Re: Parallel query and temp_file_limit - Mailing list pgsql-hackers

From Robert Haas
Subject Re: Parallel query and temp_file_limit
Date
Msg-id CA+TgmoYovxjU=e+eqLWsqup5c1r2K7zuZR4eoqRhXFWWVJUOwg@mail.gmail.com
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In response to Re: Parallel query and temp_file_limit  (Robert Haas <robertmhaas@gmail.com>)
Responses Re: Parallel query and temp_file_limit  (Peter Geoghegan <pg@heroku.com>)
List pgsql-hackers
On Tue, Jun 21, 2016 at 8:15 AM, Robert Haas <robertmhaas@gmail.com> wrote:
> On Mon, Jun 20, 2016 at 11:01 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> Peter Geoghegan <pg@heroku.com> writes:
>>> On Wed, May 18, 2016 at 3:40 AM, Robert Haas <robertmhaas@gmail.com> wrote:
>>>> What I'm tempted to do is trying to document that, as a point of
>>>> policy, parallel query in 9.6 uses up to (workers + 1) times the
>>>> resources that a single session might use.  That includes not only CPU
>>>> but also things like work_mem and temp file space.  This obviously
>>>> isn't ideal, but it's what could be done by the ship date.
>>
>>> Where would that be documented, though? Would it need to be noted in
>>> the case of each such GUC?
>>
>> Why can't we just note this in the number-of-workers GUCs?  It's not like
>> there even *is* a GUC for many of our per-process resource consumption
>> behaviors.
>
> +1.

Since Peter doesn't seem in a hurry to produce a patch for this issue,
I wrote one.  It is attached.  I'll commit this in a day or two if
nobody objects.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

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