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https://issues.apache.org/jira/browse/IMPALA-10861?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17602106#comment-17602106
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Baike Xia commented on IMPALA-10861:
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Hi, [~baggio000] , I'm very interested in this question, and can you assign
this ticket to me?
> Optimize the plan for identical predicates
> ------------------------------------------
>
> Key: IMPALA-10861
> URL: https://issues.apache.org/jira/browse/IMPALA-10861
> Project: IMPALA
> Issue Type: Improvement
> Components: Frontend
> Reporter: Yida Wu
> Priority: Trivial
>
> For the query with two same predicates, right now the plan doesn't seem to
> deal with the case and include all the predicates even identical. It could be
> better to do deduplication for this case.
> {code:java}
> Query: explain SELECT c_custkey from tpch.customer c left outer join
> tpch.lineitem l
> ON c.c_custkey = l.l_orderkey and c.c_custkey = l.l_orderkey
> +----------------------------------------------------------------------------+
> | Explain String |
> +----------------------------------------------------------------------------+
> | Max Per-Host Resource Reservation: Memory=32.50MB Threads=6 |
> | Per-Host Resource Estimates: Memory=798MB |
> | |
> | PLAN-ROOT SINK |
> | | |
> | 05:EXCHANGE [UNPARTITIONED] |
> | | |
> | 02:HASH JOIN [RIGHT OUTER JOIN, PARTITIONED] |
> | | hash predicates: l.l_orderkey = c.c_custkey, l.l_orderkey = c.c_custkey |
> | | runtime filters: RF000 <- c.c_custkey, RF001 <- c.c_custkey |
> | | row-size=16B cardinality=150.00K |
> | | |
> | |--04:EXCHANGE [HASH(c.c_custkey,c.c_custkey)] |
> | | | |
> | | 00:SCAN HDFS [tpch.customer c] |
> | | HDFS partitions=1/1 files=1 size=23.08MB |
> | | row-size=8B cardinality=150.00K |
> | | |
> | 03:EXCHANGE [HASH(l.l_orderkey,l.l_orderkey)] |
> | | |
> | 01:SCAN HDFS [tpch.lineitem l] |
> | HDFS partitions=1/1 files=1 size=718.94MB |
> | runtime filters: RF000 -> l.l_orderkey, RF001 -> l.l_orderkey |
> | row-size=8B cardinality=6.00M |
> +----------------------------------------------------------------------------+{code}
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