Re: [HACKERS] parallel explain analyze support not exercised - Mailing list pgsql-hackers

From Andres Freund
Subject Re: [HACKERS] parallel explain analyze support not exercised
Date
Msg-id 20170406205019.yi4avldebc3ca4df@alap3.anarazel.de
Whole thread Raw
Responses Re: [HACKERS] parallel explain analyze support not exercised  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
Hi,

On 2017-04-03 17:11:33 -0400, Robert Haas wrote:
> On Mon, Apr 3, 2017 at 3:31 PM, Andres Freund <andres@anarazel.de> wrote:
> >> If this is 'make check', then we should have 8 parallel workers
> >> allowed, so if we only do one of these at a time, then I think we're
> >> OK.  But if somebody changes that configuration setting or if it's
> >> 'make installcheck', then the configuration could be anything.
> >
> > Hm - we already rely on max_parallel_workers_per_gather being set with
> > some of the explains in the test.  So I guess we're ok also relying on
> > actual workers being present?
> 
> I'm not really sure about that one way or the other.  Our policy on
> which configurations are supported vis-a-vis 'make installcheck' seems
> to be, essentially, that if a sufficiently-prominent community member
> cares about it, then it ends up getting made to work, unless an
> even-more-prominent community member objects.  That's why, for
> example, our regression tests pass in Czech.  I can't begin to guess
> whether breaking installcheck against configurations with low values
> of max_parallel_workers or max_worker_processes will bother anybody.

I guess we'll have to see. My personal conclusion is that greater
coverage of parallelism is worth some very minor config trouble for
people doing installcheck against clusters with non-default config.

Thanks Rafia!

- Andres



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