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https://issues.apache.org/jira/browse/BEAM-6350?focusedWorklogId=183027&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-183027
]
ASF GitHub Bot logged work on BEAM-6350:
----------------------------------------
Author: ASF GitHub Bot
Created on: 09/Jan/19 11:22
Start Date: 09/Jan/19 11:22
Worklog Time Spent: 10m
Work Description: mareksimunek commented on pull request #7399:
[BEAM-6350] Reuse PCollectionView when created in translators
URL: https://github.com/apache/beam/pull/7399#discussion_r246311325
##########
File path:
sdks/java/extensions/euphoria/src/main/java/org/apache/beam/sdk/extensions/euphoria/core/translate/BroadcastHashJoinTranslator.java
##########
@@ -35,22 +38,41 @@
* Translator for {@link
org.apache.beam.sdk.extensions.euphoria.core.client.operator.RightJoin} and
* {@link
org.apache.beam.sdk.extensions.euphoria.core.client.operator.LeftJoin} when one
side of
* the join fits in memory so it can be distributed in hash map with the other
side.
+ *
+ * <p>Note that when reusing smaller join side to several broadcast hash joins
there are some rules
+ * to follow to avoid data to be send to executors repeatedly:
+ *
+ * <ul>
+ * <li>Input {@link PCollection} of broadcasted side has to be the same
instance
+ * <li>Key extractor of broadcasted side has to be the same {@link
UnaryFunction} instance
+ * </ul>
*/
public class BroadcastHashJoinTranslator<LeftT, RightT, KeyT, OutputT>
extends AbstractJoinTranslator<LeftT, RightT, KeyT, OutputT> {
+ /**
+ * Used to prevent multiple views to the same input PCollection. And
therefore multiple broadcasts
+ * of the same data.
+ */
+ private Table<PCollection<?>, UnaryFunction<?, KeyT>, PCollectionView<?>>
pViews =
Review comment:
better to add `final` to this field
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Issue Time Tracking
-------------------
Worklog Id: (was: 183027)
Time Spent: 1h 10m (was: 1h)
> Reuse same PCollectionView when created in translators
> -------------------------------------------------------
>
> Key: BEAM-6350
> URL: https://issues.apache.org/jira/browse/BEAM-6350
> Project: Beam
> Issue Type: Improvement
> Components: dsl-euphoria
> Affects Versions: 2.11.0
> Reporter: Marek Simunek
> Assignee: David Moravek
> Priority: Major
> Time Spent: 1h 10m
> Remaining Estimate: 0h
>
> If for LeftJoin is used BroadcastHashJoinTranslator then from right side is
> created PCollectionView (as sideInput).
> If we use right side in multiple joins then PCollectionView is created
> multiple times which is not optimal behavior.
> Eg.
> {code:java}
> LeftJoin.of(left, right)..
> LeftJoin.of(anotherLeftPcollection, right)..
> {code}
> For example it will happen when we want to solve skew Join.
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