使用索引数目',
39.
`NO_GOOD_INDEX_USED` bigint(20) unsigned NOT NULL COMMENT '',
40.
`NESTING_EVENT_ID` bigint(20) unsigned DEFAULT NULL COMMENT '该事件对应的父事件ID',
41.
`NESTING_EVENT_TYPE` enum('STATEMENT','STAGE','WAIT') DEFAULT NULL COMMENT '父事件类型(STATEMENT, STAGE, WAIT)'
42.
) ENGINE=PERFORMANCE_SCHEMA DEFAULT CHARSET=utf8
六：Connection 表
1，users：记录用户连接数信息
2，hosts：记录了主机连接数信息
3，accounts：记录了用户主机连接数信息
01.
zjy@performance_schema 12:03:27>select * from users;
02.
+------------------+---------------------+-------------------+
03.
| USER | CURRENT_CONNECTIONS | TOTAL_CONNECTIONS |
04.
+------------------+---------------------+-------------------+
05.
| debian-sys-maint | 0 | 36 |
06.
| zjy | 1 | 22285 |
07.
| dchat_php | 0 | 37864 |
08.
| dxyslave | 2 | 9 |
09.
| nagios | 0 | 10770 |
10.
| dchat_data | 140 | 2233023 |
11.
| NULL | 0 | 15866 |
12.
| dchat_api | 160 | 2754212 |
13.
| mha_data | 1 | 36 |
14.
| backup | 0 | 15 |
15.
| cacti | 0 | 4312 |
16.
| kol | 10 | 172414 |
17.
+------------------+---------------------+-------------------+
18.
12 rows in set (0.00 sec)
19.
20.
zjy@performance_schema 12:03:34>select * from hosts;
21.
+-----------------+---------------------+-------------------+
22.
| HOST | CURRENT_CONNECTIONS | TOTAL_CONNECTIONS |
23.
+-----------------+---------------------+-------------------+
24.
| 192.168.100.218 | 150 | 2499422 |
25.
| 192.168.100.240 | 10 | 172429 |
26.
| 192.168.100.139 | 0 | 698 |
27.
| 192.168.100.21 | 0 | 2 |
28.
| 192.168.100.220 | 150 | 2526136 |
29.
| 192.168.100.25 | 1 | 7 |
30.
| NULL | 0 | 15867 |
31.
| 192.168.100.241 | 0 | 21558 |
32.
| 192.168.100.191 | 1 | 34 |
33.
| localhost | 0 | 10807 |
34.
| 192.168.100.118 | 1 | 2 |
35.
| 192.168.100.251 | 0 | 4312 |
36.
| 192.168.100.23 | 1 | 31 |
37.
| 192.168.100.193 | 0 | 15 |
38.
+-----------------+---------------------+-------------------+
39.
14 rows in set (0.01 sec)
40.
41.
zjy@performance_schema 12:05:21>select * from accounts;
42.
+------------------+-----------------+---------------------+-------------------+
43.
| USER | HOST | CURRENT_CONNECTIONS | TOTAL_CONNECTIONS |
44.
+------------------+-----------------+---------------------+-------------------+
45.
| cacti | 192.168.100.251 | 0 | 4313 |
46.
| debian-sys-maint | localhost | 0 | 36 |
47.
| backup | 192.168.100.193 | 0 | 15 |
48.
| dchat_api | 192.168.100.220 | 80 | 1382585 |
49.
| dchat_php | 192.168.100.220 | 0 | 20292 |
50.
| zjy | 192.168.100.139 | 0 | 698 |
51.
| zjy | 192.168.100.241 | 0 | 21558 |
52.
| mha_data | 192.168.100.191 | 1 | 34 |
53.
| dxyslave | 192.168.100.118 | 1 | 2 |
54.
| kol | 192.168.100.240 | 10 | 172431 |
55.
| dxyslave | 192.168.100.25 | 1 | 7 |
56.
| dchat_data | 192.168.100.218 | 70 | 1109974 |
57.
| zjy | 192.168.100.23 | 1 | 31 |
58.
| dchat_php | 192.168.100.218 | 0 | 17572 |
59.
| dchat_data | 192.168.100.220 | 70 | 1123306 |
60.
| NULL | NULL | 0 | 15868 |
61.
| mha_data | 192.168.100.21 | 0 | 2 |
62.
| dchat_api | 192.168.100.218 | 80 | 1371918 |
63.
| nagios | localhost | 0 | 10771 |
64.
