[Enhancement] Push eventstats down by rewriting RexOver to Join + Aggregate (#5483)#5495

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RyanL1997 wants to merge 8 commits into

opensearch-project:mainfrom

RyanL1997:worktree-eventstats-pushdown-5483

Commits on Jun 2, 2026

[BugFix] Push eventstats down by rewriting RexOver to Join + Aggregate (#5483)
RyanL1997
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Fix predicate to accept PPL Function inner node + update test expectations
RyanL1997
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Tighten predicate: reject non-windowable aggregates and dotted-path BY keys
RyanL1997
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Regenerate eventstats EXPLAIN expected outputs for both pushdown modes
RyanL1997
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spotless: rewrap predicate JavaDoc
RyanL1997
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Fix composite-agg size in pushdown expected files to 1000 to match CI
RyanL1997
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Extend rewrite to dc / distinct_count via canonical-name translation
RyanL1997
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Commits on Jun 3, 2026

Force hash/merge join on no-BY rewrite to fix N-call OS round-trip blowup
RyanL1997
committed