On 2017-04-03 10:26:27 +0530, Rafia Sabih wrote: > On Sat, Apr 1, 2017 at 12:25 AM, Andres Freund <and...@anarazel.de> wrote: > > Hi, > > > > As visible in [1], the explain analyze codepaths of parallel query isn't > > exercised in the tests. That used to be not entirely trivial if the > > output was to be displayed (due to timing), but we should be able to do > > that now that we have the SUMMARY option. > > > > E.g. > > SET max_parallel_workers = 0; > > EXPLAIN (analyze, timing off, summary off, costs off) SELECT * FROM blarg2 > > WHERE generate_series < 0; > > ┌───────────────────────────────────────────────────────────┐ > > │ QUERY PLAN │ > > ├───────────────────────────────────────────────────────────┤ > > │ Gather (actual rows=0 loops=1) │ > > │ Workers Planned: 10 │ > > │ Workers Launched: 0 │ > > │ -> Parallel Seq Scan on blarg2 (actual rows=0 loops=1) │ > > │ Filter: (generate_series < 0) │ > > │ Rows Removed by Filter: 10000000 │ > > └───────────────────────────────────────────────────────────┘ > > > > should be reproducible. I'd suggest additionally adding one tests that > > throws the EXPLAIN output away, but actually enables paralellism. > > > > Greetings, > > > > Andres Freund > > > > [1] > > https://coverage.postgresql.org/src/backend/executor/execParallel.c.gcov.html > > Please find the attached for the same.
> +-- to increase the parallel query test coverage > +EXPLAIN (analyze, timing off, summary off, costs off) SELECT * FROM tenk1; > + QUERY PLAN > +------------------------------------------------------------- > + Gather (actual rows=10000 loops=1) > + Workers Planned: 4 > + Workers Launched: 4 > + -> Parallel Seq Scan on tenk1 (actual rows=2000 loops=5) > +(4 rows) Is there an issue that we might not actually be able to start all four workers? Serious question, not rhetorical. Regards, Andres -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
