高性能MYSQL ------- 查询阻塞语句以及锁

MYSQL 服务器逻辑架构图

连接/线程处理 == 》 （解析器 –> 查询缓存） ===》 优化器 ===》 存储引擎

服务器级别锁

MYSQL 使用的锁类型：
表锁（显式:LOCK TABLE，隐式）
全局锁（read_only=1,FLUSH TABLE WITH READ LOCK）
命名锁 ：服务器重命名或者删除一个表时创建。重命名可能会影响到触发器相关的表
字符锁

LOCK TABLES film READ;
LOCK TABLES film WRITE;

查看那些线程持有并阻塞查询的表锁。 SHOW PROCESSLIST;
state
LOCKED 表锁
WAITING for release of readlock 全局锁
Wating for table 命名锁
user Lock 用户锁 ：SELECT GET_LOCK(‘my lock’, 100);

存储引擎中的锁

InnoDB中的锁

• 查看InnoDb锁信息————-（5.1以下）SHOW INNODB STATUS; 更高 版本show engine innodb status\G;
• 查看INFROMATION_SCHEMA表中 INNODB_LOCKS表，5.5版本以上默认安装，5.1中可能会没有

INFROMATION_SCHEMA来查询mysql使用情况

• 使用information_schema 来查询哪条sql阻塞，谁在等待方法 转自 http://blog.csdn.net/yabingshi_tech/article/details/46562985
• SELECT
p2.HOSTBlockedhost,
p2.USERBlockedUser,
r.trx_id BlockedTrxId,
r.trx_mysql_thread_id BlockedThreadId,
TIMESTAMPDIFF(
SECOND,
r.trx_wait_started,
CURRENT_TIMESTAMP
) WaitTime,
r.trx_query BlockedQuery,
l.lock_table BlockedTable,
m.lock_modeBlockedLockMode,
m.lock_typeBlockedLockType,
m.lock_indexBlockedLockIndex,
m.lock_spaceBlockedLockSpace,
m.lock_page BlockedLockPage,
m.lock_rec BlockedLockRec,
m.lock_data BlockedLockData,
p.HOSTblocking_host,
p.USERblocking_user,
b.trx_id BlockingTrxid,
b.trx_mysql_thread_id BlockingThreadId,
b.trx_query BlockingQuery,
l.lock_modeBlockingLockMode,
l.lock_typeBlockingLockType,
l.lock_indexBlockingLockIndex,
l.lock_spaceBlockingLockSpace,
l.lock_page BlockingLockPage,
l.lock_rec BlockingLockRec,
l.lock_data BlockingLockData,
IF (p.COMMAND = 'Sleep', CONCAT(p.TIME,' seconds'), 0) idel_in_trx
FROM
information_schema.INNODB_LOCK_WAITS w
INNER JOIN information_schema.INNODB_TRX b ON b.trx_id = w.blocking_trx_id
INNER JOIN information_schema.INNODB_TRX r ON r.trx_id = w.requesting_trx_id
INNER JOIN information_schema.INNODB_LOCKS l ON w.blocking_lock_id = l.lock_id AND l.lock_trx_id=b.trx_id
INNER JOIN information_schema.INNODB_LOCKS m ON m.lock_id=w.requested_lock_idAND m.lock_trx_id=r.trx_id
INNER JOIN information_schema. PROCESSLIST p ON p.ID = b.trx_mysql_thread_id
INNER JOIN information_schema. PROCESSLIST p2 ON p2.ID = r.trx_mysql_thread_id
ORDER BY
WaitTime DESC \G;
• *************************** 1. row ***************************
被阻塞方host: 10.192.203.9:54401
被阻塞方用户: root
被阻塞方事务id: 2844
被阻塞方线程号: 312
等待时间: 6
被阻塞的查询: update eip.t_offer_instanceset description='jiao' where id = 431
阻塞方锁住的表:eip.t_offer_instance
被阻塞方的锁模式: X
被阻塞方的锁类型(表锁还是行锁): RECORD
被阻塞方锁住的索引:PRIMARY
被阻塞方锁对象的space_id: 62
被阻塞方事务锁定页的数量: 7
被阻塞方事务锁定行的数量: 116
被阻塞方事务锁定记录的主键值: 431
阻塞方主机: 10.192.203.9:54392
阻塞方用户: root
阻塞方事务id: 2841
阻塞方线程号: 310
阻塞方查询: NULL
阻塞方的锁模式: X
阻塞方的锁类型(表锁还是行锁): RECORD
阻塞方锁住的索引:PRIMARY
阻塞方锁对象的space_id: 62
阻塞方事务锁定页的数量: 7
阻塞方事务锁定行的数量: 116
阻塞方事务锁定记录的主键值: 431
阻塞方事务空闲的时间: 19 秒

