[GitHub] [spark] cloud-fan commented on a change in pull request #34504: [SPARK-37226][SQL] Filter push down through window if partitionSpec isEmpty

2021-11-23 Thread GitBox


cloud-fan commented on a change in pull request #34504:
URL: https://github.com/apache/spark/pull/34504#discussion_r755214307



##
File path: 
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala
##
@@ -1548,6 +1548,31 @@ object PushPredicateThroughNonJoin extends 
Rule[LogicalPlan] with PredicateHelpe
 filter
   }
 
+case filter @ Filter(condition, w: Window) if w.partitionSpec.isEmpty =>
+  w.windowExpressions match {
+case Seq(alias @ Alias(WindowExpression(_: RowNumber, 
WindowSpecDefinition(Nil, orderSpec,
+SpecifiedWindowFrame(RowFrame, UnboundedPreceding, CurrentRow))), 
_)) =>
+  val aliasAttr = alias.toAttribute
+  val limitValue = splitConjunctivePredicates(condition).collectFirst {
+case LessThanOrEqual(e, IntegerLiteral(v)) if 
e.semanticEquals(aliasAttr) => v
+case Equality(e, IntegerLiteral(v)) if e.semanticEquals(aliasAttr) 
=> v
+case LessThan(e, IntegerLiteral(v)) if e.semanticEquals(aliasAttr) 
=> v - 1
+  }
+
+  limitValue match {
+case Some(lv) if lv <= 0 =>
+  LocalRelation(filter.output, data = Seq.empty, isStreaming = 
filter.isStreaming)
+case Some(lv)
+if lv < conf.topKSortFallbackThreshold && 
w.child.maxRows.forall(_ > lv) =>
+  filter.copy(child =
+w.copy(child = Limit(Literal(lv), Sort(orderSpec, true, 
w.child

Review comment:
   BTW, is `orderSpec` always specified?




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[GitHub] [spark] cloud-fan commented on a change in pull request #34504: [SPARK-37226][SQL] Filter push down through window if partitionSpec isEmpty

2021-11-23 Thread GitBox


cloud-fan commented on a change in pull request #34504:
URL: https://github.com/apache/spark/pull/34504#discussion_r755213627



##
File path: 
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala
##
@@ -1548,6 +1548,31 @@ object PushPredicateThroughNonJoin extends 
Rule[LogicalPlan] with PredicateHelpe
 filter
   }
 
+case filter @ Filter(condition, w: Window) if w.partitionSpec.isEmpty =>
+  w.windowExpressions match {
+case Seq(alias @ Alias(WindowExpression(_: RowNumber, 
WindowSpecDefinition(Nil, orderSpec,
+SpecifiedWindowFrame(RowFrame, UnboundedPreceding, CurrentRow))), 
_)) =>
+  val aliasAttr = alias.toAttribute
+  val limitValue = splitConjunctivePredicates(condition).collectFirst {
+case LessThanOrEqual(e, IntegerLiteral(v)) if 
e.semanticEquals(aliasAttr) => v
+case Equality(e, IntegerLiteral(v)) if e.semanticEquals(aliasAttr) 
=> v
+case LessThan(e, IntegerLiteral(v)) if e.semanticEquals(aliasAttr) 
=> v - 1
+  }
+
+  limitValue match {
+case Some(lv) if lv <= 0 =>
+  LocalRelation(filter.output, data = Seq.empty, isStreaming = 
filter.isStreaming)
+case Some(lv)
+if lv < conf.topKSortFallbackThreshold && 
w.child.maxRows.forall(_ > lv) =>
+  filter.copy(child =
+w.copy(child = Limit(Literal(lv), Sort(orderSpec, true, 
w.child

Review comment:
   One worry is what if other optimizer rules put/move operators between 
Limit and Sort? Then we can't use the `TakeOrderedAndProjectExec` and introduce 
a big overhead by this global sort.




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[GitHub] [spark] cloud-fan commented on a change in pull request #34504: [SPARK-37226][SQL] Filter push down through window if partitionSpec isEmpty

2021-11-23 Thread GitBox


cloud-fan commented on a change in pull request #34504:
URL: https://github.com/apache/spark/pull/34504#discussion_r755210674



##
File path: 
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala
##
@@ -1548,6 +1548,31 @@ object PushPredicateThroughNonJoin extends 
Rule[LogicalPlan] with PredicateHelpe
 filter
   }
 
+case filter @ Filter(condition, w: Window) if w.partitionSpec.isEmpty =>
+  w.windowExpressions match {
+case Seq(alias @ Alias(WindowExpression(_: RowNumber, 
WindowSpecDefinition(Nil, orderSpec,
+SpecifiedWindowFrame(RowFrame, UnboundedPreceding, CurrentRow))), 
_)) =>

Review comment:
   I think this optimization should also apply if there are more than one 
window expressions. The algorithm should simply be
   ```
   val limits = w.windowExpressions.map {
 case row_number_func => calcuate the limit
 case _ => none
   }
   val limit = limits.min
   add limit + sort
   ``` 




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