[
https://issues.apache.org/jira/browse/KAFKA-2400?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14654050#comment-14654050
]
Jason Gustafson commented on KAFKA-2400:
----------------------------------------
[~jkreps] I was thinking defaults in the ballpark of 30s for session timeout,
and 1-5s for heartbeat. 300ms seems a little short, but perhaps it's not
unreasonable since heartbeats are so cheap.
> Expose heartbeat frequency in new consumer configuration
> --------------------------------------------------------
>
> Key: KAFKA-2400
> URL: https://issues.apache.org/jira/browse/KAFKA-2400
> Project: Kafka
> Issue Type: Improvement
> Reporter: Jason Gustafson
> Assignee: Jason Gustafson
> Priority: Minor
>
> The consumer coordinator communicates the need to rebalance through responses
> to heartbeat requests sent from each member of the consumer group. The
> heartbeat frequency therefore controls how long normal rebalances will take.
> Currently, the frequency is hard-coded to 3 heartbeats per the configured
> session timeout, but it would be nice to expose this setting so that the user
> can control the impact from rebalancing.
> Since the consumer is currently single-threaded and heartbeats are sent in
> poll(), we cannot guarantee that the heartbeats will actually be sent at the
> configured frequency. In practice, the user may have to adjust their fetch
> size to ensure that poll() is called often enough to get the desired
> heartbeat frequency. For most users, the consumption rate is probably fast
> enough for this not to matter, but we should make the documentation clear on
> this point. In any case, we expect that most users will accept the default
> value.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
