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https://issues.apache.org/jira/browse/FLINK-7629?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Gabor Gevay updated FLINK-7629:
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Description:
In the Scala API, {{KeyedStream.maxBy}} and similar methods currently only work
with a field name, and not with nested field expressions, such as
"fieldA.fieldX". (Their documentation says this should work.)
The reason for this is that the string overload of {{KeyedStream.aggregate}}
uses {{fieldNames2Indices}} and then calls the integer overload. Instead, it
should create a {{SumAggregator}} or {{ComparableAggregator}} directly, as the
integer overload does (and as the Java API does). The ctors of
{{SumAggregator}} or {{ComparableAggregator}} will call
{{FieldAccessorFactory.getAccessor}}, which will correctly handle a nested
field expression.
was:
In the Scala API, {{KeyedStream.maxBy}} and similar methods currently only work
with a field name, and not with nested field expressions, such as
"fieldA.fieldX". (This contradicts their documentation.)
The reason for this is that the string overload of {{KeyedStream.aggregate}}
uses {{fieldNames2Indices}} and then calls the integer overload. Instead, it
should create a {{SumAggregator}} or {{ComparableAggregator}} directly, as the
integer overload does (and as the Java API does). The ctors of
{{SumAggregator}} or {{ComparableAggregator}} will call
{{FieldAccessorFactory.getAccessor}}, which will correctly handle a nested
field expression.
> Scala stream aggregations should support nested field expressions
> -----------------------------------------------------------------
>
> Key: FLINK-7629
> URL: https://issues.apache.org/jira/browse/FLINK-7629
> Project: Flink
> Issue Type: Bug
> Components: Scala API, Streaming
> Reporter: Gabor Gevay
> Assignee: Gabor Gevay
> Priority: Minor
> Fix For: 1.4.0
>
>
> In the Scala API, {{KeyedStream.maxBy}} and similar methods currently only
> work with a field name, and not with nested field expressions, such as
> "fieldA.fieldX". (Their documentation says this should work.)
> The reason for this is that the string overload of {{KeyedStream.aggregate}}
> uses {{fieldNames2Indices}} and then calls the integer overload. Instead, it
> should create a {{SumAggregator}} or {{ComparableAggregator}} directly, as
> the integer overload does (and as the Java API does). The ctors of
> {{SumAggregator}} or {{ComparableAggregator}} will call
> {{FieldAccessorFactory.getAccessor}}, which will correctly handle a nested
> field expression.
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