fix.

Author: gatorsmile

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

@@ -1328,18 +1328,12 @@ object EliminateOuterJoin extends Rule[LogicalPlan] with PredicateHelper {
   }
 
   private def buildNewJoinType(filter: Filter, join: Join): JoinType = {
-    val splitConjunctiveConditions: Seq[Expression] = splitConjunctivePredicates(filter.condition)
-    val leftConditions = splitConjunctiveConditions
-      .filter(_.references.subsetOf(join.left.outputSet))
-    val rightConditions = splitConjunctiveConditions
-      .filter(_.references.subsetOf(join.right.outputSet))
-
-    val leftHasNonNullPredicate = leftConditions.exists(canFilterOutNull) ||
-      filter.constraints.filter(_.isInstanceOf[IsNotNull])
-        .exists(expr => join.left.outputSet.intersect(expr.references).nonEmpty)
-    val rightHasNonNullPredicate = rightConditions.exists(canFilterOutNull) ||
-      filter.constraints.filter(_.isInstanceOf[IsNotNull])
-        .exists(expr => join.right.outputSet.intersect(expr.references).nonEmpty)
+    val conditions = splitConjunctivePredicates(filter.condition) ++ filter.constraints
+    val leftConditions = conditions.filter(_.references.subsetOf(join.left.outputSet))
+    val rightConditions = conditions.filter(_.references.subsetOf(join.right.outputSet))
+
+    val leftHasNonNullPredicate = leftConditions.exists(canFilterOutNull)
+    val rightHasNonNullPredicate = rightConditions.exists(canFilterOutNull)
 
     join.joinType match {
       case RightOuter if leftHasNonNullPredicate => Inner

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

@@ -20,6 +20,7 @@ package org.apache.spark.sql.catalyst.optimizer
 import org.apache.spark.sql.catalyst.analysis.EliminateSubqueryAliases
 import org.apache.spark.sql.catalyst.dsl.expressions._
 import org.apache.spark.sql.catalyst.dsl.plans._
+import org.apache.spark.sql.catalyst.expressions.{Coalesce, IsNotNull}
 import org.apache.spark.sql.catalyst.plans._
 import org.apache.spark.sql.catalyst.plans.logical._
 import org.apache.spark.sql.catalyst.rules._
@@ -192,4 +193,42 @@ class OuterJoinEliminationSuite extends PlanTest {
 
     comparePlans(optimized, correctAnswer)
   }
+
+  test("joins: no outer join elimination if the filter is not NULL eliminated") {
+    val x = testRelation.subquery('x)
+    val y = testRelation1.subquery('y)
+
+    val originalQuery =
+      x.join(y, FullOuter, Option("x.a".attr === "y.d".attr))
+        .where(Coalesce("y.e".attr :: "x.a".attr :: Nil))
+
+    val optimized = Optimize.execute(originalQuery.analyze)
+
+    val left = testRelation
+    val right = testRelation1
+    val correctAnswer =
+      left.join(right, FullOuter, Option("a".attr === "d".attr))
+        .where(Coalesce("e".attr :: "a".attr :: Nil)).analyze
+
+    comparePlans(optimized, correctAnswer)
+  }
+
+  test("joins: no outer join elimination if the filter's constraints are not NULL eliminated") {
+    val x = testRelation.subquery('x)
+    val y = testRelation1.subquery('y)
+
+    val originalQuery =
+      x.join(y, FullOuter, Option("x.a".attr === "y.d".attr))
+        .where(IsNotNull(Coalesce("y.e".attr :: "x.a".attr :: Nil)))
+
+    val optimized = Optimize.execute(originalQuery.analyze)
+
+    val left = testRelation
+    val right = testRelation1
+    val correctAnswer =
+      left.join(right, FullOuter, Option("a".attr === "d".attr))
+        .where(IsNotNull(Coalesce("e".attr :: "a".attr :: Nil))).analyze
+
+    comparePlans(optimized, correctAnswer)
+  }
 }

sql/core/src/test/scala/org/apache/spark/sql/SQLQuerySuite.scala

@@ -2602,6 +2602,14 @@ class SQLQuerySuite extends QueryTest with SharedSQLContext {
       Row(s"$expected") :: Nil)
   }
 
+  test("SPARK-16991: Full outer join followed by inner join produces wrong results") {
+    val a = Seq((1, 2), (2, 3)).toDF("a", "b")
+    val b = Seq((2, 5), (3, 4)).toDF("a", "c")
+    val c = Seq((3, 1)).toDF("a", "d")
+    val ab = a.join(b, Seq("a"), "fullouter")
+    checkAnswer(ab.join(c, "a"), Row(3, null, 4, 1) :: Nil)
+  }
+
   test("SPARK-15752 optimize metadata only query for datasource table") {
     withSQLConf(SQLConf.OPTIMIZER_METADATA_ONLY.key -> "true") {
       withTable("srcpart_15752") {