Re: Test "tablespace" fails during `make installcheck` on master-replica setup

Michael, all,

* Michael Paquier (michael(dot)paquier(at)gmail(dot)com) wrote:
> On Wed, Dec 07, 2016 at 03:42:53PM +0300, Aleksander Alekseev wrote:
> > > In the same host, primary and standby will try to use the tablespace
> > > in the same path. That's the origin of this breakage.
> >
> > Sorry, I don't follow. Don't master and replica use different
> > directories to store _all_ data? Particularly in my case:
> >
> > ```
> > $ find path/to/postgresql-install/ -type d -name pg_tblspc
> > /home/eax/work/postgrespro/postgresql-install/data-slave/pg_tblspc
> > /home/eax/work/postgrespro/postgresql-install/data-master/pg_tblspc
> > ```
> >
> > Where exactly a collision happens?
>
> At the location of the tablespaces, pg_tblspc just stores symlinks to
> the place data is stored, and both point to the same path, the same path
> being stream to the standby when replaying the create tablespace record.

It would be really nice if we would detect that some other postmaster is
already using a given tablespace directory and to throw an error and
complain rather than starting up thinking everything is fine.

We do that already for $PGDATA, of course, but not tablespaces.

Thanks!

Stephen