Re: Choosing parallel_degree

From: Simon Riggs <simon(at)2ndQuadrant(dot)com>
To: Robert Haas <robertmhaas(at)gmail(dot)com>
Cc: Simon Riggs <simon(at)2ndquadrant(dot)com>, Paul Ramsey <pramsey(at)cleverelephant(dot)ca>, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>, Julien Rouhaud <julien(dot)rouhaud(at)dalibo(dot)com>, James Sewell <james(dot)sewell(at)lisasoft(dot)com>, David Rowley <david(dot)rowley(at)2ndquadrant(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>, Andreas Ulbrich <andreas(dot)ulbrich(at)matheversum(dot)de>
Subject: Re: Choosing parallel_degree
Date: 2016-04-12 13:11:28
Message-ID: CANP8+j+PCuSjfp2o3SNMof0akXjZnpGusg0BnVoaeC1W7Tohcg@mail.gmail.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers

On 12 April 2016 at 13:53, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:

> On Mon, Apr 11, 2016 at 5:45 PM, Simon Riggs <simon(at)2ndquadrant(dot)com>
> wrote:
> > On 8 April 2016 at 17:49, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> >> With the patch, you can - if you wish - substitute
> >> some other number for the one the planner comes up with.
> >
> > I saw you're using AccessExclusiveLock, the reason being it affects
> SELECTs.
> >
> > That is supposed to apply when things might change the answer from a
> SELECT,
> > whereas this affects only the default for a plan.
> >
> > Can I change this to a lower setting? I would have done this before
> applying
> > the patch, but you beat me to it.
>
> I don't have a problem with reducing the lock level there, if we're
> convinced that it's safe.

I'll run up a patch, with appropriate comments.

--
Simon Riggs http://www.2ndQuadrant.com/
<http://www.2ndquadrant.com/>
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

In response to

Responses

Browse pgsql-hackers by date

  From Date Subject
Next Message Yury Zhuravlev 2016-04-12 13:12:23 Re: Lets (not) break all the things. Was: [pgsql-advocacy] 9.6 -> 10.0
Previous Message Alexander Korotkov 2016-04-12 13:09:05 Re: Some other things about contrib/bloom and generic_xlog.c