[FLINK-3480] Add hash-based strategy for ReduceFunction

• Type: Sub-task
• Status: Closed
• Priority: Major
• Resolution: Won't Do
• Component/s: Runtime / Task
• Assignee: Unassigned
• Reporter: Fabian Hueske
• Created: 23/Feb/16 09:39
• Updated: 08/Jul/19 13:51
• Resolved: 08/Jul/19 13:51

Description

This issue is related to FLINK-3477.
While FLINK-3477 proposes to add hash-based combine strategy for ReduceFunction, this issue aims to add a hash-based strategy for the final aggregation.

This will need again a special hash-table aggregation which allows for in-place updates and append updates. However, it also needs to support spilling to disk in case of too tight memory budgets.