David Huntsperger created BEAM-13160:
----------------------------------------
Summary: Clarify windowing behavior in Javadoc
Key: BEAM-13160
URL: https://issues.apache.org/jira/browse/BEAM-13160
Project: Beam
Issue Type: Improvement
Components: sdk-java-core
Reporter: David Huntsperger
Feedback from a user:
{quote}I'm confused by the documentation around
AfterProcessingTime.pastFirstElementInPane(). The javadoc text seems somewhat
contrived:
"Creates a trigger that fires when the current processing time passes the
processing time at which this trigger saw the first element in a pane."
Doesn't this just mean that the trigger fires as soon it sees the first element
in the pane? Processing time, IIUC, always increases monotonically.
The text in the Beam documentation is also not very illuminating:
"the AfterProcessingTime.pastFirstElementInPane() trigger emits a window after
a certain amount of processing time has passed since data was received"
It's not clear what the "certain amount of processing time" is. Is it some
small, fixed epsilon? Is it configurable?
Another point of confusion: there seems to be inconsistency between the
AfterWatermark Javadoc and the Beam documentation on triggers w.r.t. the
behavior of the default trigger. The Javadoc makes it sound as though the
default trigger is sufficient for handling late data. However, the Beam
documentation states that late data is discarded. It's not clear which is
correct. It seems that the Javadoc is the misleading one, as it omits
discussion of accumulation modes and allowed lateness.{quote}
Note: If this requires additional work after the changes to the Javadoc, please
assign to the website component after the changes to the Java source files are
complete.
--
This message was sent by Atlassian Jira
(v8.3.4#803005)
