小编给大家分享一下mysql中怎么利用performance_schema进行故障诊断，希望大家阅读完这篇文章之后都有所收获，下面让我们一起去探讨吧！
instrunments:生产者，用于采集mysql中各种操作产生的事件信息，对应配置表中的配置项，我们可以称之为采集配置项。
consumers:消费者，对应的消费者用于存储来自instruments采集的数据，对应配置表的配置项，我们可以称之为消费存储配置项。
启用所有等待事件的instruments:
use performance_schema
update setup_instruments set enabled='yes',timed='yes' where name like 'wait/%';
select * from setup_instruments where name like 'wait/%';
启用等待事件的consumers
update setup_consumers set enabled='yes' where name like '%wait%';
select * from setup_consumers where name like '%wait%';
实时统计当前等待事件：
create view sys.test_waits as select sum(timer_wait) as timer_wait ,sum(number_of_bytes) as number_of_bytes,event_name,operation from events_waits_current where event_name !='idle' group by event_name,operation;
select sys.format_time(timer_wait),sys.format_bytes(number_of_bytes),event_name,operation from sys.test_waits where sys.format_time(timer_wait) not regexp 'ns|us' order by timer_wait desc;
select thread_id,event_name,sys.format_time(timer_wait),index_name,nesting_event_type,operation,number_of_bytes from events_waits_current where event_name !='idle' order by timer_wait desc;
找出谁持有全局读锁：
通过performance_schema.metadata_locks 表来排查谁持有全局读锁，全局读锁在该表中通常记录着同一个会话的object_type为global和commit、lock_type都为shared的两把显式锁, LOCK_TYPE: INTENTION_EXCLUSIVE 意向排他锁
select * from performance_schema.metadata_locks where owner_thread_id!=sys.ps_thread_id(connection_id())\G;
找出OWNER_THREAD_ID为内部线程id,可以查询threads表找出对应会话id：
select * from performance_schema.threads where THREAD_ID in (31,30)\G;
*************************** 1. row ***************************
OBJECT_TYPE: GLOBAL
OBJECT_SCHEMA: NULL
OBJECT_NAME: NULL
OBJECT_INSTANCE_BEGIN: 140514110025712
LOCK_TYPE: SHARED
LOCK_DURATION: EXPLICIT
LOCK_STATUS: GRANTED
SOURCE: lock.cc:1110
OWNER_THREAD_ID: 31 持有锁的内部线程id为31
OWNER_EVENT_ID: 43
*************************** 2. row ***************************
OBJECT_TYPE: COMMIT
OBJECT_SCHEMA: NULL
OBJECT_NAME: NULL
OBJECT_INSTANCE_BEGIN: 140514110303360
LOCK_TYPE: SHARED
LOCK_DURATION: EXPLICIT
LOCK_STATUS: GRANTED
SOURCE: lock.cc:1194
OWNER_THREAD_ID: 31 持有锁的内部线程id为31
OWNER_EVENT_ID: 97
*************************** 3. row ***************************
OBJECT_TYPE: GLOBAL
OBJECT_SCHEMA: NULL
OBJECT_NAME: NULL
OBJECT_INSTANCE_BEGIN: 140514110036384
LOCK_TYPE: INTENTION_EXCLUSIVE n意向排他锁
LOCK_DURATION: STATEMENT
LOCK_STATUS: PENDING 状态为pending，表示正在等待被授权
SOURCE: sql_base.cc:3190
OWNER_THREAD_ID: 30 被阻塞
OWNER_EVENT_ID: 2507
3 rows in set (0.04 sec)
找出谁持有MDL锁：
一个shared_write锁处于granted状态，其余是shared_upgradable、execlusive锁，shared_upgradable处于granted状态，exclusive处于pending状态
select * from performance_schema.metadata_locks where owner_thread_id!=sys.ps_thread_id(connection_id())\G;
通过information_schema.innodb_trx表确认源阻塞线程是否存在一个没有提交的事务：
select * from information_schema.innodb_trx\G;
通过performance_schema.events_statements_current来查询某个线程正在执行或者最后一次执行完成的语句事件信息：
select * from performance_schema.events_statements_current where thread_id=11\G;
找出谁持有表级锁：
找出持有表READ EXTERNAL表级锁的内部线程id
select * from performance_schema.table_handles where owner_thread_id!=0\G;
找出线程正在执行什么sql:
select * from performance_schema.events_statements_current where thread_id=30\G;
