SQLOSDMV’s Continue

sys.dm_os_waiting_tasks One can run lots of interesting queries using this view.  You can even use this view to perform deadlock detection that is not resolvable by deadlock monitor, DM. For example if you have tasks waiting on external resources such as extended stored procedures and blocking others from running. This type of deadlock DM can’t…


SQLOS’s DMVs Continue

sys.dm_os_schedulers Q. Do I need to by more CPUs? In order to answer this question you have to find out if your load is really CPU bounded.  Your load is really CPU bounded if a number of runnable tasks per each scheduler always greater than 1 and all of your queries have correct plan.  The…


Talking points around SQL Server 2005 scalability

Couple of weeks ago I did a talk on SQL Server 2005 scalability. The actual talk was not about the enormous amount of features that you can leverage in SQL Serve 2005 to make your application scale but rather how SQL 2005 achieves its scalability. In this post I present a set of talking points…


Set of new features in SQL Server 2005 enabled by SQLOS

Couple of weeks ago I had a chance to visit set of our customers and talk to them directly. It was an unforgettable experience. As a part of the visit I made set of presentations related to SQLOS and new features it enables in SQL Server 2005. I thought that some of you might be…


Be aware: To Hyper or not to Hyper

Our customers observed very interesting behavior on high end Hyperthreading (HT) enabled hardware. They noticed that in some cases when high load is applied SQL Server CPU usage increases significantly but SQL Server performance degrades. Occasionally they would also see message in errorlog indicating one of the threads can’t acquire a spinlock (Spinlock is a…


Configuring SQL Server 2005 for Soft NUMA

Sometimes I am surprised how issues come up the moment you mention them J. Recently, I have discussed Soft NUMA configurations in the article http://blogs.msdn.com/slavao/articles/441058.aspx. This week one of our customers had an interesting problem. The customer wanted to partition single SQL server instance based on the load. Customer’s application is heterogynous. It consists of…


SQL Server 2005 NUMA support & troubleshooting

SQL Server 2005 has been designed to take advantage of NUMA features exposed by both hardware and the Windows operating system. There are several caveats that you need to be aware when attempting to run SQL Server on NUMA platforms.   In this post I would like to go over both Windows’s and SQL Server’s…


SQLOS helps SQL Server to leverage hardware capabilities

I just finished an article on how SQLOS helps SQL Server to leverage hardware capabilities http://blogs.msdn.com/slavao/articles/441058.aspx.  It will be interesting to hear your comments, thoughts. Thanks a lot in advance


Be aware: FLS-Fiber Local Storage

Problem: In the last several months there were several publications describing usage of fibers.  When covering SQLOS’s scheduling I will go into more details about them. Today I would like to touch on the subject on how to make your dlls/libraries more robust in the fiber environment.   As you know, when running SQL server…


SQLOS – unleashed

With SQL Server 2005 Beta 1 and Beta 2 you might have noticed that there is no ums.dll in the bin directory. The reason is simple it is no longer exists.  In SQL2000 ums.dll provided SQL Server with user mode non-preemptive scheduling. So what happened in latest version? Have we removed non-preemptive scheduling? The answer…