Kyle Kingsbury created KAFKA-13574:
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Summary: NotLeaderOrFollowerException thrown for a successful send
Key: KAFKA-13574
URL: https://issues.apache.org/jira/browse/KAFKA-13574
Project: Kafka
Issue Type: Bug
Components: clients
Affects Versions: 3.0.0
Environment: openjdk version "11.0.13" 2021-10-19
Reporter: Kyle Kingsbury
With org.apache.kafka/kafka-clients 3.0.0, under rare circumstances involving
multiple node and network failures, I've observed a call to `producer.send()`
throw `NotLeaderOrFollowerException` for a message which later appears in
`consumer.poll()` return values.
I don't have a reliable repro case for this yet, but the case I hit involved
retries=1000, acks=all, and idempotence enabled. I suspect what might be
happening here is that an initial attempt to send the message makes it to the
server and is committed, but the acknowledgement is lost e.g. due to timeout;
the Kafka producer then automatically retries the send attempt, and on that
retry hits a NotLeaderOrFollowerException, which is thrown back to the caller.
If we interpret NotLeaderOrFollowerException as a definite failure, then this
would constitute an aborted read.
I've seen issues like this in a number of databases around client or
server-internal retry mechanisms, and I think the thing to do is: rather than
throwing the most *recent* error, throw the {*}most indefinite{*}. That way
clients know that their request may have actually succeeded, and they won't
(e.g.) attempt to re-submit a non-idempotent request again.
As a side note: is there... perhaps documentation on which errors in Kafka are
supposed to be definite vs indefinite? NotLeaderOrFollowerException is a
subclass of RetriableException, but it looks like RetriableException is more
about transient vs permanent errors than whether it's safe to retry.
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