mysql死锁

1. 查看正在进行中的事务

SELECT * FROM information_schema.INNODB_TRX;

mysql> SELECT * FROM information_schema.INNODB_TRX \G;
*************************** 1. row ***************************
                    trx_id: 331123705
                 trx_state: RUNNING
               trx_started: 2022-07-19 13:47:12
     trx_requested_lock_id: NULL
          trx_wait_started: NULL
                trx_weight: 0
       trx_mysql_thread_id: 11355
                 trx_query: NULL
       trx_operation_state: NULL
         trx_tables_in_use: 0
         trx_tables_locked: 0
          trx_lock_structs: 0
     trx_lock_memory_bytes: 360
           trx_rows_locked: 0
         trx_rows_modified: 0
   trx_concurrency_tickets: 0
       trx_isolation_level: REPEATABLE READ
         trx_unique_checks: 1
    trx_foreign_key_checks: 1
trx_last_foreign_key_error: NULL
 trx_adaptive_hash_latched: 0
 trx_adaptive_hash_timeout: 10000
          trx_is_read_only: 0
trx_autocommit_non_locking: 0
*************************** 2. row ***************************
                    trx_id: 331123681
                 trx_state: RUNNING
               trx_started: 2022-07-19 13:47:09
     trx_requested_lock_id: NULL
          trx_wait_started: NULL
                trx_weight: 397
       trx_mysql_thread_id: 11409
                 trx_query: update sys_role_user ru
                          inner join sys_role r on ru.client_role_id = r.client_role_id
                          inner join sys_user_center uc on ru.client_user_id = uc.id
        set ru.role_id = r.id, ru.open_id = uc.open_id
        where (ru.role_id is null or ru.open_id is null)  and ru.update_time >= '2022-07-19 13:47:09'
            and ru.client_id = 'webApp' and ru.`enable` = '1000102'
       trx_operation_state: fetching rows
         trx_tables_in_use: 3
         trx_tables_locked: 3
          trx_lock_structs: 397
     trx_lock_memory_bytes: 63016
           trx_rows_locked: 109781
         trx_rows_modified: 0
   trx_concurrency_tickets: 0
       trx_isolation_level: REPEATABLE READ
         trx_unique_checks: 1
    trx_foreign_key_checks: 1
trx_last_foreign_key_error: NULL
 trx_adaptive_hash_latched: 0
 trx_adaptive_hash_timeout: 9974
          trx_is_read_only: 0
trx_autocommit_non_locking: 0
2 rows in set (0.00 sec)

如果发现 trx_state 为 LOCK_WAIT 则发生死锁 ，可以用trx_mysql_thread_id mysql线程来，通过kill 线程 杀死线程

2 . 查看正在锁的事务

SELECT * FROM INFORMATION_SCHEMA.INNODB_LOCKS;

3. 查看等待锁的事务

SELECT * FROM INFORMATION_SCHEMA.INNODB_LOCK_WAITS;

4. 查询是否锁表

SHOW OPEN TABLES where In_use > 0;

5. 解决死锁

解除死锁

如果需要解除死锁，有一种最简单粗暴的方式，那就是找到进程id之后，直接干掉。

查看当前正在进行中的进程

show processlist

// 也可以使用

SELECT * FROM information_schema.INNODB_TRX;

这两个命令找出来的进程id 是同一个。

杀掉进程对应的进程

kill id

验证(kill后再看是否还有锁)

SHOW OPEN TABLES where In_use > 0;