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Posted to issues@hive.apache.org by "ASF GitHub Bot (JIRA)" <ji...@apache.org> on 2018/05/23 06:37:00 UTC
[jira] [Commented] (HIVE-19653) Incorrect predicate pushdown for
groupby with grouping sets
[ https://issues.apache.org/jira/browse/HIVE-19653?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16486793#comment-16486793 ]
ASF GitHub Bot commented on HIVE-19653:
---------------------------------------
GitHub user richox opened a pull request:
https://github.com/apache/hive/pull/354
HIVE-19653: Incorrect predicate pushdown for groupby with grouping sets
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/richox/hive master
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/hive/pull/354.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #354
----
commit ae60a4802d0f9301d737a247ba85ed4cc56d34a7
Author: zhanglirich <zh...@...>
Date: 2018-05-22T13:41:35Z
HIVE-19653: Incorrect predicate pushdown for groupby with grouping sets
----
> Incorrect predicate pushdown for groupby with grouping sets
> -----------------------------------------------------------
>
> Key: HIVE-19653
> URL: https://issues.apache.org/jira/browse/HIVE-19653
> Project: Hive
> Issue Type: Bug
> Components: Logical Optimizer
> Affects Versions: 3.1.0
> Reporter: Zhang Li
> Priority: Major
> Labels: pull-request-available
> Fix For: 3.1.0
>
> Attachments: HIVE-19653.patch
>
>
> Consider the following query:
> {code:java}
> CREATE TABLE T1(a STRING, b STRING, s BIGINT);
> INSERT OVERWRITE TABLE T1 VALUES ('aaaa', 'bbbb', 123456);
> SELECT * FROM (
> SELECT a, b, sum(s)
> FROM T1
> GROUP BY a, b GROUPING SETS ((), (a), (b), (a, b))
> ) t WHERE a IS NOT NULL;
> {code}
> When hive.optimize.ppd is enabled (and hive.cbo.enable=false), the query will output:
> {code:java}
> NULL NULL 123456
> NULL bbbb 123456
> aaaa NULL 123456
> aaaa bbbb 123456
> {code}
> We can see the predicate "a IS NOT NULL" takes no effect, which is incorrect.
> When performing PPD optimization for a GBY operator, we should make sure all grouping sets contains the processing expr before pushdown. otherwise the expr value after GBY is changed and the result is wrong.
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