On Tue, Aug 26, 2014 at 10:17:05AM +0100, Dave Page wrote: > On Tue, Aug 26, 2014 at 1:46 AM, Tom Lane <t...@sss.pgh.pa.us> wrote: > > For the last month or so, these two buildfarm animals (which I believe are > > the same physical machine) have been erratically failing with errors that > > reflect low-order differences in floating-point calculations. > > > > A recent example is at > > > > http://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=protosciurus&dt=2014-08-25%2010%3A39%3A52 > > > > where the only regression diff is > > > > *** > > /export/home/dpage/pgbuildfarm/protosciurus/HEAD/pgsql.22860/src/test/regress/expected/hash_index.out > > Mon Aug 25 11:41:00 2014 > > --- > > /export/home/dpage/pgbuildfarm/protosciurus/HEAD/pgsql.22860/src/test/regress/results/hash_index.out > > Mon Aug 25 11:57:26 2014 > > *************** > > *** 171,179 **** > > SELECT h.seqno AS i8096, h.random AS f1234_1234 > > FROM hash_f8_heap h > > WHERE h.random = '-1234.1234'::float8; > > ! i8096 | f1234_1234 > > ! -------+------------ > > ! 8906 | -1234.1234 > > (1 row) > > > > UPDATE hash_f8_heap > > --- 171,179 ---- > > SELECT h.seqno AS i8096, h.random AS f1234_1234 > > FROM hash_f8_heap h > > WHERE h.random = '-1234.1234'::float8; > > ! i8096 | f1234_1234 > > ! -------+------------------- > > ! 8906 | -1234.12356777216 > > (1 row) > > > > UPDATE hash_f8_heap > > > > ... a result that certainly makes no sense. The results are not > > repeatable, failing in equally odd ways in different tests on different > > runs. This is happening in all the back branches too, not just HEAD.
> I have > no idea what is causing the current issue - the machine is stable > software-wise, and only has private builds of dependency libraries > update periodically (which are not used for the buildfarm). If I had > to hazard a guess, I'd suggest this is an early symptom of an old > machine which is starting to give up. Agreed. Rerunning each animal against older commits would test that theory. Say, run against the last 6 months of REL9_0_STABLE commits. If those runs show today's failure frequencies instead of historic failure frequencies, it's not a PostgreSQL regression. Not that I see a commit back-patched near the time of the failure uptick (2014-08-06) that looks remotely likely to have introduced such a regression. It would be sad to lose our only buildfarm coverage of plain Solaris and of the Sun Studio compiler, but having buildfarm members this unstable is a pain. Perhaps have those animals retry the unreliable steps up to, say, 7 times? -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers