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https://issues.apache.org/jira/browse/FLINK-3665?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15230443#comment-15230443
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ASF GitHub Bot commented on FLINK-3665:
---------------------------------------
Github user fhueske commented on a diff in the pull request:
https://github.com/apache/flink/pull/1848#discussion_r58895362
--- Diff:
flink-java/src/main/java/org/apache/flink/api/java/operators/PartitionOperator.java
---
@@ -98,6 +101,14 @@ public PartitionOperator(DataSet<T> input, Keys<T>
pKeys, Partitioner<?> customP
this.customPartitioner = customPartitioner;
this.distribution = distribution;
}
+
+ public PartitionOperator<T> withOrders(Order... orders) {
--- End diff --
We should check that the number of `orders` is the same as the number of
specified keys. Unfortunately, this is not as trivial as it sounds, because
`Keys` does not give access to the the originally specified keys but only to
the flattened logical keys. If a program specifies a `Tuple2<Long, Long>` as
key, it will only specify a single order but the logical keys will be flattened
to `[Long, Long]`. I think we should extend the `Keys` class by a method
`TypeInformation<?>[] getOriginalKeyFieldTypes()` which returns the unflattened
field types. Using that method we can see how many flat fields exist for each
specified key field.
> Range partitioning lacks support to define sort orders
> ------------------------------------------------------
>
> Key: FLINK-3665
> URL: https://issues.apache.org/jira/browse/FLINK-3665
> Project: Flink
> Issue Type: Improvement
> Components: DataSet API
> Affects Versions: 1.0.0
> Reporter: Fabian Hueske
> Fix For: 1.1.0
>
>
> {{DataSet.partitionByRange()}} does not allow to specify the sort order of
> fields. This is fine if range partitioning is used to reduce skewed
> partitioning.
> However, it is not sufficient if range partitioning is used to sort a data
> set in parallel.
> Since {{DataSet.partitionByRange()}} is {{@Public}} API and cannot be easily
> changed, I propose to add a method {{withOrders(Order... orders)}} to
> {{PartitionOperator}}. The method should throw an exception if the
> partitioning method of {{PartitionOperator}} is not range partitioning.
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