[jira] [Commented] (IMPALA-1262) user initiated query cancellation should return operation_state = CANCELED_STATE

["Tim Armstrong (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/IMPALA-1262?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16637110#comment-16637110 ] 

Tim Armstrong commented on IMPALA-1262:
---------------------------------------

[~jeszyb] mentioned on IMPALA-4714 that EXCEPTION might cause confusion because admins look at queries in the EXCEPTION state to understand errors.

> user initiated query cancellation should return operation_state = CANCELED_STATE
> --------------------------------------------------------------------------------
>
>                 Key: IMPALA-1262
>                 URL: https://issues.apache.org/jira/browse/IMPALA-1262
>             Project: IMPALA
>          Issue Type: Bug
>          Components: Backend
>    Affects Versions: Impala 1.4
>            Reporter: Dan Hecht
>            Assignee: Bikramjeet Vig
>            Priority: Minor
>              Labels: query-lifecycle
>
> I've been told that if the user cancels the query, our intention is to not set query_state to EXCEPTION.  (Is that the desired behavior?)  Adding a test case to test_cancellation.py as follows, shows that this is not the current behavior (at least not in all circumstances).
> {code}
> --- a/tests/query_test/test_cancellation.py
> +++ b/tests/query_test/test_cancellation.py
> @@ -102,6 +102,7 @@ class TestCancellation(ImpalaTestSuite):
>        sleep(vector.get_value('cancel_delay'))
>        assert self.client.get_state(handle) != self.client.QUERY_STATES['EXCEPTION']
>        cancel_result = self.client.cancel(handle)
> +      assert self.client.get_state(handle) != self.client.QUERY_STATES['EXCEPTION']
>        assert cancel_result.status_code == 0,\
>            'Unexpected status code from cancel request: %s' % cancel_result
>        thread.join()
> {code}
> One example of how this can happen is if the cancel happens while the wait thread is still in WaitInternal, then WaitInternal will return Status::CANCELLED, and UpdateQueryStatus indiscriminately sets query_state_ to EXCEPTION if !ok().  But, I don't think that side of the execution can distinguish between user initiated cancel and error initiated cancel.  Probably, QueryExecState::Cancel needs to remember which kind of cancellation it was so that the cancelled side can do the right thing.
> We don't have a general workaround.



--
This message was sent by Atlassian JIRA
(v7.6.3#76005)

---------------------------------------------------------------------
To unsubscribe, e-mail: issues-all-unsubscribe@impala.apache.org
For additional commands, e-mail: issues-all-help@impala.apache.org