+------------------+-----------------+---------------------+-------------------+
七：Summary 表： Summary表聚集了各个维度的统计信息包括表维度，索引维度，会话维度，语句维度和锁维度的统计信息
1，events_waits_summary_global_by_event_name：按等待事件类型聚合，每个事件一条记录
1.
CREATE TABLE `events_waits_summary_global_by_event_name` (
2.
`EVENT_NAME` varchar(128) NOT NULL COMMENT '事件名称',
3.
`COUNT_STAR` bigint(20) unsigned NOT NULL COMMENT '事件计数',
4.
`SUM_TIMER_WAIT` bigint(20) unsigned NOT NULL COMMENT '总的等待时间',
5.
`MIN_TIMER_WAIT` bigint(20) unsigned NOT NULL COMMENT '最小等待时间',
6.
`AVG_TIMER_WAIT` bigint(20) unsigned NOT NULL COMMENT '平均等待时间',
7.
`MAX_TIMER_WAIT` bigint(20) unsigned NOT NULL COMMENT '最大等待时间'
8.
) ENGINE=PERFORMANCE_SCHEMA DEFAULT CHARSET=utf8
2，events_waits_summary_by_instance：按等待事件对象聚合，同一种等待事件，可能有多个实例，每个实例有不同的内存地址，因此
event_name+object_instance_begin唯一确定一条记录。
01.
CREATE TABLE `events_waits_summary_by_instance` (
02.
`EVENT_NAME` varchar(128) NOT NULL COMMENT '事件名称',
03.
`OBJECT_INSTANCE_BEGIN` bigint(20) unsigned NOT NULL COMMENT '内存地址',
04.
`COUNT_STAR` bigint(20) unsigned NOT NULL COMMENT '事件计数',
05.
`SUM_TIMER_WAIT` bigint(20) unsigned NOT NULL COMMENT '总的等待时间',
06.
`MIN_TIMER_WAIT` bigint(20) unsigned NOT NULL COMMENT '最小等待时间',
07.
`AVG_TIMER_WAIT` bigint(20) unsigned NOT NULL COMMENT '平均等待时间',
08.
`MAX_TIMER_WAIT` bigint(20) unsigned NOT NULL COMMENT '最大等待时间'
09.
) ENGINE=PERFORMANCE_SCHEMA DEFAULT CHARSET=utf8
3，events_waits_summary_by_thread_by_event_name：按每个线程和事件来统计，thread_id+event_name唯一确定一条记录。
01.
CREATE TABLE `events_waits_summary_by_thread_by_event_name` (
02.
`THREAD_ID` bigint(20) unsigned NOT NULL COMMENT '线程ID',
03.
`EVENT_NAME` varchar(128) NOT NULL COMMENT '事件名称',
04.
`COUNT_STAR` bigint(20) unsigned NOT NULL COMMENT '事件计数',
05.
`SUM_TIMER_WAIT` bigint(20) unsigned NOT NULL COMMENT '总的等待时间',
06.
`MIN_TIMER_WAIT` bigint(20) unsigned NOT NULL COMMENT '最小等待时间',
07.
`AVG_TIMER_WAIT` bigint(20) unsigned NOT NULL COMMENT '平均等待时间',
08.
`MAX_TIMER_WAIT` bigint(20) unsigned NOT NULL COMMENT '最大等待时间'
09.
) ENGINE=PERFORMANCE_SCHEMA DEFAULT CHARSET=utf8
4，events_stages_summary_global_by_event_name：按事件阶段类型聚合，每个事件一条记录，表结构同上。
5，events_stages_summary_by_thread_by_event_name：按每个线程和事件来阶段统计，表结构同上。
6，events_statements_summary_by_digest：按照事件的语句进行聚合。
01.
CREATE TABLE `events_statements_summary_by_digest` (
02.
`SCHEMA_NAME` varchar(64) DEFAULT NULL COMMENT '库名',
03.
