What exactly is the issue? I've been working on Spark dev for a long time and very rarely do I actually run into an issue that only manifest on Jenkins but not locally. I don't have some magic local setup either.
We should definitely cut down test flakiness. On Thu, Feb 16, 2017 at 5:26 PM, Saikat Kanjilal <sxk1...@hotmail.com> wrote: > I'd just like to follow up again on this thread, should we devote some > energy to fixing unit tests based on module, there wasn't much interest in > this last time but given the nature of this thread I'd be willing to deep > dive into this again with some help. > ------------------------------ > *From:* Saikat Kanjilal <sxk1...@hotmail.com> > *Sent:* Wednesday, February 15, 2017 6:12 PM > *To:* Josh Rosen > *Cc:* Armin Braun; Kay Ousterhout; dev@spark.apache.org > > *Subject:* Re: File JIRAs for all flaky test failures > > The issue was not with a lack of tooling, I used the url you are > describing below to drill down to the exact test failure/stack trace, the > problem was that my builds would work like a charm locally but fail with > these errors on Jenkins, this was the whole challenge in fixing the unit > tests, it was rare (if ever) where I would be able to replicate test > failures locally. > > Sent from my iPhone > > On Feb 15, 2017, at 5:40 PM, Josh Rosen <joshro...@databricks.com> wrote: > > A useful tool for investigating test flakiness is my Jenkins Test Explorer > service, running at https://spark-tests.appspot.com/ > > This has some useful timeline views for debugging flaky builds. For > instance, at https://spark-tests.appspot.com/jobs/spark-master- > test-maven-hadoop-2.6 (may be slow to load) you can see this chart: > https://i.imgur.com/j8LV3pX.png. Here, each column represents a test run > and each row represents a test which failed at least once over the > displayed time period. > > In that linked example screenshot you'll notice that a few columns have > grey squares indicating that tests were skipped but lack any red squares to > indicate test failures. This usually indicates that the build failed due to > a problem other than an individual test failure. For example, I clicked > into one of those builds and found that one test suite failed in test setup > because the previous suite had not properly cleaned up its SparkContext > (I'll file a JIRA for this). > > You can click through the interface to drill down to reports on individual > builds, tests, suites, etc. As an example of an individual test's detail > page, https://spark-tests.appspot.com/test-details? > suite_name=org.apache.spark.rdd.LocalCheckpointSuite&test_ > name=missing+checkpoint+block+fails+with+informative+message shows the > patterns of flakiness in a streaming checkpoint test. > > Finally, there's an experimental "interesting new test failures" report > which tries to surface tests which have started failing very recently: > https://spark-tests.appspot.com/failed-tests/new. Specifically, entries > in this feed are test failures which a) occurred in the last week, b) were > not part of a build which had 20 or more failed tests, and c) were not > observed to fail in during the previous week (i.e. no failures from [2 > weeks ago, 1 week ago)), and d) which represent the first time that the > test failed this week (i.e. a test case will appear at most once in the > results list). I've also exposed this as an RSS feed at > https://spark-tests.appspot.com/rss/failed-tests/new. > > > On Wed, Feb 15, 2017 at 12:51 PM Saikat Kanjilal <sxk1...@hotmail.com> > wrote: > > I would recommend we just open JIRA's for unit tests based on module > (core/ml/sql etc) and we fix this one module at a time, this at least keeps > the number of unit tests needing fixing down to a manageable number. > > > ------------------------------ > *From:* Armin Braun <m...@obrown.io> > *Sent:* Wednesday, February 15, 2017 12:48 PM > *To:* Saikat Kanjilal > *Cc:* Kay Ousterhout; dev@spark.apache.org > *Subject:* Re: File JIRAs for all flaky test failures > > I think one thing that is contributing to this a lot too is the general > issue of the tests taking up a lot of file descriptors (10k+ if I run them > on a standard Debian machine). > There are a few suits that contribute to this in particular like > `org.apache.spark.ExecutorAllocationManagerSuite` which, like a few > others, appears to consume a lot of fds. > > Wouldn't it make sense to open JIRAs about those and actively try to > reduce the resource consumption of these tests? > Seems to me these can cause a lot of unpredictable behavior (making the > reason for flaky tests hard to identify especially when there's timeouts > etc. involved) + they make it prohibitively expensive for many to test > locally imo. > > On Wed, Feb 15, 2017 at 9:24 PM, Saikat Kanjilal <sxk1...@hotmail.com> > wrote: > > I was working on something to address this a while ago > https://issues.apache.org/jira/browse/SPARK-9487 but the difficulty in > testing locally made things a lot more complicated to fix for each of the > unit tests, should we resurface this JIRA again, I would whole heartedly > agree with the flakiness assessment of the unit tests. > [SPARK-9487] Use the same num. worker threads in Scala ... > <https://issues.apache.org/jira/browse/SPARK-9487> > issues.apache.org > In Python we use `local[4]` for unit tests, while in Scala/Java we use > `local[2]` and `local` for some unit tests in SQL, MLLib, and other > components. If the ... > > > > ------------------------------ > *From:* Kay Ousterhout <kayousterh...@gmail.com> > *Sent:* Wednesday, February 15, 2017 12:10 PM > *To:* dev@spark.apache.org > *Subject:* File JIRAs for all flaky test failures > > Hi all, > > I've noticed the Spark tests getting increasingly flaky -- it seems more > common than not now that the tests need to be re-run at least once on PRs > before they pass. This is both annoying and problematic because it makes > it harder to tell when a PR is introducing new flakiness. > > To try to clean this up, I'd propose filing a JIRA *every time* Jenkins > fails on a PR (for a reason unrelated to the PR). Just provide a quick > description of the failure -- e.g., "Flaky test: DagSchedulerSuite" or > "Tests failed because 250m timeout expired", a link to the failed build, > and include the "Tests" component. If there's already a JIRA for the > issue, just comment with a link to the latest failure. I know folks don't > always have time to track down why a test failed, but this it at least > helpful to someone else who, later on, is trying to diagnose when the issue > started to find the problematic code / test. > > If this seems like too high overhead, feel free to suggest alternative > ways to make the tests less flaky! > > -Kay > > >
