[FLINK-16729] Offer an out-of-the-box Set serializer

• Type: New Feature
• Status: Open
• Priority: Not a Priority
• Resolution: Unresolved
• Affects Version/s: 1.11.0
• Component/s: API / Type Serialization System
• Labels: auto-deprioritized-major auto-deprioritized-minor
• Assignee: Unassigned
• Reporter: Nico Kruber
• Created: 23/Mar/20 17:30
• Updated: 17/Nov/21 10:43

Description

Currently, Set types are serialized by Kryo by default, since Flink does not come with an own SetSerializer (only one for maps). While the MapSerializer can be easily adapted to cover sets instead, I think, this should be available by default to get the maximum performance out of Flink (kryo is slow!)

 

When this is added, however, we need to provide a migration path for old state (or not use the new SetSerializer by default but offer to opt-in). This may need further investigation as to whether it is possible to migrate from kryo automatically and whether we can check potential changes to the encapsulated entry class.