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User defined function performance is awful, Micorosft please sort this out

User defined functions looked like something great when they were introduced in SQL 2005. They are a very logical step to make more code reuseable by wrapping common code in functions. It is an approach that is in development 101 and something everyone does and looks to doing. So what is the problem...

Posted to Simons SQL Blog (Weblog) by simonsabin on Thu, Jan 14 2010
SQL Server 2008 - Whats this abut 30,000 columns?

Its all about Sparse columns and they are a great feature of Katmai Imagine you have a products table, you will have attributes for some products that don't apply to others i.e. cup size applies to bras but not to socks. There are a number of ways of modelling this each with downsides. With sparse...

Posted to Simons SQL Blog (Weblog) by simonsabin on Sun, Mar 16 2008
SQL Server The Truth - Rebuilding a clustered index does not rebuild the non clustered indexes

It used to be fact that the leaf page of a non-clustered index pointed to the row for the page, because it pointed to the file, page and row if the file or page of the row changed the nonclustered index had to be updated. Now however the non-clustered index has the Unique Clustering Key value for the...

Posted to Simons SQL Blog (Weblog) by simonsabin on Fri, Jul 20 2007
To cluster of not

Tony's blogged about the use of heaps http://sqlblogcasts.com/blogs/tonyrogerson/archive/2007/06/24/row-fragmentation-hopscotch-heap-v-clustered-and-io-cost.aspx . Whilst this highlights data on a page being out of sequence and thus yoyoing when you scan the data, it doesn't mean you should always...

Posted to Simons SQL Blog (Weblog) by simonsabin on Tue, Jun 26 2007
What is the cost of a query? Is it a beard?

I used to work on a project where we discussed what exactly the cost of a query was. You know that figured shown in execution plans. I knew it was used to age plans in a cache but not sure what unit it actually was. One of the guys on the project (Mike I think) decided to call them "Beards"...

Posted to Simons SQL Blog (Weblog) by simonsabin on Wed, Apr 4 2007
Online Index White Paper

Paul Randal recently informed me of a new white paper on online index operations. The whitepaper can be found here Online Index White Paper . This is one of many whitepapers that have been published lately by Bob Internals Troubleshooting ImplementingScaleOut ConnectivitySSIS - var height=90;var width...

Posted to Simons SQL Blog (Weblog) by simonsabin on Fri, Mar 16 2007
When is full recovery mode not full recovery mode

I was recently trying to develop a test for DBAs. The scenario of the test was that you have taken over responsibility of a server what needs to be done to make it production ready. The server is really badly configured and the aim is for the tester to find them and make suggestions of what needs to...

Posted to Simons SQL Blog (Weblog) by simonsabin on Wed, Dec 13 2006
Checkpointing is now throttled in SQL 2005

During the iinterview with the SQLOS team this morning Slava mentioned that as part of the new design for the SQLOS the checkpoint process is much tightly controlled. If the checkpoint process has issues pages to be written and the latency has become too high (20ms was mentioned) then it will stop issuing...

Posted to Simons SQL Blog (Weblog) by simonsabin on Thu, Nov 16 2006
SQL Engine - Storage of Large Object Data

If you are currently using text, ntext or image data in SQL 2000 and are looking to use "max" data types in SQL 2005 you will be interested in my first article for SQLServerCentral on the use of LOB data . The point I cover is the storage of data in and out of row and that the default behaviour...

Posted to Simons SQL Blog (Weblog) by simonsabin on Wed, Oct 4 2006

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