From: | "Jim C(dot) Nasby" <jim(at)nasby(dot)net> |
---|---|
To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | pgsql-general(at)postgresql(dot)org |
Subject: | Re: Analyze not doing anything? |
Date: | 2004-02-10 00:39:48 |
Message-ID: | 20040210003948.GV32360@nasby.net |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-general |
Hrm, I didn't realize that. Is it in the docs anywhere? I didn't see it
in Chapter 11... I'm particularly interested in why NULL/NOT NULL isn't
indexable.
Are where clauses on indexes like
email_contrib__team_id btree (team_id) WHERE (team_id IS NOT NULL)
still valid/usefull? If I wanted to create the converse of that index,
could I do something like
CREATE INDEX email_contrib__no_team ON
email_contrib(COALESCE(team_id,true)) WHERE team_id IS NULL;
and
SELECT ... WHERE COALESCE(team_id, true) = true;
?
On Thu, Feb 05, 2004 at 03:23:16PM -0500, Tom Lane wrote:
> "Jim C. Nasby" <jim(at)nasby(dot)net> writes:
> > I build a table to test the theory that PGSQL wouldn't use an index to
> > satisfy 'SELECT * FROM table WHERE field IS NOT NULL'.
>
> IS NULL/IS NOT NULL are not indexable operators.
>
> regards, tom lane
>
--
Jim C. Nasby, Database Consultant jim(at)nasby(dot)net
Member: Triangle Fraternity, Sports Car Club of America
Give your computer some brain candy! www.distributed.net Team #1828
Windows: "Where do you want to go today?"
Linux: "Where do you want to go tomorrow?"
FreeBSD: "Are you guys coming, or what?"
From | Date | Subject | |
---|---|---|---|
Next Message | Jim C. Nasby | 2004-02-10 00:44:38 | Re: fsync = true beneficial on ext3? |
Previous Message | Ed Wong | 2004-02-10 00:01:43 | book for postgresql |