找出processlist_id来进行kill
select * from performance_schema.threads where THREAD_ID =30\G;
找出谁持有行级锁：
mysql8
select * from performance_schema.data_locks\G;
mysql 5.7
select * from sys.innodb_lock_waits\G;
查询最近的topsql语句：
select thread_id,event_name,source,sys.format_time(timer_wait),sys.format_time(lock_time),sql_text,current_schema,message_text,rows_affected,rows_sent,rows_examined from performance_schema.events_statements_history where current_schema!='performance_schema' order by timer_wait desc limit 10\G;
统计后sql:
select schema_name,digest_text,COUNT_STAR,sys.format_time(sum_timer_wait) as sum_time,sys.format_time(min_timer_wait) as min_time,sys.format_time(avg_timer_wait) as avg_time,sys.format_time(max_timer_wait) as max_time,sys.format_time(sum_lock_time) as sum_lock_time,sum_rows_affected,sum_rows_sent,sum_rows_examined from performance_schema.events_statements_summary_by_digest where schema_name is not null order by count_star desc limit 10\G;
查看最近执行失败的sql语句：
select thread_id,event_name,source,sys.format_time(timer_wait) as exec_time, sys.format_time(lock_time) as lock_time,sql_text,current_schema,message_text,rows_affected,rows_sent,rows_examined ,mysql_errno from performance_schema.events_statements_history where mysql_errno=1064\G;
select thread_id,event_name,source,sys.format_time(timer_wait) as exec_time, sys.format_time(lock_time) as lock_time,sql_text,current_schema,message_text,rows_affected,rows_sent,rows_examined ,mysql_errno ,errors from performance_schema.events_statements_history where errors>0\G;
select schema_name,digest_text,COUNT_STAR,sys.format_time(sum_timer_wait) as sum_time,sys.format_time(min_timer_wait) as min_time,sys.format_time(avg_timer_wait) as avg_time,sys.format_time(max_timer_wait) as max_time,sys.format_time(sum_lock_time) as sum_lock_time,sum_errors,first_seen,last_seen from performance_schema.events_statements_summary_by_digest where sum_errors!=0\G;
查看sql语句执行阶段和进度信息：
use performance_schema
update setup_instruments set enabled='yes',timed='yes' where name like 'stage/%';
update setup_consumers set enabled='yes' where name like '%stage%';
查看语句执行全过程以及每个过程时间开销等。
select thread_id,event_name,source,sys.format_time(timer_wait) as exec_time,work_completed,work_estimated from performance_schema.events_stages_history_long;
查看sql语句执行进度信息：
select * from sys.session where conn_id!=connection_id()\G;
查询最近的事务执行信息：
use performance_schema
update setup_instruments set enabled='yes',timed='yes' where name like 'transaction%';
update setup_consumers set enabled='yes' where name like '%transaction%';
select thread_id,event_name,state,trx_id,gtid,source,timer_wait,access_mode,isolation_level,autocommit,nesting_event_id,nesting_event_type from performance_schema.events_transactions_current\G;
select thread_id,event_name,state,trx_id,gtid,source,timer_wait,access_mode,isolation_level,autocommit,nesting_event_id,nesting_event_type from performance_schema.events_transactions_history_long\G;
查询多线程复制报错详情：
show slave status\G;
select * from performance_schema.replication_applier_status_by_worker where last_error_message!=''\G
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