SQL Server 2005中的死锁！两个实时批量upsert正在战斗。为什么？

时间：2010-06-11 13:01:55

标签： sql-server-2005 deadlock bulk primary-key database-deadlocks

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以下是该方案：

我有一个名为MarketDataCurrent（MDC）的表，它具有实时更新股票价格。

我有一个名为'LiveFeed'的进程，它读取从线路流出的价格，排队插入，并使用'批量上传到临时表然后插入/更新到MDC表'。 （BulkUpsert）

我有另一个进程然后读取这些数据，计算其他数据，然后使用类似的BulkUpsert存储过程将结果保存回同一个表中。

第三，有很多用户在运行C＃Gui轮询MDC表并从中读取更新。

现在，在数据快速变化的那一天，事情运行得相当顺利，但是在市场营业时间之后，我们最近开始看到越来越多的死锁异常从数据库出来，现在我们看到10-每天20。这里需要注意的重要一点是，当值不变时会发生这些。

以下是所有相关信息：

表格默认：

CREATE TABLE [dbo].[MarketDataCurrent](
 [MDID] [int] NOT NULL,
 [LastUpdate] [datetime] NOT NULL,
 [Value] [float] NOT NULL,
 [Source] [varchar](20) NULL, 
CONSTRAINT [PK_MarketDataCurrent] PRIMARY KEY CLUSTERED 
(
 [MDID] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, 
ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]

-

alt text

我有一个Sql Profiler跟踪正在运行，捕获死锁，这就是所有图形的样子。

alt text

进程258被重复地称为以下'BulkUpsert'存储过程，而73正在调用下一个：

ALTER proc [dbo].[MarketDataCurrent_BulkUpload]
 @updateTime datetime,
 @source varchar(10)
as

begin transaction

update c with (rowlock) set LastUpdate = getdate(), Value = t.Value, Source = @source 
from MarketDataCurrent c INNER JOIN #MDTUP t ON c.MDID = t.mdid
where c.lastUpdate < @updateTime
and   c.mdid not in (select mdid from MarketData where LiveFeedTicker is not null     and     PriceSource like 'LiveFeed.%')
and   c.value <> t.value

insert  into MarketDataCurrent
with (rowlock)
select  MDID, getdate(), Value, @source from #MDTUP 
where mdid not in (select mdid from MarketDataCurrent with (nolock))
and  mdid not in (select mdid from MarketData where LiveFeedTicker is not null     and PriceSource like 'LiveFeed.%')

commit

另一个：

ALTER PROCEDURE [dbo].[MarketDataCurrent_LiveFeedUpload] 
AS
begin transaction

 -- Update existing mdid
 UPDATE c WITH (ROWLOCK) SET LastUpdate = t.LastUpdate, Value = t.Value, Source = t.Source 
 FROM MarketDataCurrent c INNER JOIN #TEMPTABLE2 t ON c.MDID = t.mdid;

 -- Insert new MDID
 INSERT INTO MarketDataCurrent with (ROWLOCK) SELECT * FROM #TEMPTABLE2 
 WHERE MDID NOT IN (SELECT MDID FROM MarketDataCurrent with (NOLOCK))

 -- Clean up the temp table
 DELETE #TEMPTABLE2

commit

为了澄清，这些临时表是由同一连接上的C＃代码创建的，并使用C＃SqlBulkCopy类进行填充。

对我而言，它看起来像是桌面PK上的死锁，所以我尝试删除那个PK并转而使用Unique Constraint，但这会使死锁数量增加10倍。

我完全不知道如何处理这种情况，并且对任何建议持开放态度。

HELP !!

