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Posted to issues-all@impala.apache.org by "Aman Sinha (Jira)" <ji...@apache.org> on 2019/12/10 19:25:00 UTC
[jira] [Resolved] (IMPALA-9162) Incorrect redundant predicate
applied to outer join
[ https://issues.apache.org/jira/browse/IMPALA-9162?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Aman Sinha resolved IMPALA-9162.
--------------------------------
Fix Version/s: Impala 3.4.0
Resolution: Fixed
> Incorrect redundant predicate applied to outer join
> ---------------------------------------------------
>
> Key: IMPALA-9162
> URL: https://issues.apache.org/jira/browse/IMPALA-9162
> Project: IMPALA
> Issue Type: Bug
> Components: Frontend
> Reporter: Aman Sinha
> Assignee: Aman Sinha
> Priority: Major
> Fix For: Impala 3.4.0
>
> Attachments: create.sql.txt
>
>
> Run the attached create.sql script to create the tables and view. The following query shows an incorrect redundant predicate applied to the outer join. This seems another variant of past issues such as IMPALA-7957 and IMPALA-8386.
> {noformat}
> // Has a redundant predicate as 'Other predicates' on Outer Join
> Query: explain select x.* from (select v1.c3, v1.max_c3 from v.t2 left join v.v1 on t2.c2=v1.c3) as x
>
> 06:HASH JOIN [RIGHT OUTER JOIN, PARTITIONED]
> hash predicates: c3 = t2.c2
> other predicates: c3 = max(c3) . <-- WRONG
> runtime filters: RF000 <- t2.c2
> row-size=20B cardinality=397
>
> --13:EXCHANGE [HASH(t2.c2)]
>
> 00:SCAN HDFS [v.t2]
> HDFS partitions=1/1 files=1 size=639B
> row-size=4B cardinality=397
>
> 12:EXCHANGE [HASH(c3)]
>
> 05:HASH JOIN [INNER JOIN, BROADCAST]
> hash predicates: c3 = max(c3)
> runtime filters: RF002 <- max(c3)
> row-size=16B cardinality=207
> {noformat}
>
> By comparison, the following query which does not have the v1.max_c3 column in the SELECT list produces the correct plan:
> {noformat}
> // Does not have the redundant predicate
> Query: explain select x.* from (select v1.c3 from v.t2 left join v.v1 on t2.c2=v1.c3) as x
> 06:HASH JOIN [RIGHT OUTER JOIN, PARTITIONED]
> hash predicates: c3 = t2.c2
> runtime filters: RF000 <- t2.c2
> row-size=20B cardinality=397
> --13:EXCHANGE [HASH(t2.c2)]
> 00:SCAN HDFS [v.t2]
> HDFS partitions=1/1 files=1 size=639B
> row-size=4B cardinality=397
> 12:EXCHANGE [HASH(c3)]
> 05:HASH JOIN [INNER JOIN, BROADCAST]
> hash predicates: c3 = max(c3)
> runtime filters: RF002 <- max(c3)
> row-size=16B cardinality=207
> {noformat}
> Due the redundant predicate, the first query produces wrong results.
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