Re: intermittent failures in Cygwin from select_parallel tests

On Tue, Jun 22, 2021 at 5:21 PM Noah Misch <noah@leadboat.com> wrote:
> On Thu, Aug 03, 2017 at 10:45:50AM -0400, Robert Haas wrote:
> > On Wed, Aug 2, 2017 at 11:47 PM, Noah Misch <noah@leadboat.com> wrote:
> > > postmaster algorithms rely on the PG_SETMASK() calls preventing that.  Without
> > > such protection, duplicate bgworkers are an understandable result.  I caught
> > > several other assertions; the PMChildFlags failure is another case of
> > > duplicate postmaster children:
> > >
> > >       6 TRAP: FailedAssertion("!(entry->trans == ((void *)0))", File: "pgstat.c", Line: 871)
> > >       3 TRAP: FailedAssertion("!(PMSignalState->PMChildFlags[slot] == 1)", File: "pmsignal.c", Line: 229)
> > >      20 TRAP: FailedAssertion("!(RefCountErrors == 0)", File: "bufmgr.c", Line: 2523)
> > >      21 TRAP: FailedAssertion("!(vmq->mq_sender == ((void *)0))", File: "shm_mq.c", Line: 221)
> > >      Also, got a few "select() failed in postmaster: Bad address"
> > >
> > > I suspect a Cygwin signals bug.  I'll try to distill a self-contained test
> > > case for the Cygwin hackers.  The lack of failures on buildfarm member brolga
> > > argues that older Cygwin is not affected.
> >
> > Nice detective work.
>
> Thanks.  http://marc.info/?t=150183296400001 has my upstream report.  The
> Cygwin project lead reproduced this, but a fix remained elusive.
>
> I guess we'll ignore weird postmaster-associated lorikeet failures for the
> foreseeable future.

While reading a list of recent build farm assertion failures I learned that
this is still broken in Cygwin 3.2, and eventually found my way back
to this thread.  I was wondering about suggesting some kind of
official warning, but I guess the manual already covers it with this
10 year old notice.  I don't know much about Windows or Cygwin so I'm
not sure if it needs updating or not, but I would guess that there are
no longer any such systems?

  <productname>Cygwin</productname> is not recommended for running a
  production server, and it should only be used for running on
  older versions of <productname>Windows</productname> where
  the native build does not work.