响应XDL的请求，这里是：

<deadlock-list>
 <deadlock victim="processc19978">
  <process-list>
   <process id="processaf0b68" taskpriority="0" logused="0" waitresource="KEY: 6:72057594090487808 (d900ed5a6cc6)" waittime="718" ownerId="1102128174" transactionname="user_transaction" lasttranstarted="2010-06-11T16:30:44.750" XDES="0xffffffff817f9a40" lockMode="U" schedulerid="3" kpid="8228" status="suspended" spid="73" sbid="0" ecid="0" priority="0" transcount="2" lastbatchstarted="2010-06-11T16:30:44.750" lastbatchcompleted="2010-06-11T16:30:44.750" clientapp=".Net SqlClient Data Provider" hostname="RISKAPPS_VM" hostpid="3836" loginname="RiskOpt" isolationlevel="read committed (2)" xactid="1102128174" currentdb="6" lockTimeout="4294967295" clientoption1="671088672" clientoption2="128056">
    <executionStack>
     <frame procname="MKP_RISKDB.dbo.MarketDataCurrent_BulkUpload" line="28" stmtstart="1062" stmtend="1720" sqlhandle="0x03000600a28e5e4ef4fd8e00849d00000100000000000000">
UPDATE c WITH (ROWLOCK) SET LastUpdate = getdate(), Value = t.Value, Source = @source 
FROM MarketDataCurrent c INNER JOIN #MDTUP t ON c.MDID = t.mdid
WHERE c.lastUpdate &lt; @updateTime
and   c.mdid not in (select mdid from MarketData where BloombergTicker is not null and PriceSource like &apos;Blbg.%&apos;)
and   c.value &lt;&gt; t.value     </frame>
     <frame procname="adhoc" line="1" stmtstart="88" sqlhandle="0x01000600c1653d0598706ca7000000000000000000000000">
exec MarketDataCurrent_BulkUpload @clearBefore, @source     </frame>
     <frame procname="unknown" line="1" sqlhandle="0x000000000000000000000000000000000000000000000000">
unknown     </frame>
    </executionStack>
    <inputbuf>
(@clearBefore datetime,@source nvarchar(10))exec MarketDataCurrent_BulkUpload @clearBefore, @source    </inputbuf>
   </process>
   <process id="processc19978" taskpriority="0" logused="0" waitresource="KEY: 6:72057594090487808 (74008e31572b)" waittime="718" ownerId="1102128228" transactionname="user_transaction" lasttranstarted="2010-06-11T16:30:44.780" XDES="0x380be9d8" lockMode="U" schedulerid="5" kpid="8464" status="suspended" spid="248" sbid="0" ecid="0" priority="0" transcount="2" lastbatchstarted="2010-06-11T16:30:44.780" lastbatchcompleted="2010-06-11T16:30:44.780" clientapp=".Net SqlClient Data Provider" hostname="RISKBBG_VM" hostpid="4480" loginname="RiskOpt" isolationlevel="read committed (2)" xactid="1102128228" currentdb="6" lockTimeout="4294967295" clientoption1="671088672" clientoption2="128056">
    <executionStack>
     <frame procname="MKP_RISKDB.dbo.MarketDataCurrentBlbgRtUpload" line="14" stmtstart="840" stmtend="1220" sqlhandle="0x03000600005f9d24c8878f00849d00000100000000000000">
UPDATE c WITH (ROWLOCK) SET LastUpdate = t.LastUpdate, Value = t.Value, Source = t.Source 
        FROM MarketDataCurrent c INNER JOIN #TEMPTABLE2 t ON c.MDID = t.mdid;

        -- Insert new MDID     </frame>
     <frame procname="adhoc" line="1" sqlhandle="0x010006004a58132228bf8d73000000000000000000000000">
MarketDataCurrentBlbgRtUpload     </frame>
    </executionStack>
    <inputbuf>
MarketDataCurrentBlbgRtUpload    </inputbuf>
   </process>
  </process-list>
  <resource-list>
   <keylock hobtid="72057594090487808" dbid="6" objectname="MKP_RISKDB.dbo.MarketDataCurrent" indexname="PK_MarketDataCurrent" id="lock5ba77b00" mode="U" associatedObjectId="72057594090487808">
    <owner-list>
     <owner id="processc19978" mode="U"/>
    </owner-list>
    <waiter-list>
     <waiter id="processaf0b68" mode="U" requestType="wait"/>
    </waiter-list>
   </keylock>
   <keylock hobtid="72057594090487808" dbid="6" objectname="MKP_RISKDB.dbo.MarketDataCurrent" indexname="PK_MarketDataCurrent" id="lock65dca340" mode="U" associatedObjectId="72057594090487808">
    <owner-list>
     <owner id="processaf0b68" mode="U"/>
    </owner-list>
    <waiter-list>
     <waiter id="processc19978" mode="U" requestType="wait"/>
    </waiter-list>
   </keylock>
  </resource-list>
 </deadlock>
</deadlock-list>

