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ASF GitHub Bot commented on FLINK-3761: --------------------------------------- Github user tillrohrmann commented on the pull request: https://github.com/apache/flink/pull/1988#issuecomment-220289629 In order to support scaling for non-partitioned state, the next step could be the introduction of a kind of union state. The idea would be to aggregate the non-partitioned state of each subtask and then sending it to all subtasks upon recovery. Then every subtask can pick from the union state what it needs for its execution > Introduce key group state backend > --------------------------------- > > Key: FLINK-3761 > URL: https://issues.apache.org/jira/browse/FLINK-3761 > Project: Flink > Issue Type: Sub-task > Components: state backends > Reporter: Till Rohrmann > Assignee: Till Rohrmann > > After an off-line discussion with [~aljoscha], we came to the conclusion that > it would be beneficial to reflect the differences between a keyed and a > non-keyed stream also in the state backends. A state backend which is used > for a keyed stream offers a value, list, folding and value state and has to > group its keys into key groups. > A state backend for non-keyed streams can only offer a union state to make it > work with dynamic scaling. A union state is a state which is broadcasted to > all tasks in case of a recovery. The state backends can then select what > information they need to recover from the whole state (formerly distributed). -- This message was sent by Atlassian JIRA (v6.3.4#6332)