Re: Tablespaces

Greg Stark wrote:
>
> Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> writes:
>
> > Greg Stark wrote:
> > >
> > > > > I am expecting to hear some bleating about this from people whose
> > > > > preferred platforms don't support symlinks ;-). However, if we don't
> > >
> > > Well, one option would be to have the low level filesystem storage (md.c?)
> > > routines implement a kind of symlink themselves. Just a file with a special
> > > magic number followed by a path.
>
> On further contemplation it doesn't seem like using symlinks really ought to
> be necessary. It should be possible to drive everything off the catalog tables
> while avoidin having the low level filesystem code know anything about them.
>
> Instead of having the low level code fetch the pg_* records themselves, some
> piece of higher level code would do the query and call down to storage layer
> to inform it of the locations for everything. It would have to do this on
> database initialization and on any subsequent object creation.
>
> Basically maintain an in-memory hash table of oid -> path, and call down to
> the low level code whenever that hash changes. (Or more likely oid->ts_id and
> a separate list of ts_id -> path.)

The advantage of symlinks is that an administrator could see how things
are laid out from the command line.

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