Repository: spark
Updated Branches:
  refs/heads/master 00a2911c5 -> c6f8135ee


[SPARK-10539] [SQL] Project should not be pushed down through Intersect or 
Except #8742

Intersect and Except are both set operators and they use the all the columns to 
compare equality between rows. When pushing their Project parent down, the 
relations they based on would change, therefore not an equivalent 
transformation.

JIRA: https://issues.apache.org/jira/browse/SPARK-10539

I added some comments based on the fix of 
https://github.com/apache/spark/pull/8742.

Author: Yijie Shen <[email protected]>
Author: Yin Huai <[email protected]>

Closes #8823 from yhuai/fix_set_optimization.


Project: http://git-wip-us.apache.org/repos/asf/spark/repo
Commit: http://git-wip-us.apache.org/repos/asf/spark/commit/c6f8135e
Tree: http://git-wip-us.apache.org/repos/asf/spark/tree/c6f8135e
Diff: http://git-wip-us.apache.org/repos/asf/spark/diff/c6f8135e

Branch: refs/heads/master
Commit: c6f8135ee52202bd86adb090ab631e80330ea4df
Parents: 00a2911
Author: Yijie Shen <[email protected]>
Authored: Fri Sep 18 13:20:13 2015 -0700
Committer: Yin Huai <[email protected]>
Committed: Fri Sep 18 13:20:13 2015 -0700

----------------------------------------------------------------------
 .../sql/catalyst/optimizer/Optimizer.scala      | 37 ++++++++++----------
 .../optimizer/SetOperationPushDownSuite.scala   | 23 ++++++------
 .../org/apache/spark/sql/DataFrameSuite.scala   |  9 +++++
 3 files changed, 39 insertions(+), 30 deletions(-)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/spark/blob/c6f8135e/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala
----------------------------------------------------------------------
diff --git 
a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala
 
b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala
index 648a65e..324f40a 100644
--- 
a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala
+++ 
b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala
@@ -85,7 +85,22 @@ object SamplePushDown extends Rule[LogicalPlan] {
 }
 
 /**
- * Pushes operations to either side of a Union, Intersect or Except.
+ * Pushes certain operations to both sides of a Union, Intersect or Except 
operator.
+ * Operations that are safe to pushdown are listed as follows.
+ * Union:
+ * Right now, Union means UNION ALL, which does not de-duplicate rows. So, it 
is
+ * safe to pushdown Filters and Projections through it. Once we add UNION 
DISTINCT,
+ * we will not be able to pushdown Projections.
+ *
+ * Intersect:
+ * It is not safe to pushdown Projections through it because we need to get the
+ * intersect of rows by comparing the entire rows. It is fine to pushdown 
Filters
+ * because we will not have non-deterministic expressions.
+ *
+ * Except:
+ * It is not safe to pushdown Projections through it because we need to get the
+ * intersect of rows by comparing the entire rows. It is fine to pushdown 
Filters
+ * because we will not have non-deterministic expressions.
  */
 object SetOperationPushDown extends Rule[LogicalPlan] {
 
@@ -122,40 +137,26 @@ object SetOperationPushDown extends Rule[LogicalPlan] {
         Filter(condition, left),
         Filter(pushToRight(condition, rewrites), right))
 
-    // Push down projection into union
+    // Push down projection through UNION ALL
     case Project(projectList, u @ Union(left, right)) =>
       val rewrites = buildRewrites(u)
       Union(
         Project(projectList, left),
         Project(projectList.map(pushToRight(_, rewrites)), right))
 
-    // Push down filter into intersect
+    // Push down filter through INTERSECT
     case Filter(condition, i @ Intersect(left, right)) =>
       val rewrites = buildRewrites(i)
       Intersect(
         Filter(condition, left),
         Filter(pushToRight(condition, rewrites), right))
 
