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https://issues.apache.org/jira/browse/IMPALA-4714?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16634817#comment-16634817
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Tim Armstrong commented on IMPALA-4714:
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I think there are a variety of considerations here, but I'd consider the
FINISHED state for expired queries to be more problematic than the EXCEPTION
state, since it implies that the query finished cleanly, but in fact it was
terminated by the server. IMPALA-7561 provides some evidence that it's simpler
for clients if the EXCEPTION state is used, because it's clear then that the
query was terminated.
The right fix is for clients to close queries promptly - having them timed out
by the server is not a clean way to close the query
I.e. I don't think it's a good idea to make this change.
> Idle session expired query goes in to exception state - And this is confusing
> -----------------------------------------------------------------------------
>
> Key: IMPALA-4714
> URL: https://issues.apache.org/jira/browse/IMPALA-4714
> Project: IMPALA
> Issue Type: Bug
> Components: Backend
> Affects Versions: Impala 2.6.0
> Reporter: Mala Chikka Kempanna
> Priority: Major
> Labels: query-lifecycle
>
> After setting idle_session_timeout , impala server, after completing
> execution of query, moves it into exception state , if there is no client
> activity.
> Example profile excerpt showing this behavior:
> {code}
> Query Timeline
> Start execution: 0ns (0ns)
> Planning finished: 9ms (9ms)
> Child queries finished: 8.3m (8.3m)
> Metastore update finished: 8.3m (661ms)
> Rows available: 8.3m (0ns)
> Cancelled: 11.3m (3.0m)
> Unregister query: 12.0m (42.55s)
> {code}
> Query status and query state-
> {code}
> Query Type: DDL
> Query State: EXCEPTION
> Start Time: Dec 22, 2016 11:45:01 AM
> End Time: Dec 22, 2016 11:57:01 AM
> Duration: 11m, 59s
> Admission Result: Unknown
> Client Fetch Wait Time: 3.7m
> Client Fetch Wait Time Percentage: 31
> Connected User: admin
> DDL Type: COMPUTE_STATS
> File Formats:
> Impala Version: impalad version 2.5.0-cdh5.7.2 RELEASE (build
> 1140f8289dc0d2b1517bcf70454bb4575eb8cc70)
> Network Address: 10.17.100.123:44618
> Out of Memory: false
> Planning Wait Time: 9ms
> Planning Wait Time Percentage: 0
> Query Status: Query d141e0d996c91e72:bb8726fb917537bb expired due to client
> inactivity (timeout is 3m)
> Session ID: 3043ff5042860968:8f92bc3bd2a0ca83
> Session Type: HIVESERVER2
> {code}
> Though query status string is very clear saying "expired due to client
> inactivity (timeout is 3m)", the problem is with "Query State: EXCEPTION"
> This makes user, think something went wrong with query execution.
> So I recommend that queries completed, but expired due to client-inactivity
> be marked as
> "Query State: FINISHED"
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