From: | Amit Langote <amitlangote09(at)gmail(dot)com> |
---|---|
To: | Justin Pryzby <pryzby(at)telsasoft(dot)com> |
Cc: | Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: ALTER tbl rewrite loses CLUSTER ON index (consider moving indisclustered to pg_class) |
Date: | 2020-02-17 05:31:42 |
Message-ID: | CA+HiwqHn7PWZobKdTeg=T9xmkeecaC_uS01Emy8PGeGk9sUUxA@mail.gmail.com |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
Hi Justin,
On Fri, Feb 7, 2020 at 11:39 PM Justin Pryzby <pryzby(at)telsasoft(dot)com> wrote:
> On Thu, Feb 06, 2020 at 02:24:47PM -0300, Alvaro Herrera wrote:
> > On 2020-Feb-06, Justin Pryzby wrote:
> >
> > > I wondered if it wouldn't be better if CLUSTER ON was stored in pg_class as the
> > > Oid of a clustered index, rather than a boolean in pg_index.
> >
> > Maybe. Do you want to try a patch?
>
> I think the attached is 80% complete (I didn't touch pg_dump).
>
> One objection to this change would be that all relations (including indices)
> end up with relclustered fields, and pg_index already has a number of bools, so
> it's not like this one bool is wasting a byte.
>
> I think relisclustered was a's clever way of avoiding that overhead (c0ad5953).
> So I would be -0.5 on moving it to pg_class..
Are you still for fixing ALTER TABLE losing relisclustered with the
patch we were working on earlier [1], if not for moving relisclustered
to pg_class anymore?
I have read elsewhere [2] that forcing ALTER TABLE to rewrite in
clustered order might not be a good option, but maybe that one is a
more radical proposal than this.
Thanks,
Amit
[1] https://postgr.es/m/CA%2BHiwqEt1HnXYckCdaO8%2BpOoFs7NNS5byoZ6Xg2B7epKbhS85w%40mail.gmail.com
[2] https://postgr.es/m/10984.1581181029%40sss.pgh.pa.us
From | Date | Subject | |
---|---|---|---|
Next Message | Justin Pryzby | 2020-02-17 05:49:49 | Re: ALTER tbl rewrite loses CLUSTER ON index (consider moving indisclustered to pg_class) |
Previous Message | Kasahara Tatsuhito | 2020-02-17 05:28:34 | Re: small improvement of the elapsed time for truncating heap in vacuum |