Re: views: performance implication

On Thu, 4 Jul 2002, John Moore wrote:

> We hope to use views as a way to....
> So the question is: are there any negative performance implications of
> doing so ... Back in the old days, views were a
> performance no-no in Informix, so I want to be sure we aren't setting a big
> trap for ourselves.

Yes, there may be. There are some cases where the optimizer won't
optimize a view the way it will optimize an equivalant query. (I posted
a query about this a while back--I don't remember whether it was here
or on -hackers.) So after creating a view, you'll want to check with
EXPLAIN that you're still getting the same query plan.

But I don't think this is true of every view, just some of them.

cjs
--
Curt Sampson  <cjs@cynic.net>   +81 90 7737 2974   http://www.netbsd.org
    Don't you know, in this new Dark Age, we're all light.  --XTC