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From: Amit Kapila <amit.kapila16@gmail.com>
Date: Fri, 22 Jun 2018 14:53:36 +0530
Message-ID: 
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Subject: Re: add default parallel query to v10 release notes? (Re: [PERFORM]
 performance drop after upgrade (9.6 > 10))
To: Bruce Momjian <bruce@momjian.us>
Cc: Justin Pryzby <pryzby@telsasoft.com>,
	PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
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On Wed, Jun 20, 2018 at 8:43 PM, Bruce Momjian <bruce@momjian.us> wrote:
> On Thu, May 24, 2018 at 08:00:25PM -0500, Justin Pryzby wrote:
>
> So I did some research on this, particularly to find out how it was
> missed in the PG 10 release notes.  It turns out that
> max_parallel_workers_per_gather has always defaulted to 2 in head, and
> this was changed to default to 0 in the 9.6 branch:
>
>         commit f85b1a84152f7bf019fd7a2c5eede97867dcddbb
>         Author: Robert Haas <rhaas@postgresql.org>
>         Date:   Tue Aug 16 08:09:15 2016 -0400
>
>             Disable parallel query by default.
>
>             Per discussion, set the default value of max_parallel_workers_per_gather
>             to 0 in 9.6 only.  We'll leave it enabled in master so that it gets
>             more testing and in the hope that it can be enable by default in v10.
>
> Therefore, there was no commit to find in the PG 10 commit logs.  :-O
> Not sure how we can avoid this kind of problem in the future.
>
> The attached patch adds a PG 10.0 release note item about this change.
>

Your proposed text looks good to me.

-- 
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com