Re: union optimization in views

On Thu, 29 Aug 2002, Josh Berkus wrote:

> Joe,
>
> > We are attempting to move a couple of systems from Oracle to Postgres but
> can not do so without application rewrites due to the current use of views
> with UNIONs and the criticality of the performances of these views.
> >
> > I was wondering if a decision has been made on the optimization with the
> UNION clause in views.  There are many documents in the SQL archive showing
> that the "push down" is not occuring and thus the use of UNION's in views is
> limited to case where the data set is small or performance is not a
> consideration.  I also looked through the TODO list and didn't see anything
> (of course I could have missed references).
>
> I'd take this up on PGSQL-HACKERS.   The UNION VIEW optimization, last I
> checked, was stalled mainly because nobody wanted to work on it.  Maybe you
> can?

Tom sent a patch to -patches against then cvs head that did
union/intersect [all] push down last week.  Unless someone comes
up with a complaint, I'd guess that's going to make it in 7.3