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Query performance and table variables
Technorati Tags: Performance Frequently, we see our customers using table variables in their stored procedures and batches and experience performance problems. In general, these performance problems...
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Slow query performance because inaccurate cardinality estimate when using...
We have a few customers who reported that some of their queries run slower following upgrade from SQL Server 2000 to SQL Sever 2005, 2008 and 2008 R2. Specifically, queries experiencing the issue...
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Error 17953 - SidePageTable::Init() DeviceIoControl() : Operating system...
When attempting to run dbcc checkdb or create a snapshot database you may encounter the following errors when using a UNC location that does not support all sparse file operations. 2010-09-21...
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Case of using filtered statistics
Technorati Tags: Performance SQL Server 2008 introduces a new feature called filtered statistics. When used properly, it can dramatically improve cardinality estimate. Let’s use an example below to...
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Query performance and plan cache issues when parameter length not specified...
We recently worked with a customer who reported his update to a linked server table runs very slow. This only happens when he doesn’t specify the character parameter length in the .NET code. This...
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Numbers are better than letters…
Back in a post from May (http://blogs.msdn.com/b/psssql/archive/2010/05/30/don-t-touch-that-schema.aspx), I reported that SSRS referenced fields by index instead of by name in code for performance...
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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...
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Query Performance and multi-statement table valued functions
Lately I worked with a customer to help tune his query involving multi-statement table valued function. When using table valued functions, you should be aware of a couple of things First, there are...
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How It Works: SQL Parsing of Number(s), Numeric and Float Conversions
SQL Server and other documentation have always indicated that float values are not precise and comparison or conversion of them can be problematic and imprecise. Working on a recent customer...
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CSS once again comes to the SQL PASS Summit
I’m proud once again to be a part of our CSS team coming to the US SQL PASS Summit next week in Seattle. As in the past, our team will be speaking at a pre-conference seminar, main conference talks,...
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The week that was PASS…
I’m sitting in SEATAC Airport waiting for my flight, so I thought now would be a great time to write up some thoughts and share some experiences of my week at PASS. There was a ton of great...
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Microsoft Atlanta Begins….
There is an incredible level of satisfaction in being able to turn an idea into something real. Something valuable. Years go at Microsoft I talked to my colleagues about a vision where we could...
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HOW IT WORKS: IO Affinity Mask - Should I Use It?
The IO Affinity mask question has come across my desk several times in the last week so it is time to blog about it again. The IO Affinity mask is a very targeted optimization for SQL Server. I have...
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AlwaysON - HADRON Learning Series - What Is HADRON?
I have been reviewing and working on supportability aspects of HADRON (High Availability Disaster Recovery - AlwaysON) for months and I am kicking off a blog post series related my 'HADRON Learning...
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AlwaysON - HADRON Learning Series - New DMVs
As I have been reviewing and learning about HADRON I have found a great wealth of information exposed in the DMVs. I have pulled together a starting, entity relationship diagram and the HADRON PMs...
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AlwaysON - HADRON Learning Series - Running DBCC On A Secondary
HADRON allows DBCC to be executed directly against a secondary replica. The DBCC can be run online, as is, or with TABLOCK if the HADR activity is suspended so the DBCC can acquire the database lock...
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How It Works: Error 18056 - The client was unable to reuse a session - Part 2
I have had several questions on my blog post:...
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Tracking database recovery progress using information from DMV
Technorati Tags: Engine,SQL Server 2008 You must be very familiar with the database recovery related messages printed to the SQL Server Error log. These come in very handy when troubleshooting issues...
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Discussion About SQL Server I/O
I received a request today for help on how SQL Server I/O behaves. As I was writing up my e-mail response I thought it would also make an interesting blog post. Sent: Friday, January 07, 2011 2:53 AM...
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SQL Server 7.0: “She sure was a good ship”….
In December of 1997, I was asked by my manager whether I would like to visit Seattle to spend time with the SQL Server Development team as they built our next generation of the database engine, SQL...
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