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ASF GitHub Bot logged work on BEAM-8347: ---------------------------------------- Author: ASF GitHub Bot Created on: 01/Nov/19 20:10 Start Date: 01/Nov/19 20:10 Worklog Time Spent: 10m Work Description: drobert commented on issue #9820: [BEAM-8347]: Consistently advance UnboundedRabbitMqReader watermark URL: https://github.com/apache/beam/pull/9820#issuecomment-548933689 Quick note: I may be seeing a problem with this implementation locally. This isn't mergeable due to a need to rebase anyway, but there may be an issue updating the watermark when no messages come in (DirectRunner reports "Processing stuck in step (read from rabbit) for at least 05m00s without outputting or completing in state process"). Looking. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org Issue Time Tracking ------------------- Worklog Id: (was: 337532) Time Spent: 2h 40m (was: 2.5h) > UnboundedRabbitMqReader can fail to advance watermark if no new data comes in > ----------------------------------------------------------------------------- > > Key: BEAM-8347 > URL: https://issues.apache.org/jira/browse/BEAM-8347 > Project: Beam > Issue Type: Bug > Components: io-java-rabbitmq > Affects Versions: 2.15.0 > Environment: testing has been done using the DirectRunner. I also > have DataflowRunner available > Reporter: Daniel Robert > Assignee: Jean-Baptiste Onofré > Priority: Major > Time Spent: 2h 40m > Remaining Estimate: 0h > > I stumbled upon this and then saw a similar StackOverflow post: > [https://stackoverflow.com/questions/55736593/apache-beam-rabbitmqio-watermark-doesnt-advance] > When calling `advance()` if there are no messages, no state changes, > including no changes to the CheckpointMark or Watermark. If there is a > relatively constant rate of new messages coming in, this is not a problem. If > data is bursty, and there are periods of no new messages coming in, the > watermark will never advance. > Contrast this with some of the logic in PubsubIO which will make provisions > for periods of inactivity to advance the watermark (although it, too, is > imperfect: https://issues.apache.org/jira/browse/BEAM-7322 ) > The example given in the StackOverflow post is something like this: > > {code:java} > pipeline > .apply(RabbitMqIO.read() > .withUri("amqp://guest:guest@localhost:5672") > .withQueue("test") > .apply("Windowing", > Window.<RabbitMqMessage>into( > FixedWindows.of(Duration.standardSeconds(10))) > .triggering(AfterWatermark.pastEndOfWindow()) > .withAllowedLateness(Duration.ZERO) > .accumulatingFiredPanes()){code} > If I push 2 messages into my rabbit queue, I see 2 unack'd messages and a > window that never performs an on time trigger. > -- This message was sent by Atlassian Jira (v8.3.4#803005)