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https://issues.apache.org/jira/browse/CALCITE-1965?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16140624#comment-16140624
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Christian Beikov commented on CALCITE-1965:
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The impl in {{getAllPredicates}} depends on the change in the lineage code, so
I am not sure I can apply that independently.
Maybe you can explain the expected lineage concept to me so that I understand
why this might be problematic? I must know the _lineage_ in the outer join case
of {{getAllPredicates}} since I have to add {{ISNULL}} predicates for all
expressions. I guess if I don't add these predicates, the joins would really be
treated like a inner join and rewrites would happen where they shouldn't.
I thought really hard and even enumerated the scenarios for 4 relations with
alternating join types and a materialization covering 2 relations, but couldn't
find a correctnes violation of my approach, of course assuming I have the
correct understand of the rewriting that is happening. Maybe you can enlighten
me? :)
As always, time problems. Know them very good :D
Thanks in advance for all the assistance! Looking forward to see the outer join
support for MVs in master.
> Support outer joins for materialized views
> ------------------------------------------
>
> Key: CALCITE-1965
> URL: https://issues.apache.org/jira/browse/CALCITE-1965
> Project: Calcite
> Issue Type: Improvement
> Components: core
> Reporter: Christian Beikov
> Assignee: Julian Hyde
>
> Currently, only inner joins are supported for materialized view
> substitutions. The support for outer joins involves creating new pulled up
> predicates in case of outer joins that represent semantics of the join. For a
> join predicate like "a.id = b.id" the inner join just pulls up that
> predicate. When having a left join like e.g. {{select * from a left join b on
> a.id = b.id}}, the actual pulled up predicate would be {{OR(=(a.id,
> b.id),ISNULL(b.id))}}. For a right join it would be {{OR(=(a.id,
> b.id),ISNULL(a.id))}} and for a full outer join it would be {{OR(=(a.id,
> b.id),ISNULL(a.id),ISNULL(b.id))}}
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