查找原始MySQL死锁ID

转载地址：http://yueliangdao0608.blog.51cto.com/397025/1180917

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=;
Query OK,  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             |
+----------------+
 rows in set (0.00 sec) 

mysql> select * from t3;
+----+--------+--------+------------+----+----+----+
| id | fname  | lname  | birthday   | c1 | c2 | c3 |
+----+--------+--------+------------+----+----+----+
|  | lily19 | lucy19 | -- |  |   |   |
|  | lily20 | lucy20 | -- |  |   |   |
+----+--------+--------+------------+----+----+----+
 rows in set (0.00 sec) 

mysql> update t3 set birthday = '2022-02-23' where id = ;
Query OK,  row affected (0.00 sec)
Rows matched:   Changed:   Warnings:  

mysql> select connection_id();
+-----------------+
| connection_id() |
+-----------------+
|               |
+-----------------+
 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 |
+--------------+
|             |
+--------------+
 row in set (0.00 sec) 

mysql> update t3 set birthday='2018-01-03' where id = ;
ERROR  (HY000): Lock wait timeout exceeded; try restarting transaction
mysql> select connection_id();
+-----------------+
| connection_id() |
+-----------------+
|               |
+-----------------+
 row in set (0.00 sec) 

mysql> show processlist;
+----+------+-----------+------+---------+------+-------+------------------+
| Id | User | Host      | db   | Command | Time | State | Info             |
+----+------+-----------+------+---------+------+-------+------------------+
|  | root | localhost | NULL | Sleep   |  |       | NULL             |
|  | root | localhost | NULL | Sleep   |   |       | NULL             |
|  | root | localhost | test | Sleep   |   |       | NULL             |
|  | root | localhost | test | Query   |     | init  | show processlist |
|  | root | localhost | NULL | Sleep   |     |       | NULL             |
+----+------+-----------+------+---------+------+-------+------------------+
 rows in set (0.00 sec) 

mysql> show engine innodb status\G 

------------
TRANSACTIONS
------------
Trx id counter
Purge done for trx's n:o < 189323 undo n:o < 0 state: running but idle
History list length
LIST OF TRANSACTIONS FOR EACH SESSION:
---TRANSACTION , not started
MySQL thread id , OS thread handle 0x7f70a0c98700, query id  localhost root init
show engine innodb status
---TRANSACTION , ACTIVE  sec starting index read
mysql tables in use , locked
LOCK WAIT  lock struct(s), heap size ,  row lock(s)
MySQL thread id , OS thread handle 0x7f70a0bd5700, query id  localhost root updating
update t3 set birthday='2018-01-03' where id =
------- TRX HAS BEEN WAITING  SEC FOR THIS LOCK TO BE GRANTED:
RECORD LOCKS space id  page no  n bits  index `PRIMARY` of table `test`.`t3` trx id  lock_mode X waiting
Record lock, heap no  PHYSICAL RECORD: n_fields ; compact format; info bits
 : len ; hex ; asc ;;
 : len ; hex 00000002e38c; asc       ;;
 : len ; hex 7e00000d2827c9; asc ~   (' ;;
 : len ; hex 6c696c793139; asc lily19;;
 : len ; hex 6c7563793139; asc lucy19;;
 : len ; hex 8fcc57; asc   W;;
 : len ; hex ; asc     ;;
 : len ; hex ; asc     ;;
 : len ; hex ; asc     ;; 

------------------
---TRANSACTION , ACTIVE  sec
 lock struct(s), heap size ,  row lock(s), undo log entries
MySQL thread id , OS thread handle 0x7f70a0b94700, query id  localhost root cleaning up
Trx read view will not see trx with id >= , sees <
 

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
*************************** . row ***************************
                    trx_id:
                 trx_state: RUNNING
               trx_started: -- ::
     trx_requested_lock_id: NULL
          trx_wait_started: NULL
                trx_weight:
       trx_mysql_thread_id:
                 trx_query: NULL
       trx_operation_state: NULL
         trx_tables_in_use:
         trx_tables_locked:
          trx_lock_structs:
     trx_lock_memory_bytes:
           trx_rows_locked:
         trx_rows_modified:
   trx_concurrency_tickets:
       trx_isolation_level: REPEATABLE READ
         trx_unique_checks:
    trx_foreign_key_checks:
trx_last_foreign_key_error: NULL
 trx_adaptive_hash_latched:
 trx_adaptive_hash_timeout:
          trx_is_read_only:
trx_autocommit_non_locking:
 row in set (0.01 sec) 

mysql>  

原来是线程16忘掉COMMIT了。