Re: Remove xmin and cmin from frozen tuples

On Tue, Sep 06, 2005 at 05:37:06PM -0400, Alvaro Herrera wrote:
> On Tue, Sep 06, 2005 at 03:58:28PM -0500, Jim C. Nasby wrote:
> > On Fri, Sep 02, 2005 at 03:51:15PM -0400, Bruce Momjian wrote:
> > > One possible solution is to create a phantom cid which represents a
> > > cmin/cmax pair and is stored in local memory.
> >
> > If we're going to look at doing that I think it would also be good to
> > consider including xmin and xmax as well.
>
> If you do that, you'll never be able to delete or update the tuple.

My idea was to use an int to represent combinations of (c|x)(min|max),
probably on a per-table basis. Essentially, it would normalize these
values. I don't see how this would eliminate the ability to update or
delete.

Of course this would actually hurt on tables that had mostly single-row
operations, so it would have to be a table-creation option. I believe it
could substantially reduce the size of tables that don't see a lot of
transactions. It would be good just to have a quick and dirty patch just
to see if this is the case or not.
--
Jim C. Nasby, Sr. Engineering Consultant jnasby(at)pervasive(dot)com
Pervasive Software http://pervasive.com work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461