4 个答案:

答案 0 :(得分：2)

死锁似乎是关键访问顺序的直接死锁。一个简单的解释是两个批量更新操作之间的更新密钥的重叠。

一个不太重要的解释是，在SQL Server（以及其他服务器）中，锁定的密钥是哈希，并且存在（非常重要的）哈希冲突概率。这可以解释为什么你最近看到更多的死锁与之前相比：只是你的数据量增加了，因此碰撞概率增加了。如果这看起来很深奥且不太可能，请阅读%%lockres%% collision probability magic marker: 16,777,215，并从中链接文章。概率非常高，对于完美密钥分布，在仅约16M插入后，您有50％的碰撞概率。对于普通的，真实的世界，关键分布，你只有几千个插入物具有显着的碰撞概率。不幸的是，没有解决方法。如果这确实是问题，那么唯一的解决方案是减小批量的大小（#temp表的大小），以便降低碰撞概率。或者处理死锁并重试......无论如何你都必须这样做，但至少你可以处理更少的死锁。

答案 1 :(得分：1)

这是在主要工作时间之后发生的，数据没有变化，而且最近刚刚开始。服务器上最近有什么变化吗？我怀疑一些新的数据库维护工作可能会干扰。

顺便说一句，如果您知道市场已关闭且数据未发生变化，为什么您的流程仍在运行？

答案 2 :(得分：1)

我想回答我在评论中提出的一个问题，即

“你如何识别锁定的行？”。

在以下死锁XDL中，在锁定的两个“进程”节点上，存在waitresource属性。在这种情况下：

waitresource="KEY: 6:72057594090487808 (d4005c04b35f)

和

waitresource="KEY: 6:72057594090487808 (b00072ea4ffd)

使用Remus指向的%%lockres%%关键字，

select %%lockres%%, * from MarketDataCurrent 
   where %%lockres%% in ('(d4005c04b35f)', '(b00072ea4ffd)')

