mysql8定位被锁语句

线上mysql版本为8.0.11，对于最近的几个版本越来越像Orale了，有了较为丰富的系统字典，也可以查看系统的等待事件，现在线上出现被锁语句的情况也可以通过数据字典直接查询出来了，在此记录下以供参考。

首先查看系统锁情况，下面这条语句可以看到持有锁的线程以及线程ID，这里需要注意下，session_id也就是show processlist查询出来的链接ID，在这个表里表现为PID，同时该表也记录了trx_id，最后还给出了解决方案也就是如何kill持有锁的进程。

mysql> SELECT * FROM sys.`innodb_lock_waits` \G
*************************** 1. row ***************************
                wait_started: 2019-01-28 14:27:03
                    wait_age: 00:00:03
               wait_age_secs: 3
                locked_table: `test`.`t`
         locked_table_schema: test
           locked_table_name: t
      locked_table_partition: NULL
   locked_table_subpartition: NULL
                locked_index: GEN_CLUST_INDEX
                 locked_type: RECORD
              waiting_trx_id: 19758723
         waiting_trx_started: 2019-01-28 14:27:03
             waiting_trx_age: 00:00:03
     waiting_trx_rows_locked: 1
   waiting_trx_rows_modified: 0
                 waiting_pid: 4202
               waiting_query: update t set id=8
             waiting_lock_id: 19758723:4998:4:2
           waiting_lock_mode: X
             blocking_trx_id: 19748728
                blocking_pid: 4200
              blocking_query: NULL
            blocking_lock_id: 19748728:4998:4:2
          blocking_lock_mode: X
        blocking_trx_started: 2019-01-28 10:58:27
            blocking_trx_age: 03:28:39
    blocking_trx_rows_locked: 2
  blocking_trx_rows_modified: 1
     sql_kill_blocking_query: KILL QUERY 4200
sql_kill_blocking_connection: KILL 4200
1 row in set (0.02 sec

查看当前被锁的语句

##等待锁的语句
SELECT * FROM performance_schema.events_statements_history WHERE thread_id IN(
SELECT b.`THREAD_ID` FROM sys.`innodb_lock_waits` AS a , performance_schema.threads AS b
WHERE a.waiting_pid = b.`PROCESSLIST_ID`)
ORDER BY timer_start ASC;

mysql8定位被锁语句

查看持有锁的语句可以通过如下方式

##持有锁的语句
SELECT * FROM performance_schema.events_statements_history WHERE thread_id IN(
SELECT b.`THREAD_ID` FROM sys.`innodb_lock_waits` AS a , performance_schema.threads AS b
WHERE a.`blocking_pid` = b.`PROCESSLIST_ID`)
ORDER BY timer_start ASC;

mysql8定位被锁语句