如何解决MySQL中的锁定问题？

Question

我想这个问题适用于死锁,实时锁定或只是锁定等待超时.

我试图找出导致阻止另一个查询执行的锁的查询.Oracle(如果内存服务)有一个LOCK表,您可以将其连接到自身以确定哪些查询正在锁定其他查询.我需要一种在MySQL中完成相同的方法.

方案是我们有长时间运行的作业,偶尔会创建一个更新进度字段的嵌套事务.这样,我们就不会失去工作的交易性,同时让用户了解进度(即完成百分比).嵌套事务有时会抛出锁定超时异常.

这很奇怪,因为其他任何工作都不应该从Job表中写入 - 甚至是读取 - .筛选原始SQL日志确认了这一点.这是SHOW ENGINE INNODB状态的交易部分:

------------
TRANSACTIONS
------------
Trx id counter 0 479427
Purge done for trx's n:o < 0 479425 undo n:o < 0 0
History list length 19
LIST OF TRANSACTIONS FOR EACH SESSION:
---TRANSACTION 0 0, not started, OS thread id 3192
MySQL thread id 31, query id 17417 localhost 127.0.0.1 root
show engine innodb status
---TRANSACTION 0 0, not started, OS thread id 3776
MySQL thread id 29, query id 13062 localhost 127.0.0.1 root
---TRANSACTION 0 479190, not started, OS thread id 2540
MySQL thread id 23, query id 16103 localhost 127.0.0.1 testuser
---TRANSACTION 0 479422, not started, OS thread id 2536
MySQL thread id 19, query id 17338 localhost 127.0.0.1 testuser
---TRANSACTION 0 479194, not started, OS thread id 2528
MySQL thread id 20, query id 16103 localhost 127.0.0.1 testuser
---TRANSACTION 0 479189, not started, OS thread id 2776
MySQL thread id 22, query id 16103 localhost 127.0.0.1 testuser
---TRANSACTION 0 479426, ACTIVE 3 sec, OS thread id 2544 starting index read
mysql tables in use 1, locked 1
LOCK WAIT 2 lock struct(s), heap size 320, 1 row lock(s)
MySQL thread id 18, query id 17414 localhost 127.0.0.1 testuser Updating
update Job set progress=0.000482780829770491 where id=28
------- TRX HAS BEEN WAITING 3 SEC FOR THIS LOCK TO BE GRANTED:
RECORD LOCKS space id 0 page no 23927 n bits 72 index "PRIMARY" of table "test"."job" trx id 0 479426 lock_mode X locks rec but not gap waiting
Record lock, heap no 5 PHYSICAL RECORD: n_fields 12; compact format; info bits 0
 0: len 8; hex 000000000000001c; asc         ;; 1: len 6; hex 0000000750bf; asc     P ;; 2: len 7; hex 0000005d4d2aeb; asc    ]M* ;; 3: len 8; hex 0000000000000005; asc         ;; 4: len 8; hex 0000000000000004; asc         ;; 5: len 8; hex 0000000000000006; asc         ;; 6: len 1; hex 49; asc I;; 7: len 14; hex 800000000000000002749e0e51a6; asc          t  Q ;; 8: len 30; hex 3c6d61703e0a20203c656e7472793e0a202020203c737472696e673e7061; asc <map>   <entry>     <string>pa;...(truncated); 9: len 8; hex 80001245d33e7e3c; asc    E >~<;; 10: SQL NULL; 11: SQL NULL;

------------------
---TRANSACTION 0 479418, ACTIVE 31 sec, OS thread id 960
14 lock struct(s), heap size 1024, 8 row lock(s), undo log entries 3
MySQL thread id 21, query id 17404 localhost 127.0.0.1 testuser

很明显,只有两个交易,并且交易479418的14个锁中的一个是阻止交易479426.我想知道违规查询是什么.有任何想法吗？即使列出14个锁和导致它们的查询也会很棒.

谢谢!

Answer 1

在 msql> 会话中尝试

12.5.5.31。显示进程列表语法

显示[完整]流程列表

SHOW PROCESSLIST 显示哪些线程正在运行。您还可以从 INFORMATION_SCHEMA PROCESSLIST 表或 mysqladmin processlist 命令获取此信息。如果您具有 PROCESS 权限，则可以查看所有线程。否则，您只能看到您自己的线程（即与您正在使用的 MySQL 帐户关联的线程）。如果不使用 FULL 关键字，则信息字段中仅显示每个语句的前 100 个字符。