复制这个代码执行的时候报错：
[Err] 3167 - The ‘INFORMATION_SCHEMA.GLOBAL_STATUS’ feature is disabled; see the documentation for ‘show_compatibility_56’
5.7提供了show_compatibility_56参数，设置为ON可以兼容5.7之前的用法，否则就会报上面的错。

执行   set global show_compatibility_56=on; 
      show variables like '%show_compatibility_56%';
+-----------------------+-------+
| Variable_name         | Value |
+-----------------------+-------+
| show_compatibility_56 | ON    |
+-----------------------+-------+

再次执行不会报错了~~ ( : 嘿嘿~

1分钟内产生binlog大小计算

select @a1:=VARIABLE_VALUE as a1
from information_schema.GLOBAL_STATUS
where VARIABLE_NAME=’innodb_os_log_written’
union all
select sleep(60)
union all
select @a2:=VARIABLE_VALUE as a2
from information_schema.GLOBAL_STATUS
where VARIABLE_NAME=’innodb_os_log_written’;

select round((@a2-@a1)/1024/1024/@@innodb_log_files_in_group) as MB;

查看某段时间以来未关闭事务：
select
trx_id,
trx_started,
trx_mysql_thread_id
from
information_schema.innodb_trx
where
trx_started < date_sub(now(), interval 1 minute)
and trx_operation_state is null
and trx_query is null;

查看事务等待状况：
select
r.trx_id waiting_trx_id,
r.trx_mysql_thread_id waiting_thread,
r.trx_query waiting_query,
b.trx_id blocking_trx_id,
b.trx_mysql_thread_id blocking_thread,
b.trx_query blocking_query
from
information_schema.innodb_lock_waits w
inner join information_schema.innodb_trx b on b.trx_id = w.blocking_trx_id
inner join information_schema.innodb_trx r on r.trx_id = w.requesting_trx_id;

查看更具体的事务等待状况：
select
b.trx_state,
e.state,
e.time,
d.state as block_state,
d.time as block_time,
a.requesting_trx_id,
a.requested_lock_id,
b.trx_query,
b.trx_mysql_thread_id,
a.blocking_trx_id,
a.blocking_lock_id,
c.trx_query as block_trx_query,
c.trx_mysql_thread_id as block_trx_mysql_tread_id
from
information_schema.innodb_lock_waits a
left join information_schema.innodb_trx b on a.requesting_trx_id = b.trx_id
left join information_schema.innodb_trx c on a.blocking_trx_id = c.trx_id
left join information_schema.processlist d on c.trx_mysql_thread_id = d.id
left join information_schema.processlist e on b.trx_mysql_thread_id = e.id
order by
a.requesting_trx_id;

查看未关闭的事务：
–mysql 5.6
select
a.trx_id,
a.trx_state,
a.trx_started,
a.trx_query,
b.id,
b.user,
b.db,
b.command,
b.time,
b.state,
b.info,
c.processlist_user,
c.processlist_host,
c.processlist_db,
d.sql_text
from
information_schema.innodb_trx a
left join information_schema.processlist b on a.trx_mysql_thread_id = b.id
and b.command = ‘sleep’
left join performance_schema.threads c on b.id = c.processlist_id
left join performance_schema.events_statements_current d on d.thread_id = c.thread_id;

–mysql 5.5(别人写的，我在5.7里面测了也可以用)
select
a.trx_id,
a.trx_state,
a.trx_started,
a.trx_query,
b.id,
b. user,
b. host,
b.db,
b.command,
b.time,
b.state,
b.info
from
information_schema.innodb_trx a
left join information_schema.processlist b on a.trx_mysql_thread_id = b.id
where
b.command = ‘sleep’;