为什么相同事务的两个并行执行之间会出现死锁？
Why is there a deadlock between two parallel executions of identical transactions?
我有一个应用程序使用 SQL 事务来更新 SQL 服务器上的 msdb 数据库。此事务以不规则的间隔定期执行。 SQL 使用了 Server 2012 (SP4)。一段时间后，SQL 服务器报告 msdb.dbo.backupset table 上的死锁，唯一的参与者是执行上述 SQL 事务的进程
下面是事务的功能示例，将参数替换为示例值，以便可以在 msdb 上轻松执行。应用程序在每次调用事务时传递新参数。
BEGIN TRAN UpdateMediaTables
DECLARE @SqlVersion int
DECLARE @LogDevName nvarchar(512)
DECLARE @MediaSetId int
DECLARE @FamilySequenceNumber tinyint
DECLARE @MaxFamilySequence tinyint
DECLARE @Mirror tinyint
DECLARE @BackupFileName nvarchar(1024)
DECLARE @BackupFileNumber int
DECLARE @MediaFamilyCount int
DECLARE @MirrorCount int
DECLARE @CompressedSize numeric(20, 0)
DECLARE @sql as nvarchar(4000)
SET @SqlVersion = @@microsoftversion / 0x1000000
SET @MediaSetId = 3498233
SET @BackupFileNumber = 1
SET @MediaFamilyCount = 1
SET @MirrorCount = 1
SET @CompressedSize = 378880
SELECT @LogDevName = name
FROM master..sysdevices AS sdev
WHERE phyname = @BackupFileName
SET @sql = N'UPDATE bs SET position = @BackupFileNumber, last_family_number = @MediaFamilyCount'
IF @SqlVersion > 9 -- 2008+
BEGIN
SET @sql = @sql + N', compressed_backup_size = @CompressedSize'
END
SET @sql = @sql + N' FROM msdb..backupset AS bs
WHERE media_set_id = @MediaSetId'
EXEC sp_executesql @sql, N'@MediaFamilyCount int, @BackupFileNumber int, @CompressedSize numeric(20, 0), @MediaSetId int', @BackupFileNumber = @BackupFileNumber,@MediaFamilyCount = @MediaFamilyCount, @CompressedSize = @CompressedSize, @MediaSetId = @MediaSetId
UPDATE bms
SET media_family_count = @MediaFamilyCount, mirror_count = @MirrorCount
FROM msdb..backupmediaset AS bms
WHERE media_set_id = @MediaSetId
-- All bmf's
SET @FamilySequenceNumber = 1
SET @BackupFileName = N'\testcase\Test_TLog_20211121180001.trn'
SET @Mirror = 0
UPDATE bmf
SET bmf.physical_device_name = @BackupFileName
FROM msdb..backupmediafamily AS bmf
WHERE bmf.media_set_id = @MediaSetId
AND bmf.family_sequence_number = @FamilySequenceNumber
AND bmf.mirror = @Mirror
UPDATE bmf
SET bmf.logical_device_name = @LogDevName
FROM msdb..backupmediafamily AS bmf
WHERE bmf.media_set_id = @MediaSetId
AND bmf.family_sequence_number = @FamilySequenceNumber
AND bmf.mirror = @Mirror
SET @MaxFamilySequence = 1
DELETE FROM msdb..backupmediafamily WITH (ROWLOCK)
WHERE media_set_id = @MediaSetId AND family_sequence_number > @MaxFamilySequence
COMMIT TRAN UpdateMediaTables
这里是死锁图的xml：
<deadlock>
<victim-list>
<victimProcess id="process2d890c8"/>
</victim-list>
<process-list>
<process id="process2d890c8" taskpriority="-5" logused="0" waitresource="PAGE: 4:1:8623 " waittime="1550" ownerId="1566457106" transactionname="UpdateMediaTables" lasttranstarted="2021-12-21T15:00:05.697" XDES="0xb16d09b80" lockMode="U" schedulerid="8" kpid="19856" status="suspended" spid="488" sbid="0" ecid="5" priority="5" trancount="0" lastbatchstarted="2021-12-21T15:00:05.660" lastbatchcompleted="2021-12-21T15:00:05.633" lastattention="1900-01-01T00:00:00.633" clientapp="Demo" hostname="AA-SQL1" hostpid="14200" isolationlevel="read uncommitted (1)" xactid="1566457106" currentdb="1" lockTimeout="4294967295" clientoption1="671088672" clientoption2="128056">
<executionStack>
<frame procname="adhoc" line="1" stmtstart="190" sqlhandle="0x020000000aac851a57d841f58dc63ba4bbe4b4059b68c6ab0000000000000000000000000000000000000000">
UPDATE bs SET position = @BackupFileNumber, last_family_number = @MediaFamilyCount, compressed_backup_size = @CompressedSize FROM msdb..backupset AS bs
WHERE media_set_id = @MediaSetId </frame>
<frame procname="mssqlsystemresource.sys.sp_executesql" line="1" stmtstart="-1" sqlhandle="0x0400ff7f427f99d9010000000000000000000000000000000000000000000000000000000000000000000000">
sp_executesql </frame>
<frame procname="adhoc" line="36" stmtstart="1996" stmtend="2528" sqlhandle="0x02000000a5af092360e1ef5edb55dab1b8cfba609a9b02e50000000000000000000000000000000000000000">
EXEC sp_executesql @sql, N'@MediaFamilyCount int, @BackupFileNumber int, @CompressedSize numeric(20, 0), @MediaSetId int', @BackupFileNumber = @BackupFileNumber,@MediaFamilyCount = @MediaFamilyCount, @CompressedSize = @CompressedSize, @MediaSetId = @MediaSetId </frame>
</executionStack>
<inputbuf>
BEGIN TRAN UpdateMediaTables
DECLARE @SqlVersion int
DECLARE @LogDevName nvarchar(512)
DECLARE @MediaSetId int
DECLARE @FamilySequenceNumber tinyint
DECLARE @MaxFamilySequence tinyint
DECLARE @Mirror tinyint
DECLARE @BackupFileName nvarchar(1024)
