Slava Oks's WebLog

Changing gears

slavao — Wed, 07 Mar 2007 16:15:00 GMT

You haven't heard from me in while and there is a reason. I moved from SQL Server's Storage Engine team to a new incubation team that is involved in exploring new directions in operating systems. This subject area has been always very fascinating for...(read more)

Q and A: Ratio between AWE Allocated and VM Committed/Reserved in DBCC MEMORYSTATUS output

slavao — Wed, 03 Jan 2007 01:02:00 GMT

Q: What kind of ratio should you expect to see between AWE Allocated and VM Committed/Reserved? We are running 8GB with a cap of 7GB in the max server memory and yet the VM Committed is around 100MB. I was first shocked to see that the sqlservice in task...(read more)

Q & A: I am running on 64 bit and all of my tasks are waiting on SOS_RESERVEDMEMBLOCKLIST, What is going on?

slavao — Tue, 14 Nov 2006 18:29:00 GMT

This wait type represents waiting on multi page allocations inside of SQLOS's memory manager. As you remember from my description of memory manager's working internals, it has two major allocators single page allocator, SPA and multi page allocator, MPA....(read more)

SQLOSDMV's Continue

slavao — Tue, 14 Nov 2006 18:26:00 GMT

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...(read more)

Q & A: Does SQL Server always respond to memory pressure?

slavao — Mon, 13 Nov 2006 20:39:00 GMT

Q: I thought I've seen reference recently to problems with SQL2005 not releasing memory when under pressure, and this was possibly due to the Lock Pages In Memory option. We have a server where this seems to be happening, i.e. SQL2005 uses all available...(read more)

SQLOS's DMVs Continue

slavao — Fri, 29 Sep 2006 02:22:00 GMT

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...(read more)

SQLOS's DMVs

slavao — Tue, 22 Aug 2006 23:54:00 GMT

SQL Server 2005 has a large number of DMVs that you can take advantage of especially when you try to understand behavioral characteristics of your SQL Server 2005 installation. DMVs expose enormous amount of information but how can you make use of it?...(read more)

Talking points around SQL Server 2005 scalability

slavao — Thu, 03 Aug 2006 15:09:00 GMT

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...(read more)

Q & A: I can't make SQL Server 2005 32 bit version to use all memory on the machine

slavao — Thu, 03 Aug 2006 14:41:00 GMT

I’m currently using the RTM+SP1 x86-SQL2005 build on a server which has 32GB of physical memory. I notice that during ramp-up the memory usage (as seen under task manager) increases to about 28GB (i.e. “Available memory” reduces to 4GB) and stays there....(read more)

Set of new features in SQL Server 2005 enabled by SQLOS

slavao — Wed, 12 Apr 2006 18:57:00 GMT

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...(read more)

Q and A: Enabling AWE settings for SQL Server 32 bit edition in WOW

slavao — Wed, 12 Apr 2006 18:25:00 GMT

Q. A customer wants to run SQL 2000 SP4 in a Windows Server 2003 SP1 x64 edition. They did the installation without problems but SQL Server is not using more than 4GB of memory. Is it possible to enable AWE in this configuration? A. The answer is yes,...(read more)

Q and A: Some questions about output from dbcc memorystatus

slavao — Mon, 20 Mar 2006 01:18:00 GMT

Recently I have recieved following question: A customer of mine is getting this output on an Itanium with 16GB of memory: Memory Manager KB ------------------------------ -------------------- VM Reserved 16979888 VM Committed 217928 AWE Allocated 14116272...(read more)

Q and A: SQL Server memory allocated outside of Buffer Pool, formerly known as MemToLeave

slavao — Tue, 14 Mar 2006 18:14:00 GMT

Q. Under SQL Server 2000 Is the memtoleave concept still valid under 64-bit? A. Yes. If SQL Server’s component requests memory larger than 8 KB block, the block will be allocated outside of Buffer Pool. Remember, inside of SQL Server, Buffer Pool is preferable...(read more)

Q and A: Do I need to run "sp_configure 'awe enabled', 1" to make 64 bit version of SQL Server use locked pages?

slavao — Mon, 13 Mar 2006 17:44:00 GMT

The answer is No. The source of possible confusion came from one of my previous posts: http://blogs.msdn.com/slavao/archive/2005/11/15/493019.aspx . I apologize for the confusion. In order to make 64 bit version of SQL Server leverage locked pages all...(read more)

Be Aware: 4GB of VAS under WOW, does it really worth it?

slavao — Mon, 13 Mar 2006 00:12:00 GMT

By now you have heard a lot about the fact that under WOW a 32 bit process can get 4GB of VAS. I agree this is great, but I would like you to be aware of something that might hit you really hard. As it turns out enabling 4GB VAS can be problematic due...(read more)