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https://issues.apache.org/jira/browse/HIVE-22578?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17029122#comment-17029122
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Jesus Camacho Rodriguez commented on HIVE-22578:
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[~hamvas.aron], if there is a bug in CBO, we need to fix it. Copying the AST
when we start optimization is just a workaround that harms compilation
performance badly.
Which error were you observing? This patch does not contain a test to reproduce
it.
> CBO genOPTree is not failsafe for CTAS and VIEW statements
> ----------------------------------------------------------
>
> Key: HIVE-22578
> URL: https://issues.apache.org/jira/browse/HIVE-22578
> Project: Hive
> Issue Type: Bug
> Components: CBO
> Affects Versions: 3.0.0, 3.1.2
> Reporter: Aron Hamvas
> Assignee: Aron Hamvas
> Priority: Major
> Fix For: 4.0.0
>
> Attachments: HIVE-22578.2.patch, HIVE-22578.patch
>
>
> If CBO fails during OT generation, it is supposed to skip CBO and fall back
> to SemanticAnalyzer generating the OT for the original AST. However, for CTAS
> and VIEW statements, the original AST is discarded and replaced with the new
> AST.
> If OT generation for the new AST fails with a SemanticException, the
> compilation is destined to fail completely since we cannot fall back to the
> original and possibly valid AST.
> Also, the SemanticException sometimes gets hidden and misjudged as a missing
> column statistics issue due to bad error handling.
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