Re: pgsql: Add parallel-aware hash joins.

2018-01-24 Thread Robert Haas
On Wed, Jan 24, 2018 at 11:02 PM, Tom Lane wrote: > I may be wasting my breath here, but in one more attempt to convince > you that "time make check" on your laptop is not the only number that > anyone should be interested in, ... Now that is not what I said, or at least not what I intended to sa

Re: pgsql: Add parallel-aware hash joins.

2018-01-24 Thread Tom Lane
Robert Haas writes: > There is no need to collect years of data in order to tell whether or > not the time to run the tests has increased by as much on developer > machines as it has on prairiedog. You showed the time going from 3:36 > to 8:09 between 2014 and the present. That is a 2.26x increa

Re: pgsql: Add parallel-aware hash joins.

2018-01-24 Thread Robert Haas
On Wed, Jan 24, 2018 at 4:01 PM, Tom Lane wrote: > The progress-display output of pg_regress would need a complete rethink > anyhow. First thought is to emit two lines per test, one when we > launch it and one when it finishes and we check the results: > > foreign_data: launched > ... > foreign_d

Re: pgsql: Add parallel-aware hash joins.

2018-01-24 Thread Robert Haas
On Wed, Jan 24, 2018 at 2:31 PM, Tom Lane wrote: > I find that to be a completely bogus straw-man argument. The point of > looking at the prairiedog time series is just to see a data series in > which the noise level is small enough to discern the signal. If anyone's > got years worth of data of

Re: pgsql: Add parallel-aware hash joins.

2018-01-24 Thread Andres Freund
Hi, On 2018-01-24 15:58:16 -0500, Tom Lane wrote: > Yeah. We already have topo sort code in pg_dump, maybe we could push that > into someplace like src/common or src/fe_utils? Although pg_dump hasn't > got any need for edge weights, so maybe sharing code isn't worth it. I suspect it may be more

Re: pgsql: Add parallel-aware hash joins.

2018-01-24 Thread Tom Lane
Andres Freund writes: > On 2018-01-24 15:36:35 -0500, Tom Lane wrote: >> I'm concerned that we'd end up with a higher number of irreproducible >> test failures with no good way to investigate them. > Hm. We probably should dump the used ordering of tests somwhere upon > failure, to make it easier

Re: pgsql: Add parallel-aware hash joins.

2018-01-24 Thread Tom Lane
Andres Freund writes: > On 2018-01-24 17:18:26 -0300, Alvaro Herrera wrote: >> Yeah, I proposed this a decade ago but never had the wits to write the >> code. > It shouldn't be too hard, right? Leaving defining the file format, > parsing it, creating the new schedule with depencencies and adaptin

Re: pgsql: Add parallel-aware hash joins.

2018-01-24 Thread Andres Freund
Hi, On 2018-01-24 15:36:35 -0500, Tom Lane wrote: > There'd be a lot of followup work to sanitize the tests better. For > instance, if two tests transiently create tables named "foo", it doesn't > matter as long as they're not in the same group. It would matter with > this. Right. I suspect we'

Re: pgsql: Add parallel-aware hash joins.

2018-01-24 Thread Andres Freund
Hi, On 2018-01-24 17:18:26 -0300, Alvaro Herrera wrote: > Andres Freund wrote: > > Besides larger groups, starting the next test(s) earlier, another way to > > gain pretty large improvements would be a test schedule feature that > > allowed to stat dependencies between tests. So instead of manuall

Re: pgsql: Add parallel-aware hash joins.

2018-01-24 Thread Tom Lane
Alvaro Herrera writes: > Andres Freund wrote: >> Besides larger groups, starting the next test(s) earlier, another way to >> gain pretty large improvements would be a test schedule feature that >> allowed to stat dependencies between tests. So instead of manually >> grouping the schedule, have 'nu

Re: pgsql: Add parallel-aware hash joins.

2018-01-24 Thread Alvaro Herrera
Thomas Munro wrote: > On Wed, Jan 24, 2018 at 12:10 PM, Tom Lane wrote: > > However, the trend over the last two months is very bad, and I do > > not think that we can point to any large improvement in test > > coverage that someone committed since November. > > I'm not sure if coverage.postgres

Re: pgsql: Add parallel-aware hash joins.

2018-01-24 Thread Alvaro Herrera
Andres Freund wrote: > Besides larger groups, starting the next test(s) earlier, another way to > gain pretty large improvements would be a test schedule feature that > allowed to stat dependencies between tests. So instead of manually > grouping the schedule, have 'numerology' state that it depen

Re: pgsql: Add parallel-aware hash joins.

2018-01-24 Thread Andres Freund
Hi, On 2018-01-24 14:31:47 -0500, Tom Lane wrote: > However ... if you spend any time looking at the behavior of that, > the hashjoin tests are still problematic. I think my main problem with your arguments is that you basically seem to say that one of the more complex features in postgres can't

Re: pgsql: Add parallel-aware hash joins.

2018-01-24 Thread Tom Lane
I wrote: > I find that to be a completely bogus straw-man argument. The point of > looking at the prairiedog time series is just to see a data series in > which the noise level is small enough to discern the signal. If anyone's > got years worth of data off a more modern machine, and they can ext

Re: pgsql: Add parallel-aware hash joins.

