Joel Koshy created KAFKA-3234:
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Summary: Minor documentation edits: clarify minISR; some
topic-level configs are missing
Key: KAFKA-3234
URL: https://issues.apache.org/jira/browse/KAFKA-3234
Project: Kafka
Issue Type: Improvement
Components: website
Reporter: Joel Koshy
Assignee: Joel Koshy
Fix For: 0.9.0.1
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:
{quote}
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.
{quote}
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.
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