这产生了两行冲突。它们确实是独特的ids，没有碰撞。我仍然不知道为什么我在这里陷入僵局，但我越来越近了。

我会注意到两个id都应该只来自LiveFeed程序，但同样，更新中有一个子句应该从另一端实际更新过滤掉这一行。 / p> 

<deadlock-list>
 <deadlock victim="processffffffff8f5872e8">
  <process-list>
   <process id="process8dcb68" taskpriority="0" logused="1256" waitresource="KEY: 6:72057594090487808 (d4005c04b35f)" waittime="1906" ownerId="1349627324" transactionname="user_transaction" lasttranstarted="2010-06-16T16:50:04.727" XDES="0x424e6258" lockMode="U" schedulerid="2" kpid="1004" status="suspended" spid="683" sbid="0" ecid="0" priority="0" transcount="2" lastbatchstarted="2010-06-16T16:50:04.727" lastbatchcompleted="2010-06-16T16:50:04.727" clientapp=".Net SqlClient Data Provider" hostname="RISKAPPS_VM" hostpid="2600" loginname="RiskOpt" isolationlevel="read committed (2)" xactid="1349627324" currentdb="6" lockTimeout="4294967295" clientoption1="671088672" clientoption2="128056">
    <executionStack>
     <frame procname="MKP_RISKDB.dbo.MarketDataCurrent_BulkUpload" line="28" stmtstart="1062" stmtend="1720" sqlhandle="0x03000600a28e5e4ef4fd8e00849d00000100000000000000">
        UPDATE c WITH (ROWLOCK) SET LastUpdate = getdate(), Value = t.Value, Source = @source 
        FROM MarketDataCurrent c INNER JOIN #MDTUP t ON c.MDID = t.mdid
        WHERE c.lastUpdate &lt; @updateTime
        and   c.mdid not in (select mdid from MarketData where BloombergTicker is not null and PriceSource like &apos;Blbg.%&apos;)
        and   c.value &lt;&gt; t.value     </frame>
             <frame procname="adhoc" line="1" stmtstart="88" sqlhandle="0x01000600c1653d0598706ca7000000000000000000000000">
        exec MarketDataCurrent_BulkUpload @clearBefore, @source     </frame>
     <frame procname="unknown" line="1" sqlhandle="0x000000000000000000000000000000000000000000000000">unknown</frame>
    </executionStack>
    <inputbuf>(@clearBefore datetime,@source nvarchar(10))exec MarketDataCurrent_BulkUpload @clearBefore, @source</inputbuf>
   </process>
   <process id="processffffffff8f5872e8" taskpriority="0" logused="0" waitresource="KEY: 6:72057594090487808 (b00072ea4ffd)" waittime="1921" ownerId="1349627388" transactionname="user_transaction" lasttranstarted="2010-06-16T16:50:04.757" XDES="0x289ea040" lockMode="U" schedulerid="5" kpid="11192" status="suspended" spid="382" sbid="0" ecid="0" priority="0" transcount="2" lastbatchstarted="2010-06-16T16:50:04.757" lastbatchcompleted="2010-06-16T16:50:04.757" clientapp=".Net SqlClient Data Provider" hostname="RISKBBG_VM" hostpid="2452" loginname="RiskOpt" isolationlevel="read committed (2)" xactid="1349627388" currentdb="6" lockTimeout="4294967295" clientoption1="671088672" clientoption2="128056">
    <executionStack>
     <frame procname="MKP_RISKDB.dbo.MarketDataCurrentBlbgRtUpload" line="14" stmtstart="840" stmtend="1220" sqlhandle="0x03000600005f9d24c8878f00849d00000100000000000000">
        UPDATE c WITH (ROWLOCK) SET LastUpdate = t.LastUpdate, Value = t.Value, Source = t.Source 
        FROM MarketDataCurrent c INNER JOIN #TEMPTABLE2 t ON c.MDID = t.mdid;
    </frame>
     <frame procname="adhoc" line="1" sqlhandle="0x010006004a58132228bf8d73000000000000000000000000">
        MarketDataCurrentBlbgRtUpload     </frame>
    </executionStack>
    <inputbuf>
        MarketDataCurrentBlbgRtUpload    </inputbuf>
   </process>
  </process-list>
  <resource-list>
   <keylock hobtid="72057594090487808" dbid="6" objectname="MKP_RISKDB.dbo.MarketDataCurrent" indexname="PK_MarketDataCurrent" id="lock409d32c0" mode="U" associatedObjectId="72057594090487808">
    <owner-list>
     <owner id="processffffffff8f5872e8" mode="U"/>
    </owner-list>
    <waiter-list>
     <waiter id="process8dcb68" mode="U" requestType="wait"/>
    </waiter-list>
   </keylock>
   <keylock hobtid="72057594090487808" dbid="6" objectname="MKP_RISKDB.dbo.MarketDataCurrent" indexname="PK_MarketDataCurrent" id="lock706647c0" mode="U" associatedObjectId="72057594090487808">
    <owner-list>
     <owner id="process8dcb68" mode="U"/>
    </owner-list>
    <waiter-list>
     <waiter id="processffffffff8f5872e8" mode="U" requestType="wait"/>
    </waiter-list>
   </keylock>
  </resource-list>
 </deadlock>
</deadlock-list>

答案 3 :(得分：0)

经过近两年恼人的死锁警告电子邮件后，我终于解决了这个问题。

我在竞争插页上使用FULL TABLE LOCKING解决了这个问题。我曾尝试将锁定减少到行级别，但锁定升级到表级别。最后，我认为该表足够小，即使很多用户每秒都在阅读和写入，但完全锁定是我愿意为数据一致性所做的一小部分性能打击。

此外，使用MERGE将插入/更新组合到一个原子语句允许我这样做。

这是已解决的生产代码（它有效！）：

declare @date datetime;
set @date = getdate();

merge marketdatacurrent with (tablockx) as mdc

using #MDTUP as upload
    on mdc.MDID = upload.MDID

when matched then
    update
    set mdc.lastupdate = @date,
        mdc.value = upload.value,
        mdc.source = @source

when not matched then
    insert ( mdid, lastupdate, value, source )
    values ( upload.mdid, @date, upload.value, @source);
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