Re: recent deadlock regression test failures

On 2017-04-07 12:49:22 -0500, Kevin Grittner wrote:
> On Fri, Apr 7, 2017 at 12:28 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> > Andrew Dunstan <andrew.dunstan@2ndquadrant.com> writes:
> >> On 04/07/2017 12:57 PM, Andres Freund wrote:
> >>> I don't think any recent changes are supposed to affect deadlock
> >>> detector behaviour?
> >
> >> Both these machines have CLOBBER_CACHE_ALWAYS set. And on both machines
> >> recent changes have made the isolation tests run much much longer.
> >
> > Ouch.  I see friarbird's run time for the isolation tests has gone from an
> > hour and change to over 5 hours in one fell swoop.  hyrax not much better.
> > Oddly, non-CCA animals don't seem to have changed much.
> >
> > Eyeing recent patches, it seems like the culprit must be Kevin's
> > addition to isolationtester's wait query:
> 
> Ouch.  Without this we don't have regression test coverage for the
> SERIALIZABLE READ ONLY DEFERRABLE code, but it's probably not worth
> adding 4 hours to any tests, even if it only shows up with
> CLOBBER_CACHE_ONLY.  I assume the consensus is that I should revert
> it?

I'd rather fix the issue, than remove the tests entirely.  Seems quite
possible to handle blocking on Safesnapshot in a similar manner as pg_blocking_pids?

Greetings,

Andres Freund