Re: infinite loop in parallel hash joins / DSA / get_best_segment

On Tue, Sep 18, 2018 at 11:35 AM Thomas Munro
<thomas(dot)munro(at)enterprisedb(dot)com> wrote:
> On Mon, Sep 17, 2018 at 9:12 PM Thomas Munro
> <thomas(dot)munro(at)enterprisedb(dot)com> wrote:
> > On Mon, Sep 17, 2018 at 10:42 AM Thomas Munro
> > <thomas(dot)munro(at)enterprisedb(dot)com> wrote:
> > > On Mon, Sep 17, 2018 at 10:38 AM Tomas Vondra
> > > <tomas(dot)vondra(at)2ndquadrant(dot)com> wrote:
> > > > While performing some benchmarks on REL_11_STABLE (at 444455c2d9), I've
> > > > repeatedly hit an apparent infinite loop on TPC-H query 4. I don't know
> > > > what exactly are the triggering conditions, but the symptoms are these:
> >
> > With the attached draft patch, Tomas's benchmark script runs happily
> > for long periods. A bit more study required with fresh eyes,
> > tomorrow.
>
> Here is a tidied up version that I propose to back-patch to 10 & 11.

Done.

I figured reviews would be unlikely to show up soon for a dsa.c patch,
but of course post-commit review is very welcome. I thought it best
to have this fix in REL_11_STABLE being tested for as long as possible
before any potential RC1 tag, especially if Tomas plans to continue
his "big join" testing on that branch.

--
Thomas Munro
http://www.enterprisedb.com