[FLINK-1073] SortGroup() does not sort Combiner input

• Type: Bug
• Status: Resolved
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 0.6.1-incubating, 0.7.0-incubating
• Fix Version/s: 0.6.1-incubating, 0.7.0-incubating
• Assignee: Fabian Hueske
• Reporter: Fabian Hueske
• Created: 27/Aug/14 22:23
• Updated: 28/Feb/19 14:29
• Resolved: 24/Sep/14 10:27

Description

Flink supports sorted input for GroupReduce operators by calling for example

myData.groupBy(1).sortGroup(2, Order.ASCENDING).reduceGroup(new MyReducer());

This code will sort the input of the function MyReducer.reduce() on the third field.
However, the input of MyReducer.combine() is not sorted, which is an unexpected behavior, IMO.