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https://issues.apache.org/jira/browse/FLINK-3665?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15249905#comment-15249905
]
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_r60408415
--- Diff:
flink-tests/src/test/java/org/apache/flink/test/javaApiOperators/PartitionITCase.java
---
@@ -546,43 +549,274 @@ public void testRangePartitionInIteration() throws
Exception {
result.collect(); // should fail
}
+
+
+ @Test
+ public void testRangePartitionerOnSequenceDataWithOrders() throws
Exception {
+ final ExecutionEnvironment env =
ExecutionEnvironment.getExecutionEnvironment();
+ DataSet<Tuple2<Long, Long>> dataSet = env.generateSequence(0,
10000)
+ .map(new MapFunction<Long, Tuple2<Long,
Long>>() {
+ @Override
+ public Tuple2<Long, Long> map(Long value) throws
Exception {
+ return new Tuple2<>(value / 5000, value % 5000);
+ }
+ });
+
+ final Tuple2Comparator<Long> tuple2Comparator = new
Tuple2Comparator<>(new LongComparator(true),
+
new
LongComparator(false));
+
+ MinMaxSelector<Tuple2<Long, Long>> minMaxSelector = new
MinMaxSelector<>(tuple2Comparator);
+
+ final List<Tuple2<Tuple2<Long, Long>, Tuple2<Long, Long>>>
collected = dataSet.partitionByRange(0, 1)
+ .withOrders(Order.ASCENDING, Order.DESCENDING)
+ .mapPartition(minMaxSelector)
+ .collect();
+
+ Collections.sort(collected, new
Tuple2Comparator<>(tuple2Comparator));
--- End diff --
The outer `Comparator<Tuple2<Tuple2<Long, Long>, Tuple2<Long, Long>>>`
which wraps `tuple2Comparator` should only check on the first (min) value and
fail if the min-values of two elements of `collected` are identical.
> 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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