Re: pg_upgrade problem with invalid indexes

On 2012-12-11 15:12:37 -0500, Bruce Momjian wrote:
> On Fri, Dec  7, 2012 at 04:49:19PM -0500, Bruce Momjian wrote:
> > On Fri, Dec  7, 2012 at 10:38:39PM +0100, Andres Freund wrote:
> > > On 2012-12-07 16:30:36 -0500, Bruce Momjian wrote:
> > > > On Fri, Dec  7, 2012 at 04:21:48PM -0500, Tom Lane wrote:
> > > > > Andres Freund <andres@2ndquadrant.com> writes:
> > > > > > On 2012-12-07 13:59:41 -0500, Tom Lane wrote:
> > > > > >> indisvalid should be sufficient.  If you try to test more than that
> > > > > >> you're going to make the code more version-specific, without actually
> > > > > >> buying much.
> > > > >
> > > > > > Doesn't the check need to be at least indisvalid && indisready? Given
> > > > > > that 9.2 represents !indislive as indisvalid && !indisready?
> > > > >
> > > > > Um, good point.  It's annoying that we had to do it like that ...
> > > >
> > > > So, does this affect pg_upgrade?  Which PG versions?
> > >
> > > Only 9.2 :(. Before that there was no DROP INDEX CONCURRENTLY and in 9.3
> > > there's an actual indislive field and indisready is always set to false
> > > there if indislive is false.
> > >
> > > But I see no problem using !indisvalid || !indisready as the condition
> > > in all (supported) versions.
> >
> > OK, updated patch attached.
>
> Patch applied back to 9.0.
>
> Now that it is applied, I need to publicize this.  How do I do that?
> Josh mentioned my blog.

Not really sure why this needs to be so much more prominent than other
fixes?

> What would cause these invalid indexes?  Just CREATE INDEX CONCURRENTLY
> failures?  What types of failures would users have if these invalid
> indexes had been upgraded by pg_upgrade?

Afaics it could be anything from wrong responses to queries to crashes
although the former seems to be more likely.

> Can they test their indexes in any way?  I assume they can't run
> queries on the old cluster to check.

I don't see how.

Greetings,

Andres Freund

--Andres Freund                       http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training &
Services