Re: Tablespaces

On Sun, 20 Jun 2004, Simon Riggs wrote:

> On Thu, 2004-05-27 at 07:59, Gavin Sherry wrote:
> > Attached is my latest patch implementing tablespaces. This has all the
> > functionality I was planning for 7.5.
> >
> > Most of the information about the patch is contained in the
> > patch/documentation, previous submissions and the archives.
> >
> > Testing, review, comments would be greatly appreciated.
> >
>
> I've reviewed your patch by eye, but can't see anything in your patch
> about relocating the pg_xlog directory.

I didn't intend on looking at that in this patch.

> pg_xlog is only referred to in 4 lines in the code (incl. PITR patch):
> - xlog.c
> - pgarch.c (PITR patch)
> - initdb.c
> - pgresetxlog.c
> Each time it is simply setting a string to the location of the xlog
> directory.
>
> If we could work out a way of...
> i) letting the pg_xlog be created by default
> ii) then transferring this to another tablespace later?
> That would give us maximum flexibility, since you may wish to change
> location later when workload changes/increases.

Sounds reasonable.

>
> Perhaps adding a GUC...for wal_tablespace (pls suggest name!)
> defaults to the pg_xlog directory, when not listed?
> Changeable only at postmaster startup...
>
> This could be done independently of tablespaces, but I think any
> directory flexibility/change should work using the tablespace
> infrastructure, not in addition to it.

If the change is as simple as you propose, it has nothing to do with
the tablespace code. Also, I don't see any situation where we would want
to make use of the tablespace code.

> Could we discuss this? it sounds like a change we could make happen
> fairly quickly now your code is in place.

Again, I don't think my code really has any affect on the location of
xlog.

>
> Of course, I accept that many may say that such a change is not really
> needed, but then...

Comments anyone?

Gavin