RE: DROP COLUMN status

From: "Hiroshi Inoue" <Inoue(at)tpf(dot)co(dot)jp>
To: "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: "Bruce Momjian" <pgman(at)candle(dot)pha(dot)pa(dot)us>, "PostgreSQL-development" <pgsql-hackers(at)postgresql(dot)org>
Subject: RE: DROP COLUMN status
Date: 2000-06-08 18:01:43
Message-ID: EKEJJICOHDIEMGPNIFIJCEJMCBAA.Inoue@tpf.co.jp
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> -----Original Message-----
> From: Tom Lane [mailto:tgl(at)sss(dot)pgh(dot)pa(dot)us]
>
> "Hiroshi Inoue" <Inoue(at)tpf(dot)co(dot)jp> writes:
> > The implementation makes the dropped column invisible by
> > changing its attnum to -attnum - offset(currently 20) and
> > attnam to ("*already Dropped%d",attnum).
>
> Ugh. No wonder you had to hack so many places in such an ugly fashion.
> Why not leave the attnum as-is, and just add a bool saying "column is
> dropped" to pg_attribute?

First,it's only a trial and I haven't gotten any final consensus.
It has had the following advantages as a trial.

1) It doesn't require initdb.
2) It makes debugging easier. If I've forgotten to change some
places it would cause aborts/asserts in most cases.

Now I love my trial implementation more than that of you
suggests(it was my original idea) because it's more robust
than dropped(invisible) flag implementation. I could hardly
expect that no one would ignore the invisible(dropped) flag
forever.

Anyway I had hidden details behind MACROs mostly so it
wouldn't be so difficult to change the implementation as
you suggests.

Regards.

Hiroshi Inoue
Inoue(at)tpf(dot)co(dot)jp

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