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Gyula Fora commented on FLINK-2283: ----------------------------------- I would use stateful java maps using PartitionedState for now. I see several reasons to do this instead of more complex out-of-core implementations: -State will be properly checkpointed with no additional implementation -We can use the state backend (if necessary) to handle out-of-core state (this is probably a perfect candidate for lazy state fetching) -This implementation will scale easily if we implement it for the partitioned state -It's a trivial implementation, while managed memory will probably be a lot of overhead > Make grouped reduce/fold/aggregations stateful using Partitioned state > ---------------------------------------------------------------------- > > Key: FLINK-2283 > URL: https://issues.apache.org/jira/browse/FLINK-2283 > Project: Flink > Issue Type: Improvement > Components: Streaming > Affects Versions: 0.10 > Reporter: Gyula Fora > Priority: Minor > > Currently the inner state of the grouped aggregations are not persisted as an > operator state. > These operators should be reimplemented to use the newly introduced > partitioned state abstractions which will make them fault tolerant and > scalable for the future. > A suggested implementation would be to use a stateful mapper to implement the > desired behaviour. -- This message was sent by Atlassian JIRA (v6.3.4#6332)