`DIGEST` varchar(32) DEFAULT NULL COMMENT '对SQL_TEXT做MD5产生的32位字符串。如果为consumer表中没有打开statement_digest选项，则为NULL',
04.
`DIGEST_TEXT` longtext COMMENT '将语句中值部分用问号代替，用于SQL语句归类。如果为consumer表中没有打开statement_digest选项，则为NULL。',
05.
`COUNT_STAR` bigint(20) unsigned NOT NULL COMMENT '事件计数',
06.
`SUM_TIMER_WAIT` bigint(20) unsigned NOT NULL COMMENT '总的等待时间',
07.
`MIN_TIMER_WAIT` bigint(20) unsigned NOT NULL COMMENT '最小等待时间',
08.
`AVG_TIMER_WAIT` bigint(20) unsigned NOT NULL COMMENT '平均等待时间',
09.
`MAX_TIMER_WAIT` bigint(20) unsigned NOT NULL COMMENT '最大等待时间',
10.
`SUM_LOCK_TIME` bigint(20) unsigned NOT NULL COMMENT '锁时间总时长',
11.
`SUM_ERRORS` bigint(20) unsigned NOT NULL COMMENT '错误数的总',
12.
`SUM_WARNINGS` bigint(20) unsigned NOT NULL COMMENT '警告的总数',
13.
`SUM_ROWS_AFFECTED` bigint(20) unsigned NOT NULL COMMENT '影响的总数目',
14.
`SUM_ROWS_SENT` bigint(20) unsigned NOT NULL COMMENT '返回总数目',
15.
`SUM_ROWS_EXAMINED` bigint(20) unsigned NOT NULL COMMENT '总的扫描的数目',
16.
`SUM_CREATED_TMP_DISK_TABLES` bigint(20) unsigned NOT NULL COMMENT '创建磁盘临时表的总数目',
17.
`SUM_CREATED_TMP_TABLES` bigint(20) unsigned NOT NULL COMMENT '创建临时表的总数目',
18.
`SUM_SELECT_FULL_JOIN` bigint(20) unsigned NOT NULL COMMENT '第一个表全表扫描的总数目',
19.
`SUM_SELECT_FULL_RANGE_JOIN` bigint(20) unsigned NOT NULL COMMENT '总的采用range方式扫描的数目',
20.
`SUM_SELECT_RANGE` bigint(20) unsigned NOT NULL COMMENT '第一个表采用range方式扫描的总数目',
21.
`SUM_SELECT_RANGE_CHECK` bigint(20) unsigned NOT NULL COMMENT '',
22.
`SUM_SELECT_SCAN` bigint(20) unsigned NOT NULL COMMENT '第一个表位全表扫描的总数目',
23.
`SUM_SORT_MERGE_PASSES` bigint(20) unsigned NOT NULL COMMENT '',
24.
`SUM_SORT_RANGE` bigint(20) unsigned NOT NULL COMMENT '范围排序总数',
25.
`SUM_SORT_ROWS` bigint(20) unsigned NOT NULL COMMENT '排序的记录总数目',
26.
`SUM_SORT_SCAN` bigint(20) unsigned NOT NULL COMMENT '第一个表排序扫描总数目',
27.
`SUM_NO_INDEX_USED` bigint(20) unsigned NOT NULL COMMENT '没有使用索引总数',
28.
`SUM_NO_GOOD_INDEX_USED` bigint(20) unsigned NOT NULL COMMENT '',
29.
`FIRST_SEEN` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00' COMMENT '第一次执行时间',
30.
`LAST_SEEN` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00' COMMENT '最后一次执行时间'
31.
