Repository: spark
Updated Branches:
  refs/heads/master 815f3eece -> 7b06a8948


[SPARK-16686][SQL] Remove PushProjectThroughSample since it is handled by 
ColumnPruning

## What changes were proposed in this pull request?

We push down `Project` through `Sample` in `Optimizer` by the rule 
`PushProjectThroughSample`. However, if the projected columns produce new 
output, they will encounter whole data instead of sampled data. It will bring 
some inconsistency between original plan (Sample then Project) and optimized 
plan (Project then Sample). In the extreme case such as attached in the JIRA, 
if the projected column is an UDF which is supposed to not see the sampled out 
data, the result of UDF will be incorrect.

Since the rule `ColumnPruning` already handles general `Project` pushdown. We 
don't need  `PushProjectThroughSample` anymore. The rule `ColumnPruning` also 
avoids the described issue.

## How was this patch tested?

Jenkins tests.

Author: Liang-Chi Hsieh <sim...@tw.ibm.com>

Closes #14327 from viirya/fix-sample-pushdown.


Project: http://git-wip-us.apache.org/repos/asf/spark/repo
Commit: http://git-wip-us.apache.org/repos/asf/spark/commit/7b06a894
Tree: http://git-wip-us.apache.org/repos/asf/spark/tree/7b06a894
Diff: http://git-wip-us.apache.org/repos/asf/spark/diff/7b06a894

Branch: refs/heads/master
Commit: 7b06a8948fc16d3c14e240fdd632b79ce1651008
Parents: 815f3ee
Author: Liang-Chi Hsieh <sim...@tw.ibm.com>
Authored: Tue Jul 26 12:00:01 2016 +0800
Committer: Wenchen Fan <wenc...@databricks.com>
Committed: Tue Jul 26 12:00:01 2016 +0800

----------------------------------------------------------------------
 .../sql/catalyst/optimizer/Optimizer.scala      | 12 ----------
 .../catalyst/optimizer/ColumnPruningSuite.scala | 15 ++++++++++++
 .../optimizer/FilterPushdownSuite.scala         | 17 -------------
 .../org/apache/spark/sql/DatasetSuite.scala     | 25 ++++++++++++++++++++
 4 files changed, 40 insertions(+), 29 deletions(-)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/spark/blob/7b06a894/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 c8e9d8e..fe328fd 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
@@ -76,7 +76,6 @@ abstract class Optimizer(sessionCatalog: SessionCatalog, 
conf: CatalystConf)
     Batch("Operator Optimizations", fixedPoint,
       // Operator push down
       PushThroughSetOperations,
-      PushProjectThroughSample,
       ReorderJoin,
       EliminateOuterJoin,
       PushPredicateThroughJoin,
@@ -149,17 +148,6 @@ class SimpleTestOptimizer extends Optimizer(
   new SimpleCatalystConf(caseSensitiveAnalysis = true))
 
 /**
- * Pushes projects down beneath Sample to enable column pruning with sampling.
- */
-object PushProjectThroughSample extends Rule[LogicalPlan] {
-  def apply(plan: LogicalPlan): LogicalPlan = plan transform {
-    // Push down projection into sample
-    case Project(projectList, Sample(lb, up, replace, seed, child)) =>
-      Sample(lb, up, replace, seed, Project(projectList, child))()
-  }
-}
-
-/**
  * Removes the Project only conducting Alias of its child node.
  * It is created mainly for removing extra Project added in 
EliminateSerialization rule,
  * but can also benefit other operators.

http://git-wip-us.apache.org/repos/asf/spark/blob/7b06a894/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/optimizer/ColumnPruningSuite.scala
----------------------------------------------------------------------
diff --git 
a/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/optimizer/ColumnPruningSuite.scala
 
b/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/optimizer/ColumnPruningSuite.scala
index b5664a5..589607e 100644
--- 
a/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/optimizer/ColumnPruningSuite.scala
+++ 
b/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/optimizer/ColumnPruningSuite.scala
@@ -346,5 +346,20 @@ class ColumnPruningSuite extends PlanTest {
     comparePlans(Optimize.execute(plan1.analyze), correctAnswer1)
   }
 
