mysql持有并等待相同的锁

qmelpv7a  于 2021-06-20  发布在  Mysql
关注(0)|答案(1)|浏览(354)

我正在努力 mysql5.6.34innoDB . 有一个僵局发生了,我跟在后面 show engine innodb status . 我不知道僵局是怎么发生的,为什么 TRANSACTION-2 保持并等待相同的x锁,然后 ROLLBACK 是吗?
日志:

------------------------
LATEST DETECTED DEADLOCK
------------------------
2018-08-15 05:58:56 7fdff5872700

***(1) TRANSACTION:

TRANSACTION 81567872, ACTIVE 0 sec inserting
mysql tables in use 1, locked 1
LOCK WAIT 4 lock struct(s), heap size 1184, 2 row lock(s), undo log entries 2
MySQL thread id 455326, OS thread handle 0x7fdff9083700, query id 255309181 10.8.201.34 slnbdata update
INSERT INTO XXX

***(1) WAITING FOR THIS LOCK TO BE GRANTED:

RECORD LOCKS space id 8065 page no 11084 n bits 192 index `PRIMARY` of table `XXX` trx id 81567872 lock_mode X insert intention waiting
Record lock, heap no 1 PHYSICAL RECORD: n_fields 1; compact format; info bits 0
 0: len 8; hex 73757072656d756d; asc supremum;;

***(2) TRANSACTION:

TRANSACTION 81567879, ACTIVE 0 sec inserting
mysql tables in use 1, locked 1
4 lock struct(s), heap size 1184, 2 row lock(s), undo log entries 2
MySQL thread id 455338, OS thread handle 0x7fdff5872700, query id 255309187 10.8.201.34 slnbdata update
INSERT INTO XXX

***(2) HOLDS THE LOCK(S):

RECORD LOCKS space id 8065 page no 11084 n bits 192 index `PRIMARY` of table `XXX` trx id 81567879 lock_mode X
Record lock, heap no 1 PHYSICAL RECORD: n_fields 1; compact format; info bits 0
 0: len 8; hex 73757072656d756d; asc supremum;;

***(2) WAITING FOR THIS LOCK TO BE GRANTED:

RECORD LOCKS space id 8065 page no 11084 n bits 192 index `PRIMARY` of table `XXX` trx id 81567879 lock_mode X insert intention waiting
Record lock, heap no 1 PHYSICAL RECORD: n_fields 1; compact format; info bits 0
 0: len 8; hex 73757072656d756d; asc supremum;;

***WE ROLL BACK TRANSACTION (2)

------------
TRANSACTIONS
------------
There do have a query before the insert:
SELECT
    pk_1,
    max(pk_2)
FROM
    table
WHERE
    pk_1 IN (...)
GROUP BY
    pk_1
but no queries between each insert.
And let me correct my reply above, the insert statement is:
insert into table_name(pk_1,pk_2 ...) values (1,1_1 ...) and insert into table_name(pk_1,pk_2 ...) values (2,2_1 ...)
We use foreach of mybatis like this:
   <insert id="save">
        <foreach collection="list" item="item" separator=";">
            INSERT INTO ...
CREATE TABLE `customer_address_info` (
  `customer_no` char(10) NOT NULL,
  `addr_index` int(1) unsigned NOT NULL,
  `addr_type` tinyint(1) NOT NULL,
  `province_code` char(6) DEFAULT NULL,
  `province_name` varchar(20) DEFAULT NULL,
  `city_code` char(6) DEFAULT NULL,
  `city_name` varchar(50) DEFAULT NULL,
  `county_code` char(6) DEFAULT NULL,
  `county_name` varchar(100) DEFAULT NULL,
  `zip_code` char(6) DEFAULT NULL,
  `detail` varchar(100) NOT NULL,
  `status` tinyint(4) unsigned NOT NULL,
  `create_date` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `create_user` varchar(30) NOT NULL,
  `modify_date` datetime DEFAULT NULL ON UPDATE CURRENT_TIMESTAMP,
  `modify_user` varchar(30) DEFAULT NULL,
  PRIMARY KEY (`customer_no`,`addr_index`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
wgeznvg7

wgeznvg71#

正如我所评论的,发布的信息不足以看到全貌并知道真正的原因。我只分两分钱。
show engine innodb status表示每个事务都锁定了两行,并且有两个挂起的提交更改(2行锁定,undo log entries 2),因此在同一事务中应该有其他语句,但没有显示。
事务1正在等待ix锁,ix锁阻止事务2的x锁保持;事务2正在等待事务1持有的ix锁。
ix可以通过从表中选择*来获取以进行更新。op添加的select语句是一个简单的select语句,不需要锁。
由于隔离级别是repeatable\u read,这在mysql中是默认的,因此事务期间获取的每个锁都会在事务期间保留,因此需要分析从事务开始到insert语句的查询,以查看可能获取的锁。

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