RE: [HACKERS] Re: ALTER TABLE DROP COLUMN

> -----Original Message-----
> From: The Hermit Hacker [mailto:scrappy@hub.org]
> 
> On Mon, 28 Feb 2000, Hiroshi Inoue wrote:
> 
> > > -----Original Message-----
> > > From: Tom Lane [mailto:tgl@sss.pgh.pa.us]
> > > 
> > > "Hiroshi Inoue" <Inoue@tpf.co.jp> writes:
> > > > Hmm,tuples of multiple version in a table ?
> > > > This is neither clean nor easy for me.
> > > 
> > > I'm worried about it too.  I think it could maybe be made to work,
> > > but it seems fragile.
> > > 
> > > > I may be able to provide another implementation on trial and it
> > > > may be easier than only objecting to your proposal.
> > > 
> > > If you have a better idea, let's hear it!
> > >
> >

[snip]
> 
> Okay, just curious here, but ... what you are proposing *sounds* to me
> like half-way to what started this thread. (*Please* correct me if I'm
> wrong) ...
>

My proposal is essentially same as what I proposed once in this thread.
I don't think DROP COLUMN feature is very important.
DROP/ADD CONSTRAINT feature seems much more important.  
Why do you want a heavy iplementation like vacuum after 2x disk
usage for this feature ?
My implementation won't touch the target table at all and would never
remove dropped columns practically. It would only make them invisible
and NULL would be set for newly insert/updated columns.

If you want a really clean table for DROP TABLE command,my
proposal is useless.

Regards.

Hiroshi Inoue
Inoue@tpf.co.jp