A. Sophie Blee-Goldman created KAFKA-12486:
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Summary: Utilize HighAvailabilityTaskAssignor to avoid downtime on
corrupted task
Key: KAFKA-12486
URL: https://issues.apache.org/jira/browse/KAFKA-12486
Project: Kafka
Issue Type: Improvement
Components: streams
Reporter: A. Sophie Blee-Goldman
In KIP-441, we added the HighAvailabilityTaskAssignor to address certain common
scenarios which tend to lead to heavy downtime for tasks, such as scaling out.
The new assignor will always place an active task on a client which has a
"caught-up" copy of that tasks' state, if any exists, while the intended
recipient will instead get a standby task to warm up the state in the
background. This way we keep tasks live as much as possible, and avoid the long
downtime imposed by state restoration on active tasks.
We can actually expand on this to reduce downtime due to restoring state:
specifically, we may throw a TaskCorruptedException on an active task which
leads to wiping out the state stores of that task and restoring from scratch.
There are a few cases where this may be thrown:
# No checkpoint found with EOS
# TimeoutException when processing a StreamTask
# TimeoutException when committing offsets under eos
# RetriableException in RecordCollectorImpl
(There is also the case of OffsetOutOfRangeException, but that is excluded here
since it only applies to standby tasks).
We should consider triggering a rebalance when we hit TaskCorruptedException on
an active task so that the assignor has the chance to redirect this to another
client who can resume work on the task while the original owner works on
restoring the state from scratch.
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