Re: Multiple Storage per Tablespace, or Volumes

Andrew Sullivan wrote:
> On Mon, Feb 19, 2007 at 10:33:24AM -0500, Tom Lane wrote:
> > Martijn van Oosterhout <kleptog(at)svana(dot)org> writes:
> > > Somehow this seems like implementing RAID within postgres,
> >
> > RAID and LVM too. I can't get excited about re-inventing those wheels
> > when perfectly good implementations already exist for us to sit on top of.
>
> Ok, warning, this is a "you know what would be sweet" moment.
>
> What would be nice is to be able to detach one of the volumes, and
> know the span of the data in there without being able to access the
> data.
>
> The problem that a lot of warehouse operators have is something like
> this: "We know we have all this data, but we don't know what we will
> want to do with it later. So keep it all. I'll get back to you when
> I want to know something."

You should be able to do that with tablespaces and VACUUM FREEZE, the
point of the latter being that you can take the disk containing the
"read only" data offline, and still have the data readable after
plugging it back in, no matter how far along the transaction ID counter
is.

--
Alvaro Herrera http://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.