DECLARE @BackupFileNumber int
DECLARE @MediaFamilyCount int
DECLARE @MirrorCount int
DECLARE @CompressedSize numeric(20, 0)
DECLARE @sql as nvarchar(4000)
SET @SqlVersion = @@microsoftversion / 0x1000000
SET @MediaSetId = 566952
SET @BackupFileNumber = 1
SET @MediaFamilyCount = 1
SET @MirrorCount = 1
SET @CompressedSize = 156160
SELECT @LogDevName = name
FROM master..sysdevices AS sdev
WHERE phyname = @BackupFileName
SET @sql = N'UPDATE bs SET position = @BackupFileNumber, last_family_number = @MediaFamilyCount'
IF @SqlVersion > 9 -- 2008+
BEGIN
SET @sql = @sql + N', compressed_backup_size = @CompressedSize'
END
SET @sql = @sql + N' FROM msdb..backupset AS bs
WHERE media_set_id = @MediaSetId'
EXEC sp_executesql @sql, </inputbuf>
</process>
<process id="process2daa928" taskpriority="-5" logused="0" waitresource="PAGE: 4:1:9263 " waittime="1550" ownerId="1566457106" transactionname="UpdateMediaTables" lasttranstarted="2021-12-21T15:00:05.697" XDES="0x14b82acbd0" lockMode="U" schedulerid="1" kpid="8248" status="suspended" spid="488" sbid="0" ecid="6" priority="5" trancount="0" lastbatchstarted="2021-12-21T15:00:05.660" lastbatchcompleted="2021-12-21T15:00:05.633" lastattention="1900-01-01T00:00:00.633" clientapp="Demo" hostname="AA-SQL1" hostpid="14200" isolationlevel="read uncommitted (1)" xactid="1566457106" currentdb="1" lockTimeout="4294967295" clientoption1="671088672" clientoption2="128056">
<executionStack>
<frame procname="adhoc" line="1" stmtstart="190" sqlhandle="0x020000000aac851a57d841f58dc63ba4bbe4b4059b68c6ab0000000000000000000000000000000000000000">
UPDATE bs SET position = @BackupFileNumber, last_family_number = @MediaFamilyCount, compressed_backup_size = @CompressedSize FROM msdb..backupset AS bs
WHERE media_set_id = @MediaSetId </frame>
<frame procname="mssqlsystemresource.sys.sp_executesql" line="1" stmtstart="-1" sqlhandle="0x0400ff7f427f99d9010000000000000000000000000000000000000000000000000000000000000000000000">
sp_executesql </frame>
<frame procname="adhoc" line="36" stmtstart="1996" stmtend="2528" sqlhandle="0x02000000a5af092360e1ef5edb55dab1b8cfba609a9b02e50000000000000000000000000000000000000000">
EXEC sp_executesql @sql, N'@MediaFamilyCount int, @BackupFileNumber int, @CompressedSize numeric(20, 0), @MediaSetId int', @BackupFileNumber = @BackupFileNumber,@MediaFamilyCount = @MediaFamilyCount, @CompressedSize = @CompressedSize, @MediaSetId = @MediaSetId </frame>
</executionStack>
<inputbuf>
BEGIN TRAN UpdateMediaTables
DECLARE @SqlVersion int
DECLARE @LogDevName nvarchar(512)
DECLARE @MediaSetId int
DECLARE @FamilySequenceNumber tinyint
DECLARE @MaxFamilySequence tinyint
DECLARE @Mirror tinyint
DECLARE @BackupFileName nvarchar(1024)
DECLARE @BackupFileNumber int
DECLARE @MediaFamilyCount int
DECLARE @MirrorCount int
DECLARE @CompressedSize numeric(20, 0)
DECLARE @sql as nvarchar(4000)
SET @SqlVersion = @@microsoftversion / 0x1000000
SET @MediaSetId = 566952
SET @BackupFileNumber = 1
SET @MediaFamilyCount = 1
SET @MirrorCount = 1
SET @CompressedSize = 156160
SELECT @LogDevName = name
FROM master..sysdevices AS sdev
WHERE phyname = @BackupFileName
SET @sql = N'UPDATE bs SET position = @BackupFileNumber, last_family_number = @MediaFamilyCount'
IF @SqlVersion > 9 -- 2008+
BEGIN
SET @sql = @sql + N', compressed_backup_size = @CompressedSize'
END
SET @sql = @sql + N' FROM msdb..backupset AS bs
WHERE media_set_id = @MediaSetId'
EXEC sp_executesql @sql, </inputbuf>
</process>
<process id="process2bb4558" taskpriority="-5" logused="328" waitresource="PAGE: 4:1:9263 " waittime="948" ownerId="1566456428" transactionname="UpdateMediaTables" lasttranstarted="2021-12-21T15:00:04.410" XDES="0x14981ffb80" lockMode="U" schedulerid="7" kpid="19408" status="suspended" spid="470" sbid="0" ecid="7" priority="5" trancount="0" lastbatchstarted="2021-12-21T15:00:04.393" lastbatchcompleted="2021-12-21T15:00:04.393" lastattention="1900-01-01T00:00:00.393" clientapp="Demo" hostname="AA-SQL1" hostpid="14732" isolationlevel="read uncommitted (1)" xactid="1566456428" currentdb="1" lockTimeout="4294967295" clientoption1="671088672" clientoption2="128056">
<executionStack>
<frame procname="adhoc" line="1" stmtstart="190" sqlhandle="0x020000000aac851a57d841f58dc63ba4bbe4b4059b68c6ab0000000000000000000000000000000000000000">
UPDATE bs SET position = @BackupFileNumber, last_family_number = @MediaFamilyCount, compressed_backup_size = @CompressedSize FROM msdb..backupset AS bs
