等待的线程首先将自己想要获取的 ticket 加入到 MDL_lock 的 m_waiting 队列,然后根据配置的等待时间调用 MDL_wait 的函数进行超时等待: /** Wait for the status to be assigned to this wait slot. */ MDL_wait::enum_wait_status MDL_wait::timed_wait( MDL_context_owner *owner, struct timespec *ab...
/*innodb 行锁等待脚本*/SELECTr.trx_mysql_thread_id waiting_thread,r.trx_query waiting_query,concat(timestampdiff(SECOND,r.trx_wait_started,CURRENT_TIMESTAMP()),'s')ASduration,b.trx_mysql_thread_id blocking_thread,t.processlist_command state,b.trx_query blocking_current_query,e.sql_text bl...
/*开启performance_schema相关监控项,需要提前开启performance_schema*/ UPDATE performance_schema.setup_instruments SET ENABLED = 'YES', TIMED = 'YES' where name = 'transaction'; UPDATE performance_schema.setup_consumers SET ENABLED = 'YES' where name like '%events_transactions%'; UPDATE performance_...
1./*innodb 行锁等待脚本*/ 2.SELECT r.trx_mysql_thread_id waiting_thread,r.trx_query waiting_query, 3.concat(timestampdiff(SECOND,r.trx_wait_started,CURRENT_TIMESTAMP()),'s') AS duration, 4.b.trx_mysql_thread_id blocking_thread,t.processlist_command state,b.trx_query blocking_current_...
SELECT r.trx_mysql_thread_id waiting_thread,r.trx_query waiting_query, concat(timestampdiff(SECOND,r.trx_wait_started,CURRENT_TIMESTAMP()),'s') AS duration, b.trx_mysql_thread_id blocking_thread,t.processlist_command state,b.trx_query blocking_current_query,e.sql_text blocking_last_query...
是指在与MySQL数据库建立连接或执行查询操作时,由于连接超时时间设置不合理或网络延迟等原因导致无法成功访问数据库而产生的错误。 MySQL是一种开源的关系型数据库管理系统,被广泛应用于各种Web应用和服务器端开发中。在使用MySQL时,由于网络环境或数据库服务器负载等原因,可能会出现访问超时错误。
/*innodb 行锁等待脚本*/SELECT r.trx_mysql_thread_id waiting_thread,r.trx_query waiting_query,concat(timestampdiff(SECOND,r.trx_wait_started,CURRENT_TIMESTAMP()),'s') AS duration,b.trx_mysql_thread_id blocking_thread,t.processlist_command state,b.trx_query blocking_current_query,e.sql_tex...
/*innodb 行锁等待脚本*/SELECT r.trx_mysql_thread_id waiting_thread,r.trx_query waiting_query,concat(timestampdiff(SECOND,r.trx_wait_started,CURRENT_TIMESTAMP()),'s') AS duration,b.trx_mysql_thread_id blocking_thread,t.processlist_command state,b.trx_query blocking_current_query,e.sql_tex...
SELECT r.trx_mysql_thread_id waiting_thread,r.trx_query waiting_query, concat(timestampdiff(SECOND,r.trx_wait_started,CURRENT_TIMESTAMP()),'s') AS duration, b.trx_mysql_thread_id blocking_thread,t.processlist_command state,b.trx_query blocking_current_query,e.sql_text blocking_last_query...
第4步与第5步之间,所有的访问该表的会话都处于“waiting for table flush”状态,唯有大查询结束后,等待状态才能解除。 主备切换场景 在生产环境中,为了容灾一般mysql服务都由主备库组成,当主库出现问题时,可以切换到备库运行,保证服务的高可用。在这个过程中有一点很重要,避免双写。因为导致切换的场景有很多,可能...