Do you ever have a stored procedure that you know is performing badly and needs tuning, but you’re struggling to capture when it is run or what parameters were passed in?I had this problem recently, I knew that a particular stored procedure was running slowly for some parameters, but figuring out what the bad combination […]
If you have a complex query, a CTE (Common Table Expression) can be a great way to break down the query into individual parts. What is often overlooked by developers is that CTEs can cause significant performance problems when used incorrectly. A common pattern I have seen is joining to a CTE multiple times. This […]
When doing query tuning, sometimes the answer can be that it’s just better to get SQL Server to recompile a plan based on the data passed in. You might have a batch process that runs every hour and sometimes it has only a few hundred rows, other times it has a few billion rows. The […]
Does SQL Server always cache your parameters? Does it always keep track of what you pass in?
This week, I was trying to improve the performance of a bit of SQL and noticed that it generated significantly different query plans depending on the parameters passed in. So I tried to work out how to make it run well for all scenarios.
