Re: Explain buffers wrong counter with parallel plans

On 2018-May-07, Robert Haas wrote:

> On Sat, May 5, 2018 at 8:56 AM, Amit Kapila <amit.kapila16@gmail.com> wrote:
> > The reason why I think the current behavior is okay because it is
> > coincidental that they were displayed correctly.  We have not made any
> > effort to percolate it to upper nodes.  For ex., before that commit
> > also, it was not being displayed for Gather Merge or Gather with some
> > kind of node like 'Limit' where we have to stop before reaching the
> > end of the result.
> 
> It's not entirely coincidental.  I had the intention to try to ensure
> that the workers would be shut down before the Gather or Gather Merge,
> and I think that various things in the code testify to that intention.
> It sounds like I missed some cases, but now we're missing even more
> cases.

So, apparently this is not a Postgres 11 open item, but rather a bug
that goes back to pg10.  However, maybe it would be worth fixing soon
anyway?  In particular, if we want to perturb the explain output as
suggested upthread, maybe *that* should be considered an open item?

Anyway, this has stalled for a month now.

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services