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https://issues.apache.org/jira/browse/FLINK-3665?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15249685#comment-15249685
]
ASF GitHub Bot commented on FLINK-3665:
---------------------------------------
Github user dawidwys commented on a diff in the pull request:
https://github.com/apache/flink/pull/1848#discussion_r60392270
--- Diff:
flink-tests/src/test/java/org/apache/flink/test/javaApiOperators/PartitionITCase.java
---
@@ -546,43 +549,264 @@ 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));
+
+ Tuple2<Long, Long> previousMax = null;
+ for (Tuple2<Tuple2<Long, Long>, Tuple2<Long, Long>> tuple2 :
collected) {
--- End diff --
In fact I tried to do similar as what you described with some differences.
Ad. 1 I performed this step in two different places - I simplified it a
bit and added a comment.
Ad.2 I sort on both fields but don't think it is a problem, as the min
value is of greater importance.
Ad.3 In fact I forgot about this step which I added.
4. I also check for cases like described in my response to your comment on
line 809 regarding the Tuple2Comparator. Ensuring that partitioning on the
second part of composite key is done properly.
> 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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