[
https://issues.apache.org/jira/browse/FLINK-958?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14037895#comment-14037895
]
Fabian Hueske edited comment on FLINK-958 at 6/19/14 9:12 PM:
--------------------------------------------------------------
I haven't looked at this issue in detail, but one quick comment.
Sorting the elements of groups on the same key as their grouping key does not
make sense ;-)
Within a group the grouping key is always the same, so sorting the elements of
a group on the grouping key does not change anything.
Anyways, this does of course not invalidate this issue.
We should
- give a meaningful error message if a user tries to sort groups on their
grouping key.
- check if the problem occurs because the sort key is the same as the grouping
key
- fix the issue if that is not the case
was (Author: fhueske):
I haven't looked at this issue in detail, but one quick comment.
Sorting a the elements of groups on the same key as their grouping key does not
make sense ;-)
Within a group the grouping key is always the same, so sorting the elements of
a group on the grouping key does not change anything.
Anyways, this does of course not invalidate this issue.
We should
- give a meaningful error message if a user tries to sort groups on their
grouping key.
- check if the problem occurs because the sort key is the same as the grouping
key
- fix the issue if that is not the case
> Sorting a group when key is a Writable gives a NonSerializable Error
> --------------------------------------------------------------------
>
> Key: FLINK-958
> URL: https://issues.apache.org/jira/browse/FLINK-958
> Project: Flink
> Issue Type: Bug
> Components: Java API
> Reporter: Artem Tsikiridis
>
> I cannot sort an unsorted group by key when the key Is a Writable. Is it a
> bug?
> Consider:
> {code}
> Grouping<Tuple2<Text, LongWritable>> res = myData
> .map(new MapFunction<Tuple2<String, Long>,
> Tuple2<Text, LongWritable>>() {
> @Override
> public Tuple2<Text, LongWritable> map(
> Tuple2<String, Long>
> value) throws Exception {
> return new Tuple2<Text,
> LongWritable>(new Text(value.f0), new LongWritable(value.f1));
> }
> })
> .groupBy(0).sortGroup(0, Order.ASCENDING);
> {code}
> This gives the following stacktrace:
> {code}
> Caused by: java.io.NotSerializableException: sun.misc.Launcher$AppClassLoader
> at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1183)
> at
> java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1547)
> at
> java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1508)
> at
> java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1431)
> at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1177)
> at java.io.ObjectOutputStream.writeArray(ObjectOutputStream.java:1377)
> at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1173)
> at
> java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1547)
> at
> java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1508)
> at
> java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1431)
> at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1177)
> at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:347)
> at
> eu.stratosphere.util.InstantiationUtil.serializeObject(InstantiationUtil.java:250)
> at
> eu.stratosphere.util.InstantiationUtil.writeObjectToConfig(InstantiationUtil.java:231)
> at
> eu.stratosphere.api.java.typeutils.runtime.RuntimeComparatorFactory.writeParametersToConfig(RuntimeComparatorFactory.java:40)
> ... 14 more
> {code}
> Is it not supported to sort groupings with writables as keys? I understand
> this is a hadoop serialization error, but so far I am not able to fix it.
> Any ideas?
--
This message was sent by Atlassian JIRA
(v6.2#6252)
