Re: First steps with 8.3 and autovacuum launcher

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

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Alvaro Herrera <alvherre@commandprompt.com>
Cc: Heikki Linnakangas <heikki@enterprisedb.com>, Gregory Stark <stark@enterprisedb.com>, Stefan Kaltenbrunner <stefan@kaltenbrunner.cc>, Guillaume Smet <guillaume.smet@gmail.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2007-10-01T20:26:00Z
Lists: pgsql-hackers
Alvaro Herrera <alvherre@commandprompt.com> writes:
> This is an interesting idea, but I think it's attacking the wrong
> problem.  To me, the problem here is that an ANALYZE should not block
> CREATE INDEX or certain forms of ALTER TABLE.

I doubt that that will work; in particular I'm pretty dubious that you
can safely make CREATE INDEX and VACUUM run together.  Since they'd be
unlikely to be using the identical OldestXmin horizon, you'd likely end
up with dangling index entries (ie, CREATE INDEX indexes a tuple that
the VACUUM removes shortly afterward).

			regards, tom lane