Re: Rename max_parallel_degree?

On 06/07/2016 11:01 PM, Robert Haas wrote:
> On Fri, Jun 3, 2016 at 9:39 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> Robert Haas <robertmhaas(at)gmail(dot)com> writes:
>>> I think we should just go with max_parallel_workers for a limit on
>>> total parallel workers within max_work_processes, and
>>> max_parallel_workers_per_gather for a per-Gather limit. It's slightly
>>> annoying that we may end up renaming the latter GUC, but not as
>>> annoying as spending another three weeks debating this and missing
>>> beta2.
>>
>> +1. I'm not as convinced as you are that we'll replace the GUC later,
>> but in any case this is an accurate description of the current
>> semantics. And I'm really *not* in favor of fudging the name with
>> the intent of changing the GUC's semantics later --- that would fail
>> all sorts of compatibility expectations.
>
> Here's a patch change max_parallel_degree to
> max_parallel_workers_per_gather, and also changing parallel_degree to
> parallel_workers. I haven't tackled adding a separate
> max_parallel_workers, at least not yet. Are people OK with this?

+1

>
> Note that there is a dump/restore hazard if people have set the
> parallel_degree reloption on a beta1 install, or used ALTER { USER |
> DATABASE } .. SET parallel_degree. Can everybody live with that?
> Should I bump catversion when applying this?

IMHO, we just need to call it out in the beta2 announcement.

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