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https://issues.apache.org/jira/browse/BEAM-12040?focusedWorklogId=586111&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-586111
]
ASF GitHub Bot logged work on BEAM-12040:
-----------------------------------------
Author: ASF GitHub Bot
Created on: 20/Apr/21 19:16
Start Date: 20/Apr/21 19:16
Worklog Time Spent: 10m
Work Description: nehsyc commented on a change in pull request #14530:
URL: https://github.com/apache/beam/pull/14530#discussion_r616967664
##########
File path: sdks/java/core/src/main/java/org/apache/beam/sdk/io/WriteFiles.java
##########
@@ -744,7 +735,84 @@ public void processElement(@Element UserT element,
ProcessContext context)
KV.of(hashDestination(destination,
destinationCoder), element));
}
}))
- .setCoder(KvCoder.of(VarIntCoder.of(), input.getCoder()))
+ .setCoder(KvCoder.of(VarIntCoder.of(), input.getCoder()));
+
+ if (input.getWindowingStrategy().needsMerge()) {
+ // To make sure that the elements are partitioned by original input
windows and to work with
+ // merging windows such as sessions, we firstly group the elements by
destination to reify
+ // the window, if the window needs to be merged, and then perform
sharded writes for each
+ // destination and window pair.
+ Coder<BoundedWindow> windowCoder =
+ (Coder<BoundedWindow>)
input.getWindowingStrategy().getWindowFn().windowCoder();
+ return reifyWindowAndWrite(keyedInput, windowCoder, input.getCoder());
+ } else {
+ return write(keyedInput, input.getCoder());
+ }
+ }
+
+ private PCollection<List<FileResult<DestinationT>>> reifyWindowAndWrite(
+ PCollection<KV<Integer, UserT>> keyedInput,
+ Coder<BoundedWindow> windowCoder,
+ Coder<UserT> inputCoder) {
+ PCollection<KV<ValueInSingleWindow<Integer>, UserT>> windowedInput =
+ keyedInput
+ .apply("GroupByDestination", GroupByKey.create())
Review comment:
This GBK could be a bottleneck although we "reshard" before the write
which is potentially more expensive. I don't have a better idea other than
reifying the window in the keys.
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Issue Time Tracking
-------------------
Worklog Id: (was: 586111)
Time Spent: 4h 50m (was: 4h 40m)
> WriteFiles withRunnerDeterminedSharding for unbounded data doesn't work with
> merging 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
> Assignee: Siyuan Chen
> Priority: P2
> Time Spent: 4h 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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