[jira] [Created] (IMPALA-15236) Expose HBO matching provenance in query profiles

["Aleksandr Efimov (Jira)" <ji...@apache.org>]

Aleksandr Efimov created IMPALA-15236:
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             Summary: 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


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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