This article introduces and explains the new LAG function in SQL Server. It also shows how to use it for SQL Server wait time analysis. [more…]
T-SQL Tuesday #27 is hosted by Steve Jones (blog|twitter). This month’s topic is “Big Data”. Purge Problems in Big Data – Not only a SELECT needs an index Recently I was called to an issue at a 5+ TB customer. [more…]
T-SQL Tuesday #26 is hosted by David Howard (blog|twitter). This month’s topic is “Second Chances”. Index Misconceptions The topic this month is “Second Chances” which means that we can write about anything, we would have liked to write about before [more…]
T-SQL Tuesday #25 is hosted by Allen White (blog). This month’s topic is “SQL Server Tips and Tricks”. Transaction Log Reuse Wait One question that keeps coming up in forums, at user group meetings and on twitter is: Why is [more…]
A lot has been written about the performanmce impact of functions.
Amongst other effects, functions used in a WHERE clause will prevent the use of an index seek for the columns involved.
Sometimes however it makes sense to use functions to encapsulate a complicated calculation or to make code reuse possible.
It is therefore important that to understand just how big the impact is, that functions have on queries.
I would like to use this blog post to look at the call overhead of different kinds of functions in SQL Server.