[KAFKA-3234] Minor documentation edits: clarify minISR; some topic-level configs are missing

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: website
• Assignee: Joel Jacob Koshy
• Reporter: Joel Jacob Koshy
• Created: 12/Feb/16 00:16
• Updated: 09/Feb/22 19:33

Description

Based on an offline conversation with junrao and gwenshap

The current documentation is somewhat confusing on minISR in that it says that it offers a trade-off between consistency and availability. From the user's view-point, consistency (at least in the usual sense of the term) is achieved by disabling unclean leader election - since no replica that was out of ISR can be elected as the leader. So a consumer will never see a message that was not acknowledged to a producer that set acks to "all". Or to put it another way, setting minISR alone will not prevent exposing uncommitted messages - disabling unclean leader election is the stronger requirement. You can achieve the same effect though by setting minISR equal to the number of replicas.

There is also some stale documentation that needs to be removed:

In our current release we choose the second strategy and favor choosing a potentially inconsistent replica when all replicas in the ISR are dead. In the future, we would like to make this configurable to better support use cases where downtime is preferable to inconsistency.

Finally, it was reported on the mailing list (from Elias Levy) that compression.type should be added under the topic configs. Same goes for unclean leader election. Would be good to have these auto-generated.

Issue Links

• links to: GitHub Pull Request #907