Re: a raft of parallelism-related bug fixes

On Mon, Feb 8, 2016 at 4:11 PM, Peter Geoghegan <pg@heroku.com> wrote:
> All that I wanted to do was look at EXPLAIN ANALYZE output that showed
> a parallel seq scan on my laptop, simply because I wanted to see a
> cool thing happen. I had to complain about it [1] to get clarification
> from you [2].
>
> I accept that this might have been a somewhat isolated incident (that
> I couldn't easily get *at least* a little instant gratification), but
> it still should be avoided. You've accused me of burying the lead
> plenty of times. Don't tell me that it was too hard to prominently
> place those details somewhere where I or any other contributor could
> reasonably expect to find them, like the CF app page, or a wiki page
> that is maintained on an ongoing basis (and linked to at the start of
> each thread). If I said that that was too much to you, you'd probably
> shout at me. If I persisted, you wouldn't commit my patch, and for me
> that probably means it's DOA.
>
> I don't think I'm asking for much here.

I don't think you are asking for too much; what I think is that Amit
and I were trying to do exactly the thing you asked for, and mostly
did.  On March 20th, Amit posted version 11 of the sequential scan
patch, and included directions about the order in which to apply the
patches:

http://www.postgresql.org/message-id/CAA4eK1JSSonzKSN=L-DWuCEWdLqkbMUjvfpE3fGW2tn2zPo2RQ@mail.gmail.com

On March 25th, Amit posted version 12 of the sequential scan patch,
and again included directions about which patches to apply:

http://www.postgresql.org/message-id/CAA4eK1L50Y0Y1OGt_DH2eOUyQ-rQCnPvJBOon2PcGjq+1byi4w@mail.gmail.com

On March 27th, Amit posted version 13 of the sequential scan patch,
which did not include those directions:

http://www.postgresql.org/message-id/CAA4eK1LFR8sR9viUpLPMKRqUVcRhEFDjSz1019rpwgjYftrXeQ@mail.gmail.com

While perhaps Amit might have included directions again, I think it's
pretty reasonable that he felt that it might not be entirely necessary
to do so given that he had already done it twice in the last week.
This was still the state of affairs when you asked your question on
April 20th.  Two days after you asked that question, Amit posted
version 14 of the patch, and again included directions about what
patches to apply:

http://www.postgresql.org/message-id/CAA4eK1JLv+2y1AwjhsQPFisKhBF7jWF_Nzirmzyno9uPBRCpGw@mail.gmail.com

Far from the negligence that you seem to be implying, I think Amit was
remarkably diligent about providing these kinds of updates.  I
admittedly didn't duplicate those same updates on the parallel
mode/contexts thread to which you replied, but that's partly because I
would often whack around that patch first and then Amit would adjust
his patch to cope with my changes after the fact.  That doesn't seem
to have been the case in this particular example, but if this is the
closest thing you can come up with to a process failure during the
development of parallel query, I'm not going to be sad about it: I'm
going to have a beer.  Seriously: we worked really hard at this.

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