From: | Alvaro Herrera <alvherre(at)dcc(dot)uchile(dot)cl> |
---|---|
To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>, Jan Wieck <JanWieck(at)Yahoo(dot)com>, btober(at)seaworthysys(dot)com, scrawford(at)pinpointresearch(dot)com, kleptog(at)svana(dot)org, m_tessier(at)sympatico(dot)ca, pgsql-general(at)postgresql(dot)org |
Subject: | Re: How many fields in a table are too many |
Date: | 2003-06-28 17:58:13 |
Message-ID: | 20030628175813.GC10521@dcc.uchile.cl |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-general |
On Sat, Jun 28, 2003 at 01:43:32PM -0400, Tom Lane wrote:
> Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> writes:
> > Is this a TODO?
> > When columns can be reordered, move varlena columns to the end?
>
> I believe that really what you want is fixed-width NOT NULL columns
> first, then fixed-width nullable, then var-width. This ordering will
> improve the odds of actually being able to use the fixed offset for
> a particular column.
This means that when you do ALTER TABLE ... SET/DROP NOT NULL the table
may have to be completely rewritten? Altering the physical order is
sure to provoke a rewrite, but I think people will expect a change in
constraints to be a fast operation.
--
Alvaro Herrera (<alvherre[a]dcc.uchile.cl>)
Essentially, you're proposing Kevlar shoes as a solution for the problem
that you want to walk around carrying a loaded gun aimed at your foot.
(Tom Lane)
From | Date | Subject | |
---|---|---|---|
Next Message | Bruce Momjian | 2003-06-28 18:04:57 | Re: How many fields in a table are too many |
Previous Message | Tom Lane | 2003-06-28 17:43:32 | Re: How many fields in a table are too many |