Re: Multiple Storage per Tablespace, or Volumes

On Mon, Feb 19, 2007 at 05:10:36PM +0100, Dimitri Fontaine wrote:
> > 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.
>
> I though moving some knowledge about data availability into PostgreSQL code
> could provide some valuable performance benefit, allowing to organize reads
> (for example parallel tables scan/indexes scan to different volumes) and
> obtaining data from 'quicker' known volume (or least used/charged).

Well, organising requests to be handled quickly is a function of
LVM/RAID, so we don't go there. However, speeding up scans by having
multiple requests is an interesting approach, as would perhaps a
different random_page_cost for different tablespaces.

My point is, don't try to implement the mechanics of LVM/RAID into
postgres, instead, work on providing ways for users to take advantage
of these mechanisms if they have them. Look at it as if you have got
LVM/RAID setup for your ideas, how do you get postgres to take
advantage of them?

Have a nice day,
--
Martijn van Oosterhout   <kleptog@svana.org>   http://svana.org/kleptog/
> From each according to his ability. To each according to his ability to litigate.