Re: [PATCH] Relocation of tablespaces in pg_basebackup

On 2014-01-10 12:27:23 +0100, Magnus Hagander wrote:
> On Fri, Jan 10, 2014 at 12:25 PM, Gabriele Bartolini <
> gabriele(dot)bartolini(at)2ndquadrant(dot)it> wrote:
>
> > Hi Steeve,
> >
> > Il 09/01/14 22:38, Steeve Lennmark ha scritto:
> > > I'm a barman user myself so that was actually my initial thought.
> >
> > Ah! Very good!
> > > If there aren't some kind of hidden internal that I've missed I don't see
> > > a way to convert an OID (only have OID and path at this stage) to a
> > > tablespace name. This solution, even though not optimal, is a lot
> > > better than my initial one where I used the OID directly.
> >
> > Try:
> >
> > SELECT spcname, oid, pg_tablespace_location(oid) FROM pg_tablespace
> >
> >
> That would require a second connection to the database. You cannot run that
> query from the walsender session. And that's exactly the issue that Steeve
> pointed out in his first email.

Theoretically nothing is stopping us from providing a command outputting
that information - it's a global catalog, so we can access it without
problems.

> I think it's better to let pg_basebackup work at the lower level, and then
> leave it to higher level tools to be able to do the mapping to names.

That doesn't negate this argument though. Not really convinced either
way yet.

Greetings,

Andres Freund

--
Andres Freund http://www.2ndQuadrant.com/
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