Re: pg_migrator issues

Robert Haas wrote:
> >> But can't we just call a special function first before running the
> >> CREATE TABLESPACE, like:
> >>
> >> pg_tablespace_dont_really_create_this_tablespace_because_we_are_in_pg_migrator()?
> >>
> >> Sorta like what you did to preserve ENUM OIDs, etc.?
> >
> > Well, the problem is that we are creating something in a file system,
> > and the old and new contents of the tablespace directories must exist
> > after the migration (in case the migration is reverted). ?We were able
> > to get away with this for enum because we were only creating this in the
> > _new_ database. ?With the file system, we have a resource/namespace
> > shared between the old and new server.
> 
> Oh, I thought you were hard-linking the files, not copying them, so
> the old directory would be destroyed anyway.

The default mode is COPY but there is a --link option.  You are right
that if we only did linking things would be much simpler.

> > What were you thinking this function call would do?
> 
> Basically, make PostgreSQL not reinitialize the directory as it
> normally would when a new tablespace is created.  Or make it ignore
> the existence of the directory until told to stop ignoring it.  Or
> whatever is needed to avoid having to move the thing around.  Sorry,
> I'm hand-waving wildly here; I haven't read the code.  Maybe I should
> shut up.

Sorry, I can't figure out how that would work.

-- 
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

  + If your life is a hard drive, Christ can be your backup. +