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https://issues.apache.org/jira/browse/CALCITE-2454?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16740583#comment-16740583
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Julian Hyde commented on CALCITE-2454:
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Yes, the problem with adding type info is bloat. More text to compute, store,
and for humans to read. Would it be less invasive to add print the row type as
part of the digest of Values? Then the type of each column would only appear
once.
> HepPlanner should not pick cached RelNode when type mismatch while digest
> matches
> ---------------------------------------------------------------------------------
>
> Key: CALCITE-2454
> URL: https://issues.apache.org/jira/browse/CALCITE-2454
> Project: Calcite
> Issue Type: Bug
> Components: core
> Affects Versions: 1.17.0
> Reporter: Yuzhao Chen
> Assignee: Julian Hyde
> Priority: Major
> Labels: pull-request-available
> Attachments: project_with_literals_digest.png
>
>
> After CALCITE-2116, a RelNode will be reused based on digest, but now many
> nodes's digests do not have type info, e.g. LogicalProject, this will affect
> some rules when we wanna transform to a node with same digest and same type
> (HepPlanner may pick out a RelNode with different type).
> So, we should add type info just like VolcanoPlanner.
> We encounter this problem with plan like below:
> {code:java}
> Union
> +-- project1(a: int, b:int, c: double)
> | +-- project2(a: bigint: b: int, c:double)
> +-- project3
> {code}
> We wanna cast a from bigint -> int so we can have a union with project1 and
> project3, but with ProjectMergeRule, while merging project1 and project2,
> HepPlanner will think project2 and project1 are identical and it gives back
> project2. But actually we wanna pick project1.
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