[
https://issues.apache.org/jira/browse/IMPALA-341?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16503547#comment-16503547
]
Dan Hecht commented on IMPALA-341:
----------------------------------
Things have changed a bit since the original description was written, but the
basic problem still exists.
I think this will be a bit easier to do once IMPALA-4063 is complete since the
per-backend state will be simplified and easier to reason about when to stop
accepting profiles from a particular backend. cc [~sailesh]
> Remote profiles may be ignored by coordinator if query has a limit
> ------------------------------------------------------------------
>
> Key: IMPALA-341
> URL: https://issues.apache.org/jira/browse/IMPALA-341
> Project: IMPALA
> Issue Type: Bug
> Components: Backend
> Affects Versions: Impala 1.0, Impala 2.3.0
> Reporter: Henry Robinson
> Assignee: Thomas Tauber-Marshall
> Priority: Major
> Labels: query-lifecycle, supportability
>
> For a query with a {{LIMIT}}, the coordinator cancels remote fragments once
> the limit has been reached. This can happen before the backends have
> successfully sent a profile update, and any subsequent updates are ignored
> because the query is cancelled, so the complete profile is never fleshed out.
> When the query is an {{INSERT}}, it is possible that a race in the
> coordinator code handling the remote profiles leads to a crash. This only
> seems to happen occasionally with large clusters (as reported), and we
> haven't been able to reproduce this internally yet.
> We should probably wait until all backends have completed one way or the
> other before tearing down a query completely.
> A workaround is to remove the {{LIMIT}}.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
---------------------------------------------------------------------
To unsubscribe, e-mail: issues-all-unsubscr...@impala.apache.org
For additional commands, e-mail: issues-all-h...@impala.apache.org
