On 2017-11-30 08:06:44 -0800, Andres Freund wrote: > Hi, > > On 2017-11-30 23:53:55 +1300, Thomas Munro wrote: > > On Thu, Nov 30, 2017 at 4:47 PM, Thomas Munro > > <[email protected]> wrote: > > > On Thu, Nov 30, 2017 at 4:13 PM, Tom Lane <[email protected]> wrote: > > >> Andres Freund <[email protected]> writes: > > >>> Add some regression tests that exercise hash join code. > > >> > > >> At least one buildfarm member doesn't like this ... > > > > > > $$); > > > initially_multibatch | increased_batches > > > ----------------------+------------------- > > > ! t | f > > > (1 row) > > > > > > rollback to settings; > > > --- 6002,6008 ---- > > > $$); > > > initially_multibatch | increased_batches > > > ----------------------+------------------- > > > ! | > > > (1 row) > > > > > > Hmm. aholehole didn't give me the hash join EXPLAIN ANALYZE output. > > > All other animals are fine so far. Gah. My guess is that this is the > > > following unlikely sequence: > > > > > > 1. Worker launched. > > > 2. Leader descheduled. > > > 3. Worker runs whole join. > > > 4. Leader awakes from slumber, begins running plan and tries to scan > > > outer relation, sees EOF, takes empty-outer optimisation and skips > > > building hash table. > > > 5. Explain has no data. > > > > > > It's arguably a bug that EXPLAIN ANALYZE can fail to give you what you > > > asked for because of details of timing and I have a patch in > > > development to fix that but it's not yet baked. Hmm. Wondering if > > > there is a quick way to avoid that case in the meantime... > > > > A couple more have failed in the same way. If my theory above is > > correct, the attached should fix the problem by skipping the affected > > bits of the test for now. Once we fix EXPLAIN so that it reliably > > prints hash table info no matter what (for which I should have a patch > > fairly soon), we can uncomment them again. Is that an acceptable > > solution for now? BTW this commit tipped nodeHash.c from yellow to > > green on coverage.postgresql.org :-) > > At the current rate of failure I'm slightly inclined to just leave the > occasionally failing test, which sounds like an actual bug imo, in place > till we have the fix. But if there's any pushback I'll go with your > disablign patch till then.
Thomas, any updates on the status of that explain fix? Greetings, Andres Freund