+  test("push project down into sample") {
+    val testRelation = LocalRelation('a.int, 'b.int, 'c.int)
+    val x = testRelation.subquery('x)
+
+    val query1 = Sample(0.0, 0.6, false, 11L, x)().select('a)
+    val optimized1 = Optimize.execute(query1.analyze)
+    val expected1 = Sample(0.0, 0.6, false, 11L, x.select('a))()
+    comparePlans(optimized1, expected1.analyze)
+
+    val query2 = Sample(0.0, 0.6, false, 11L, x)().select('a as 'aa)
+    val optimized2 = Optimize.execute(query2.analyze)
+    val expected2 = Sample(0.0, 0.6, false, 11L, x.select('a))().select('a as 
'aa)
+    comparePlans(optimized2, expected2.analyze)
+  }
+
   // todo: add more tests for column pruning
 }

http://git-wip-us.apache.org/repos/asf/spark/blob/7b06a894/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/optimizer/FilterPushdownSuite.scala
----------------------------------------------------------------------
diff --git 
a/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/optimizer/FilterPushdownSuite.scala
 
b/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/optimizer/FilterPushdownSuite.scala
index 780e78e..596b8fc 100644
--- 
a/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/optimizer/FilterPushdownSuite.scala
+++ 
b/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/optimizer/FilterPushdownSuite.scala
@@ -34,7 +34,6 @@ class FilterPushdownSuite extends PlanTest {
       Batch("Subqueries", Once,
         EliminateSubqueryAliases) ::
       Batch("Filter Pushdown", FixedPoint(10),
-        PushProjectThroughSample,
         CombineFilters,
         PushDownPredicate,
         BooleanSimplification,
@@ -585,22 +584,6 @@ class FilterPushdownSuite extends PlanTest {
     comparePlans(optimized, originalQuery)
   }
 
-  test("push project and filter down into sample") {
-    val x = testRelation.subquery('x)
-    val originalQuery =
-      Sample(0.0, 0.6, false, 11L, x)().select('a)
-
-    val originalQueryAnalyzed =
-      EliminateSubqueryAliases(analysis.SimpleAnalyzer.execute(originalQuery))
-
-    val optimized = Optimize.execute(originalQueryAnalyzed)
-
-    val correctAnswer =
-      Sample(0.0, 0.6, false, 11L, x.select('a))()
-
-    comparePlans(optimized, correctAnswer.analyze)
-  }
-
   test("aggregate: push down filter when filter on group by expression") {
     val originalQuery = testRelation
                         .groupBy('a)('a, count('b) as 'c)

http://git-wip-us.apache.org/repos/asf/spark/blob/7b06a894/sql/core/src/test/scala/org/apache/spark/sql/DatasetSuite.scala
----------------------------------------------------------------------
diff --git a/sql/core/src/test/scala/org/apache/spark/sql/DatasetSuite.scala 
b/sql/core/src/test/scala/org/apache/spark/sql/DatasetSuite.scala
index 0b6f408..7e3b7b6 100644
--- a/sql/core/src/test/scala/org/apache/spark/sql/DatasetSuite.scala
+++ b/sql/core/src/test/scala/org/apache/spark/sql/DatasetSuite.scala
@@ -422,6 +422,31 @@ class DatasetSuite extends QueryTest with SharedSQLContext 
{
       3, 17, 27, 58, 62)
   }
 
+  test("SPARK-16686: Dataset.sample with seed results shouldn't depend on 
downstream usage") {
+    val simpleUdf = udf((n: Int) => {
+      require(n != 1, "simpleUdf shouldn't see id=1!")
+      1
+    })
+
+    val df = Seq(
+      (0, "string0"),
+      (1, "string1"),
+      (2, "string2"),
+      (3, "string3"),
+      (4, "string4"),
+      (5, "string5"),
+      (6, "string6"),
+      (7, "string7"),
+      (8, "string8"),
+      (9, "string9")
+    ).toDF("id", "stringData")
+    val sampleDF = df.sample(false, 0.7, 50)
+    // After sampling, sampleDF doesn't contain id=1.
+    assert(!sampleDF.select("id").collect.contains(1))
+    // simpleUdf should not encounter id=1.
+    checkAnswer(sampleDF.select(simpleUdf($"id")), 
List.fill(sampleDF.count.toInt)(Row(1)))
+  }
+
   test("SPARK-11436: we should rebind right encoder when join 2 datasets") {
     val ds1 = Seq("1", "2").toDS().as("a")
     val ds2 = Seq(2, 3).toDS().as("b")


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