WHERE media_set_id = @MediaSetId </frame>
<frame procname="mssqlsystemresource.sys.sp_executesql" line="1" stmtstart="-1" sqlhandle="0x0400ff7f427f99d9010000000000000000000000000000000000000000000000000000000000000000000000">
sp_executesql </frame>
<frame procname="adhoc" line="36" stmtstart="1996" stmtend="2528" sqlhandle="0x02000000a9093d2c0a0d22ed2f73dc20e182fd1d912553b10000000000000000000000000000000000000000">
EXEC sp_executesql @sql, N'@MediaFamilyCount int, @BackupFileNumber int, @CompressedSize numeric(20, 0), @MediaSetId int', @BackupFileNumber = @BackupFileNumber,@MediaFamilyCount = @MediaFamilyCount, @CompressedSize = @CompressedSize, @MediaSetId = @MediaSetId </frame>
</executionStack>
<inputbuf>
BEGIN TRAN UpdateMediaTables
DECLARE @SqlVersion int
DECLARE @LogDevName nvarchar(512)
DECLARE @MediaSetId int
DECLARE @FamilySequenceNumber tinyint
DECLARE @MaxFamilySequence tinyint
DECLARE @Mirror tinyint
DECLARE @BackupFileName nvarchar(1024)
DECLARE @BackupFileNumber int
DECLARE @MediaFamilyCount int
DECLARE @MirrorCount int
DECLARE @CompressedSize numeric(20, 0)
DECLARE @sql as nvarchar(4000)
SET @SqlVersion = @@microsoftversion / 0x1000000
SET @MediaSetId = 566948
SET @BackupFileNumber = 1
SET @MediaFamilyCount = 1
SET @MirrorCount = 1
SET @CompressedSize = 259072
SELECT @LogDevName = name
FROM master..sysdevices AS sdev
WHERE phyname = @BackupFileName
SET @sql = N'UPDATE bs SET position = @BackupFileNumber, last_family_number = @MediaFamilyCount'
IF @SqlVersion > 9 -- 2008+
BEGIN
SET @sql = @sql + N', compressed_backup_size = @CompressedSize'
END
SET @sql = @sql + N' FROM msdb..backupset AS bs
WHERE media_set_id = @MediaSetId'
EXEC sp_executesql @sql, </inputbuf>
</process>
<process id="process2daacf8" taskpriority="-5" logused="328" waitresource="PAGE: 4:1:8623 " waittime="972" ownerId="1566456428" transactionname="UpdateMediaTables" lasttranstarted="2021-12-21T15:00:04.410" XDES="0x14b82ace80" lockMode="U" schedulerid="1" kpid="7048" status="suspended" spid="470" sbid="0" ecid="4" priority="5" trancount="0" lastbatchstarted="2021-12-21T15:00:04.393" lastbatchcompleted="2021-12-21T15:00:04.393" lastattention="1900-01-01T00:00:00.393" clientapp="Demo" hostname="AA-SQL1" hostpid="14732" isolationlevel="read uncommitted (1)" xactid="1566456428" currentdb="1" lockTimeout="4294967295" clientoption1="671088672" clientoption2="128056">
<executionStack>
<frame procname="adhoc" line="1" stmtstart="190" sqlhandle="0x020000000aac851a57d841f58dc63ba4bbe4b4059b68c6ab0000000000000000000000000000000000000000">
UPDATE bs SET position = @BackupFileNumber, last_family_number = @MediaFamilyCount, compressed_backup_size = @CompressedSize FROM msdb..backupset AS bs
WHERE media_set_id = @MediaSetId </frame>
<frame procname="mssqlsystemresource.sys.sp_executesql" line="1" stmtstart="-1" sqlhandle="0x0400ff7f427f99d9010000000000000000000000000000000000000000000000000000000000000000000000">
sp_executesql </frame>
<frame procname="adhoc" line="36" stmtstart="1996" stmtend="2528" sqlhandle="0x02000000a9093d2c0a0d22ed2f73dc20e182fd1d912553b10000000000000000000000000000000000000000">
EXEC sp_executesql @sql, N'@MediaFamilyCount int, @BackupFileNumber int, @CompressedSize numeric(20, 0), @MediaSetId int', @BackupFileNumber = @BackupFileNumber,@MediaFamilyCount = @MediaFamilyCount, @CompressedSize = @CompressedSize, @MediaSetId = @MediaSetId </frame>
</executionStack>
<inputbuf>
BEGIN TRAN UpdateMediaTables
DECLARE @SqlVersion int
DECLARE @LogDevName nvarchar(512)
DECLARE @MediaSetId int
DECLARE @FamilySequenceNumber tinyint
DECLARE @MaxFamilySequence tinyint
DECLARE @Mirror tinyint
DECLARE @BackupFileName nvarchar(1024)
DECLARE @BackupFileNumber int
DECLARE @MediaFamilyCount int
DECLARE @MirrorCount int
DECLARE @CompressedSize numeric(20, 0)
DECLARE @sql as nvarchar(4000)
SET @SqlVersion = @@microsoftversion / 0x1000000
SET @MediaSetId = 566948
SET @BackupFileNumber = 1
SET @MediaFamilyCount = 1
SET @MirrorCount = 1
SET @CompressedSize = 259072
SELECT @LogDevName = name
FROM master..sysdevices AS sdev
WHERE phyname = @BackupFileName
SET @sql = N'UPDATE bs SET position = @BackupFileNumber, last_family_number = @MediaFamilyCount'
IF @SqlVersion > 9 -- 2008+
BEGIN
SET @sql = @sql + N', compressed_backup_size = @CompressedSize'
END
SET @sql = @sql + N' FROM msdb..backupset AS bs
WHERE media_set_id = @MediaSetId'
EXEC sp_executesql @sql, </inputbuf>
</process>
