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Posted to issues@hive.apache.org by "Lefty Leverenz (JIRA)" <ji...@apache.org> on 2015/09/09 08:28:46 UTC
[jira] [Commented] (HIVE-11375) Broken processing of queries
containing NOT (x IS NOT NULL and x <> 0)
[ https://issues.apache.org/jira/browse/HIVE-11375?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14736287#comment-14736287 ]
Lefty Leverenz commented on HIVE-11375:
---------------------------------------
This was backported to branch-1.2 (commit 300717b39428a7898e4228139fbb08ca5c425ca7) so the Fix Version/s should include 1.2.2.
I don't see any commit to branch-1 for the 1.3.0 release.
> Broken processing of queries containing NOT (x IS NOT NULL and x <> 0)
> ----------------------------------------------------------------------
>
> Key: HIVE-11375
> URL: https://issues.apache.org/jira/browse/HIVE-11375
> Project: Hive
> Issue Type: Bug
> Components: Logical Optimizer
> Affects Versions: 2.0.0
> Reporter: Mariusz Sakowski
> Assignee: Aihua Xu
> Fix For: 2.0.0
>
> Attachments: HIVE-11375.2.patch, HIVE-11375.3.patch, HIVE-11375.4.patch, HIVE-11375.branch-1.patch, HIVE-11375.patch
>
>
> When running query like this:
> {code}explain select * from test where (val is not null and val <> 0);{code}
> hive will simplify expression in parenthesis and omit is not null check:
> {code}
> Filter Operator
> predicate: (val <> 0) (type: boolean)
> {code}
> which is fine.
> but if we negate condition using NOT operator:
> {code}explain select * from test where not (val is not null and val <> 0);{code}
> hive will also simplify thing, but now it will break stuff:
> {code}
> Filter Operator
> predicate: (not (val <> 0)) (type: boolean)
> {code}
> because valid predicate should be *val == 0 or val is null*, while above row is equivalent to *val == 0* only, filtering away rows where val is null
> simple example:
> {code}
> CREATE TABLE example (
> val bigint
> );
> INSERT INTO example VALUES (1), (NULL), (0);
> -- returns 2 rows - NULL and 0
> select * from example where (val is null or val == 0);
> -- returns 1 row - 0
> select * from example where not (val is not null and val <> 0);
> {code}
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