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https://issues.apache.org/jira/browse/IMPALA-14031?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17952702#comment-17952702
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ASF subversion and git services commented on IMPALA-14031:
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Commit c7f946991961a147dcad835ac7933237ea90bfd2 in impala's branch
refs/heads/master from Joe McDonnell
[ https://gitbox.apache.org/repos/asf?p=impala.git;h=c7f946991 ]
IMPALA-14031: Enable keepalive by default for client connections
Keepalive is useful for detecting dead client connections. In
particular, it has come up several times with load balancers that
drop idle connections. In IMPALA-13253, we added startup flags
that can turn on keepalive and tune the timeouts, but that change
did not enable keepalive by default.
This enables keepalive by default by setting
client_keepalive_probe_period_s to 10 minutes / 600 seconds. The
usual OS setting has a probe period of 2 hours / 7200 seconds.
This uses a more aggressive default, because a client connection
counts towards the fe_service_threads limit. Detecting dead clients
quickly frees up those threads.
This has no impact on idle connections where the TCP connection is
still alive. That is handled through separate controls.
Testing:
- There is already a custom cluster test for keepalive that
continues to pass
- Ran core tests
Change-Id: Ie358b5cabaff884516f7117d20d18c25124e59d5
Reviewed-on: http://gerrit.cloudera.org:8080/22861
Tested-by: Impala Public Jenkins <[email protected]>
Reviewed-by: Michael Smith <[email protected]>
Reviewed-by: Riza Suminto <[email protected]>
> Enable keepalive for client connections by default
> --------------------------------------------------
>
> Key: IMPALA-14031
> URL: https://issues.apache.org/jira/browse/IMPALA-14031
> Project: IMPALA
> Issue Type: Task
> Components: Backend
> Affects Versions: Impala 5.0.0
> Reporter: Joe McDonnell
> Assignee: Joe McDonnell
> Priority: Major
>
> IMPALA-13253 added support for enabling keepalive for client connections by
> setting some startup flags, but it kept keepalive off by default. We should
> switch to enabling keepalive for client connections by default. This is
> particularly important for setups that use load balancers with idle timeouts,
> as that can cause client connections to pile up and hit the
> fe_service_threads limit.
> We'll need to decide on the default settings. The OS default is to start
> keepalive after 2 hours. I think the Impala defaults should be much more
> aggressive (e.g. client_keepalive_probe_period_s could be 10 minutes).
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