[SPARK-20246][SQL] should not push predicate down through aggregate with non-deterministic expressions

## What changes were proposed in this pull request?

Similar to `Project`, when `Aggregate` has non-deterministic expressions, we should not push predicate down through it, as it will change the number of input rows and thus change the evaluation result of non-deterministic expressions in `Aggregate`.

## How was this patch tested?

new regression test

Author: Wenchen Fan <wenchen@databricks.com>

Closes #17562 from cloud-fan/filter.

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala

@@ -755,7 +755,8 @@ object PushDownPredicate extends Rule[LogicalPlan] with PredicateHelper {
     // implies that, for a given input row, the output are determined by the expression's initial
     // state and all the input rows processed before. In another word, the order of input rows
     // matters for non-deterministic expressions, while pushing down predicates changes the order.
-    case filter @ Filter(condition, project @ Project(fields, grandChild))
+    // This also applies to Aggregate.
+    case Filter(condition, project @ Project(fields, grandChild))
       if fields.forall(_.deterministic) && canPushThroughCondition(grandChild, condition) =>
 
       // Create a map of Aliases to their values from the child projection.
@@ -766,33 +767,8 @@ object PushDownPredicate extends Rule[LogicalPlan] with PredicateHelper {
 
       project.copy(child = Filter(replaceAlias(condition, aliasMap), grandChild))
 
-    // Push [[Filter]] operators through [[Window]] operators. Parts of the predicate that can be
-    // pushed beneath must satisfy the following conditions:
-    // 1. All the expressions are part of window partitioning key. The expressions can be compound.
-    // 2. Deterministic.
-    // 3. Placed before any non-deterministic predicates.
-    case filter @ Filter(condition, w: Window)
-        if w.partitionSpec.forall(_.isInstanceOf[AttributeReference]) =>
-      val partitionAttrs = AttributeSet(w.partitionSpec.flatMap(_.references))
-
-      val (candidates, containingNonDeterministic) =
-        splitConjunctivePredicates(condition).span(_.deterministic)
-
-      val (pushDown, rest) = candidates.partition { cond =>
-        cond.references.subsetOf(partitionAttrs)
-      }
-
-      val stayUp = rest ++ containingNonDeterministic
-
-      if (pushDown.nonEmpty) {
-        val pushDownPredicate = pushDown.reduce(And)
-        val newWindow = w.copy(child = Filter(pushDownPredicate, w.child))
-        if (stayUp.isEmpty) newWindow else Filter(stayUp.reduce(And), newWindow)
-      } else {
-        filter
-      }
-
-    case filter @ Filter(condition, aggregate: Aggregate) =>
+    case filter @ Filter(condition, aggregate: Aggregate)
+      if aggregate.aggregateExpressions.forall(_.deterministic) =>
       // Find all the aliased expressions in the aggregate list that don't include any actual
       // AggregateExpression, and create a map from the alias to the expression
       val aliasMap = AttributeMap(aggregate.aggregateExpressions.collect {
@@ -823,6 +799,32 @@ object PushDownPredicate extends Rule[LogicalPlan] with PredicateHelper {
         filter
       }
 
+    // Push [[Filter]] operators through [[Window]] operators. Parts of the predicate that can be
+    // pushed beneath must satisfy the following conditions:
+    // 1. All the expressions are part of window partitioning key. The expressions can be compound.
+    // 2. Deterministic.
+    // 3. Placed before any non-deterministic predicates.
+    case filter @ Filter(condition, w: Window)
+      if w.partitionSpec.forall(_.isInstanceOf[AttributeReference]) =>
+      val partitionAttrs = AttributeSet(w.partitionSpec.flatMap(_.references))
+
+      val (candidates, containingNonDeterministic) =
+        splitConjunctivePredicates(condition).span(_.deterministic)
+
+      val (pushDown, rest) = candidates.partition { cond =>
+        cond.references.subsetOf(partitionAttrs)
+      }
+
+      val stayUp = rest ++ containingNonDeterministic
+
+      if (pushDown.nonEmpty) {
+        val pushDownPredicate = pushDown.reduce(And)
+        val newWindow = w.copy(child = Filter(pushDownPredicate, w.child))
+        if (stayUp.isEmpty) newWindow else Filter(stayUp.reduce(And), newWindow)
+      } else {
+        filter
+      }
+
     case filter @ Filter(condition, union: Union) =>
       // Union could change the rows, so non-deterministic predicate can't be pushed down
       val (pushDown, stayUp) = splitConjunctivePredicates(condition).span(_.deterministic)
@@ -848,7 +850,7 @@ object PushDownPredicate extends Rule[LogicalPlan] with PredicateHelper {
         filter
       }
 
-    case filter @ Filter(condition, u: UnaryNode)
+    case filter @ Filter(_, u: UnaryNode)
         if canPushThrough(u) && u.expressions.forall(_.deterministic) =>
       pushDownPredicate(filter, u.child) { predicate =>
         u.withNewChildren(Seq(Filter(predicate, u.child)))

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/optimizer/FilterPushdownSuite.scala

@@ -134,15 +134,20 @@ class FilterPushdownSuite extends PlanTest {
     comparePlans(optimized, correctAnswer)
   }
 
-  test("nondeterministic: can't push down filter with nondeterministic condition through project") {
+  test("nondeterministic: can always push down filter through project with deterministic field") {
     val originalQuery = testRelation
-      .select(Rand(10).as('rand), 'a)
-      .where('rand > 5 || 'a > 5)
+      .select('a)
+      .where(Rand(10) > 5 || 'a > 5)
       .analyze
 
     val optimized = Optimize.execute(originalQuery)
 
-    comparePlans(optimized, originalQuery)
+    val correctAnswer = testRelation
+      .where(Rand(10) > 5 || 'a > 5)
+      .select('a)
+      .analyze
+
+    comparePlans(optimized, correctAnswer)
   }
 
   test("nondeterministic: can't push down filter through project with nondeterministic field") {
@@ -156,6 +161,34 @@ class FilterPushdownSuite extends PlanTest {
     comparePlans(optimized, originalQuery)
   }
 
+  test("nondeterministic: can't push down filter through aggregate with nondeterministic field") {
+    val originalQuery = testRelation
+      .groupBy('a)('a, Rand(10).as('rand))
+      .where('a > 5)
+      .analyze
+
+    val optimized = Optimize.execute(originalQuery)
+
+    comparePlans(optimized, originalQuery)
+  }
+
+  test("nondeterministic: push down part of filter through aggregate with deterministic field") {
+    val originalQuery = testRelation
+      .groupBy('a)('a)
+      .where('a > 5 && Rand(10) > 5)
+      .analyze
+
+    val optimized = Optimize.execute(originalQuery.analyze)
+
+    val correctAnswer = testRelation
+      .where('a > 5)
+      .groupBy('a)('a)
+      .where(Rand(10) > 5)
+      .analyze
+
+    comparePlans(optimized, correctAnswer)
+  }
+
   test("filters: combines filters") {
     val originalQuery = testRelation
       .select('a)