feat: derive SMJ sort options from left child during plan creation#43
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zhuqi-lucas
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One minor note: this optimization is most effective when the join key is a prefix of the left child's ordering (e.g., left ordered by [a DESC, b ASC], join key is a). When the join key is deeper in the ordering (e.g., join key is b), the extracted sort direction is correct but won't avoid a re-sort — same as the previous behavior though.
zhuqi-lucas
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Could you add tests for:
- Left child already sorted DESC on join key → verify SortExec is avoided on the left side
- Left child not sorted on join key → verify fallback to default ASC behavior
- Multi-column join key where left child's ordering partially matches
zhuqi-lucas
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LGTM — please add a test as mentioned above.
xudong963
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Added! Also added one more case where both sides are sorted by left side's ordering (no sort needed) |
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