I wonder if the watermark is accidentally advancing too early, causing Apex
to shut down the pipeline before the final finalize DoFn executes?
On Wed, Jul 5, 2017 at 1:45 PM, Thomas Weise <t...@apache.org> wrote:
> I don't think this is a problem with the test and if anything this problem
> to me shows the test is useful in catching similar issues during unit test
> runs.
>
> Is there any form of asynchronous/trigger based processing in this pipeline
> that could cause this?
>
> The Apex runner will shutdown the pipeline after the final watermark, the
> shutdown signal traverses the pipeline just like a watermark, but it is not
> seen by user code.
>
> Thomas
>
> --
> sent from mobile
> On Jul 5, 2017 1:19 PM, "Kenneth Knowles" <k...@google.com.invalid> wrote:
>
> > Upon further investigation, this tests always writes to
> > ./target/wordcountresult-00000-of-00002 and
> > ./target/wordcountresult-00001-of-00002. So after a successful test run,
> > any further run without a `clean` will spuriously succeed. I was running
> > via IntelliJ so did not do the ritual `mvn clean` workaround. So
> > reproduction appears to be easy and we could fix the test (if we don't
> > remove it) to use a fresh temp dir.
> >
> > This seems to point to a bug in waitUntilFinish() and/or Apex if the
> > topology is shut down before this ParDo is run. This is a ParDo with
> > trivial bounded input but with side inputs. So I would guess the bug is
> > either in watermark tracking / readiness of the side input or just how
> > PushbackSideInputDoFnRunner is used.
> >
> > On Wed, Jul 5, 2017 at 12:23 PM, Reuven Lax <re...@google.com.invalid>
> > wrote:
> >
> > > I've done a bit more debugging with logging. It appears that the
> finalize
> > > ParDo is never being invoked in this Apex test (or at least the
> LOG.info
> > in
> > > that ParDo never runs). This ParDo is run on a constant element (code
> > > snippet below), so it should always run.
> > >
> > > PCollection<Void> singletonCollection = p.apply(Create.of((Void)
> null));
> > > singletonCollection
> > > .apply("Finalize", ParDo.of(new DoFn<Void, Integer>() {
> > > @ProcessElement
> > > public void processElement(ProcessContext c) throws Exception {
> > > LOG.info("Finalizing write operation {}.", writeOperation);
> > >
> > >
> > > On Wed, Jul 5, 2017 at 11:22 AM, Kenneth Knowles
> <k...@google.com.invalid
> > >
> > > wrote:
> > >
> > > > Data-dependent file destinations is a pretty great feature. We also
> > have
> > > > another change to make to this @Experimental feature, and it would be
> > > nice
> > > > to get them both into 2.1.0 if we can unblock this quickly.
> > > >
> > > > I just tried this too, and failed to reproduce it. But Jenkins and
> > Reuven
> > > > both have a reliable repro.
> > > >
> > > > Questionss:
> > > >
> > > > - Any ideas about how these configurations differ?
> > > > - Does this actually affect users?
> > > > - Once we have another test that catches this issue, can we delete
> > this
> > > > test?
> > > >
> > > > Every other test passes, including the actual example WordCountIT.
> > Since
> > > > the PR doesn't change primitives, it also seems like it is an
> existing
> > > > issue. And the test seems redundant with our other testing but won't
> > get
> > > as
> > > > much maintenance attention. I don't want to stop catching whatever
> this
> > > > issue is, though.
> > > >
> > > > Kenn
> > > >
> > > > On Wed, Jul 5, 2017 at 10:31 AM, Reuven Lax <re...@google.com.invalid
> >
> > > > wrote:
> > > >
> > > > > Hi Thomas,
> > > > >
> > > > > This only happens with https://github.com/apache/beam/pull/3356.
> > > > >
> > > > > Reuven
> > > > >
> > > > > On Mon, Jul 3, 2017 at 6:11 AM, Thomas Weise <t...@apache.org>
> wrote:
> > > > >
> > > > > > Hi Reuven,
> > > > > >
> > > > > > I'm not able to reproduce the issue locally. I was hoping to see
> > > which
> > > > > > thread is attempting to emit the results. In Apex, only the
> > operator
> > > > > thread
> > > > > > can emit the results, any other thread that is launched by the
> > > operator
> > > > > > cannot. I'm not aware of ParDo managing separate threads though
> and
> > > > > assume
> > > > > > this must be a race. If you still have the log, can you send it
> to
> > > me?
> > > > > >
> > > > > > Thanks,
> > > > > > Thomas
> > > > > >
> > > > > >
> > > > > >
> > > > > > On Sat, Jul 1, 2017 at 5:51 AM, Reuven Lax
> > <re...@google.com.invalid
> > > >
> > > > > > wrote:
> > > > > >
> > > > > > > pr/3356 fails in the Apex WordCountTest. The failed test is
> here
> > > > > > > <https://builds.apache.org/job/beam_PreCommit_Java_
> > > > > > > MavenInstall/12829/org.apache.beam$beam-runners-apex/
> > > > > > > testReport/org.apache.beam.runners.apex.examples/
> WordCountTest/
> > > > > > > testWordCountExample/>
> > > > > > > :
> > > > > > >
> > > > > > > Upon debugging, it looks like this is likely a problem in the
> > Apex
> > > > > runner
> > > > > > > itself. A ParDo calls output(), and that triggers an exception
> > > thrown
> > > > > > from
> > > > > > > inside the Apex runner. The Apex runner calls emit on a
> > > > > DefaultOutputPort
> > > > > > > (ApexParDoOperator.java:275), and that throws an exception
> inside
> > > of
> > > > > > > verifyOperatorThread().
> > > > > > >
> > > > > > > I'm going to ignore this failure for now as it seems unrelated
> to
> > > my
> > > > > PR,
> > > > > > > but does someone want to take a look?
> > > > > > >
> > > > > > > Reuven
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
>