<process id="process12ee786188" taskpriority="-5" logused="10000" waittime="730" schedulerid="12" kpid="1808" status="suspended" spid="470" sbid="0" ecid="0" priority="5" trancount="2" lastbatchstarted="2021-12-21T15:00:04.393" lastbatchcompleted="2021-12-21T15:00:04.393" lastattention="1900-01-01T00:00:00.393" clientapp="Demo" hostname="AA-SQL1" hostpid="14732" loginname="DEMO\test" isolationlevel="read uncommitted (1)" xactid="1566456428" currentdb="1" lockTimeout="4294967295" clientoption1="671088672" clientoption2="128056">
<executionStack>
<frame procname="adhoc" line="1" stmtstart="190" sqlhandle="0x020000000aac851a57d841f58dc63ba4bbe4b4059b68c6ab0000000000000000000000000000000000000000">
UPDATE bs SET position = @BackupFileNumber, last_family_number = @MediaFamilyCount, compressed_backup_size = @CompressedSize FROM msdb..backupset AS bs
WHERE media_set_id = @MediaSetId </frame>
<frame procname="mssqlsystemresource.sys.sp_executesql" line="1" stmtstart="-1" sqlhandle="0x0400ff7f427f99d9010000000000000000000000000000000000000000000000000000000000000000000000">
sp_executesql </frame>
<frame procname="adhoc" line="36" stmtstart="1996" stmtend="2528" sqlhandle="0x02000000a9093d2c0a0d22ed2f73dc20e182fd1d912553b10000000000000000000000000000000000000000">
EXEC sp_executesql @sql, N'@MediaFamilyCount int, @BackupFileNumber int, @CompressedSize numeric(20, 0), @MediaSetId int', @BackupFileNumber = @BackupFileNumber,@MediaFamilyCount = @MediaFamilyCount, @CompressedSize = @CompressedSize, @MediaSetId = @MediaSetId </frame>
</executionStack>
<inputbuf>
BEGIN TRAN UpdateMediaTables
DECLARE @SqlVersion int
DECLARE @LogDevName nvarchar(512)
DECLARE @MediaSetId int
DECLARE @FamilySequenceNumber tinyint
DECLARE @MaxFamilySequence tinyint
DECLARE @Mirror tinyint
DECLARE @BackupFileName nvarchar(1024)
DECLARE @BackupFileNumber int
DECLARE @MediaFamilyCount int
DECLARE @MirrorCount int
DECLARE @CompressedSize numeric(20, 0)
DECLARE @sql as nvarchar(4000)
SET @SqlVersion = @@microsoftversion / 0x1000000
SET @MediaSetId = 566948
SET @BackupFileNumber = 1
SET @MediaFamilyCount = 1
SET @MirrorCount = 1
SET @CompressedSize = 259072
SELECT @LogDevName = name
FROM master..sysdevices AS sdev
WHERE phyname = @BackupFileName
SET @sql = N'UPDATE bs SET position = @BackupFileNumber, last_family_number = @MediaFamilyCount'
IF @SqlVersion > 9 -- 2008+
BEGIN
SET @sql = @sql + N', compressed_backup_size = @CompressedSize'
END
SET @sql = @sql + N' FROM msdb..backupset AS bs
WHERE media_set_id = @MediaSetId'
EXEC sp_executesql @sql, </inputbuf>
</process>
</process-list>
<resource-list>
<pagelock fileid="1" pageid="8623" dbid="4" subresource="FULL" objectname="msdb.dbo.backupset" id="lock5e1d530780" mode="U" associatedObjectId="72057594045595648">
<owner-list>
<owner id="process12ee786188" mode="U"/>
</owner-list>
<waiter-list>
<waiter id="process2d890c8" mode="U" requestType="wait"/>
</waiter-list>
</pagelock>
<pagelock fileid="1" pageid="9263" dbid="4" subresource="FULL" objectname="msdb.dbo.backupset" id="lockf1b4c0980" mode="U" associatedObjectId="72057594045595648">
<owner-list>
<owner id="process12ee786188" mode="U"/>
</owner-list>
<waiter-list>
<waiter id="process2daa928" mode="U" requestType="wait"/>
</waiter-list>
</pagelock>
<pagelock fileid="1" pageid="9263" dbid="4" subresource="FULL" objectname="msdb.dbo.backupset" id="lockf1b4c0980" mode="U" associatedObjectId="72057594045595648">
<owner-list>
<owner id="process2daa928" mode="U" requestType="wait"/>
</owner-list>
<waiter-list>
<waiter id="process2bb4558" mode="U" requestType="wait"/>
</waiter-list>
</pagelock>
<pagelock fileid="1" pageid="8623" dbid="4" subresource="FULL" objectname="msdb.dbo.backupset" id="lock5e1d530780" mode="U" associatedObjectId="72057594045595648">
<owner-list>
<owner id="process2d890c8" mode="U" requestType="wait"/>
</owner-list>
<waiter-list>
<waiter id="process2daacf8" mode="U" requestType="wait"/>
</waiter-list>
</pagelock>
<exchangeEvent id="Pipe25c250400" WaitType="e_waitPipeGetRow" nodeId="2">
<owner-list>
<owner id="process2daacf8"/>
<owner id="process2bb4558"/>
</owner-list>
<waiter-list>
<waiter id="process12ee786188"/>
</waiter-list>
</exchangeEvent>
</resource-list>
</deadlock>
我不明白这种情况怎么会导致僵局。即使这两个进程并行重合，这两个事务也是相同的，因此以相同的顺序执行它们的查询。此外，更新备份集 table 的查询没有与谁死锁，因为它是整个事务中唯一查询此 table 的查询。锁定是的，但不是死锁。有人可以帮助我了解这种僵局情况是如何发生的吗？
我不想诊断这个，我只想点击“简单按钮”，并使用应用程序锁序列化交易：
BEGIN TRAN UpdateMediaTables
exec sp_getapplock 'UpdateMediaTables', 'Exclusive'
. . .
