Hussein Awala created SPARK-60135:
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Summary: Prune unnecessary subquery-expression traversal in
DeduplicateRelations
Key: SPARK-60135
URL: https://issues.apache.org/jira/browse/SPARK-60135
Project: Spark
Issue Type: Improvement
Components: SQL
Affects Versions: 5.0.0
Reporter: Hussein Awala
DeduplicateRelations.deduplicate unconditionally calls
plan.transformExpressions with a partial function that matches only
SubqueryExpression. This also walks operator expressions that cannot contain a
subquery.
QueryPlan propagates expression tree-pattern bits, and SubqueryExpression
inherits the PLAN_EXPRESSION marker. A narrowly scoped optimization can skip
this expression scan when that marker is absent from the plan, and prune
expression subtrees without the marker when the scan is needed.
The relation-renewal traversal, attribute remapping, subquery recursion and
processing order must remain unchanged. The expression transform must retain
UnknownRuleId because its closure reads and updates traversal state;
ineffective-rule memoization would be inappropriate here.
Suggested validation uses generic Catalyst plans: projects containing
arithmetic/literal expressions, subqueries wrapped in aliases or other
expressions, nested/correlated subqueries, and the same subquery object reused
in multiple positions.
This is narrower than SPARK-49881 (conditional rule-wide skipping), and
distinct from SPARK-59452 (wide UNION branch comparisons and related synthetic
self-join overhead).
Generated-by: Pi Coding Agent 1.1.0
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