| From: | "Simon Riggs" <simon(at)2ndquadrant(dot)com> |
|---|---|
| To: | "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Improving NOT IN |
| Date: | 2007-01-30 23:24:40 |
| Message-ID: | 1170199480.3681.319.camel@silverbirch.site |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On Tue, 2007-01-30 at 18:06 -0500, Tom Lane wrote:
> "Simon Riggs" <simon(at)2ndquadrant(dot)com> writes:
> > What would be wrong with checking for a NOT NULL constraint? Thats how
> > other planners cope with it. Or are you thinking about lack of plan
> > invalidation?
>
> Yup, without that, depending on constraints for plan correctness is
> pretty risky.
>
> Basically what I see here is a whole lot of work and new executor
> infrastructure for something that will be a win in a very narrow
> use-case and a significant loss the rest of the time. I think there
> are more productive ways to spend our development effort.
For that part of the email, I was talking about your ideas on NOT IN.
Checking for the explicit exclusion of NULLs is worthwhile with/without
plan invalidation.
--
Simon Riggs
EnterpriseDB http://www.enterprisedb.com
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