) ENGINE=PERFORMANCE_SCHEMA DEFAULT CHARSET=utf8
7，events_statements_summary_global_by_event_name：按照事件的语句进行聚合。表结构同上。
8，events_statements_summary_by_thread_by_event_name：按照线程和事件的语句进行聚合，表结构同上。
9，file_summary_by_instance：按事件类型统计（物理IO维度）
10，file_summary_by_event_name：具体文件统计（物理IO维度）
9和10一起说明：
统计IO操作：COUNT_STAR，SUM_TIMER_WAIT,MIN_TIMER_WAIT,AVG_TIMER_WAIT,MAX_TIMER_WAIT
统计读 ：COUNT_READ,SUM_TIMER_READ,MIN_TIMER_READ,AVG_TIMER_READ,MAX_TIMER_READ, SUM_NUMBER_OF_BYTES_READ
统计写 ：COUNT_WRITE,SUM_TIMER_WRITE,MIN_TIMER_WRITE,AVG_TIMER_WRITE,MAX_TIMER_WRITE, SUM_NUMBER_OF_BYTES_WRITE
统计其他IO事件，比如create，delete，open，close等：COUNT_MISC,SUM_TIMER_MISC,MIN_TIMER_MISC,AVG_TIMER_MISC,MAX_TIMER_MISC
11，table_io_waits_summary_by_table：根据wait/io/table/sql/handler，聚合每个表的I/O操作（逻辑IO纬度）
统计IO操作：COUNT_STAR,SUM_TIMER_WAIT,MIN_TIMER_WAIT,AVG_TIMER_WAIT,MAX_TIMER_WAIT
统计读 ：COUNT_READ,SUM_TIMER_READ,MIN_TIMER_READ,AVG_TIMER_READ,MAX_TIMER_READ
：COUNT_FETCH,SUM_TIMER_FETCH,MIN_TIMER_FETCH,AVG_TIMER_FETCH, MAX_TIMER_FETCH
统计写 ：COUNT_WRITE,SUM_TIMER_WRITE,MIN_TIMER_WRITE,AVG_TIMER_WRITE,MAX_TIMER_WRITE
INSERT统计，相应的还有DELETE和UPDATE统计：COUNT_INSERT,SUM_TIMER_INSERT,MIN_TIMER_INSERT,AVG_TIMER_INSERT,MAX_TIMER_INSERT
12，table_io_waits_summary_by_index_usage：与table_io_waits_summary_by_table类似，按索引维度统计
13，table_lock_waits_summary_by_table：聚合了表锁等待事件，包括internal lock 和 external lock
internal lock通过SQL层函数thr_lock调用，OPERATION值为：
read normal、read with shared locks、read high priority、read no insert、write allow write、write concurrent insert、write delayed、write low priority、write normal
external lock则通过接口函数handler::external_lock调用存储引擎层，OPERATION列的值为：read external、write external
14，Connection Summaries表：account、user、host
events_waits_summary_by_account_by_event_name
events_waits_summary_by_user_by_event_name
events_waits_summary_by_host_by_event_name
events_stages_summary_by_account_by_event_name
events_stages_summary_by_user_by_event_name
events_stages_summary_by_host_by_event_name
events_statements_summary_by_account_by_event_name
events_statements_summary_by_user_by_event_name
events_statements_summary_by_host_by_event_name
15，socket_summary_by_instance、socket_summary_by_event_name：socket聚合统计表。
八：其他相关表
1，performance_timers：系统支持的统计时间单位
2，threads：监视服务端的当前运行的线程
统计应用：
关于SQL维度的统计信息主要集中在events_statements_summary_by_digest表中，通过将SQL语句抽象出digest，可以统计某类SQL语句在各个维度的统计信息
1，哪个SQL执行最多：
01.
zjy@performance_schema 11:36:22>SELECT SCHEMA_NAME,DIGEST_TEXT,COUNT_STAR,SUM_ROWS_SENT,SUM_ROWS_EXAMINED,FIRST_SEEN,LAST_SEEN FROM events_statements_summary_by_digest ORDER BY COUNT_STAR desc LIMIT 1G
02.
*************************** 1. row ***************************
03.
SCHEMA_NAME: dchat
04.
DIGEST_TEXT: SELECT ...
05.
COUNT_STAR: 1161210102
06.
SUM_ROWS_SENT: 1161207842
07.
SUM_ROWS_EXAMINED: 008.
FIRST_SEEN: 2016-02-17 00:36:4609.
LAST_SEEN: 2016-03-07 11:36:29
各个字段的注释可以看上面的表结构说明：从2月17号到3月7号该SQL执行了1161210102次。
2，哪个SQL平均响应时间最多：
01.
zjy@performance_schema 11:36:28>SELECT SCHEMA_NAME,DIGEST_TEXT,COUNT_STAR,AVG_TIMER_WAIT,SUM_ROWS_SENT,SUM_ROWS_EXAMINED,FIRST_SEEN,LAST_SEEN FROM events_statements_summary_by_digest ORDER BY AVG_TIMER_WAIT desc LIMIT 1G
02.
