From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
cc: "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Subject: Re: [COMMITTERS] pgsql: Simplify plpgsql's check for simple
 expressions.
In-reply-to: 
 <CA+TgmoZ6QK_+s7FNLx=gYeGAQC8hop_S-aF9_nzc67hQij6nSg@mail.gmail.com>
References: <E1dhehy-00034e-8N@gemulon.postgresql.org>
 <23425.1502822098@sss.pgh.pa.us>
 <CA+TgmoaRuLrYSonO5y4-Dhiaw13yTukKWyJuRuCy2XHEAQ5O8A@mail.gmail.com>
 <31094.1502827694@sss.pgh.pa.us> <29231.1502831727@sss.pgh.pa.us>
 <CA+Tgmoa+h--4STWwP-+XkrSwcU8wWtNCV7ODcQZgyy=Xi+Np6g@mail.gmail.com>
 <7013.1502836842@sss.pgh.pa.us>
 <CA+TgmoYB4EfN4FkpWf3UFRgMgrA2Go7FgFmu-p7Yzh+WDx9E5A@mail.gmail.com>
 <23848.1502895834@sss.pgh.pa.us>
 <CA+Tgmoan1cPF+rSPhX8NQ2p1pNPv+1NiqrPi-yA9ft6tyv+78A@mail.gmail.com>
 <26168.1502898994@sss.pgh.pa.us>
 <CA+TgmoZ6QK_+s7FNLx=gYeGAQC8hop_S-aF9_nzc67hQij6nSg@mail.gmail.com>
Comments: In-reply-to Robert Haas <robertmhaas@gmail.com>
	message dated "Wed, 16 Aug 2017 12:17:31 -0400"
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-ID: <28588.1502902172.1@sss.pgh.pa.us>
Date: Wed, 16 Aug 2017 12:49:32 -0400
Message-ID: <28589.1502902172@sss.pgh.pa.us>
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org

Robert Haas <robertmhaas@gmail.com> writes:
> On Wed, Aug 16, 2017 at 11:56 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> I can get on board with that statement.  Can you draft a better wording?

> Here is an attempt.  Feel free to edit.

I think s/plan/query/ in the last bit would be better.  Perhaps

+	 * However, if force_parallel_mode = on or force_parallel_mode = regress,
+	 * then we impose parallel mode whenever it's safe to do so, even if the
+	 * final plan doesn't use parallelism.  It's not safe to do so if the query
+	 * contains anything parallel-unsafe; parallelModeOK will be false in that
+	 * case.  Otherwise, everything in the query is either parallel-safe or
+	 * parallel-restricted, and in either case it should be OK to impose
+	 * parallel-mode restrictions.  If that ends up breaking something, then
+	 * either some function the user included in the query is incorrectly
+	 * labelled as parallel-safe or parallel-restricted when in reality it's
+	 * parallel-unsafe, or else the query planner itself has a bug.
 	 */

			regards, tom lane


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