【原创】查找原始MySQL死锁ID

luobo2ni

　　如果遇到死锁了，怎么解决呢？找到原始的锁ID，然后KILL掉一直持有的那个线程就可以了， 但是众多线程，可怎么找到引起死锁的线程ID呢？ MySQL 发展到现在，已经非常强大了，这个问题很好解决。 直接从数据字典连查找。

我们来演示下。
　　


线程A，我们用来锁定某些记录，假设这个线程一直没提交，或者忘掉提交了。 那么就一直存在，但是数据里面显示的只是SLEEP状态。　　

• mysql> set @@autocommit=0;
  
• Query OK, 0 rows affected (0.00 sec)
  
• 
  
• mysql> use test;
  
• Reading table information for completion of table and column names
  
• You can turn off this feature to get a quicker startup with -A
  
• 
  
• Database changed
  
• mysql> show tables;
  
• +----------------+
  
• | Tables_in_test |
  
• +----------------+
  
• | demo_test      |
  
• | t3             |
  
• +----------------+
  
• 2 rows in set (0.00 sec)
  
• 
  
• mysql> select * from t3;
  
• +----+--------+--------+------------+----+----+----+
  
• | id | fname  | lname  | birthday   | c1 | c2 | c3 |
  
• +----+--------+--------+------------+----+----+----+
  
• | 19 | lily19 | lucy19 | 2013-04-18 | 19 |  0 |  0 |
  
• | 20 | lily20 | lucy20 | 2013-03-13 | 20 |  0 |  0 |
  
• +----+--------+--------+------------+----+----+----+
  
• 2 rows in set (0.00 sec)
  
• 
  
• mysql> update t3 set birthday = '2022-02-23' where id = 19;
  
• Query OK, 1 row affected (0.00 sec)
  
• Rows matched: 1  Changed: 1  Warnings: 0
  
• 
  
• mysql> select connection_id();
  
• +-----------------+
  
• | connection_id() |
  
• +-----------------+
  
• |              16 |
  
• +-----------------+
  
• 1 row in set (0.00 sec)
  
• 
  
• mysql>
  

　　


线程B， 我们用来进行普通的更新，但是遇到问题了，此时不知道是哪个线程把这行记录给锁定了？　　

• mysql> use test;
  
• Reading table information for completion of table and column names
  
• You can turn off this feature to get a quicker startup with -A
  
• 
  
• Database changed
  
• mysql> select @@autocommit;
  
• +--------------+
  
• | @@autocommit |
  
• +--------------+
  
• |            1 |
  
• +--------------+
  
• 1 row in set (0.00 sec)
  
• 
  
• mysql> update t3 set birthday='2018-01-03' where id = 19;
  
• ERROR 1205 (HY000): Lock wait timeout exceeded; try restarting transaction
  
• mysql> select connection_id();
  
• +-----------------+
  
• | connection_id() |
  
• +-----------------+
  
• |              17 |
  
• +-----------------+
  
• 1 row in set (0.00 sec)
  
• 
  
• mysql> show processlist;
  
• +----+------+-----------+------+---------+------+-------+------------------+
  
• | Id | User | Host      | db   | Command | Time | State | Info             |
  
• +----+------+-----------+------+---------+------+-------+------------------+
  
• | 10 | root | localhost | NULL | Sleep   | 1540 |       | NULL             |
  
• | 11 | root | localhost | NULL | Sleep   |  722 |       | NULL             |
  
• | 16 | root | localhost | test | Sleep   |  424 |       | NULL             |
  
• | 17 | root | localhost | test | Query   |    0 | init  | show processlist |
  
• | 18 | root | localhost | NULL | Sleep   |    5 |       | NULL             |
  
• +----+------+-----------+------+---------+------+-------+------------------+
  
• 5 rows in set (0.00 sec)
  
• 
  
• mysql> show engine innodb status\G
  
• 
  
• 
  
• ------------
  
• TRANSACTIONS
  
• ------------
  
• Trx id counter 189327
  
• Purge done for trx's n:o < 189323 undo n:o < 0 state: running but idle
  
• History list length 343
  
• LIST OF TRANSACTIONS FOR EACH SESSION:
  
• ---TRANSACTION 0, not started
  
• MySQL thread id 11, OS thread handle 0x7f70a0c98700, query id 994 localhost root init
  
• show engine innodb status
  
• ---TRANSACTION 189326, ACTIVE 2 sec starting index read
  
• mysql tables in use 1, locked 1
  
• LOCK WAIT 2 lock struct(s), heap size 376, 1 row lock(s)
  
• MySQL thread id 17, OS thread handle 0x7f70a0bd5700, query id 993 localhost root updating
  
• update t3 set birthday='2018-01-03' where id = 19
  
• ------- TRX HAS BEEN WAITING 2 SEC FOR THIS LOCK TO BE GRANTED:
  
• RECORD LOCKS space id 529 page no 3 n bits 72 index `PRIMARY` of table `test`.`t3` trx id 189326 lock_mode X waiting
  
• Record lock, heap no 2 PHYSICAL RECORD: n_fields 9; compact format; info bits 0
  
• 0: len 2; hex 3139; asc 19;;
  
• 1: len 6; hex 00000002e38c; asc       ;;
  
• 2: len 7; hex 7e00000d2827c9; asc ~   (' ;;
  
• 3: len 6; hex 6c696c793139; asc lily19;;
  
• 4: len 6; hex 6c7563793139; asc lucy19;;
  
• 5: len 3; hex 8fcc57; asc   W;;
  
• 6: len 4; hex 80000013; asc     ;;
  
• 7: len 4; hex 80000000; asc     ;;
  
• 8: len 4; hex 80000000; asc     ;;
  
• 
  
• ------------------
  
• ---TRANSACTION 189324, ACTIVE 641 sec
  
• 2 lock struct(s), heap size 376, 3 row lock(s), undo log entries 1
  
• MySQL thread id 16, OS thread handle 0x7f70a0b94700, query id 985 localhost root cleaning up
  
• Trx read view will not see trx with id >= 189325, sees < 189325
  

　　


上面的信息很繁多，也看不清楚到底哪里是哪里。
不过现在，我们只要从数据字典里面拿出来这部分信息就OK了。　　

• mysql> SELECT * FROM information_schema.INNODB_TRX\G
  
• *************************** 1. row ***************************
  
•                     trx_id: 189324
  
•                  trx_state: RUNNING
  
•                trx_started: 2013-04-18 17:48:14
  
•      trx_requested_lock_id: NULL
  
•           trx_wait_started: NULL
  
•                 trx_weight: 3
  
•        trx_mysql_thread_id: 16
  
•                  trx_query: NULL
  
•        trx_operation_state: NULL
  
•          trx_tables_in_use: 0
  
•          trx_tables_locked: 0
  
•           trx_lock_structs: 2
  
•      trx_lock_memory_bytes: 376
  
•            trx_rows_locked: 3
  
•          trx_rows_modified: 1
  
•    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
  
• 1 row in set (0.01 sec)
  
• 
  
• mysql>
  

　　


原来是线程16忘掉COMMIT了。