Re: [GENERAL] pg_upgrade & tablespaces

Bruce Momjian <bruce@momjian.us> writes:
> On Sat, Jan 11, 2014 at 12:48:51PM -0800, Adrian Klaver wrote:
>> I see, though I have another question. If pg_tablespace and the
>> symlinks can get out of sync, as you say below, why is pg_tablespace
>> considered the authority? Or to put it another way, why not just
>> look at the symlinks as in 9.2+?

> Uh, good question.  I think I used the system tables because they were
> easier to access.  I can't remember if we used the symlinks for some
> things and pg_tablespace for other things in pre-9.2.

Well, pre-9.2 pg_dumpall is going to make use of the pg_tablespace
entries, because it has no other choice.  We could conceivably teach
pg_upgrade to look at the symlinks for itself, but we're not going
to do that in pg_dumpall.  Which means that the intermediate dump
script would contain inconsistent location values anyway if the
catalog entries are wrong.  So I don't see any value in changing the
quoted code in pg_upgrade.

It does however seem reasonable for pg_upgrade to note whether any
of the paths are prefixed by old PGDATA and warn about the risks
involved.
        regards, tom lane