Subject: Re: Rename max_parallel_degree?
To: Robert Haas <robertmhaas@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>
References: <20160426152217.GA548975@alvherre.pgsql>
 <575051AF.2090101@agliodbs.com> <21660.1464882811@sss.pgh.pa.us>
 <WM!724b24b17b93e28a639b08a6942b6a6157bfdd1279efab51af9a99d9a9c64a20e4b0cbbd1a06bbecfc8587389a6f6b67!@mailstronghold-1.zmailcloud.com>
 <57508E69.9000505@agliodbs.com>
 <CAKFQuwbJwf26X0JFOWMLZYpaUobmDVEsp3YDvNhHtM8YDNbaKQ@mail.gmail.com>
 <WM!de247c8715b277e7427f9aaacd540544aa13b6024b86cc6bd18c6481f34478ca83e1c40296c1e8a66a23a078bb07191d!@mailstronghold-3.zmailcloud.com>
 <57509894.9080507@agliodbs.com>
 <CAKFQuwaBbH53x+i0MbaFzBDh3DhAXPS7EzjpEGKVvPRW-6HzNg@mail.gmail.com>
 <CA+TgmobYx11xuXy_GtuT=1ejh27K5t-jrc=gOk+XWhxUbpLbkQ@mail.gmail.com>
 <11330.1464961183@sss.pgh.pa.us>
 <CA+TgmoZF+-ckDHethxzznM-b-vraFvUXz-jXTDA8-cCUodpzGg@mail.gmail.com>
 <WM!a97c0cfedc9cd65ee73bc40bafb7ef019892cb9797432fc9c5209f5ce29a85ceab4031e102c0b11649cc454d31683eb4!@mailstronghold-1.zmailcloud.com>
Cc: "David G. Johnston" <david.g.johnston@gmail.com>,
 Amit Kapila <amit.kapila16@gmail.com>, Peter Geoghegan <pg@heroku.com>,
 Noah Misch <noah@leadboat.com>, David Rowley <david.rowley@2ndquadrant.com>,
 Alvaro Herrera <alvherre@2ndquadrant.com>,
 Magnus Hagander <magnus@hagander.net>, Bruce Momjian <bruce@momjian.us>,
 PostgreSQL-development <pgsql-hackers@postgresql.org>
From: Josh Berkus <josh@agliodbs.com>
Message-ID: <57581603.3040309@agliodbs.com>
Date: Wed, 8 Jun 2016 08:56:35 -0400
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101
 Thunderbird/38.6.0
MIME-Version: 1.0
In-Reply-To: 
 <WM!a97c0cfedc9cd65ee73bc40bafb7ef019892cb9797432fc9c5209f5ce29a85ceab4031e102c0b11649cc454d31683eb4!@mailstronghold-1.zmailcloud.com>
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org

On 06/07/2016 11:01 PM, Robert Haas wrote:
> On Fri, Jun 3, 2016 at 9:39 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> Robert Haas <robertmhaas@gmail.com> writes:
>>> I think we should just go with max_parallel_workers for a limit on
>>> total parallel workers within max_work_processes, and
>>> max_parallel_workers_per_gather for a per-Gather limit.  It's slightly
>>> annoying that we may end up renaming the latter GUC, but not as
>>> annoying as spending another three weeks debating this and missing
>>> beta2.
>>
>> +1.  I'm not as convinced as you are that we'll replace the GUC later,
>> but in any case this is an accurate description of the current
>> semantics.  And I'm really *not* in favor of fudging the name with
>> the intent of changing the GUC's semantics later --- that would fail
>> all sorts of compatibility expectations.
> 
> Here's a patch change max_parallel_degree to
> max_parallel_workers_per_gather, and also changing parallel_degree to
> parallel_workers.  I haven't tackled adding a separate
> max_parallel_workers, at least not yet.  Are people OK with this?

+1

> 
> Note that there is a dump/restore hazard if people have set the
> parallel_degree reloption on a beta1 install, or used ALTER { USER |
> DATABASE } .. SET parallel_degree.  Can everybody live with that?
> Should I bump catversion when applying this?

IMHO, we just need to call it out in the beta2 announcement.


-- 
--
Josh Berkus
Red Hat OSAS
(any opinions are my own)


-- 
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers