how to avoid deadlock by delete/insert statements

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how to avoid deadlock by delete/insert statements

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Topic

salmanshehbaz
Starting Member

3 Posts

Posted - 2011-03-14 : 18:37:41

Guys

Recently I have come across a deadlock scenario on OLTP box (Sql server 2005) of a client
and found that it's caused by two stored procedures being called by 2 different threads.

1. Insert sp that inserts data in X table.

Insert Into X (col1 , col2 , col3 )
Values ('value 1' , 'value 2' , 'value 3' )

2. Delete sp that deletes data from X table.

DELETE X
FROM X T1 WITH (NOLOCK)
INNER JOIN Y T2 WITH (NOLOCK)
ON T1.[col2] = T2.[col2]
WHERE t2.date < 'date time value'

X table has one unique, clustered primary key and two non clustered, non unique indexes.
I have analysed the deadlock by setting t1222 tace flag on and the output is summarized below;

Insert sp acquired a IX lock on Non clustered index for Column 1.
Delete sp is waiting for X lock on the same Non clustered index for column 1 during this time.

Delete sp acquired a U lock on Non clustered index for Column 2.
Insert sp is waiting for a IX lock on the same Non clustered index for Column 2 during this time.

Any idea or suggestion to avoid deadlock would be really appreciated.
Thanks,
-Salman.

jeffw8713
Aged Yak Warrior

819 Posts

Posted - 2011-03-14 : 22:04:03

What columns are the non-clustered indexes created on? For something like this, I would see if I could create another non-clustered index on a different column that can be used by the delete statement.

I would also recommend (strongly) that you remove the NOLOCK hints on the delete.

Jeff

salmanshehbaz
Starting Member

3 Posts

Posted - 2011-03-15 : 02:34:45

Jeff

Non clustered indexes are on Col1 and Col2 of X table.
below is the output of trace file just for reference;

deadlock-list
deadlock victim=process3c77d68
process-list
process id=process3c12c58 taskpriority=0 logused=1044 waitresource=PAGE: 17:8:7726 waittime=1250 ownerId=5169682909 transactionname=user_transaction lasttranstarted=2011-02-03T03:34:03.443 XDES=0xfe64d78b0 lockMode=IX schedulerid=2 kpid=9544 status=suspended spid=219 sbid=0 ecid=0 priority=0 transcount=2 lastbatchstarted=2011-02-03T03:34:03.457 lastbatchcompleted=2011-02-03T03:34:03.453 clientapp=.Net SqlClient Data Provider hostname=HQMTSRV026 hostpid=3308 loginname=EASUser isolationlevel=read committed (2) xactid=5169682909 currentdb=17 lockTimeout=4294967295 clientoption1=671088672 clientoption2=128056
executionStack
frame procname=adhoc line=1 stmtend=296 sqlhandle=0x0200000084ce2a1d0e95a5623fa3a9c0981d422e33cab999
(@1 int<c/>@2 varchar(8000)<c/>@3 nvarchar(4000))INSERT INTO [VB_Audit_TransactionDetail]([ItemID]<c/>[TransactionID]<c/>[ItemValue]) values(@1<c/>@2<c/>@3)
frame procname=adhoc line=1 stmtend=296 sqlhandle=0x02000000afcb1733f435fb93e13556600acf32bb32e10020
Insert Into VB_Audit_TransactionDetail (ItemID <c/> TransactionID <c/> ItemValue ) Values (4 <c/> '0255978c-f56e-477e-b361-8abe62433cff' <c/> N'HQOLB006' )
frame procname=EAS.dbo.SP_Insert line=13 stmtstart=482 stmtend=522 sqlhandle=0x03001100805efa5997d69400719600000100000000000000
exec (@CommandText)
inputbuf
Proc [Database Id = 17 Object Id = 1509580416]
process id=process3c77d68 taskpriority=0 logused=364 waitresource=PAGE: 17:6:334008 waittime=1234 ownerId=5169682116 transactionname=user_transaction lasttranstarted=2011-02-03T03:34:03.053 XDES=0xa8e297cd0 lockMode=X schedulerid=12 kpid=10300 status=suspended spid=327 sbid=0 ecid=0 priority=0 transcount=2 lastbatchstarted=2011-02-03T03:33:41.137 lastbatchcompleted=2011-02-03T03:33:41.133 clientapp=Microsoft SQL Server hostname=HQSSISSRV002 hostpid=7632 loginname=NBKDOM\SQLCSRVC isolationlevel=read committed (2) xactid=5169682116 currentdb=17 lockTimeout=4294967295 clientoption1=671350816 clientoption2=128056
executionStack
frame procname=EAS.dbo.PurgeAuditTransactionTables line=59 stmtstart=4202 stmtend=4728 sqlhandle=0x030011006354a2313d11ae00979a00000100000000000000
DELETE [dbo].[Audit_TransactionDetail]
FROM [dbo].[Audit_TransactionDetail] T1 WITH (NOLOCK)
INNER JOIN [dbo].[Audit_NBKTransaction] T2 WITH (NOLOCK)ON T1.[TransactionID] = T2.[TransactionID]
WHERE TransactionPostedDateTime < @LastReplicationDateTime
frame procname=adhoc line=1 sqlhandle=0x0100110096968c0560c430ff190000000000000000000000
EXEC PurgeAuditTransactionTables '02 Feb 2011 19:00:13:870'
inputbuf
EXEC PurgeAuditTransactionTables '02 Feb 2011 19:00:13:870'
resource-list
pagelock fileid=8 pageid=7726 dbid=17 objectname=EAS.dbo.Audit_TransactionDetail id=lock4f79500 mode=U associatedObjectId=886415243542528
owner-list
owner id=process3c77d68 mode=U
waiter-list
waiter id=process3c12c58 mode=IX requestType=wait
pagelock fileid=6 pageid=334008 dbid=17 objectname=EAS.dbo.Audit_TransactionDetail id=lock846afca00 mode=IX associatedObjectId=604940266831872
owner-list
owner id=process3c12c58 mode=IX
waiter-list
waiter id=process3c77d68 mode=X requestType=wait

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