记一次公司仓库数据库服务器死锁过程及解决办

编程学习 2021-07-05 13:43www.dzhlxh.cn编程入门
根据操作系统中的定义:死锁是指在一组进程中的各个进程均占有不会释放的资源,但因互相申请被其他进程所站用不会释放的资源而处于的一种永久等待状态。狼蚁网站SEO优化长沙网络推广给大家分享一次公司仓库数据库服务器死锁过程及解决办法,需要的朋友一起看看吧

死锁的四个必要条件:

互斥条件(Mutual exclusion):资源不能被共享,只能由一个进程使用。

请求与保持条件(Hold and wait):已经得到资源的进程可以再次申请新的资源。

非剥夺条件(No pre-emption):已经分配的资源不能从相应的进程中被强制地剥夺。

循环等待条件(Circular wait):系统中若干进程组成环路,该环路中每个进程都在等待相邻进程正占用的资源。

仓库拣货卡死,排查了数据库的很多地方,都没有头绪,最后到SQL Server 错误日志里查看,终于发现了蛛丝马迹

EXEC xp_readerrorlog 0,1,NULL,NULL,'2015-09-21','2015-10-10','DESC'
   waiter id=process5c30e08 mode=U requestType=wait
  waiter-list
   owner id=process5c26988 mode=X
  owner-list
  keylock hobtid=72057597785604096 dbid=33 objectname=stoxxx.dbo.Orderxxx indexname=IX_PricingExpressProductCode_State id=lock17fa96980 mode=X associatedObjectId=72057597785604096
   waiter id=process5c26988 mode=U requestType=wait
  waiter-list
   owner id=process5c30e08 mode=X
  owner-list
  keylock hobtid=72057597785604096 dbid=33 objectname=stoxxx.dbo.Orderxxx indexname=IX_PricingExpressProductCode_State id=lock87d69e780 mode=X associatedObjectId=72057597785604096
 resource-list
(@OperateState money,@HandledByNewWms bit,@State int,@OrderOut int)
UPDATE [Orderxx] SET [OperateState] = @OperateState,[HandledByNewWms] = @HandledByNewWms WHERE (([Orderxxx].[State] = @State) And ([Orderxxx].[OrderOut] = @OrderOut) And ([Orderxxx].[PricingExpressProductCode] IN ('UKNIR')))  
  inputbuf
unknown   
   frame procname=unknown line=1 sqlhandle=0x000000000000000000000000000000000000000000000000
UPDATE [Orderxxx] SET [OperateState] = @OperateState,[HandledByNewWms] = @HandledByNewWms WHERE (([Orderxxx].[State] = @State) And ([Orderxxx].[OrderOut] = @OrderOut) And ([Orderxxx].[PricingExpressProductCode] IN ('UKNIR')))   
   frame procname=adhoc line=1 stmtstart=134 sqlhandle=0x020000009d376d18a17e7ea51289d8caa2fb4de65c976389
  executionStack
  process id=process5c30e08 taskpriority=0 logused=10320 waitresource=KEY: 33:72057597785604096 (112399c2054a) waittime=4813 ownerId=31578743038 transactionname=user_transaction lasttranstarted=2015-09-24T10:22:58.410 XDES=0x372e95950 lockMode=U schedulerid=17 kpid=8496 status=suspended spid=153 sbid=0 ecid=0 priority=0 trancount=2 lastbatchstarted=2015-09-24T10:22:58.540 lastbatchcompleted=2015-09-24T10:22:58.540 clientapp=.Net SqlClient Data Provider hostname=CK1-WIN-WEB02 hostpid=37992 loginname=ck1.biz isolationlevel=read committed (2) xactid=31578743038 currentdb=33 lockTimeout=4294967295 clientoption1=671088672 clientoption2=128056
(@OperateState money,@HandledByNewWms bit,@State int,@OrderOut int)UPDATE [Orderxxx] SET [OperateState] = @OperateState,[HandledByNewWms] = @HandledByNewWms WHERE (([Orderxxx].[State] = @State) And ([Orderxxx].[OrderOut] = @OrderOut) And ([Orderxxx].[PricingExpressProductCode] IN ('UKNIR')))  
  inputbuf
unknown   
   frame procname=unknown line=1 sqlhandle=0x000000000000000000000000000000000000000000000000
UPDATE [Orderxxx] SET [OperateState] = @OperateState,[HandledByNewWms] = @HandledByNewWms WHERE (([Orderxxx].[State] = @State) And ([Orderxxx].[OrderOut] = @OrderOut) And ([Orderxxx].[PricingExpressProductCode] IN ('UKNIR')))   
   frame procname=adhoc line=1 stmtstart=134 sqlhandle=0x020000009d376d18a17e7ea51289d8caa2fb4de65c976389
  executionStack
  process id=process5c26988 taskpriority=0 logused=9892 waitresource=KEY: 33:72057597785604096 (70f5b089bb2b) waittime=4813 ownerId=31579268946 transactionname=user_transaction lasttranstarted=2015-09-24T10:27:01.357 XDES=0x98312f950 lockMode=U schedulerid=16 kpid=9184 status=suspended spid=454 sbid=0 ecid=0 priority=0 trancount=2 lastbatchstarted=2015-09-24T10:27:01.490 lastbatchcompleted=2015-09-24T10:27:01.487 clientapp=.Net SqlClient Data Provider hostname=CK1-WIN-WEB02 hostpid=37992 loginname=ck1.biz isolationlevel=read committed (2) xactid=31579268946 currentdb=33 lockTimeout=4294967295 clientoption1=671088672 clientoption2=128056
 process-list
 deadlock victim=process5c26988
deadlock-list

咋一看上面的错误信息,可以发现两条相同的语句造成的死锁,但是这么短的语句不可能持有排他锁太久

再仔细分析一下错误日志,发现都死锁在同一个非聚集索引上,再问了一下开发,开发那边说,这条语句是在一个大事务里面,这个事务会做7、8件事

索引属性

还有索引里面的数据,发现很多重复值


SQL语句是这样的

(@OperateState money,@HandledByNewWms bit,@State int,@OrderOut int)
@HandledByNewWms=(1) @OperateState=($1.0000) @OrderOut=(4055484) @State=(3) 
UPDATE [Orderxxx] SET [OperateState] = $1.0000,[HandledByNewWms] = 1
WHERE (([Orderxxx].[State] = 3) And ([Orderxxx].[OrderOut] = 4055484) And ([Orderxxx].[PricingExpressProductCode] IN ('UKRRM','UKRLE')))

下图为语句生成的执行计划

当时的情况是大量SQL语句被阻塞,而阻塞的语句正是狼蚁网站SEO优化这条语句

UPDATE [Orderxxx] SET [OperateState] = $1.0000,[HandledByNewWms] = 1
WHERE (([Orderxxx].[State] = 3) And ([Orderxxx].[OrderOut] = 4055484) And ([Orderxxx].[PricingExpressProductCode] IN ('UKRRM','UKRLE')))

解决方法

上面得出几个症状

1、update语句是在一个大事务里面,事务太大导致其他session等待排他锁的时间变长

2、大家都在使用同一个非聚集索引,并扫描PricingExpressProductCode字段

3、索引里的重复值很多

从上面的症状基本可以判断,这个非聚集索引无啥用,可以禁用之

ALTER INDEX [IX_PricingExpressProductCode_State] ON [dbo].[Orderxxx] DISABLE


禁用之后,死锁消失,问题解决,仓库的怨气也随之消失

这一次排查过程时间有点长,但是很好定位,SQL Server错误日志给出了足够的信息定位死锁问题,所以遇到问题的时候一定要分析清楚日志

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