Ismael Juma created KAFKA-4479:
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Summary: Streams tests should pass without hardcoded Time.SYSTEM
in GroupCoordinator
Key: KAFKA-4479
URL: https://issues.apache.org/jira/browse/KAFKA-4479
Project: Kafka
Issue Type: Improvement
Reporter: Ismael Juma
Priority: Minor
If we pass `KafkaServer.time` to `GroupCoordinator`[1], some streams tests like
QueryableStateIntegrationTest fail sem-regularly. [~damianguy] looked into it
and described it as:
{quote}
Looking at the sequence of events, one thread is stopped, and hence leaves the
group triggering a rebalance, but the other thread doesn’t seem to get the
memo, tries to commit, fails, and then game-over.
So.. the case that it fails the one alive thread is not getting a rebalance.
This would happen during a `poll(..)` right? However i can see the thread is
polling many times after the other thread has shutdown.
It tries to commit every time around the loop, so:
poll(..)
process(..)
maybeCommit(..)
and there is like < 10ms between calls to `poll`.
{quote}
A theory was that the mock time was not advancing enough to trigger a rebalance
in the group coordinator. However, the consumer is closed, so that should
trigger a `LeaveGroup` request and it's unclear why a rebalance is not
triggered for the live consumer.
PR where this issue was first seen and discussed:
https://github.com/apache/kafka/pull/2095
[1]
https://github.com/apache/kafka/blob/trunk/core/src/main/scala/kafka/server/KafkaServer.scala#L222
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