*************************** 1. row ***************************
03.
SCHEMA_NAME: dchat
04.
DIGEST_TEXT: SELECT ...
05.
COUNT_STAR: 106.
AVG_TIMER_WAIT: 273238183964000
07.
SUM_ROWS_SENT: 50208
08.
SUM_ROWS_EXAMINED: 556565109.
FIRST_SEEN: 2016-02-22 13:27:3310.
LAST_SEEN: 2016-02-22 13:27:33
各个字段的注释可以看上面的表结构说明：从2月17号到3月7号该SQL平均响应时间273238183964000皮秒（1000000000000皮秒=1秒）
3，哪个SQL扫描的行数最多：
SUM_ROWS_EXAMINED
4，哪个SQL使用的临时表最多：
SUM_CREATED_TMP_DISK_TABLES、SUM_CREATED_TMP_TABLES
5，哪个SQL返回的结果集最多：
SUM_ROWS_SENT
6，哪个SQL排序数最多：
SUM_SORT_ROWS
通过上述指标我们可以间接获得某类SQL的逻辑IO(SUM_ROWS_EXAMINED)，CPU消耗(SUM_SORT_ROWS)，网络带宽(SUM_ROWS_SENT)的对比。
通过file_summary_by_instance表，可以获得系统运行到现在，哪个文件(表)物理IO最多，这可能意味着这个表经常需要访问磁盘IO。
7，哪个表、文件逻辑IO最多（热数据）：
01.
zjy@performance_schema 12:16:18>SELECT FILE_NAME,EVENT_NAME,COUNT_READ,SUM_NUMBER_OF_BYTES_READ,COUNT_WRITE,SUM_NUMBER_OF_BYTES_WRITE FROM file_summary_by_instance ORDER BY SUM_NUMBER_OF_BYTES_READ+SUM_NUMBER_OF_BYTES_WRITE DESC LIMIT 2G
02.
*************************** 1. row ***************************
03.
FILE_NAME: /var/lib/mysql/ibdata1 #文件
04.
EVENT_NAME: wait/io/file/innodb/innodb_data_file
05.
COUNT_READ: 544
06.
SUM_NUMBER_OF_BYTES_READ: 10977280
07.
COUNT_WRITE: 3700729
08.
SUM_NUMBER_OF_BYTES_WRITE: 1433734217728
09.
*************************** 2. row ***************************
10.
FILE_NAME: /var/lib/mysql/dchat/fans.ibd #表
11.
EVENT_NAME: wait/io/file/innodb/innodb_data_file
12.
COUNT_READ: 9370680
13.
SUM_NUMBER_OF_BYTES_READ: 153529188352
14.
COUNT_WRITE: 67576376
15.
SUM_NUMBER_OF_BYTES_WRITE: 1107815432192
8，哪个索引使用最多：
1.
zjy@performance_schema 12:18:42>SELECT OBJECT_NAME, INDEX_NAME, COUNT_FETCH, COUNT_INSERT, COUNT_UPDATE, COUNT_DELETE FROM table_io_waits_summary_by_index_usage ORDER BY SUM_TIMER_WAIT DESC limit 1;
2.
+-------------+------------+-------------+--------------+--------------+--------------+
3.
| OBJECT_NAME | INDEX_NAME | COUNT_FETCH | COUNT_INSERT | COUNT_UPDATE | COUNT_DELETE |
4.
+-------------+------------+-------------+--------------+--------------+--------------+
5.
| fans | PRIMARY | 29002695158 | 0| 296373434 | 0 |
6.
+-------------+------------+-------------+--------------+--------------+--------------+
7.
