Does your query sometimes run fast and sometimes slow – even when nothing’s changed? Did it happen to you that a stored procedure, which had always been running for less than a second, suddenly started to run for more than 5 seconds consistently – even when nothing had changed?
Parameters are a fundamental part of T-SQL programming, whether they are used in stored procedures, in dynamic statements or in ad-hoc queries. Although widely used, most people aren’t aware of the crucial influence they have on query performance. In fact, wrong use of parameters is one of the common reasons for poor application performance.
In the last SQL Friday session, I explained about plan caching and how the query optimizer handles parameters. I demonstrated the pros and cons of parameter sniffing (don’t worry if you don’t know what that means).
But most important, we discussed how to identify performance problems caused by poor parameter handling, and many techniques for solving these problems to boost your application performance.
You can find the training presentation and scripts here.