然后第二个会话将被阻塞在获取任何锁之前直到第一个会话完成。
我有一个应用程序使用 SQL 事务来更新 SQL 服务器上的 msdb 数据库。此事务以不规则的间隔定期执行。 SQL 使用了 Server 2012 (SP4)。一段时间后，SQL 服务器报告 msdb.dbo.backupset table 上的死锁，唯一的参与者是执行上述 SQL 事务的进程
下面是事务的功能示例，将参数替换为示例值，以便可以在 msdb 上轻松执行。应用程序在每次调用事务时传递新参数。
BEGIN TRAN UpdateMediaTables
DECLARE @SqlVersion int
DECLARE @LogDevName nvarchar(512)
DECLARE @MediaSetId int
DECLARE @FamilySequenceNumber tinyint
DECLARE @MaxFamilySequence tinyint
DECLARE @Mirror tinyint
DECLARE @BackupFileName nvarchar(1024)
DECLARE @BackupFileNumber int
DECLARE @MediaFamilyCount int
DECLARE @MirrorCount int
DECLARE @CompressedSize numeric(20, 0)
DECLARE @sql as nvarchar(4000)
SET @SqlVersion = @@microsoftversion / 0x1000000
SET @MediaSetId = 3498233
SET @BackupFileNumber = 1
SET @MediaFamilyCount = 1
SET @MirrorCount = 1
SET @CompressedSize = 378880
SELECT @LogDevName = name
FROM master..sysdevices AS sdev
WHERE phyname = @BackupFileName
SET @sql = N'UPDATE bs SET position = @BackupFileNumber, last_family_number = @MediaFamilyCount'
IF @SqlVersion > 9 -- 2008+
BEGIN
SET @sql = @sql + N', compressed_backup_size = @CompressedSize'
END
SET @sql = @sql + N' FROM msdb..backupset AS bs
WHERE media_set_id = @MediaSetId'
EXEC sp_executesql @sql, N'@MediaFamilyCount int, @BackupFileNumber int, @CompressedSize numeric(20, 0), @MediaSetId int', @BackupFileNumber = @BackupFileNumber,@MediaFamilyCount = @MediaFamilyCount, @CompressedSize = @CompressedSize, @MediaSetId = @MediaSetId
UPDATE bms
SET media_family_count = @MediaFamilyCount, mirror_count = @MirrorCount
FROM msdb..backupmediaset AS bms
WHERE media_set_id = @MediaSetId
-- All bmf's
SET @FamilySequenceNumber = 1
SET @BackupFileName = N'\testcase\Test_TLog_20211121180001.trn'
SET @Mirror = 0
UPDATE bmf
SET bmf.physical_device_name = @BackupFileName
FROM msdb..backupmediafamily AS bmf
WHERE bmf.media_set_id = @MediaSetId
AND bmf.family_sequence_number = @FamilySequenceNumber
AND bmf.mirror = @Mirror
UPDATE bmf
SET bmf.logical_device_name = @LogDevName
FROM msdb..backupmediafamily AS bmf
WHERE bmf.media_set_id = @MediaSetId
AND bmf.family_sequence_number = @FamilySequenceNumber
AND bmf.mirror = @Mirror
SET @MaxFamilySequence = 1
DELETE FROM msdb..backupmediafamily WITH (ROWLOCK)
WHERE media_set_id = @MediaSetId AND family_sequence_number > @MaxFamilySequence
COMMIT TRAN UpdateMediaTables
这里是死锁图的xml：
<deadlock>
<victim-list>
<victimProcess id="process2d890c8"/>
</victim-list>
<process-list>
<process id="process2d890c8" taskpriority="-5" logused="0" waitresource="PAGE: 4:1:8623 " waittime="1550" ownerId="1566457106" transactionname="UpdateMediaTables" lasttranstarted="2021-12-21T15:00:05.697" XDES="0xb16d09b80" lockMode="U" schedulerid="8" kpid="19856" status="suspended" spid="488" sbid="0" ecid="5" priority="5" trancount="0" lastbatchstarted="2021-12-21T15:00:05.660" lastbatchcompleted="2021-12-21T15:00:05.633" lastattention="1900-01-01T00:00:00.633" clientapp="Demo" hostname="AA-SQL1" hostpid="14200" isolationlevel="read uncommitted (1)" xactid="1566457106" currentdb="1" lockTimeout="4294967295" clientoption1="671088672" clientoption2="128056">
<executionStack>
<frame procname="adhoc" line="1" stmtstart="190" sqlhandle="0x020000000aac851a57d841f58dc63ba4bbe4b4059b68c6ab0000000000000000000000000000000000000000">
UPDATE bs SET position = @BackupFileNumber, last_family_number = @MediaFamilyCount, compressed_backup_size = @CompressedSize FROM msdb..backupset AS bs
WHERE media_set_id = @MediaSetId </frame>
<frame procname="mssqlsystemresource.sys.sp_executesql" line="1" stmtstart="-1" sqlhandle="0x0400ff7f427f99d9010000000000000000000000000000000000000000000000000000000000000000000000">
sp_executesql </frame>
<frame procname="adhoc" line="36" stmtstart="1996" stmtend="2528" sqlhandle="0x02000000a5af092360e1ef5edb55dab1b8cfba609a9b02e50000000000000000000000000000000000000000">
EXEC sp_executesql @sql, N'@MediaFamilyCount int, @BackupFileNumber int, @CompressedSize numeric(20, 0), @MediaSetId int', @BackupFileNumber = @BackupFileNumber,@MediaFamilyCount = @MediaFamilyCount, @CompressedSize = @CompressedSize, @MediaSetId = @MediaSetId </frame>
</executionStack>
<inputbuf>
BEGIN TRAN UpdateMediaTables
DECLARE @SqlVersion int
DECLARE @LogDevName nvarchar(512)
DECLARE @MediaSetId int
DECLARE @FamilySequenceNumber tinyint
DECLARE @MaxFamilySequence tinyint
DECLARE @Mirror tinyint
DECLARE @BackupFileName nvarchar(1024)
DECLARE @BackupFileNumber int
DECLARE @MediaFamilyCount int
