I have some funny deadlock caused by a stupid simple SQL UPDATE query, on a flat plain table, under default ‘READ COMMITED’ transaction.
UPDATE table SET column=@P1 WHERE PK=@P2 Column PK is varchar(11), has a clustered index on it. no trigger or table relation..etc on the table.
I did some check and find that the deadlock happen on ‘PAGE’ level, not at ROW/record level. Then, I find that for each update query, it does take 100(and more) PAGE locks. (It does not make sense to me because I am updating one row at once)
Is there any way to prevent deadlock being happen? Or, how can reduce the number of locks it takes for one single row update without using cursor?
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Thanks for your suggestion.
I had tried to rebuild the index a few times, with high and low fill factor. I had tried to make processes update different position/slice. But nothing got improved or worst.
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I tried the SQL Server Profiler. I captued some ‘Lock:Deadlock Chain’ and ‘Lock:Deadlock’, but no ‘Deadlock Graph’ was captured. Both side are doing the simple update query in read commited, auto-commit mode.
Lock:Deadlock Chain 17887475 1 0X01 4 myserver 2008-11-28 10:16:46.210 Parallel query worker thread was involved in a deadlock 0 971497 102 - Resource type Exchange Lock:Deadlock Chain 17887476 1 0X01 4 myserver 2008-11-28 10:16:46.210 Deadlock Chain SPID = 209 1:438102 265006271 0 0X56AF060001000000000000001B0006 27 0 - LOCK 4 - U 0 72057594040352768 1 - TRANSACTION 0 6 - PAGE mydatabase 971497 101 - Resource type Lock Lock:Deadlock Chain 17887477 1 0X01 4 myserver 2008-11-28 10:16:46.210 Parallel query worker thread was involved in a deadlock 0 971497 102 - Resource type Exchange Lock:Deadlock Chain 17887478 1 0X01 4 myserver 2008-11-28 10:16:46.210 Deadlock Chain SPID = 54 1:426206 265006240 0 0XDE80060001000000000000001B0006 27 0 - LOCK 4 - U 0 72057594040352768 1 - TRANSACTION 0 6 - PAGE mydatabase 971497 101 - Resource type Lock Lock:Deadlock Chain 17887479 1 0X01 4 myserver 2008-11-28 10:16:46.210 Deadlock Chain SPID = 209 1:426206 265006271 0 0XDE80060001000000000000001B0006 27 0 - LOCK 4 - U 0 72057594040352768 1 - TRANSACTION 0 6 - PAGE mydatabase 971497 101 - Resource type Lock Lock:Deadlock Chain 17887480 1 0X01 4 myserver 2008-11-28 10:16:46.210 Parallel query worker thread was involved in a deadlock 0 971497 102 - Resource type Exchange Lock:Deadlock Chain 17887481 1 0X01 4 myserver 2008-11-28 10:16:46.210 Deadlock Chain SPID = 54 1:426066 265006240 0 0X5280060001000000000000001B0006 27 0 - LOCK 4 - U 0 72057594040352768 1 - TRANSACTION 0 6 - PAGE mydatabase 971497 101 - Resource type Lock Lock:Deadlock Chain 17887482 1 0X01 4 myserver 2008-11-28 10:16:46.210 Deadlock Chain SPID = 209 1:426066 265006271 0 0X5280060001000000000000001B0006 27 0 - LOCK 4 - U 0 72057594040352768 1 - TRANSACTION 0 6 - PAGE mydatabase 971497 101 - Resource type Lock Lock:Deadlock Chain 17887483 1 0X01 4 myserver 2008-11-28 10:16:46.210 Parallel query worker thread was involved in a deadlock 0 971497 102 - Resource type Exchange Lock:Deadlock Chain 17887484 1 0X01 4 myserver 2008-11-28 10:16:46.210 Deadlock Chain SPID = 209 1:425614 265006271 0 0X8E7E060001000000000000001B0006 27 0 - LOCK 4 - U 0 72057594040352768 1 - TRANSACTION 0 6 - PAGE mydatabase 971497 101 - Resource type Lock Lock:Deadlock Chain 17887485 1 0X01 4 myserver 2008-11-28 10:16:46.210 Parallel query worker thread was involved in a deadlock 0 971497 102 - Resource type Exchange Lock:Deadlock Chain 17887486 1 0X01 4 myserver 2008-11-28 10:16:46.210 Deadlock Chain SPID = 209 1:426687 265006271 0 0XBF82060001000000000000001B0006 27 0 - LOCK 4 - U 0 72057594040352768 1 - TRANSACTION 0 6 - PAGE mydatabase 971497 101 - Resource type Lock Lock:Deadlock Chain 17887487 1 0X01 4 myserver 2008-11-28 10:16:46.210 Parallel query worker thread was involved in a deadlock 0 971497 102 - Resource type Exchange Lock:Deadlock Chain 17887488 1 0X01 4 myserver 2008-11-28 10:16:46.210 Deadlock Chain SPID = 209 1:425392 265006271 0 0XB07D060001000000000000001B0006 27 0 - LOCK 4 - U 0 72057594040352768 1 - TRANSACTION 0 6 - PAGE mydatabase 971497 101 - Resource type Lock Lock:Deadlock Chain 17887489 1 0X01 4 myserver 2008-11-28 10:16:46.210 Parallel query worker thread was involved in a deadlock 0 971497 102 - Resource type Exchange Lock:Deadlock Chain 17887491 1 0X01 4 myserver 2008-11-28 10:16:46.210 Parallel query worker thread was involved in a deadlock 0 971497 102 - Resource type Exchange Lock:Deadlock Chain 17887493 1 0X01 4 myserver 2008-11-28 10:16:46.210 Parallel query worker thread was involved in a deadlock 0 971497 102 - Resource type Exchange Lock:Deadlock Chain 17887494 1 0X01 4 myserver 2008-11-28 10:16:46.210 Deadlock Chain SPID = 209 1:435792 265006271 0 0X50A6060001000000000000001B0006 27 0 - LOCK 4 - U 0 72057594040352768 1 - TRANSACTION 0 6 - PAGE mydatabase 971497 101 - Resource type Lock Lock:Deadlock Chain 17887495 1 0X01 4 myserver 2008-11-28 10:16:46.210 Parallel query worker thread was involved in a deadlock 0 971497 102 - Resource type Exchange Lock:Deadlock Chain 17887496 1 0X01 4 myserver 2008-11-28 10:16:46.210 Deadlock Chain SPID = 209 1:438206 265006271 0 0XBEAF060001000000000000001B0006 27 0 - LOCK 4 - U 0 72057594040352768 1 - TRANSACTION 0 6 - PAGE mydatabase 971497 101 - Resource type Lock Lock:Deadlock 17887497 myuser 0XCD85FBB269700B4AA2F4E8579D118999 209 myserver myuser 2008-11-28 10:16:45.930 1:426206 265006271 myapps 0 0XDE80060001000000000000001B0006 123 27 281 2008-11-28 10:16:46.210 myclient 0 - LOCK 4 - U 0 72057594040352768 1 - TRANSACTION 0 6 - PAGE mydatabase 971498
I finally have to do a workaround by using cusror in a stored procedure.
But it is still interesting that how the PAGE lock happen and how to resolve.
After some more search on Google, there are some other people have the same problem and they(from MSDN forum) suggest to turn off the parallelism in SQL Server 2005 but I never get a chance to try.