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Posted to commits@beam.apache.org by "Anton Kedin (JIRA)" <ji...@apache.org> on 2017/12/15 18:01:00 UTC
[jira] [Created] (BEAM-3360) [SQL] Do not assign triggers for
HOP/TUMBLE
Anton Kedin created BEAM-3360:
---------------------------------
Summary: [SQL] Do not assign triggers for HOP/TUMBLE
Key: BEAM-3360
URL: https://issues.apache.org/jira/browse/BEAM-3360
Project: Beam
Issue Type: Task
Components: dsl-sql
Reporter: Anton Kedin
Currently when parsing HOP/TUMBLE expressions we create a repeating trigger for the defined windows, see:
{code:java|title=BeamAggregationRule.java}
private Trigger createTriggerWithDelay(GregorianCalendar delayTime) {
return Repeatedly.forever(AfterWatermark.pastEndOfWindow().withLateFirings(AfterProcessingTime
.pastFirstElementInPane().plusDelayOf(Duration.millis(delayTime.getTimeInMillis()))));
}
{code}
This will not work correctly with joins, as joins with multiple trigger firings are currently broken: https://issues.apache.org/jira/browse/BEAM-3190 .
Even if joins with multiple firings worked correctly, SQL parsing stage is still probably an incorrect place to infer them.
Better alternatives:
- inherit the user-defined triggers for the input pcollection without modification;
- triggering at sinks ( https://s.apache.org/beam-sink-triggers ) might define a way to backpropagate triggers with correct semantics;
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