CSS SQL Server Engineers

High CPU Troubleshooting with DMV Queries Scenario: Recently, a customer called Microsoft Support with a critical performance issue that I worked on. Their SQL Server instance had 100% CPU utilization for a period, but the problem stopped without...

We have been troubleshooting a customer’s case and uncovered a GC behavior with SQL Server CPU affinity that is worth sharing here in a blog. Problem Customer reported that they had two instances of SQL Server 2008 running on a two-node cluster. ...

A case came up where the user was trying to use Report Builder in a Reporting Services instance that was not integrated with SharePoint.  It was in Native Mode configuration.  They indicated that they were getting a 401 error.  My initial...

Note: This blog is based on behavior as of June 2013.  At Microsoft we continue to evolve and enhance our products so the behavior may change over time. The I/O path for SQL Server, running on Windows Azure Virtual Machines, uses Windows Azure storage...

Recently we've seen an issue where some Excel 2010 workbooks containing PowerPivot models encounter errors when attempting to upgrade to Excel 2013. When opening a PowerPivot model that was created in Excel 2010 in Excel 2013 you will be prompted to...

I ran into a new Kerberos Scenario that I hadn’t hit before when I was working on the cases related to this blog post . It’s rare that I actually see a case related to the Named Pipes protocol.  When I do, it is usually a customer trying to get it...

I’m always amazed that issues usually come in batches.  I was looped into a few cases that had the following symptoms.   They were running SharePoint 2010 and Reporting Services 2012 SP1.  When they went to use a data source with Windows...

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...

I was recently going through an exercise of documenting how to discover certain aspects of Reporting Services for some Kerberos work.  RS 2012 in SharePoint is a totally different game though.  The easiest way I could discover certain items...

The topic I received most in my inbox this week was redo blocked on a secondary while attempting to acquire SCH-M (schema modify) lock. First of all, this is expected behavior and you can monitor for this with your standard blocking activities (sys.dm_exec_requests...

The distinction between these two wait types is subtle but very helpful in tuning your Always On environment. The committing of a transaction means the log block must be written locally as well as remotely for synchronous replicas.   When in...

I keep running into the question: “When will my secondary allow automatic failover?”   Based on the question I did some extended research and I will try to summarize in is blog post.  I don’t want to turn this post into a novel so I am...

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...

"Denzil and I were working on this issue for a customer and Denzil has been gracious enough to write-up a blog for all of us." – Bob Dorr From Denzil: I recently worked with a customer on a Database restore issue where the database being restored had...

The data source provider list in PowerPivot can often be a source of confusion for users since they equate the fact that a provider appears in the list as the provider being installed and available. Unfortunately, the list of providers is actually a static...

It has been well over a year when I wrote a series of blog posts about a product called System Center Advisor. You can read these posts at this link http://blogs.msdn.com/b/psssql/archive/tags/system+center+advisor/ When Advisor was first released, this...

In this blog, I will talk about a couple of things related to statistics update when rebuilding index on a partitioned table.   In past versions, when you rebuild an index, you will get statistics update equivalent to FULLSCAN for free.  ...

Recently, we received a call from a customer reported that a query was slow.  Upon further investigation, his query has a predicate that look like this: select * from t o where c1 >switchoffset (Convert(datetimeoffset, GETDATE()), '-04:00')  ...

I wanted to point out a nice performance improvement related to table valued parameters (TVP) in SQL Server 2012.   It’s not currently documented in our online documentation.   But we have had customers who inquired about this. When...

SQL Server has supported CLR usage since version 2005. But support of .NET framework assemblies within SQL Server is limited per our support policy in KB http://support.microsoft.com/kb/922672 . Some users chose to use .NET framework assemblies...

I've ran across the following error a few times and thought I would post this out there for people to understand what is happening. ERROR: Throwing Microsoft.ReportingServices.Diagnostics.Utilities.OperationNotSupportedException: , Microsoft.ReportingServices...

We have had two blog posts on this blog regarding the 18056 error.  Two from Bob Dorr (and part 2 ) and another from Tejas Shah .  However, we still see a lot of questions about this error message. This error message can show up for different reasons...

I want to make you aware of a latest SQL Server 2008 hotfix documented in http://support.microsoft.com/kb/2791745 .   Using large number of constants in IN clause can result in SQL Server termination unexpectedly.   When this happens...

I just wanted to put a quick note that QUERYTRACEON is now publically documented in http://support.microsoft.com/kb/2801413/en-us .  If you have situations where you don’t want to enable an optimizer trace flag globally on your server instance, you...

Parameter sniffing is a well known among SQL User community.   But I have seen variations of this frequently that need a bit creative handling and solution may not that straight forward. One of the variation is that a user changes the value...