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https://issues.apache.org/jira/browse/BEAM-12040?focusedWorklogId=582720&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-582720
]
ASF GitHub Bot logged work on BEAM-12040:
-----------------------------------------
Author: ASF GitHub Bot
Created on: 14/Apr/21 17:29
Start Date: 14/Apr/21 17:29
Worklog Time Spent: 10m
Work Description: nehsyc commented on a change in pull request #14530:
URL: https://github.com/apache/beam/pull/14530#discussion_r613440809
##########
File path:
sdks/java/core/src/main/java/org/apache/beam/sdk/util/IdentityWindowFn.java
##########
@@ -63,14 +62,16 @@ public IdentityWindowFn(Coder<? extends BoundedWindow>
coder) {
}
@Override
- public Collection<BoundedWindow> assignWindows(WindowFn<T,
BoundedWindow>.AssignContext c)
- throws Exception {
+ public Collection<BoundedWindow> assignWindows(WindowFn<T,
BoundedWindow>.AssignContext c) {
// The window is provided by the prior WindowFn, which also provides the
coder for them
return Collections.singleton(c.window());
}
@Override
public boolean isCompatible(WindowFn<?, ?> other) {
+ // Only compatible with itself.
+ if (this.equals(other)) return true;
Review comment:
This was needed because for stateful DoFn, the direct runner replaces it
with `GbkThenStatefulParDo` which applies a windowing without an explicit
window fn:
https://github.com/apache/beam/blob/2db98ee64a36a2e15b7a8873fbbecb8a4e3e36d9/runners/direct-java/src/main/java/org/apache/beam/runners/direct/ParDoMultiOverrideFactory.java#L202
which triggers a `Flatten` of the input although in this case there is only
one input pcollection:
https://github.com/apache/beam/blob/2db98ee64a36a2e15b7a8873fbbecb8a4e3e36d9/sdks/java/core/src/main/java/org/apache/beam/sdk/transforms/windowing/Window.java#L407
`Flatten` requires the windowing of the input(s) to be compatible including
with itself:
https://github.com/apache/beam/blob/2db98ee64a36a2e15b7a8873fbbecb8a4e3e36d9/sdks/java/core/src/main/java/org/apache/beam/sdk/transforms/Flatten.java#L104
So two options AFAIT:
- Allowing `IdentityWindowFn` to be compatible with itself (which makes
sense I guess?)
- Skipping windowing fn comparison for the same input PCollection in
`Flatten`
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Issue Time Tracking
-------------------
Worklog Id: (was: 582720)
Time Spent: 3h 50m (was: 3h 40m)
> WriteFiles withRunnerDeterminedShardingUnbounded doesn't work with session
> windows
> ----------------------------------------------------------------------------------
>
> Key: BEAM-12040
> URL: https://issues.apache.org/jira/browse/BEAM-12040
> Project: Beam
> Issue Type: Improvement
> Components: io-java-files
> Reporter: Siyuan Chen
> Priority: P2
> Time Spent: 3h 50m
> Remaining Estimate: 0h
>
> Currently the implementation of `withRunnerDeterminedShardingUnbounded` uses
> a stateful DoFn to achieve the grouping and batching of the input elements,
> which doesn't support session windows. One possible way is to add another GBK
> prior to the stateful DoFn to first get session windows merged and reify the
> window before invoking the sateful DoFn.
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