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https://issues.apache.org/jira/browse/BEAM-1517?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15876005#comment-15876005
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Jingsong Lee commented on BEAM-1517:
------------------------------------
Is it appropriate for the user to do the work of GC?
Just like this:
{code}
@ProcessElement
public void process(
ProcessContext c,
BoundedWindow window,
@StateId(stateId) ValueState<Integer> state,
@TimerId("GcTimer") Timer timer) {
Instant maxTimestamp = window.maxTimestamp();
long allowedLateness = 10 * 1000;
Instant gcTime = maxTimestamp.plus(allowedLateness);
//Can Timer have a getCurrentTime interface?
Instant currentTime = new Instant();
if (gcTime.isBefore(currentTime)) {
c.sideOutput(lateDataTag, c.element());
} else {
timer.set(gcTime);
// user logical
// ....
}
}
@OnTimer("GcTimer")
public void gc(
OnTimerContext context,
@StateId(stateId) ValueState<Integer> state) {
state.clear();
}
{code}
> Garbage collect user state in Flink Runner
> ------------------------------------------
>
> Key: BEAM-1517
> URL: https://issues.apache.org/jira/browse/BEAM-1517
> Project: Beam
> Issue Type: Bug
> Components: runner-flink
> Reporter: Aljoscha Krettek
> Assignee: Aljoscha Krettek
>
> User facing state/timers in Beam are bound to the key/window of the data.
> Right now, the Flink Runner does not clean up user state when the watermark
> passes the GC horizon for the state associated with a given window.
> Neither {{StateInternals}} nor the Flink state API support discarding state
> for a whole namespace (which is the window in this case) so we might have to
> manually set a GC timer for each window/key combination, as is done in the
> {{ReduceFnRunner}}. For this we have to know all states a user can possibly
> use, which we can get from the {{DoFn}} signature.
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