Hello Nation of Flink, while figuring out this bug: https://issues.apache.org/jira/browse/FLINK-1569 I came upon some difficulties. The problem is that the KeyExtractorMappers always return the same tuple. This is problematic, since Collection Execution does simply store the returned values in a list. These elements are not copied before they are stored when object reuse is enabled. Therefore, the whole list will contain only that one reused element.
I see two options for solving this: 1. Change KeyExtractorMappers to always return a new tuple, thereby making object-reuse mode in cluster execution useless for key extractors. 2. Change collection execution mapper to always make copies of the returned elements. This would make object-reuse in collection execution pretty much obsolete, IMHO. How should we proceed with this? Cheers, Aljoscha
