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Blog Post: SQL Server MAX DOP Beyond 64 – Is That Possible?

SQL Server Support Content

I recently posted a blog outlining how the partitions of a table can be used in the calculation for the achievable max degree of parallelism (MAX DOP). http://blogs.msdn.com/b/psssql/archive/2014/09/04/a-partitioned-table-may-limit-the-runtime-max-dop ...read more

on 30 Oct 2014
Blog Post: A Partitioned Table May Limit the Runtime MAX DOP of Create/Alter Index

SQL Server Support Content

I was working with a 1.3 trillion row table in the Microsoft lab when I learned more about the ins and outs of this behavior. This issue is alluded to in SQL Server Books Online but allow me to expand on the behavior a bit more. ( http://msdn.microsoft ...read more

on 4 Sep 2014
Blog Post: How It Works: Behavior of a 1 Trillion Row Index Build (Gather Streams from SORT)

SQL Server Support Content

I ran into this behavior working on a 1 trillion row, spatial index build but the behavior can apply to any Gather Streams operator, retaining the sort order as rows pass though it. I was just surprised a bit by the behavior until I dug deeper ...read more

on 29 Apr 2014
Blog Post: How It Works: CMemThread and Debugging Them

SQL Server Support Content

The wait type of CMemThread shows up in outputs such as sys.dm_exec_requests. This post is intended to explain what a CMemThread is and what you might be able to do to avoid the waits. The easiest way to describe a CMemThread is to talk about ...read more

on 20 Dec 2012
Blog Post: All about RollbackSnapshotTempDB...

SQL Server Support Content

I’ve been recently involved in several cases where Databases named RollbackSnapshotTempDB +<someGUID> were generating confusion. The purpose of this post is to clarify their origin and use and to enable SQL Server admins to know what to do ...read more

on 7 Nov 2013
Blog Post: How It Works: SQL Server 32 bit PAE/AWE on (SQL 2005, 2008, and 2008 R2) – Not Using As Much RAM As Expected!

SQL Server Support Content

This issue was puzzling until we stepped through the code and studied it in some detail. The report was “SQL Server won’t use the physical memory I expect it to use.” Scenario: SQL Server 2008 R2, 32GB RAM - SQL only using ~22GB ...read more

on 11 Dec 2012
Blog Post: SQLIOSim Checksum Validations

SQL Server Support Content

I had a very specific question asked of me related to the SQLIOSIM.exe, checksum validation logic. It is pretty simple logic (on purpose) but effective so here are the basics. The key is that there are multiple memory locations used to hold the ...read more

on 5 Apr 2013
Blog Post: Strange Sch-S / Sch-M Deadlock on Machines with 16 or More Schedulers

SQL Server Support Content

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 ...read more

on 31 Aug 2012
Blog Post: SQL Server–Storage Spaces/VHDx and 4K Sector Size

SQL Server Support Content

This blog outlines a new twist to my previous blog outlining issues with 4K sector sizes. SQL Server - New Drives Use 4K Sector Size: http://blogs.msdn.com/b/psssql/archive/2011/01/13/sql-server-new-drives-use-4k-sector-size.aspx In the previous post ...read more

on 15 May 2013
Blog Post: Upgrade from SQL 2005 to SQL 2012 fails with error “Service 'SQLSERVERAGENT' start request failed.”

SQL Server Support Content

I was working on a 2005 to 2012 upgrade issue and came across an interesting issue which I thought of sharing with you guys. Whilst running an upgrade from 2005 SP4 to 2012 RTM (and/or slipstreamed copy) it failed half way through, giving the error ...read more

on 24 Jul 2013
Blog Post: How It Works: Gotcha: *VARCHAR(MAX) caused my queries to be slower

SQL Server Support Content

The scenario: Table has a NTEXT column that the customer wanted converted to NVARCHAR(MAX) Data has both small and large storage for different rows Issued ALTER TABLE … ADD COLUMN …NVarCharColumn… NVARCHAR(MAX) Issued update MyTable set NVarCharColumn ...read more

on 3 Dec 2012
Blog Post: How Can Reference Counting Be A Leading Memory Scribbler Cause?

SQL Server Support Content

The concept of the memory scribbler comes up quite a bit in support. The term can often be over used but I ran into a specific example that commonly fools people, including support engineers. The random nature and even the resulting ...read more

on 12 Nov 2012

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Browse by Tags

Blog Post: SQL Server MAX DOP Beyond 64 – Is That Possible?

Blog Post: A Partitioned Table May Limit the Runtime MAX DOP of Create/Alter Index

Blog Post: How It Works: Behavior of a 1 Trillion Row Index Build (Gather Streams from SORT)

Blog Post: How It Works: CMemThread and Debugging Them

Blog Post: All about RollbackSnapshotTempDB...

Blog Post: How It Works: SQL Server 32 bit PAE/AWE on (SQL 2005, 2008, and 2008 R2) – Not Using As Much RAM As Expected!

Blog Post: SQLIOSim Checksum Validations

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

Blog Post: SQL Server–Storage Spaces/VHDx and 4K Sector Size

Blog Post: Upgrade from SQL 2005 to SQL 2012 fails with error “Service 'SQLSERVERAGENT' start request failed.”

Blog Post: How It Works: Gotcha: *VARCHAR(MAX) caused my queries to be slower

Blog Post: How Can Reference Counting Be A Leading Memory Scribbler Cause?