MYSQL死锁相关查找

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MYSQL死锁相关查找

来源: 作者: 时间:2016-02-05 10:56 【

MYSQL死锁相关查找如果遇到死锁了,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
MYSQL死锁相关查找
 
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。
 
[sql]  
> 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?
 
 
[sql]  
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。
 
[sql]  
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>   

 


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