DECLARE @MirrorCount int
DECLARE @CompressedSize numeric(20, 0)
DECLARE @sql as nvarchar(4000)
SET @SqlVersion = @@microsoftversion / 0x1000000
SET @MediaSetId = 566952
SET @BackupFileNumber = 1
SET @MediaFamilyCount = 1
SET @MirrorCount = 1
SET @CompressedSize = 156160
SELECT @LogDevName = name
FROM master..sysdevices AS sdev
WHERE phyname = @BackupFileName
SET @sql = N'UPDATE bs SET position = @BackupFileNumber, last_family_number = @MediaFamilyCount'
IF @SqlVersion > 9 -- 2008+
BEGIN
SET @sql = @sql + N', compressed_backup_size = @CompressedSize'
END
SET @sql = @sql + N' FROM msdb..backupset AS bs
WHERE media_set_id = @MediaSetId'
EXEC sp_executesql @sql, </inputbuf>
</process>
<process id="process2daa928" taskpriority="-5" logused="0" waitresource="PAGE: 4:1:9263 " waittime="1550" ownerId="1566457106" transactionname="UpdateMediaTables" lasttranstarted="2021-12-21T15:00:05.697" XDES="0x14b82acbd0" lockMode="U" schedulerid="1" kpid="8248" status="suspended" spid="488" sbid="0" ecid="6" priority="5" trancount="0" lastbatchstarted="2021-12-21T15:00:05.660" lastbatchcompleted="2021-12-21T15:00:05.633" lastattention="1900-01-01T00:00:00.633" clientapp="Demo" hostname="AA-SQL1" hostpid="14200" isolationlevel="read uncommitted (1)" xactid="1566457106" currentdb="1" lockTimeout="4294967295" clientoption1="671088672" clientoption2="128056">
<executionStack>
<frame procname="adhoc" line="1" stmtstart="190" sqlhandle="0x020000000aac851a57d841f58dc63ba4bbe4b4059b68c6ab0000000000000000000000000000000000000000">
UPDATE bs SET position = @BackupFileNumber, last_family_number = @MediaFamilyCount, compressed_backup_size = @CompressedSize FROM msdb..backupset AS bs
WHERE media_set_id = @MediaSetId </frame>
<frame procname="mssqlsystemresource.sys.sp_executesql" line="1" stmtstart="-1" sqlhandle="0x0400ff7f427f99d9010000000000000000000000000000000000000000000000000000000000000000000000">
sp_executesql </frame>
<frame procname="adhoc" line="36" stmtstart="1996" stmtend="2528" sqlhandle="0x02000000a5af092360e1ef5edb55dab1b8cfba609a9b02e50000000000000000000000000000000000000000">
EXEC sp_executesql @sql, N'@MediaFamilyCount int, @BackupFileNumber int, @CompressedSize numeric(20, 0), @MediaSetId int', @BackupFileNumber = @BackupFileNumber,@MediaFamilyCount = @MediaFamilyCount, @CompressedSize = @CompressedSize, @MediaSetId = @MediaSetId </frame>
</executionStack>
<inputbuf>
BEGIN TRAN UpdateMediaTables
DECLARE @SqlVersion int
DECLARE @LogDevName nvarchar(512)
DECLARE @MediaSetId int
DECLARE @FamilySequenceNumber tinyint
DECLARE @MaxFamilySequence tinyint
DECLARE @Mirror tinyint
DECLARE @BackupFileName nvarchar(1024)
DECLARE @BackupFileNumber int
DECLARE @MediaFamilyCount int
DECLARE @MirrorCount int
DECLARE @CompressedSize numeric(20, 0)
DECLARE @sql as nvarchar(4000)
SET @SqlVersion = @@microsoftversion / 0x1000000
SET @MediaSetId = 566952
SET @BackupFileNumber = 1
SET @MediaFamilyCount = 1
SET @MirrorCount = 1
SET @CompressedSize = 156160
SELECT @LogDevName = name
FROM master..sysdevices AS sdev
WHERE phyname = @BackupFileName
SET @sql = N'UPDATE bs SET position = @BackupFileNumber, last_family_number = @MediaFamilyCount'
IF @SqlVersion > 9 -- 2008+
BEGIN
SET @sql = @sql + N', compressed_backup_size = @CompressedSize'
END
SET @sql = @sql + N' FROM msdb..backupset AS bs
WHERE media_set_id = @MediaSetId'
EXEC sp_executesql @sql, </inputbuf>
</process>
<process id="process2bb4558" taskpriority="-5" logused="328" waitresource="PAGE: 4:1:9263 " waittime="948" ownerId="1566456428" transactionname="UpdateMediaTables" lasttranstarted="2021-12-21T15:00:04.410" XDES="0x14981ffb80" lockMode="U" schedulerid="7" kpid="19408" status="suspended" spid="470" sbid="0" ecid="7" priority="5" trancount="0" lastbatchstarted="2021-12-21T15:00:04.393" lastbatchcompleted="2021-12-21T15:00:04.393" lastattention="1900-01-01T00:00:00.393" clientapp="Demo" hostname="AA-SQL1" hostpid="14732" isolationlevel="read uncommitted (1)" xactid="1566456428" currentdb="1" lockTimeout="4294967295" clientoption1="671088672" clientoption2="128056">
<executionStack>
<frame procname="adhoc" line="1" stmtstart="190" sqlhandle="0x020000000aac851a57d841f58dc63ba4bbe4b4059b68c6ab0000000000000000000000000000000000000000">
UPDATE bs SET position = @BackupFileNumber, last_family_number = @MediaFamilyCount, compressed_backup_size = @CompressedSize FROM msdb..backupset AS bs
WHERE media_set_id = @MediaSetId </frame>
