Updating statistics sql server
In general sampling (as opposed to full scans) kicks in when we have about 8MB of data in the table (or about 1000 pages).
If you want to specify a full scan the syntax is as follows: You might want to use a sample as once your tables get large full scans can take a little time.
One nifty thing about using this procedure is that it only updates statistics objects where rows have changed, so you don’t have any overhead for refreshing statistics where the underlying data hasn’t been modified.
You can see this from this extract of the output of the stored procedure: Updating [dbo].[Test Memory] [PK__Test Memo__3214EC070D799003], update is not necessary…
Here’s some comparison figures I produced on my local machine showing how long full scans take.
Obviously this will change depending on your hardware and other factors including how much of the table is already in memory: You can see however that the time taken pretty much scales linearly as the table size increases. A full scan can run as a parallel operation on your server which can speed it up considerably.
You may want to read Part 1 , Part 2 , and Part 3 before continuing.This time around I'd like to talk about social networking. Facebook, My Space, and Twitter are all good examples of using technology to let...Last week I posted Speaking at Community Events - Time to Raise the Bar?At the heart of all the methods we’ll look at is the UPDATE STATISTICS command.There are a lot of options for using this command, but we’ll just focus on the ones you’re most likely to use.