I'm sorry for any alarms. My pseudocode should have read: GlobalWindow (triggering *Repeatedly.forever* AfterProcessingTime. pastFirstElementInPane)
I'm suspecting that this "last used trigger" does not apply to my usage .. ie, View.asMap when applied to a Combine.perKey. Perhaps this "last used trigger" only applies to views of Combine.globally-- could you confirm or clarify? Thanks. On Tue, Nov 5, 2019 at 11:54 PM Kenneth Knowles <[email protected]> wrote: > > > On Tue, Nov 5, 2019 at 9:29 PM Aaron Dixon <[email protected]> wrote: > >> From https://beam.apache.org/documentation/programming-guide/#side-inputs >> >> > If the side input has multiple trigger firings, Beam uses the value >> from the latest trigger firing. This is particularly useful if you use a >> side input with a single global window and specify a trigger. >> > > Sorry for this. The documentation is entirely wrong. If a side input has > multiple firings, then all elements from all firings are included in the > side input as though they are unrelated elements. I have filed > https://issues.apache.org/jira/browse/BEAM-8563 to at least prevent the > confusing result and give a good error message. > > I have this sub-pipeline: >> >> -> GlobalWindow (triggering AfterProcessingTime.pastFirstElementInPane) >> > > Are you sure you want this? It will drop all data after the first firing. > We are about to disable such triggers due to the data loss risk. See > https://s.apache.org/finishing-triggers-drop-data. If your intent is to > drop all subsequent data, I am interested in your use case. Can you share > more? > > >> -> Combine.perKey (Max) >> -> View.asMap >> ...which I use as a side input. >> >> But I get a "Duplicate values for <key>" error (DirectRunner). (Stack >> trace below.) >> >> But the only way for duplicate keys to come out of the global window is >> via multiple triggers. >> >> What am I missing? >> > > This is surprising. Can you share the actual code of your pipeline? > According to your pseudocode, this is impossible. The trigger you described > should never fire multiple times. But as I mentioned above, the trigger is > about to be forbidden. If we can learn about your usage, maybe that will > help. > > Kenn > > >> >> >> >> === >> java.lang.IllegalArgumentException: Duplicate values for :ihop >> at >> org.apache.beam.sdk.values.PCollectionViews$MapViewFn.apply(PCollectionViews.java:397) >> at >> org.apache.beam.sdk.values.PCollectionViews$MapViewFn.apply(PCollectionViews.java:373) >> at >> org.apache.beam.runners.direct.SideInputContainer$SideInputContainerSideInputReader.get(SideInputContainer.java:261) >> at >> org.apache.beam.repackaged.direct_java.runners.core.SimpleDoFnRunner.sideInput(SimpleDoFnRunner.java:247) >> at >> org.apache.beam.repackaged.direct_java.runners.core.SimpleDoFnRunner.access$900(SimpleDoFnRunner.java:74) >> at >> org.apache.beam.repackaged.direct_java.runners.core.SimpleDoFnRunner$DoFnProcessContext.sideInput(SimpleDoFnRunner.java:548) >> >> >>
