From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
cc: Alvaro Herrera <alvherre@2ndquadrant.com>,
        Magnus Hagander <magnus@hagander.net>,
        Bruce Momjian <bruce@momjian.us>,
        PostgreSQL-development <pgsql-hackers@postgresql.org>
Subject: Re: Rename max_parallel_degree?
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References: <2219.1461523373@sss.pgh.pa.us>
 <20160425185804.GA415608@alvherre.pgsql>
 <CA+TgmoZ5oGObjqV5CF3=7Haeui7auPCrp91R-9G7R4v0=6ajJQ@mail.gmail.com>
Comments: In-reply-to Robert Haas <robertmhaas@gmail.com>
	message dated "Mon, 25 Apr 2016 16:10:35 -0400"
Date: Mon, 25 Apr 2016 16:24:43 -0400
Message-ID: <14954.1461615883@sss.pgh.pa.us>
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Robert Haas <robertmhaas@gmail.com> writes:
>> What about calling it something even simpler, such as "max_parallelism"?
>> This avoids such cargo cult, and there's no implication that it's
>> per-query.

> So what would we call the "parallel_degree" member of the Path data
> structure, and the "parallel_degree" reloption?  I don't think
> renaming either of those to "parallelism" is going to be an
> improvement.

I think we should rename all of these to something based on the concept of
"number of worker processes", and adjust the code if necessary to match.
I think the "degree" terminology is fundamentally tainted by the question
of whether or not it counts the leader, and that we will have bugs (or
indeed may have them today) caused by getting that wrong.  Your arguments
for not changing it seem to me not to address that point; you've merely
focused on the question of whether we have the replacement terminology
right.  If we don't, let's make it so, but the current situation is not
good.

			regards, tom lane


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