<frame procname="mssqlsystemresource.sys.sp_executesql" line="1" stmtstart="-1" sqlhandle="0x0400ff7f427f99d9010000000000000000000000000000000000000000000000000000000000000000000000">
sp_executesql </frame>
<frame procname="adhoc" line="36" stmtstart="1996" stmtend="2528" sqlhandle="0x02000000a9093d2c0a0d22ed2f73dc20e182fd1d912553b10000000000000000000000000000000000000000">
EXEC sp_executesql @sql, N'@MediaFamilyCount int, @BackupFileNumber int, @CompressedSize numeric(20, 0), @MediaSetId int', @BackupFileNumber = @BackupFileNumber,@MediaFamilyCount = @MediaFamilyCount, @CompressedSize = @CompressedSize, @MediaSetId = @MediaSetId </frame>
</executionStack>
<inputbuf>
BEGIN TRAN UpdateMediaTables
DECLARE @SqlVersion int
DECLARE @LogDevName nvarchar(512)
DECLARE @MediaSetId int
DECLARE @FamilySequenceNumber tinyint
DECLARE @MaxFamilySequence tinyint
DECLARE @Mirror tinyint
DECLARE @BackupFileName nvarchar(1024)
DECLARE @BackupFileNumber int
DECLARE @MediaFamilyCount int
DECLARE @MirrorCount int
DECLARE @CompressedSize numeric(20, 0)
DECLARE @sql as nvarchar(4000)
SET @SqlVersion = @@microsoftversion / 0x1000000
SET @MediaSetId = 566948
SET @BackupFileNumber = 1
SET @MediaFamilyCount = 1
SET @MirrorCount = 1
SET @CompressedSize = 259072
SELECT @LogDevName = name
FROM master..sysdevices AS sdev
WHERE phyname = @BackupFileName
SET @sql = N'UPDATE bs SET position = @BackupFileNumber, last_family_number = @MediaFamilyCount'
IF @SqlVersion > 9 -- 2008+
BEGIN
SET @sql = @sql + N', compressed_backup_size = @CompressedSize'
END
SET @sql = @sql + N' FROM msdb..backupset AS bs
WHERE media_set_id = @MediaSetId'
EXEC sp_executesql @sql, </inputbuf>
</process>
<process id="process2daacf8" taskpriority="-5" logused="328" waitresource="PAGE: 4:1:8623 " waittime="972" ownerId="1566456428" transactionname="UpdateMediaTables" lasttranstarted="2021-12-21T15:00:04.410" XDES="0x14b82ace80" lockMode="U" schedulerid="1" kpid="7048" status="suspended" spid="470" sbid="0" ecid="4" priority="5" trancount="0" lastbatchstarted="2021-12-21T15:00:04.393" lastbatchcompleted="2021-12-21T15:00:04.393" lastattention="1900-01-01T00:00:00.393" clientapp="Demo" hostname="AA-SQL1" hostpid="14732" isolationlevel="read uncommitted (1)" xactid="1566456428" currentdb="1" lockTimeout="4294967295" clientoption1="671088672" clientoption2="128056">
<executionStack>
<frame procname="adhoc" line="1" stmtstart="190" sqlhandle="0x020000000aac851a57d841f58dc63ba4bbe4b4059b68c6ab0000000000000000000000000000000000000000">
UPDATE bs SET position = @BackupFileNumber, last_family_number = @MediaFamilyCount, compressed_backup_size = @CompressedSize FROM msdb..backupset AS bs
WHERE media_set_id = @MediaSetId </frame>
<frame procname="mssqlsystemresource.sys.sp_executesql" line="1" stmtstart="-1" sqlhandle="0x0400ff7f427f99d9010000000000000000000000000000000000000000000000000000000000000000000000">
sp_executesql </frame>
<frame procname="adhoc" line="36" stmtstart="1996" stmtend="2528" sqlhandle="0x02000000a9093d2c0a0d22ed2f73dc20e182fd1d912553b10000000000000000000000000000000000000000">
EXEC sp_executesql @sql, N'@MediaFamilyCount int, @BackupFileNumber int, @CompressedSize numeric(20, 0), @MediaSetId int', @BackupFileNumber = @BackupFileNumber,@MediaFamilyCount = @MediaFamilyCount, @CompressedSize = @CompressedSize, @MediaSetId = @MediaSetId </frame>
</executionStack>
<inputbuf>
BEGIN TRAN UpdateMediaTables
DECLARE @SqlVersion int
DECLARE @LogDevName nvarchar(512)
DECLARE @MediaSetId int
DECLARE @FamilySequenceNumber tinyint
DECLARE @MaxFamilySequence tinyint
DECLARE @Mirror tinyint
DECLARE @BackupFileName nvarchar(1024)
DECLARE @BackupFileNumber int
DECLARE @MediaFamilyCount int
DECLARE @MirrorCount int
DECLARE @CompressedSize numeric(20, 0)
DECLARE @sql as nvarchar(4000)
SET @SqlVersion = @@microsoftversion / 0x1000000
SET @MediaSetId = 566948
SET @BackupFileNumber = 1
SET @MediaFamilyCount = 1
SET @MirrorCount = 1
SET @CompressedSize = 259072
SELECT @LogDevName = name
FROM master..sysdevices AS sdev
WHERE phyname = @BackupFileName
SET @sql = N'UPDATE bs SET position = @BackupFileNumber, last_family_number = @MediaFamilyCount'
IF @SqlVersion > 9 -- 2008+
BEGIN
SET @sql = @sql + N', compressed_backup_size = @CompressedSize'
END
SET @sql = @sql + N' FROM msdb..backupset AS bs
WHERE media_set_id = @MediaSetId'
EXEC sp_executesql @sql, </inputbuf>
</process>
