September 23, 2010 at 2:40 am
We have Microsoft SQL Server 2005 - 9.00.4207.00 (X64) Enterprise Edition (64-bit) on Windows server 2003 (Build 3790: Service Pack 2) .
Periodically (~ once per 15 min) some db-clients have error messages when open connection (over SQL Native Client ) like:
Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding.
All timeouts more or equal 15 sec. Less then 15 sec is not acceptable by business rules. Performance counters (cpu,memory,disk etc.) on server does not show bottleneck. Only one sql counter - logins/sec show trouble. When problem exists then this counter = 0. Also dramatically decrease many other counters - sql batch requests/sec, transactions/sec, cpu load and some ones. SQL Server "sleep" few seconds (4 - 5) and then accessible again.
Thanks.
September 23, 2010 at 3:51 am
Few things :
1.take help of sp_lock and sp_who2, and see if you can find/trace some suspect spid.
2.Any backend process/job at the same time.
3.read the errorlog
-------Bhuvnesh----------
I work only to learn Sql Server...though my company pays me for getting their stuff done;-)
September 23, 2010 at 3:57 am
quick steps to identify the isssues are
1. run sp_who2 check any blocked SPID are there or not.
2. find out what is the blocked SPID T-SQL .
3. need to check is there any other batch job or process running on the server
Regards,
Subbu
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September 23, 2010 at 6:39 am
this is production server under heavy load... many users and jobs work simultaneously...
no unusual locks or any deadlocks in trouble time...
Symptoms very like to: http://support.microsoft.com/?id=918483
and timeouts correlate with memory reallocation events (from last query from ms article)... but i can't find core of "freezing" of server
September 29, 2010 at 7:16 am
thanks all, the problem was mostly solved.
I found that timeouts occur when 100% load of some cpu cores. Optimization of stored procedurs was helped us.
The Microsoft article, which sent us on the right way:
September 29, 2010 at 10:40 am
it is always to have the patches or hotfixes updated with our SQL Server .:) great to hear that your issuse is resolved:-)
Regards,
Subbu
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October 1, 2010 at 7:35 am
Not exactly. The patch has not helped, helped a phrase from the article:
... If you continue to have problems after you have installed this hotfix, troubleshoot the issue from an authentication and performance perspective.
Conclusion: Login timeouts occur when high cpu load (especially when 100% load on some cores) and many concurent connections.
Helps reduce the load on the processor, in our case: setting a parameter
max degree of parallelism from 0 to 2 and the cost threshold for parallelism = 30
and also optimization stored procedures and adding additional indexes.
Useful query to monitor cpu cores load:
SELECT scheduler_id, current_tasks_count, runnable_tasks_count
FROM sys.dm_os_schedulers
WHERE scheduler_id < 255
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