Re: global temporary tables

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Greg Sabino Mullane <greg@turnstep.com>, pgsql-hackers@postgresql.org
Date: 2010-04-24T17:31:23Z
Lists: pgsql-hackers
Robert Haas <robertmhaas@gmail.com> writes:
> At least AIUI, the use case for this feature is that you want to avoid
> creating "the same" temporary table over and over again.

The context that I've seen it come up in is that people don't want to
clutter their functions with create-it-if-it-doesn't-exist logic,
which you have to have given the current behavior of temp tables.
Any performance gain from reduced catalog churn would be gravy.

Aside from the DROP problem, I think this implementation proposal
has one other big shortcoming: what are you going to do about
table statistics?  In many cases, you really *have* to do an ANALYZE
once you've populated a temp table, if you want to get decent plans
for it.  Where will you put those stats?

			regards, tom lane