Re: Optimizing projections containing unused columns

On Wed, Oct 15, 2008 at 09:07:28PM +0300, Andrus wrote:
> Tom,
>
> >This question is too vague to be answerable --- especially if you want
> >an answer that applies across all 8.x releases.  I'd suggest
> >experimenting a bit using EXPLAIN ANALYZE to see what happens in your
> >actual application.
>
> Thank you very much.
> I cannot experiment with application currently since this part is at
> planning state.
> I asked this to get right designing direction.

The basic answer is: every version of pg gets smarter. And the current
version is really smart. What you really have to watch out for is that
the moving of the clause really works. In the presense of outer joins
and NULL some things arn't as obvious as they seem...

Have a nice day,
--
Martijn van Oosterhout   <kleptog@svana.org>   http://svana.org/kleptog/
> Please line up in a tree and maintain the heap invariant while
> boarding. Thank you for flying nlogn airlines.