[GitHub] [spark] ulysses-you commented on a diff in pull request #37250: [SPARK-39835][SQL] Fix EliminateSorts remove global sort below the local sort

[GitBox <gi...@apache.org>]

ulysses-you commented on code in PR #37250:
URL: https://github.com/apache/spark/pull/37250#discussion_r928077499


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sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala:
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@@ -1528,28 +1528,44 @@ object EliminateSorts extends Rule[LogicalPlan] {
       }
     case Sort(orders, false, child) if SortOrder.orderingSatisfies(child.outputOrdering, orders) =>
       applyLocally.lift(child).getOrElse(child)
-    case s @ Sort(_, _, child) => s.copy(child = recursiveRemoveSort(child))
+    case s @ Sort(_, global, child) => s.copy(child = recursiveRemoveSort(child, global))
     case j @ Join(originLeft, originRight, _, cond, _) if cond.forall(_.deterministic) =>
-      j.copy(left = recursiveRemoveSort(originLeft), right = recursiveRemoveSort(originRight))
+      j.copy(left = recursiveRemoveSort(originLeft, true),
+        right = recursiveRemoveSort(originRight, true))
     case g @ Aggregate(_, aggs, originChild) if isOrderIrrelevantAggs(aggs) =>
-      g.copy(child = recursiveRemoveSort(originChild))
+      g.copy(child = recursiveRemoveSort(originChild, true))
   }
 
-  private def recursiveRemoveSort(plan: LogicalPlan): LogicalPlan = {
+  /**
+   * If the upper sort is global then we can remove the global or local sort recursively.
+   * If the upper sort is local then we can only remove the local sort recursively.

Review Comment:
   The semantics of global + local sort should be range partition + local sort, so we can not remove the global sort which is under local sort as we can not remove range partition directly. BTW, I will add a new rule to optimzie this pattern after fix this pr.



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