[KAFKA-12453] Guidance on whether a topology is eligible for optimisation

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: streams
• Assignee: Unassigned
• Reporter: Patrick O'Keeffe
• Created: 11/Mar/21 03:30
• Updated: 25/Apr/21 20:31

Description

Since the introduction of KStream.toTable() in Kafka 2.6.x, the decision about whether a topology is eligible for optimisation is no longer a simple one, and is related to whether toTable() operations are preceded by key changing operators.

This decision requires expert level knowledge, and there are serious implications associated with getting it wrong in terms of fault tolerance

Some ideas spring to mind around how to guide developers to make the correct decision:

1. Topology.describe() could indicate whether this topology is eligible for optimisation
2. Topologies could be automatically optimised - note this may have an impact at deployment time, in that an application reset may be required. The developer would need to made aware of this and adjust the deployment plan accordingly