Question

隔离级别为READ COMMITTED

一个查询正在查找service_id为0的记录...另一个正在查找service_id不在的位置（0，...其他...）;

我认为他们会锁定不同的行？

    ------------------------
    LATEST DETECTED DEADLOCK
    ------------------------
    2017-08-18 09:01:24 7f2d05641700
    *** (1) TRANSACTION:
    TRANSACTION 201694975, ACTIVE 1 sec starting index read
    mysql tables in use 2, locked 2
    LOCK WAIT 46 lock struct(s), heap size 6544, 194 row lock(s)
    MySQL thread id 33600289, OS thread handle 0x7f2d0812b700, query id 3703173090 inf-rtpctllb02-prd.rtp.netapp.com 10.60.56.150 ctl Copying to tmp table
    SELECT
                        re.*,
                        r.config_id,
                        r.reserve_all_or_nothing,
                        r.owner,
                        r.charges
                    FROM
                        `job_charge` AS re,
                        `job` AS r WHERE
                        re.job_id = r.id AND ((re.status ='dispatched') or (re.status= 'running') or (re.status= 'held') or (re.status= 'reserved')) AND  ((re.service_id ='0')) AND r.disable = 0  ORDER BY r.priority,r.id LIMIT 10000  FOR UPDATE
    *** (1) WAITING FOR THIS LOCK TO BE GRANTED:
    RECORD LOCKS space id 1485 page no 987 n bits 104 index `PRIMARY` of table `ctl`.`job_charge` trx table locks 2 total table locks 2  trx id 201694975 lock_mode X locks rec but not gap waiting lock hold time 1 wait time before grant 0 
    *** (2) TRANSACTION:
    TRANSACTION 201691925, ACTIVE 185 sec fetching rows
    mysql tables in use 4, locked 2
    1164 lock struct(s), heap size 128552, 2 row lock(s)
    MySQL thread id 33599597, OS thread handle 0x7f2d05641700, query id 3703158120 inf-rtpctllb02-prd.rtp.netapp.com 10.60.56.150 ctl updating
    UPDATE
                `job_charge`
            SET
                service_id = '0'
            WHERE 
                service_id NOT IN ('0','ctl5-staging_command-launcher.674d8c96-7c76-11e7-bc6c-ee0cf095fd00','inf-mesos-slave001.ctl.gdl.englab.netapp.com:mesos-6b256982-4ef1-4a84-ba60-58245ee7406d-S63.3987fd54-ee31-4c81-add4-4be53a6ed363:80','ctl5-staging_scheduler.912d008f-7c76-11e7-bc6c-ee0cf095fd00','ctl5-production_capacity-manager.6a869ee7-7919-11e7-bc6c-ee0cf095fd00','ctl5-production_scheduler.91de7d76-7919-11e7-bc6c-ee0cf095fd00','mysql','inf-mesos-slave001.ctl.gdl.englab.netapp.com:mesos-6b256982-4ef1-4a84-ba60-58245ee7406d-S63.48fe0555-83e9-4811-bcbc-f301da498fa6:80','ctl5-production_cleaner.6a86c5fa-7919-11e7-bc6c-ee0cf095fd00','ctl5-production_command-launcher.9f97a534-8413-11e7-bc6c-ee0cf095fd00','ctl5-production_reservation-manager.7ac1771d-7a9e-11e7-bc6c-ee0cf095fd00','ctl5-s
    *** (2) HOLDS THE LOCK(S):
    RECORD LOCKS space id 1485 page no 987 n bits 104 index `PRIMARY` of table `ctl`.`job_charge` trx table locks 1 total table locks 2  trx id 201691925 lock_mode X locks rec but not gap lock hold time 13 wait time before grant 12 
    *** (2) WAITING FOR THIS LOCK TO BE GRANTED:
    RECORD LOCKS space id 1485 page no 1606 n bits 88 index `PRIMARY` of table `ctl`.`job_charge` trx table locks 1 total table locks 2  trx id 201691925 lock_mode X locks rec but not gap waiting lock hold time 0 wait time before grant 0 
    *** WE ROLL BACK TRANSACTION (1)

Answer 1

是。两者必须是不同的行。您可以在声明

中看到第987和1606页

此处交易1是

SELECT
                  re.*,
                  r.config_id,
                  r.reserve_all_or_nothing,
                  r.owner,
                  r.charges
              FROM
                  `job_charge` AS re,
                  `job` AS r WHERE
                  re.job_id = r.id AND ((re.status ='dispatched') or (re.status= 'running') or (re.status= 'held') or (re.status= 'reserved')) AND  ((re.service_id ='0')) AND r.disable = 0  ORDER BY r.priority,r.id LIMIT 10000  FOR UPDATE

交易2是

UPDATE
          `job_charge`
      SET
          service_id = '0'
      WHERE 
          service_id NOT IN ('0','ctl5-staging_command-launcher.674d8c96-7c76-11e7-bc6c-ee0cf095fd00','inf-mesos-slave001.ctl.gdl.englab.netapp.com:mesos-6b256982-4ef1-4a84-ba60-58245ee7406d-S63.3987fd54-ee31-4c81-add4-4be53a6ed363:80','ctl5-staging_scheduler.912d008f-7c76-11e7-bc6c-ee0cf095fd00','ctl5-production_capacity-manager.6a869ee7-7919-11e7-bc6c-ee0cf095fd00','ctl5-production_scheduler.91de7d76-7919-11e7-bc6c-ee0cf095fd00','mysql','inf-mesos-slave001.ctl.gdl.englab.netapp.com:mesos-6b256982-4ef1-4a84-ba60-58245ee7406d-S63.48fe0555-83e9-4811-bcbc-f301da498fa6:80','ctl5-production_cleaner.6a86c5fa-7919-11e7-bc6c-ee0cf095fd00','ctl5-production_command-launcher.9f97a534-8413-11e7-bc6c-ee0cf095fd00','ctl5-production_reservation-manager.7ac1771d-7a9e-11e7-bc6c-ee0cf095fd00','ctl5-s

从给定的消息中，我们可以看到事务1正在等待表'ctl'主键上的排它锁（由X锁表示，在表中写入一些值所需的锁）。

但与此同时，交易2进入图片，该图片已经持有对'ctl'表主键（第987页）的X锁定。因此，由于事务2已经对'ctl'进行了X锁定，因此事务1无法获得X锁定，因此它正在等待。

但是，事务2本身等待在'ctl'上的另一个X锁定（上面的不同行，第1606页）。我认为这一行是由事务1 持有。

所以，事务1在第1606页的行中持有一个锁，事务2正等待该行和事务2在第987页的行中持有锁，事务1正在等待

因此，两者都在等待，因此发生了死锁。

为什么这两个查询会出现死锁？

1 个答案: