Scheduler node deadlock message.

Hi:

We seem to be hitting a performance problem on SQL Server 2005. We encounter the following message frequently in the event log. We have update stats, reindexing and everything else in place. However this message keeps getting logged.

All schedulers on Node 0 appear deadlocked due to a large number
of worker threads waiting on LCK_M_IS. Process Utilization 25%%

MS Experts (Product Gurus)/MVPs can you please offer some explanation or insight into the error and also a possible resolution on how to fix it. I have the following questions:

1). Is this related to poor queries performing badly and needs to be tuned?.

2). Is this a more DIsk I/O Issue and whether we need faster disks or disk arrays?

3). Is something configured wrongly on the SQL Server?

4). Are we handling our transactions badly and thus resulting in blocking or deadlocks?.

Please provide your valuable suggestions.

Thanks

Ankith

I forgot to mention the system configuration.

The Server is Windows Server 2003 (x64 Edition) with AMD Quad (4) Processors (2.2 GHZ) and has apprx 16 GB of RAM.

Awe is enabled.

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This message indicates that there are some pretty long blocking chains on your server.

Have a look at the blocking section in http://www.microsoft.com/technet/prodtechnol/sql/2005/tsprfprb.mspx for methods of troubleshooting blocking issues.

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Hi Jerome:

Thanks for the info. Is this error anyway related to Hard disk contention (because I see worker threads waiting on LCK_M_IS). Just want to get your opinion and see if we can also take a look at our hard disks.

Thanks.

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Based on the wait type it's highly unlikely that disk issues have anything to do with the problem. Start by looking at the connection that's holding incompatible lock and determine what it's doing.

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