MySQL锁等待分析【2】

时间:2023-03-08 22:56:42
MySQL锁等待分析【2】

MySQL锁等待分析【1】中对锁等待的分析是一步一步来的、虽然最后是分析出来了,可是用时是比较长的;理清各个表之间的关系后,得到如下SQL语句,方便以后使用

select
block_trx.trx_mysql_thread_id as blocking_session_id, -- 已经持有锁的session ID
request_trx.trx_mysql_thread_id as request_session_id, -- 正在申请锁的session ID
block_trx.trx_query as blocking_sql_text, -- 已经持有锁的SQL语句
request_trx.trx_query as requesting_sql_text, -- 正在申请锁的SQL语句
waits.blocking_trx_id as blocking_trx_id, -- 已经持有锁的事务ID
waits.requesting_trx_id as requesting_trx_id, -- 正在申请锁的事务ID
waits.requested_lock_id as requested_lock_id, -- 锁对象的ID
locks.lock_table as lock_table, -- 锁对象所锁定的表
locks.lock_type as lock_type, -- 锁类型
locks.lock_mode as lock_mode -- 锁模式
from information_schema.innodb_lock_waits as waits
inner join information_schema.innodb_trx as block_trx
on waits.blocking_trx_id=block_trx.trx_id
inner join information_schema.innodb_trx as request_trx
on waits.requesting_trx_id=request_trx.trx_id
inner join information_schema.innodb_locks as locks
on waits.requested_lock_id=locks.lock_id;
+---------------------+--------------------+-------------------+-----------------------------------+-----------------+-------------------+-------------------+--------------+-----------+-----------+
| blocking_session_id | request_session_id | blocking_sql_text | requesting_sql_text | blocking_trx_id | requesting_trx_id | requested_lock_id | lock_table | lock_type | lock_mode |
+---------------------+--------------------+-------------------+-----------------------------------+-----------------+-------------------+-------------------+--------------+-----------+-----------+
| | | NULL | select * from tempdb.t for update | | | ::: | `tempdb`.`t` | RECORD | X |
| | | NULL | insert into t(x) values() | | | ::: | `tempdb`.`t` | RECORD | X |
+---------------------+--------------------+-------------------+-----------------------------------+-----------------+-------------------+-------------------+--------------+-----------+-----------+