Horton

Re: ALTER TABLE DROP COLUMN

Bruce Momjian <pgman@candle.pha.pa.us>

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From: Bruce Momjian <pgman@candle.pha.pa.us>
To: The Hermit Hacker <scrappy@hub.org>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Hiroshi Inoue <Inoue@tpf.co.jp>, PostgreSQL Development <pgsql-hackers@postgreSQL.org>
Date: 2000-10-09T20:35:18Z
Lists: pgsql-hackers 
> On Mon, 9 Oct 2000, Tom Lane wrote:
> 
> > The Hermit Hacker <scrappy@hub.org> writes:
> > >> What happens if you crash partway through?
> > 
> > > what happens if you crash partway through a vacuum?
> > 
> > Nothing.  Vacuum is crash-safe.  ALTER TABLE should be too.
> 
> Sorry, that's what I meant ... why should marking a column as 'deleted'
> and running a 'vacuum' to clean up the physical table be any less
> crash-safe?  

It is not.  The only downside is 2x disk space to make new versions of
the tuple.

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