[SPARK-40773][SQL] Refactor checkCorrelationsInSubquery #38226
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cc @cloud-fan |
cloud-fan
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Oct 13, 2022
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thanks, merging to master! |
SandishKumarHN
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Dec 12, 2022
### What changes were proposed in this pull request? This PR refactors `checkCorrelationsInSubquery` in CheckAnalysis to use recursion instead of `foreachUp`. ### Why are the changes needed? Currently, the logic in `checkCorrelationsInSubquery` is inefficient and difficult to understand. It uses `foreachUp` to traverse the subquery plan tree, and traverses down an entire subtree of a plan node to check whether it contains any outer references. We can use recursion instead to traverse the plan tree only once to improve the performance and readability. ### Does this PR introduce _any_ user-facing change? No ### How was this patch tested? Existing unit tests. Closes apache#38226 from allisonwang-db/spark-40773-check-subquery. Authored-by: allisonwang-db <[email protected]> Signed-off-by: Wenchen Fan <[email protected]>
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What changes were proposed in this pull request?
This PR refactors
checkCorrelationsInSubqueryin CheckAnalysis to use recursion instead offoreachUp.Why are the changes needed?
Currently, the logic in
checkCorrelationsInSubqueryis inefficient and difficult to understand. It usesforeachUpto traverse the subquery plan tree, and traverses down an entire subtree of a plan node to check whether it contains any outer references. We can use recursion instead to traverse the plan tree only once to improve the performance and readability.Does this PR introduce any user-facing change?
No
How was this patch tested?
Existing unit tests.