-    // Push down projection into intersect
-    case Project(projectList, i @ Intersect(left, right)) =>
-      val rewrites = buildRewrites(i)
-      Intersect(
-        Project(projectList, left),
-        Project(projectList.map(pushToRight(_, rewrites)), right))
-
-    // Push down filter into except
+    // Push down filter through EXCEPT
     case Filter(condition, e @ Except(left, right)) =>
       val rewrites = buildRewrites(e)
       Except(
         Filter(condition, left),
         Filter(pushToRight(condition, rewrites), right))
-
-    // Push down projection into except
-    case Project(projectList, e @ Except(left, right)) =>
-      val rewrites = buildRewrites(e)
-      Except(
-        Project(projectList, left),
-        Project(projectList.map(pushToRight(_, rewrites)), right))
   }
 }
 

http://git-wip-us.apache.org/repos/asf/spark/blob/c6f8135e/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/optimizer/SetOperationPushDownSuite.scala
----------------------------------------------------------------------
diff --git 
a/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/optimizer/SetOperationPushDownSuite.scala
 
b/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/optimizer/SetOperationPushDownSuite.scala
index 49c979b..3fca47a 100644
--- 
a/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/optimizer/SetOperationPushDownSuite.scala
+++ 
b/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/optimizer/SetOperationPushDownSuite.scala
@@ -60,23 +60,22 @@ class SetOperationPushDownSuite extends PlanTest {
     comparePlans(exceptOptimized, exceptCorrectAnswer)
   }
 
-  test("union/intersect/except: project to each side") {
+  test("union: project to each side") {
     val unionQuery = testUnion.select('a)
+    val unionOptimized = Optimize.execute(unionQuery.analyze)
+    val unionCorrectAnswer =
+      Union(testRelation.select('a), testRelation2.select('d)).analyze
+    comparePlans(unionOptimized, unionCorrectAnswer)
+  }
+
+  test("SPARK-10539: Project should not be pushed down through Intersect or 
Except") {
     val intersectQuery = testIntersect.select('b, 'c)
     val exceptQuery = testExcept.select('a, 'b, 'c)
 
-    val unionOptimized = Optimize.execute(unionQuery.analyze)
     val intersectOptimized = Optimize.execute(intersectQuery.analyze)
     val exceptOptimized = Optimize.execute(exceptQuery.analyze)
 
-    val unionCorrectAnswer =
-      Union(testRelation.select('a), testRelation2.select('d)).analyze
-    val intersectCorrectAnswer =
-      Intersect(testRelation.select('b, 'c), testRelation2.select('e, 
'f)).analyze
-    val exceptCorrectAnswer =
-      Except(testRelation.select('a, 'b, 'c), testRelation2.select('d, 'e, 
'f)).analyze
-
-    comparePlans(unionOptimized, unionCorrectAnswer)
-    comparePlans(intersectOptimized, intersectCorrectAnswer)
-    comparePlans(exceptOptimized, exceptCorrectAnswer)  }
+    comparePlans(intersectOptimized, intersectQuery.analyze)
+    comparePlans(exceptOptimized, exceptQuery.analyze)
+  }
 }

http://git-wip-us.apache.org/repos/asf/spark/blob/c6f8135e/sql/core/src/test/scala/org/apache/spark/sql/DataFrameSuite.scala
----------------------------------------------------------------------
diff --git a/sql/core/src/test/scala/org/apache/spark/sql/DataFrameSuite.scala 
b/sql/core/src/test/scala/org/apache/spark/sql/DataFrameSuite.scala
index c167999..1370713 100644
--- a/sql/core/src/test/scala/org/apache/spark/sql/DataFrameSuite.scala
+++ b/sql/core/src/test/scala/org/apache/spark/sql/DataFrameSuite.scala
@@ -907,4 +907,13 @@ class DataFrameSuite extends QueryTest with 
SharedSQLContext {
       assert(row.getDouble(1) - row.getDouble(3) === 0.0 +- 0.001)
     }
   }
+
+  test("SPARK-10539: Project should not be pushed down through Intersect or 
Except") {
+    val df1 = (1 to 100).map(Tuple1.apply).toDF("i")
+    val df2 = (1 to 30).map(Tuple1.apply).toDF("i")
+    val intersect = df1.intersect(df2)
+    val except = df1.except(df2)
+    assert(intersect.count() === 30)
+    assert(except.count() === 70)
+  }
 }


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