Re: TABLESPACE and directory for Foreign tables?

On 2014-05-05 11:17:18 -0700, Josh Berkus wrote:
> On 05/05/2014 10:53 AM, Tom Lane wrote:
> > Josh Berkus <josh(at)agliodbs(dot)com> writes:
> >> I'm working with the cstore_fdw project, which has an interesting
> >> property for an FDW: the FDW itself creates the files which make up the
> >> database. This raises a couple of questions:
> >
> >> 1) Do we want to establish a standard directory for FDWs which create
> >> files, such as $PGDATA/base/{database-oid}/fdw/ ? Or would we want to
> >> leave it up to each FDW to decide?
> >
> > I think we ought to vigorously discourage FDWs from storing any files
> > inside $PGDATA. This cannot lead to anything except grief. Just for
> > starters, what will operations such as pg_basebackup do with them?
>
> That was one advantage to putting them in PGDATA; you get a copy of the
> files with pg_basebackup.

A corrupted copy. There's no WAL replay to correct skew due to write
activity while copying.

> Of course, they don't replicate after that,
> but they potentially could, in the future, with Logical Streaming
> Replication.

Nope. They're not in the WAL, so they won't be streamed out.

Greetings,

Andres Freund

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