2018-01-24 Thread Tom Lane
Andres Freund writes: > On 2018-01-24 13:11:22 -0500, Robert Haas wrote: >> Now, how much should we care about the performance of software with a >> planned release date of 2018 on hardware discontinued in 2001, >> hardware that is apparently about 20 times slower than a modern >> laptop? Some, p

Re: pgsql: Add parallel-aware hash joins.

2018-01-24 Thread Andres Freund
Hi, On 2018-01-24 13:11:22 -0500, Robert Haas wrote: > So for me, the additional hash index tests don't cost anything > measurable and the additional hash join tests cost about a second. I > think this probably accounts for why committers other than you keep > "adding so much time to the regressi

Re: pgsql: Add parallel-aware hash joins.

2018-01-24 Thread Andres Freund
On 2018-01-23 14:24:56 -0500, Robert Haas wrote: > Right, but this doesn't seem to show any big spike in the runtime at > the time when parallel hash was committed, or when the preparatory > patch to add test coverage for hash joins got committed. Rather, > there's a gradual increase over time. E

Re: pgsql: Add parallel-aware hash joins.

2018-01-24 Thread Robert Haas
On Tue, Jan 23, 2018 at 6:10 PM, Tom Lane wrote: > Looking more closely at the shorter series, there are four pretty obvious > step changes since 2016-09. The PNG's x-axis doesn't have enough > resolution to match these up to commits, but looking at the underlying > data, they clearly correspond

Re: pgsql: Add parallel-aware hash joins.

2018-01-23 Thread Thomas Munro
On Wed, Jan 24, 2018 at 12:10 PM, Tom Lane wrote: > There is a very clear secular trend up in the longer data series, > which indicates that we're testing more stuff, +1 > which doesn't bother > me in itself as long as the time is well spent. However, the trend > over the last two months is ver

Re: pgsql: Add parallel-aware hash joins.

2018-01-23 Thread Tom Lane
Robert Haas writes: > On Mon, Jan 22, 2018 at 6:53 PM, Tom Lane wrote: >> Here's a possibly more useful graph of regression test timings over >> the last year. I pulled this from the buildfarm database: it is the >> reported runtime for the "installcheck-C" step in each successful >> build of HE

Re: pgsql: Add parallel-aware hash joins.

2018-01-23 Thread Robert Haas
On Mon, Jan 22, 2018 at 6:53 PM, Tom Lane wrote: > Here's a possibly more useful graph of regression test timings over > the last year. I pulled this from the buildfarm database: it is the > reported runtime for the "installcheck-C" step in each successful > build of HEAD on dromedary, going back

Re: pgsql: Add parallel-aware hash joins.

2018-01-04 Thread Andres Freund
On 2018-01-04 15:16:15 -0500, Tom Lane wrote: > Andres Freund writes: > > On 2018-01-04 11:20:33 -0800, Andres Freund wrote: > >> Some packages on skink have been upgraded. It appears that there either > >> was a libc or valgrind change that made valgrind not recognize that a > >> pointer of 0 mig

Re: pgsql: Add parallel-aware hash joins.

2018-01-04 Thread Tom Lane
Andres Freund writes: > On 2018-01-04 11:20:33 -0800, Andres Freund wrote: >> Some packages on skink have been upgraded. It appears that there either >> was a libc or valgrind change that made valgrind not recognize that a >> pointer of 0 might not point anywhere :( > ==5718== Invalid write of si

Re: pgsql: Add parallel-aware hash joins.

2018-01-04 Thread Andres Freund
On 2018-01-04 11:20:33 -0800, Andres Freund wrote: > On 2018-01-04 12:11:37 -0500, Tom Lane wrote: > > Robert Haas writes: > > > On Thu, Jan 4, 2018 at 11:00 AM, Tom Lane wrote: > > >> Also, what the devil is happening on skink? > > > > > So, skink is apparently dying during shutdown of a user-c

Re: pgsql: Add parallel-aware hash joins.

2018-01-04 Thread Andres Freund
On 2018-01-04 12:11:37 -0500, Tom Lane wrote: > Robert Haas writes: > > On Thu, Jan 4, 2018 at 11:00 AM, Tom Lane wrote: > >> Also, what the devil is happening on skink? > > > So, skink is apparently dying during shutdown of a user-connected > > backend, and specifically the one that executed th

Re: pgsql: Add parallel-aware hash joins.

2018-01-04 Thread Tom Lane
Robert Haas writes: > On Thu, Jan 4, 2018 at 11:00 AM, Tom Lane wrote: >> Also, what the devil is happening on skink? > So, skink is apparently dying during shutdown of a user-connected > backend, and specifically the one that executed the 'tablespace' test. Well, yeah, valgrind is burping: the

Re: pgsql: Add parallel-aware hash joins.

2018-01-04 Thread Robert Haas
On Thu, Jan 4, 2018 at 11:00 AM, Tom Lane wrote: > Also, what the devil is happening on skink? I looked at the server log for the first of the two skink failures. The key lines seem to be: 2018-01-04 07:45:36.764 UTC [5a4ddb98.5a97:154] LOG: statement: DROP SCHEMA testschema CASCADE; 2018-01-04