Subject: Re: Rename max_parallel_degree?
To: "David G. Johnston" <david.g.johnston@gmail.com>
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Cc: Tom Lane <tgl@sss.pgh.pa.us>, Robert Haas <robertmhaas@gmail.com>,
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From: Josh berkus <josh@agliodbs.com>
Message-ID: <57509894.9080507@agliodbs.com>
Date: Thu, 2 Jun 2016 13:35:32 -0700
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On 06/02/2016 01:08 PM, David G. Johnston wrote:
> On Thu, Jun 2, 2016 at 3:52 PM, Josh berkus <josh@agliodbs.com
> <mailto:josh@agliodbs.com>>wrote:
>=20
>     On 06/02/2016 08:53 AM, Tom Lane wrote:
>     > Josh berkus <josh@agliodbs.com <mailto:josh@agliodbs.com>> writes:
>     >> On 06/02/2016 04:58 AM, Robert Haas wrote:
>     >>> Well, I think we could drop node, if you like.  I think parallel
>     >>> wouldn't be good to drop, though, because it sounds like we want a
>     >>> global limit on parallel workers also, and that can't be just
>     >>> max_workers.  So I think we should keep parallel in there for all=
 of
>     >>> them, and have max_parallel_workers and
>     >>> max_parallel_workers_per_gather(_node).  The reloption and the Pa=
th
>     >>> struct field can be parallel_workers rather than parallel_degree.
>     >
>     >> So does that mean we'll rename it if you manage to implement a par=
ameter
>     >> which controls the number of workers for the whole statement?
>     >
>     > That would fit in as something like max_parallel_workers_per_statem=
ent.
>=20
>     ETOOMANYKNOBS
>=20
>     I'm trying to think of some way we can reasonably automate this for
>     users ...
>=20
>=20
> =E2=80=8BAre you referring to right now or if we move the goal posts to m=
aking
> this a per-statement reservation?=E2=80=8B

I was assuming that we would have *both* per-operation and per-statement
limits.  I can see reasons for having both, I can see why power users
would want both, but it's going to be overwhelming to casual users.


--=20
--
Josh Berkus
Red Hat OSAS
(any opinions are my own)


--=20
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