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https://issues.apache.org/jira/browse/CALCITE-5365?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18128786#comment-18128786
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Arnaud Jegou edited comment on CALCITE-5365 at 10/19/26 2:26 PM:
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_edit: reframed_
Splitting the condition makes sense to me. Part of the blowup comes from
something else though: above a union, lineage combines fields from different
inputs of the same union, which can never happen (CALCITE-7869). Here only 3 x
3 = 9 of the 3^14 combinations are valid. Fixing that keeps the result small in
most cases, and splitting still helps on top of it when the conjuncts relate
different unions. A limit still makes sense as a safeguard for plans that
really have many valid combinations.
note: the query in the description uses left joins, and {{getAllPredicates}}
returns null for an outer join, so as written it does not reach
{{{}createAllPossibleExpressions{}}}. It does with inner joins and
{{getAllPredicates}} does build the 3^14 combinations
was (Author: JIRAUSER310786):
_edit: reframed_
Splitting the condition makes sense to me. Part of the blowup comes from
something else though: above a union, lineage combines fields from different
union inputs, which can never happen (CALCITE-7869). Here only 3 x 3 = 9 of the
3^14 combinations are valid. Fixing that keeps the result small in most cases,
and splitting still helps on top of it when the conjuncts relate different
unions. A limit still makes sense as a safeguard for plans that really have
many valid combinations.
note: the query in the description uses left joins, and {{getAllPredicates}}
returns null for an outer join, so as written it does not reach
{{createAllPossibleExpressions}}. It does with inner joins and
{{getAllPredicates}} does build the 3^14 combinations
> RelMdExpressionLineage#createAllPossibleExpressions will create many RexCall
> lead to OOM
> ------------------------------------------------------------------------------------------
>
> Key: CALCITE-5365
> URL: https://issues.apache.org/jira/browse/CALCITE-5365
> Project: Calcite
> Issue Type: Bug
> Components: core
> Affects Versions: 1.30.0
> Reporter: hqbhoho
> Priority: Major
>
> Execute query like:
> {code:java}
> select
> *
> from
> (
> select *
> from
> (
> select * from A1
> )
> union all
> (
> select * from A2
> )
> union all
> (
> select * from A3
> )
> ) t1
> left join
> (
> select *
> from
> (
> select * from B1
> )
> union all
> (
> select * from B2
> )
> union all
> (
> select * from B3
> )
> )t2
> on t1.a1 = t2.b1
> and t1.a2 = t2.b2
> and t1.a3 = t2.b3
> and t1.a4 = t2.b4
> and t1.a5 = t2.b5
> and t1.a6 = t2.b6
> and t1.a7 = t2.b7
> left join C1 name
> on t2.b8=name.c1 {code}
> I will get all Predicates via RelMetadataQuery.getAllPredicates()，but will
> occur oom.
> RelMdExpressionLineage#createAllPossibleExpressions will retrun 3^14 RexCall
> when t1 join t2 with 7 condition? (t1.a1 will have 3 replacement)
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