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https://issues.apache.org/jira/browse/BEAM-5386?focusedWorklogId=179815&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-179815
]
ASF GitHub Bot logged work on BEAM-5386:
----------------------------------------
Author: ASF GitHub Bot
Created on: 30/Dec/18 17:42
Start Date: 30/Dec/18 17:42
Worklog Time Spent: 10m
Work Description: tweise commented on pull request #7349: [BEAM-5386]
Prevent CheckpointMarks from not getting acknowledged
URL: https://github.com/apache/beam/pull/7349#discussion_r244541323
##########
File path:
runners/flink/src/test/java/org/apache/beam/runners/flink/translation/wrappers/streaming/io/UnboundedSourceWrapperTest.java
##########
@@ -626,13 +650,30 @@ public void testSourceWithNoReaderDoesNotShutdown()
throws Exception {
try {
thread.start();
- List<UnboundedSource.UnboundedReader<KV<Integer, Integer>>>
localReaders =
- sourceWrapper.getLocalReaders();
- while (localReaders != null && !localReaders.isEmpty()) {
- Thread.sleep(200);
- // should stay alive
- assertThat(thread.isAlive(), is(true));
+ // Wait to see if the wrapper shuts down immediately in case it
doesn't have readers
+ if (!shouldHaveReaders) {
+ // The expected state is for finalizeSource to sleep instead of
exiting
+ while (true) {
+ if (thread.getStackTrace().length >= 2) {
Review comment:
Interestingly the test passes with this change, though it isn't clear why :)
Please switch the lines and do the length check as `callStack.length` (can
also be combined into existing condition).
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Issue Time Tracking
-------------------
Worklog Id: (was: 179815)
Time Spent: 4h 20m (was: 4h 10m)
> Flink Runner gets progressively stuck when Pubsub subscription is nearly empty
> ------------------------------------------------------------------------------
>
> Key: BEAM-5386
> URL: https://issues.apache.org/jira/browse/BEAM-5386
> Project: Beam
> Issue Type: Bug
> Components: io-java-gcp, runner-flink
> Affects Versions: 2.6.0
> Reporter: Encho Mishinev
> Assignee: Chamikara Jayalath
> Priority: Major
> Time Spent: 4h 20m
> Remaining Estimate: 0h
>
> I am running the Flink runner on Apache Beam 2.6.0.
> My pipeline involves reading from Google Cloud Pubsub. The problem is that
> whenever there are few messages left in the subscription I'm reading from,
> the whole job becomes progressively slower and slower, Flink's checkpoints
> start taking much more time and messages seem to not get properly
> acknowledged.
> This happens only whenever the subscription is nearly empty. For example when
> running 13 taskmanagers with parallelism of 52 for the job and a subscription
> that has 122 000 000 messages, you start feeling the slowing down after there
> are only 1 000 000 - 2 000 000 messages left.
> In one of my tests the job processed nearly 122 000 000 messages in an hour
> and then spent over 30 minutes attempting to do the few hundred thousand
> left. In the end it was reading a few hundred messages a minute and not
> reading at all for some periods. Upon stopping it the subscription still had
> 235 unacknowledged messages, even though Flink's element count was higher
> than the amount of messages I had loaded. The only explanation is that the
> messages did not get properly acknowledged and were resent.
> I have set up the subscriptions to a large acknowledgment deadline, but that
> does not help.
> I did smaller tests on subscriptions with 100 000 messages and a job that
> simply reads and does nothing else. The problem is still evident. With
> parallelism of 52 the job gets slow right away. Takes over 5min to read about
> 100 000 messages and a few hundred seem to keep cycling through never being
> acknowledged.
> On the other hand a parallelism of 1 works fine until there are about 5000
> messages left, and then slows down similarly.
> Parallelism of 16 reads about 75 000 of the 100 000 immediately (a few
> seconds) and then proceeds to slowly work on the other 25 000 for minutes.
> The PubsubIO connector is provided by Beam so I suspect the problem to be in
> Beam's Flink runner rather than Flink itself.
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