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https://issues.apache.org/jira/browse/IMPALA-15236?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Aleksandr Efimov closed IMPALA-15236.
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> Expose HBO matching provenance in query profiles
> ------------------------------------------------
>
> Key: IMPALA-15236
> URL: https://issues.apache.org/jira/browse/IMPALA-15236
> Project: IMPALA
> Issue Type: Improvement
> Components: Frontend
> Reporter: Aleksandr Efimov
> Assignee: Aleksandr Efimov
> Priority: Major
>
> h3. Problem
> When HBO replaces a plan node's estimated cardinality, the plan and profile
> currently annotate it only as "(from HBO)". This does not show which
> canonicalization strategy matched or how the HBO value differs from the
> original estimate. As a result, surprising estimates are difficult to
> investigate and profile tools such as plan-graph.py cannot explain why
> history was reused.
> h3. Proposed change
> Expose match provenance when an HBO cardinality is applied:
> * Show the selected canonicalization strategy, for example "(from HBO
> EXPR_REWRITE)".
> * Preserve the original planner estimate alongside the applied HBO
> cardinality.
> * Consider exposing the opaque HBO hash key used for the match, similar to
> TupleCacheNode.
> The descriptive canonicalized key and raw query material should not be
> exposed. Non-HBO estimates should remain unchanged. This task does not define
> matching rules for future CPU, memory, or runtime statistics and does not
> require stabilizing the V2 profile format.
> h3. Acceptance criteria
> * Text plan/profile output identifies the selected strategy for an HBO hit.
> * The original estimate remains available when HBO replaces it.
> * Tests cover an HBO hit and a non-HBO path.
> * If a key is exposed, only the opaque hash is shown.
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