Home/ Questions/Q 958761
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-05-16T00:55:03+00:00

Can someone please explain why this works. Here is the scenerio. I have a

  • 0

Can someone please explain why this works. Here is the scenerio. I have a stored proc and it starts to run slow. Then I pick a parameter and declare a variable to house its value and in the proc use the declared variable instead of the parameter. The proc will then speed up considerably.

I think it has something to do with the cached plan and statistics, but I am not sure. Is it that statistics get out of date as the database grows and changes so that the cached plan is optimized on a past state of the data which is different from the present state of the data?

thanks.

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    What you describe is commonly referred to as parameter sniffing, and it seems to be a SQL Server only issue – never had it on Oracle IME, nor am I aware of the issue on MySQL. The link I gave breaks down the issue well.

    Mind that the statistics used by the optimizer aren’t sync’d with data changes – you might need to run UPDATE STATISTICS occaissionally too.

    • 0