1 row in set (0.29 sec)
通过table_io_waits_summary_by_index_usage表，可以获得系统运行到现在，哪个表的具体哪个索引(包括主键索引，二级索引)使用最多。
9，哪个索引没有使用过：
1.
zjy@performance_schema 12:23:22>SELECT OBJECT_SCHEMA, OBJECT_NAME, INDEX_NAME FROM table_io_waits_summary_by_index_usage WHERE INDEX_NAME IS NOT NULL AND COUNT_STAR = 0 AND OBJECT_SCHEMA <> 'mysql' ORDER BY OBJECT_SCHEMA,OBJECT_NAME;
10，哪个等待事件消耗的时间最多：
1.
zjy@performance_schema 12:25:22>SELECT EVENT_NAME, COUNT_STAR, SUM_TIMER_WAIT, AVG_TIMER_WAIT FROM events_waits_summary_global_by_event_name WHERE event_name != 'idle'ORDER BY SUM_TIMER_WAIT DESC LIMIT 1;
11，类似profiling功能：
分析具体某条SQL，该SQL在执行各个阶段的时间消耗，通过events_statements_xxx表和events_stages_xxx表，就可以达到目的。两个表通过event_id与nesting_event_id关联，stages表的nesting_event_id为对应statements表的event_id；针对每个stage可能出现的锁等待，一个stage会对应一个或多个wait，通过stage_xxx表的event_id字段与waits_xxx表的nesting_event_id进行关联。如：
001.
比如分析包含count(*)的某条SQL语句，具体如下：
002.
003.
SELECT
004.
EVENT_ID,
005.
sql_text
006.
FROM events_statements_history
007.
WHERE sql_text LIKE '%count(*)%';
008.
+----------+--------------------------------------+
009.
| EVENT_ID | sql_text |
010.
+----------+--------------------------------------+
011.
| 1690 | select count(*) from chuck.test_slow |
012.
+----------+--------------------------------------+
013.
首先得到了语句的event_id为1690，通过查找events_stages_xxx中nesting_event_id为1690的记录，可以达到目的。
014.
015.
a.查看每个阶段的时间消耗：
016.
SELECT
017.
event_id,
018.
EVENT_NAME,
019.
SOURCE,
020.
TIMER_END - TIMER_START
021.
FROM events_stages_history_long
022.
WHERE NESTING_EVENT_ID = 1690;
023.
+----------+--------------------------------+----------------------+-----------------------+
024.
| event_id | EVENT_NAME | SOURCE | TIMER_END-TIMER_START |
025.
+----------+--------------------------------+----------------------+-----------------------+
026.
| 1691 | stage/sql/init | mysqld.cc:990 | 316945000 |
027.
| 1693 | stage/sql/checking permissions | sql_parse.cc:5776 | 26774000 |
028.
| 1695 | stage/sql/Opening tables | sql_base.cc:4970 | 41436934000 |
029.
| 2638 | stage/sql/init | sql_select.cc:1050 | 85757000 |
030.
| 2639 | stage/sql/System lock | lock.cc:303 | 40017000 |
031.
| 2643 | stage/sql/optimizing | sql_optimizer.cc:138 | 38562000 |
032.
| 2644 | stage/sql/statistics | sql_optimizer.cc:362 | 52845000 |
033.
| 2645 | stage/sql/preparing | sql_optimizer.cc:485 | 53196000 |
034.
| 2646 | stage/sql/executing | sql_executor.cc:112 | 3153000 |
035.
| 2647 | stage/sql/Sending data | sql_executor.cc:192 | 7369072089000 |
036.
| 4304138 | stage/sql/end | sql_select.cc:1105 | 19920000 |
037.
| 4304139 | stage/sql/query end | sql_parse.cc:5463 | 44721000 |
038.
| 4304145 | stage/sql/closing tables | sql_parse.cc:5524 | 61723000 |
039.
| 4304152 | stage/sql/freeing items | sql_parse.cc:6838 | 455678000 |
040.
| 4304155 | stage/sql/logging slow query | sql_parse.cc:2258 | 83348000 |
041.
| 4304159 | stage/sql/cleaning up | sql_parse.cc:2163 | 4433000 |
042.
+----------+--------------------------------+----------------------+-----------------------+
043.
通过间接关联，我们能分析得到SQL语句在每个阶段的时间消耗，时间单位以皮秒表示。这里展示的结果很类似profiling功能，有了performance schema，就不再需要profiling这个功能了。另外需要注意的是，由于默认情况下events_stages_history表中只为每个连接记录了最近10条记录，为了确保获取所有记录，需要访问events_stages_history_long表
044.
045.
b.查看某个阶段的锁等待情况
046.