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Posted to issues-all@impala.apache.org by "ASF subversion and git services (Jira)" <ji...@apache.org> on 2020/11/01 20:21:00 UTC
[jira] [Commented] (IMPALA-10295) Fix analytic limit pushdown when
no predicates are present
[ https://issues.apache.org/jira/browse/IMPALA-10295?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17224332#comment-17224332 ]
ASF subversion and git services commented on IMPALA-10295:
----------------------------------------------------------
Commit c3b5cf8b4c807fa4136b64addb1e7e8be8aaf6c5 in impala's branch refs/heads/master from Tim Armstrong
[ https://gitbox.apache.org/repos/asf?p=impala.git;h=c3b5cf8 ]
IMPALA-10295: fix analytic limit pushdown with no predicates
This handles the first case where analytic limit pushdown could be
applied incorrectly: when there are no predicates applied to the
output of the analytic.
If no rows are filtered out between the pre-analytic sort and the place
where the top-N will be inserted, and the order matches exactly, we
can push down the limit safely because the limit below the analytic
will filter exactly the same rows as the limit above the analytic
would.
We add a helper to check if the sort order matches exactly and then
handle the case with no select node correctly.
We leave the other cases where there is a special predicate to be
handled in the next patch of the series, as the logic there is a
bit more subtle.
Tests:
Added regression planner and query tests that demonstrate the problem.
Ran core tests.
Change-Id: I254e85edd5ea6b6e76d20cbdf27fd88059a98a21
Reviewed-on: http://gerrit.cloudera.org:8080/16663
Reviewed-by: Impala Public Jenkins <im...@cloudera.com>
Tested-by: Impala Public Jenkins <im...@cloudera.com>
> Fix analytic limit pushdown when no predicates are present
> ----------------------------------------------------------
>
> Key: IMPALA-10295
> URL: https://issues.apache.org/jira/browse/IMPALA-10295
> Project: IMPALA
> Issue Type: Sub-task
> Components: Frontend
> Affects Versions: Impala 4.0
> Reporter: Tim Armstrong
> Assignee: Tim Armstrong
> Priority: Blocker
> Labels: correctness
>
> This is to fix case 1 of the parent JIRA.
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