<process id="process12ee786188" taskpriority="-5" logused="10000" waittime="730" schedulerid="12" kpid="1808" status="suspended" spid="470" sbid="0" ecid="0" priority="5" trancount="2" lastbatchstarted="2021-12-21T15:00:04.393" lastbatchcompleted="2021-12-21T15:00:04.393" lastattention="1900-01-01T00:00:00.393" clientapp="Demo" hostname="AA-SQL1" hostpid="14732" loginname="DEMO\test" isolationlevel="read uncommitted (1)" xactid="1566456428" currentdb="1" lockTimeout="4294967295" clientoption1="671088672" clientoption2="128056">
<executionStack>
<frame procname="adhoc" line="1" stmtstart="190" sqlhandle="0x020000000aac851a57d841f58dc63ba4bbe4b4059b68c6ab0000000000000000000000000000000000000000">
UPDATE bs SET position = @BackupFileNumber, last_family_number = @MediaFamilyCount, compressed_backup_size = @CompressedSize FROM msdb..backupset AS bs
WHERE media_set_id = @MediaSetId </frame>
<frame procname="mssqlsystemresource.sys.sp_executesql" line="1" stmtstart="-1" sqlhandle="0x0400ff7f427f99d9010000000000000000000000000000000000000000000000000000000000000000000000">
sp_executesql </frame>
<frame procname="adhoc" line="36" stmtstart="1996" stmtend="2528" sqlhandle="0x02000000a9093d2c0a0d22ed2f73dc20e182fd1d912553b10000000000000000000000000000000000000000">
EXEC sp_executesql @sql, N'@MediaFamilyCount int, @BackupFileNumber int, @CompressedSize numeric(20, 0), @MediaSetId int', @BackupFileNumber = @BackupFileNumber,@MediaFamilyCount = @MediaFamilyCount, @CompressedSize = @CompressedSize, @MediaSetId = @MediaSetId </frame>
</executionStack>
<inputbuf>
BEGIN TRAN UpdateMediaTables
DECLARE @SqlVersion int
DECLARE @LogDevName nvarchar(512)
DECLARE @MediaSetId int
DECLARE @FamilySequenceNumber tinyint
DECLARE @MaxFamilySequence tinyint
DECLARE @Mirror tinyint
DECLARE @BackupFileName nvarchar(1024)
DECLARE @BackupFileNumber int
DECLARE @MediaFamilyCount int
DECLARE @MirrorCount int
DECLARE @CompressedSize numeric(20, 0)
DECLARE @sql as nvarchar(4000)
SET @SqlVersion = @@microsoftversion / 0x1000000
SET @MediaSetId = 566948
SET @BackupFileNumber = 1
SET @MediaFamilyCount = 1
SET @MirrorCount = 1
SET @CompressedSize = 259072
SELECT @LogDevName = name
FROM master..sysdevices AS sdev
WHERE phyname = @BackupFileName
SET @sql = N'UPDATE bs SET position = @BackupFileNumber, last_family_number = @MediaFamilyCount'
IF @SqlVersion > 9 -- 2008+
BEGIN
SET @sql = @sql + N', compressed_backup_size = @CompressedSize'
END
SET @sql = @sql + N' FROM msdb..backupset AS bs
WHERE media_set_id = @MediaSetId'
EXEC sp_executesql @sql, </inputbuf>
</process>
</process-list>
<resource-list>
<pagelock fileid="1" pageid="8623" dbid="4" subresource="FULL" objectname="msdb.dbo.backupset" id="lock5e1d530780" mode="U" associatedObjectId="72057594045595648">
<owner-list>
<owner id="process12ee786188" mode="U"/>
</owner-list>
<waiter-list>
<waiter id="process2d890c8" mode="U" requestType="wait"/>
</waiter-list>
</pagelock>
<pagelock fileid="1" pageid="9263" dbid="4" subresource="FULL" objectname="msdb.dbo.backupset" id="lockf1b4c0980" mode="U" associatedObjectId="72057594045595648">
<owner-list>
<owner id="process12ee786188" mode="U"/>
</owner-list>
<waiter-list>
<waiter id="process2daa928" mode="U" requestType="wait"/>
</waiter-list>
</pagelock>
<pagelock fileid="1" pageid="9263" dbid="4" subresource="FULL" objectname="msdb.dbo.backupset" id="lockf1b4c0980" mode="U" associatedObjectId="72057594045595648">
<owner-list>
<owner id="process2daa928" mode="U" requestType="wait"/>
</owner-list>
<waiter-list>
<waiter id="process2bb4558" mode="U" requestType="wait"/>
</waiter-list>
</pagelock>
<pagelock fileid="1" pageid="8623" dbid="4" subresource="FULL" objectname="msdb.dbo.backupset" id="lock5e1d530780" mode="U" associatedObjectId="72057594045595648">
<owner-list>
<owner id="process2d890c8" mode="U" requestType="wait"/>
</owner-list>
<waiter-list>
<waiter id="process2daacf8" mode="U" requestType="wait"/>
</waiter-list>
</pagelock>
<exchangeEvent id="Pipe25c250400" WaitType="e_waitPipeGetRow" nodeId="2">
<owner-list>
<owner id="process2daacf8"/>
<owner id="process2bb4558"/>
</owner-list>
<waiter-list>
<waiter id="process12ee786188"/>
</waiter-list>
</exchangeEvent>
</resource-list>
</deadlock>
我不明白这种情况怎么会导致僵局。即使这两个进程并行重合，这两个事务也是相同的，因此以相同的顺序执行它们的查询。此外，更新备份集 table 的查询没有与谁死锁，因为它是整个事务中唯一查询此 table 的查询。锁定是的，但不是死锁。有人可以帮助我了解这种僵局情况是如何发生的吗？
我不想诊断这个，我只想点击“简单按钮”，并使用应用程序锁序列化交易：
BEGIN TRAN UpdateMediaTables
exec sp_getapplock 'UpdateMediaTables', 'Exclusive'
. . .
然后第二个会话将被阻塞在获取任何锁之前直到第一个会话完成。