Capping CPU using Resource Governor – The Concurrency Mathematics

Here is what you need to know: A = πr2 Okay, not really as that is the formula for the area of a circle but it does set the stage for this discussion.   I have been working with the CAP_CPU_PERCENT (RESOURCE POOL) setting as it relates to concurrency.   This turned into a mathematical exercise I…

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Strange Sch-S / Sch-M Deadlock on Machines with 16 or More Schedulers

Since it took me several days to track down this bug, and I did learn a couple of new things along the way, I thought I would share some of my work. 16 or More CPUS When a system presents SQL Server with 16 or more CPUs, and you are using a high end SQL…

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SQL Server 2012 – True Black Box Recorder

This would be a perfect time to post a blog talking about the new SQL Server 2012 features.  However, I am going to leave that activity to the marketing folks (AlwaysOn, T-SQL Enhancements, …).   I want to talk about something that might not appear on the top of a marketing or sales checklist but for…

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How It Works: Extended Event (sqlos.wait_info*)

I was posed a good question today about how the wait_info* event works in SQL Server 2008.   The easiest way for me to answer the question was to prove the behavior.  using WAITFOR DELAY it shows the behavior nicely.   From: Robert Dorr Sent: Wednesday, October 20, 2010 2:07 PMSubject: RE: Extended Events   The…

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Why does PREEMPTIVE_OS_GETPROCADDRESS Show a Large Accumulation?

There is a bug in SQL Server 2008 that causes PREEMPTIVE_OS_GETPROCADDRESS to include and accumulate the execution time of the extended stored procedure (XPROC). The following is an example showing the increase in the GetProcAddress wait time. select * from sys.dm_os_wait_stats where wait_type = ‘PREEMPTIVE_OS_GETPROCADDRESS’ or wait_type = ‘MSQL_XP’exec master..xp_dirtree ‘f:’select * from sys.dm_os_wait_stats where…

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How It Works: Orphan DTC Transaction (Session/SPID = -2)

It looks like it would be a good post to help clarify that -2 does NOT mean ORPHAN. _____________________________________________________________________________________ CURRENT EXCHANGE _____________________________________________________________________________________ From: Robert Dorr Sent: Tuesday, April 20, 2010 8:47 AM Subject: RE: ONSITE:Orphaned Distributed Transactions   Let me clarify the term Orphaned.  A -2 is not Orphaned it means there are NO ENLISTED…

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The SQL Server Wait Type Repository…

12/10/2009: Significant updates to the blog. Check back in 2010 for more updates to the wait type table   As part of my talk at the 2009 US PASS Summit here in Seattle called Inside SQL Server Wait Types, I’m creating this blog post as a reference point that can be used to find out…

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