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Posted to issues-all@impala.apache.org by "Yida Wu (Jira)" <ji...@apache.org> on 2021/08/13 18:57:00 UTC
[jira] [Updated] (IMPALA-10861) Optimize the plan for identical
predicates
[ https://issues.apache.org/jira/browse/IMPALA-10861?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Yida Wu updated IMPALA-10861:
-----------------------------
Summary: Optimize the plan for identical predicates (was: Optimize the plan for two identical predicates)
> 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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