Re: pg_upgrade problem with invalid indexes

On 2012-12-07 09:21:58 -0500, Bruce Momjian wrote:
> On Thu, Dec  6, 2012 at 10:27:21PM -0500, Stephen Frost wrote:
> > * Bruce Momjian (bruce@momjian.us) wrote:
> > > On Thu, Dec  6, 2012 at 09:45:11PM -0500, Stephen Frost wrote:
> > > > Or preserve it as-is.  I don't really like the 'make them fix it'
> > > > option, as a user could run into that in the middle of a planned upgrade
> > > > that had been tested and never had that come up.
> > >
> > > They would get the warning during pg_upgrade --check, of course.
> >
> > Sure, if they happened to have a concurrent index creation going when
> > they ran the check...  But what if they didn't and it only happened to
> > happen during the actual pg_upgrade?  I'm still not thrilled with this
> > idea of making the user have to abort in the middle to address something
> > that, really, isn't a big deal to just preserve and deal with later...
>
> If a concurrent index creation was happening during the check,
> pg_upgrade --check would fail.  I don't think there is any indication if
> the index is failed, or in process.

There should be a lock on the table + index if the creation is in
progress.

> That is a good argument for _not_ throwing an error because index
> creation is more of an intermediate state.

Uhm. If pg_upgrade is actually running its definitely not an
intermediate state anymore...

Greetings,

Andres Freund

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