Re: Remove xmin and cmin from frozen tuples

On Wed, Sep 07, 2005 at 01:05:52PM -0400, Alvaro Herrera wrote:
> Anyway you are just moving the storage somewhere else -- instead of
> having 4 fields in the tuple itself, you have one field which points
> the same 4 fields elsewhere.  I don't see how is that a win; it's
> actually worse because you have to do two lookups.  (And actually you
> have just enlarged the storage requirements because you need to store
> the "vis_id" twice.)

It would only be of use if the table had few transactions in it; in
other words, if it was mostly read-only. For a true read-only table
there are other options people have suggested that are probably better.

BTW, this becomes even more attractive if vis_id is int2; in that case
you can keep the entire mapping in memory in ~1MB.
-- 
Jim C. Nasby, Sr. Engineering Consultant      jnasby@pervasive.com
Pervasive Software      http://pervasive.com    work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf       cell: 512-569-9461