Question

我只有一次出现MySQL死锁，我无法找到原因。

我想知道：

为什么会出现这种僵局？架构/查询有问题吗？
为什么查询等待间隙锁定？（我明确在where子句中使用主键）

第一行源代码使用以下查询获取独占锁：

SELECT
    *
  FROM
    `active_user`
  WHERE `user_id` =  111111
    AND `_id` IN (
      SELECT
        _id
      FROM
        `active_user`
      WHERE `user_id` =  111111
        AND `identifier` =  'XXXXXXXXXXXXXX@gmail.com'
        AND find_in_set (`type`,  '1,11,18') > 0
    )
  FOR UPDATE

表创建语句

CREATE TABLE `active_user` (
  `user_id` int(10) NOT NULL DEFAULT '0',
  `id` int(5) NOT NULL DEFAULT '0',
  `identifier` varchar(255) NOT NULL,
  `name` varchar(255) NOT NULL,
  `alias_name` varchar(255) DEFAULT NULL,
  `type` int(4) NOT NULL,
  `column1` text NOT NULL,
  `column2` int(2) NOT NULL,
  `column3` tinyint(1) DEFAULT '0',
  `column4` tinyint(1) DEFAULT '0',
  `column5` text,
  PRIMARY KEY (`user_id`,`id`),
  UNIQUE KEY `uuid` (`user_id`,`identifier`,`type`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8

从命令show engine innodb status的输出

------------------------
LATEST DETECTED DEADLOCK
------------------------
2016-04-07 21:05:35 2b822e806700
*** (1) TRANSACTION:
TRANSACTION 12298419769, ACTIVE 1 sec fetching rows
mysql tables in use 2, locked 1
LOCK WAIT 4 lock struct(s), heap size 1184, 3 row lock(s)
MySQL thread id 3714739237, OS thread handle 0x2b822da0f700, query id 31607921072 10.0.28.66 connection1 Sending data
SELECT
    *
  FROM
    `active_user`
  WHERE `user_id` =  111111
    AND `_id` IN (
      SELECT
        _id
      FROM
        `active_user`
      WHERE `user_id` =  111111
        AND `identifier` =  'XXXXXXXXXXXXXX@gmail.com'
        AND find_in_set (`type`,  '1,2,8') > 0
    )
  FOR UPDATE
*** (1) WAITING FOR THIS LOCK TO BE GRANTED:
RECORD LOCKS space id 76 page no 24486 n bits 96 index `PRIMARY` of table `config`.`active_user` trx id 12298419769 lock_mode X waiting
Record lock, heap no 24 PHYSICAL RECORD: n_fields 13; compact format; info bits 0
 0: len 4; hex 803a789b; asc  :x ;;
 1: len 4; hex 80000003; asc     ;;
 2: len 6; hex 0002dd0afdd5; asc       ;;
 3: len 7; hex 050000014e2e72; asc     N.r;;
 4: len 24; hex 616264616c68616b626e6968657940676d61696c2e636f6d; asc XXXXXXXXXXXXXX@gmail.com;;
 5: len 24; hex 616264616c68616b626e6968657940676d61696c2e636f6d; asc XXXXXXXXXXXXXX@gmail.com;;
 6: len 15; hex 416264616c68616b20426e69686579; asc john;;
 7: len 4; hex 80000001; asc     ;;
 8: len 30; hex 7b2263726564656e7469616c5f76657273696f6e223a352c226163636573; asc {"version":5,"recces; (total 423 bytes);
 9: len 4; hex 80000001; asc     ;;
 10: len 1; hex 80; asc  ;;
 11: len 1; hex 80; asc  ;;
 12: len 30; hex 7b227069635f75726c223a2268747470733a5c2f5c2f6c68332e676f6f67; asc {"url":"https:\/\/aaaaaa.com; (total 113 bytes);

*** (2) TRANSACTION:
TRANSACTION 12298419817, ACTIVE 1 sec starting index read
mysql tables in use 2, locked 1
3 lock struct(s), heap size 360, 2 row lock(s)
MySQL thread id 3714739267, OS thread handle 0x2b822e806700, query id 31607921318 10.0.29.120 connection1 Sending data
SELECT
    *
  FROM
    `active_user`
  WHERE `user_id` =  111111
    AND `_id` IN (
      SELECT
        _id
      FROM
        `active_user`
      WHERE `user_id` =  111111
        AND `identifier` =  'XXXXXXXXXXXXXX@gmail.com'
        AND find_in_set (`type`,  '1,2,8') > 0
    )
  FOR UPDATE
*** (2) HOLDS THE LOCK(S):
RECORD LOCKS space id 76 page no 24486 n bits 96 index `PRIMARY` of table `config`.`active_user` trx id 12298419817 lock_mode X locks rec but not gap
Record lock, heap no 24 PHYSICAL RECORD: n_fields 13; compact format; info bits 0
 0: len 4; hex 803a789b; asc  :x ;;
 1: len 4; hex 80000003; asc     ;;
 2: len 6; hex 0002dd0afdd5; asc       ;;
 3: len 7; hex 050000014e2e72; asc     N.r;;
 4: len 24; hex 616264616c68616b626e6968657940676d61696c2e636f6d; asc XXXXXXXXXXXXXX@gmail.com;;
 5: len 24; hex 616264616c68616b626e6968657940676d61696c2e636f6d; asc XXXXXXXXXXXXXX@gmail.com;;
 6: len 15; hex 416264616c68616b20426e69686579; asc john;;
 7: len 4; hex 80000001; asc     ;;
 8: len 30; hex 7b2263726564656e7469616c5f76657273696f6e223a352c226163636573; asc {"version":5,"recces; (total 423 bytes);
 9: len 4; hex 80000001; asc     ;;
 10: len 1; hex 80; asc  ;;
 11: len 1; hex 80; asc  ;;
 12: len 30; hex 7b227069635f75726c223a2268747470733a5c2f5c2f6c68332e676f6f67; asc {"url":"https:\/\/aaaaaa.com; (total 113 bytes);

*** (2) WAITING FOR THIS LOCK TO BE GRANTED:
RECORD LOCKS space id 76 page no 24486 n bits 96 index `PRIMARY` of table `config`.`active_user` trx id 12298419817 lock_mode X locks rec but not gap waiting
Record lock, heap no 18 PHYSICAL RECORD: n_fields 13; compact format; info bits 0
 0: len 4; hex 803a789b; asc  :x ;;
 1: len 4; hex 80000002; asc     ;;
 2: len 6; hex 0002dd0afdd5; asc       ;;
 3: len 7; hex 050000014e2bfc; asc     N+ ;;
 4: len 24; hex 616264616c68616b626e6968657940676d61696c2e636f6d; asc XXXXXXXXXXXXXX@gmail.com;;
 5: len 24; hex 616264616c68616b626e6968657940676d61696c2e636f6d; asc XXXXXXXXXXXXXX@gmail.com;;
 6: len 15; hex 416264616c68616b20426e69686579; asc john;;
 7: len 4; hex 80000002; asc     ;;
 8: len 30; hex 7b2263726564656e7469616c5f76657273696f6e223a352c226163636573; asc {"version":5,"recces; (total 597 bytes);
 9: len 4; hex 80000002; asc     ;;
 10: len 1; hex 80; asc  ;;
 11: len 1; hex 80; asc  ;;
 12: len 30; hex 7b227069635f75726c223a2268747470733a5c2f5c2f6c68332e676f6f67; asc {"url":"https:\/\/aaaaaa.com; (total 113 bytes);

*** WE ROLL BACK TRANSACTION (2)

mysql死锁：一行被查询锁定两次？

0 个答案: