Re: effective SELECT from child tables

Is there enough for a TODO here?

On Mon, Oct 03, 2005 at 11:24:30PM -0400, Greg Stark wrote:
> 
> Hannu Krosing <hannu@skype.net> writes:
> 
> > On P, 2005-10-02 at 23:00 -0400, Tom Lane wrote:
> > > 
> > > Here's another interesting case to think about:
> > > 
> > >     ALTER TABLE ADD foo integer DEFAULT 1
> > >     ...
> > >     ALTER TABLE ALTER foo SET DEFAULT 2
> > >
> > > You'll have to pay the table-traversal cost on one step or the other.
> > 
> > The second, ALTER ... SET DEFAULT, would only set default for newly
> > inserted columns, not the ones which are missing due to tuples being
> > created before the column existed.
> 
> Hm. So you're saying there are only ever exactly two types of defaults. The
> "initial" default that applies to all tuples that were created before the
> column was added. And the "current" default that only ever applies to newly
> created tuples.
> 
> That does seem to cleanly close this hole.
> 
> -- 
> greg
> 
> 
> ---------------------------(end of broadcast)---------------------------
> TIP 9: In versions below 8.0, the planner will ignore your desire to
>        choose an index scan if your joining column's datatypes do not
>        match
> 

-- 
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