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help / color / mirror / Atom feedFrom: Amit Kapila <amit.kapila16@gmail.com>
To: Bruce Momjian <bruce@momjian.us>
Cc: Justin Pryzby <pryzby@telsasoft.com>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Subject: Re: add default parallel query to v10 release notes? (Re: [PERFORM] performance drop after upgrade (9.6 > 10))
Date: Fri, 22 Jun 2018 14:53:36 +0530
Message-ID: <CAA4eK1+-QkCZjiDtWQhOho5TJyD2C0odndx_u+Cwm3_p_16pLQ@mail.gmail.com> (raw)
In-Reply-To: <20180620151349.GB7500@momjian.us>
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<20171026194515.GV21735@telsasoft.com>
<20180128235310.GA5024@momjian.us>
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<20180620151349.GB7500@momjian.us>
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
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To: pgsql-performance@postgresql.org
Cc: amit.kapila16@gmail.com, bruce@momjian.us, pryzby@telsasoft.com, pgsql-hackers@lists.postgresql.org
Subject: Re: add default parallel query to v10 release notes? (Re: [PERFORM] performance drop after upgrade (9.6 > 10))
In-Reply-To: <CAA4eK1+-QkCZjiDtWQhOho5TJyD2C0odndx_u+Cwm3_p_16pLQ@mail.gmail.com>
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