Re: a raft of parallelism-related bug fixes

Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> On Mon, Feb 8, 2016 at 2:36 PM, Joshua D. Drake <jd(at)commandprompt(dot)com> wrote:
>> I have no problem running any test cases you wish on a branch in a loop for
>> the next week and reporting back any errors.

> Well, what I've done is push into the buildfarm code that will allow
> us to do *the most exhaustive* testing that I know how to do in an
> automated fashion. Which is to create a file that says this:

> force_parallel_mode=regress
> max_parallel_degree=2

I did a few dozen runs of the core regression tests with those settings
(using current HEAD plus my lockGroupLeaderIdentifier-ectomy patch).
Roughly one time in ten, it fails in the stats test, with diffs as
attached. I interpret this as meaning that parallel workers don't
reliably transmit stats to the stats collector, though maybe there
is something else happening.

regards, tom lane