Re: pg_upgrade problem with invalid indexes

From: Bruce Momjian <bruce(at)momjian(dot)us>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: pg_upgrade problem with invalid indexes
Date: 2012-12-07 13:58:04
Message-ID: 20121207135804.GD31540@momjian.us
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On Thu, Dec 6, 2012 at 09:23:14PM -0500, Bruce Momjian wrote:
> On Thu, Dec 6, 2012 at 09:10:21PM -0500, Tom Lane wrote:
> > Bruce Momjian <bruce(at)momjian(dot)us> writes:
> > > On Thu, Dec 6, 2012 at 07:53:57PM -0500, Tom Lane wrote:
> > >> Because CREATE INDEX CONCURRENTLY can't drop the index if it's already
> > >> failed. It's not because we want to do that, it's an implementation
> > >> restriction of the horrid kluge that is CREATE/DROP INDEX CONCURRENTLY.
> >
> > > Well, what is the logic that pg_dump dumps it then, even in
> > > non-binary-upgrade mode?
> >
> > Actually, I was thinking about proposing exactly that. Ideally the
> > system should totally ignore an invalid index (we just fixed some bugs
> > in that line already). So it would be perfectly consistent for pg_dump
> > to ignore it too, with or without --binary-upgrade.
> >
> > One possible spanner in the works for pg_upgrade is that this would mean
> > there can be relation files in the database directories that it should
> > ignore (not transfer over). Dunno if that takes any logic changes.
>
> As soon as pg_dump stopped dumping the CREATE INDEX, pg_upgrade would
> stop creating creating it in the new cluster, and not transfer the index
> files.

Sorry, I was wrong about this. We would need to modify pg_dump to skip
invalid indexes (perhaps only for --binary-upgrade), and pg_upgrade
would also need to be modified to skip such indexes. This is necessary
because, as a safety check, pg_upgrade requires there to be an exact
match of relations between old and new clusters.

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

+ It's impossible for everything to be true. +

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