Session Details
T-SQL User-Defined Functions, or: Bad Performance Made Easy
Presentation
User-defined functions in SQL Server are very much like custom methods and properties in .Net languages. At first sight, they seem to be the perfect tool to introduce code encapsulation and reuse in T-SQL. So why is this feature mostly avoided by all T-SQL gurus? The reason is performance. In this session, you will learn how user-defined functions feed the optimizer with misleading and insufficient information, how the optimizer fails to use even what little information it has, and how this can lead to shocking query performance. However, you will also see that there is a way to avoid the problems. With just a little extra effort, you can reap the benefits of code encapsulation and reuse, and still get good performance.
The Speaker(s)
Hugo Kornelis
SQL Server MVP Hugo Kornelis is co-founder and R&D lead of perFact BV, a Dutch company that strives to improve analysis methods and to develop computer-aided tools that will generate completely functional applications from the analysis deliverable. The platform used for this development is SQL Server. In his spare time, Hugo likes to share and enhance his knowledge of SQL Server by frequenting newsgroups and forums, reading and writing books and blogs, and attending and speaking at conferences.
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