Dave Cramer wrote:
> On Mon, Oct 18, 2010 at 2:20 PM, Bruce Momjian <bruce@momjian.us> wrote:
> > Alvaro Herrera wrote:
> >> Hi Dave,
> >>
> >> Excerpts from Dave Cramer's message of lun oct 18 12:23:40 -0300 2010:
> >> > as seen below create tablespace does not throw an error or appear to
> >> > do anything other than register the tablespace.
> >> >
> >> > postgres@db01:~> less /opt/pg/data/jnj_indexes/PG_VERSION
> >> > 8.4
> >> > postgres@db01:~> /opt/pg91/bin/psql -p 5433
> >> > psql (9.0.1)
> >> > Type "help" for help.
> >> >
> >> > postgres=# select version();
> >> > ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? version
> >> >
-------------------------------------------------------------------------------------------------------------------
> >> > ?PostgreSQL 9.0.1 on x86_64-unknown-linux-gnu, compiled by GCC gcc
> >> > (GCC) 3.4.6 20060404 (Red Hat 3.4.6-11), 64-bit
> >> > (1 row)
> >> >
> >> > postgres=# create TABLESPACE jnj_indexes location '/opt/pg/data/jnj_indexes';
> >> > CREATE TABLESPACE
> >>
> >> IIRC the reason this works is that the tablespace code now creates a
> >> version-specific subdirectory inside the specified directory. ?This was
> >> done to help binary upgrades.
> >
> > Right, the directory is catalog-version named, which was done to allow
> > for pg_upgrade to work for alpha/beta upgrades (pretty cool). ?The case
> > above happened because 8.4 still has data in that tablespace.
> > pg_upgrade does supply a script to delete old data files, but it was not
> > used in the case above.
> >
>
> right that's because I did not use pg_upgrade. I was manually running
> create tablespace.
OK, so you were sharing the tablespace with old and new clusters. You
are right that in the past that would not have been possible because
PG_VERSION would have conflicted, but it is now possible with all new
releases because of the catalog-version-named subdirectory. That seems
like I a feature, I guess.
-- Bruce Momjian <bruce@momjian.us> http://momjian.us EnterpriseDB
http://enterprisedb.com
+ It's impossible for everything to be true. +