From 6e6320122ea84247c67e2d0fb0e6af54e2c5bb31 Mon Sep 17 00:00:00 2001
From: Dongjoon Hyun <dongjoon@apache.org>
Date: Mon, 2 May 2016 12:40:21 -0700
Subject: [PATCH] [SPARK-14830][SQL] Add RemoveRepetitionFromGroupExpressions
optimizer.
## What changes were proposed in this pull request?
This PR aims to optimize GroupExpressions by removing repeating expressions. `RemoveRepetitionFromGroupExpressions` is added.
**Before**
```scala
scala> sql("select a+1 from values 1,2 T(a) group by a+1, 1+a, A+1, 1+A").explain()
== Physical Plan ==
WholeStageCodegen
: +- TungstenAggregate(key=[(a#0 + 1)#6,(1 + a#0)#7,(A#0 + 1)#8,(1 + A#0)#9], functions=[], output=[(a + 1)#5])
: +- INPUT
+- Exchange hashpartitioning((a#0 + 1)#6, (1 + a#0)#7, (A#0 + 1)#8, (1 + A#0)#9, 200), None
+- WholeStageCodegen
: +- TungstenAggregate(key=[(a#0 + 1) AS (a#0 + 1)#6,(1 + a#0) AS (1 + a#0)#7,(A#0 + 1) AS (A#0 + 1)#8,(1 + A#0) AS (1 + A#0)#9], functions=[], output=[(a#0 + 1)#6,(1 + a#0)#7,(A#0 + 1)#8,(1 + A#0)#9])
: +- INPUT
+- LocalTableScan [a#0], [[1],[2]]
```
**After**
```scala
scala> sql("select a+1 from values 1,2 T(a) group by a+1, 1+a, A+1, 1+A").explain()
== Physical Plan ==
WholeStageCodegen
: +- TungstenAggregate(key=[(a#0 + 1)#6], functions=[], output=[(a + 1)#5])
: +- INPUT
+- Exchange hashpartitioning((a#0 + 1)#6, 200), None
+- WholeStageCodegen
: +- TungstenAggregate(key=[(a#0 + 1) AS (a#0 + 1)#6], functions=[], output=[(a#0 + 1)#6])
: +- INPUT
+- LocalTableScan [a#0], [[1],[2]]
```
## How was this patch tested?
Pass the Jenkins tests (with a new testcase)
Author: Dongjoon Hyun <dongjoon@apache.org>
Closes #12590 from dongjoon-hyun/SPARK-14830.
---
.../sql/catalyst/optimizer/Optimizer.scala | 15 +++++++++++++-
.../optimizer/AggregateOptimizeSuite.scala | 20 ++++++++++++++++++-
2 files changed, 33 insertions(+), 2 deletions(-)
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 0b70edec8e..a147fff274 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
@@ -68,7 +68,8 @@ abstract class Optimizer(sessionCatalog: SessionCatalog, conf: CatalystConf)
ReplaceExceptWithAntiJoin,
ReplaceDistinctWithAggregate) ::
Batch("Aggregate", fixedPoint,
- RemoveLiteralFromGroupExpressions) ::
+ RemoveLiteralFromGroupExpressions,
+ RemoveRepetitionFromGroupExpressions) ::
Batch("Operator Optimizations", fixedPoint,
// Operator push down
SetOperationPushDown,
@@ -1439,6 +1440,18 @@ object RemoveLiteralFromGroupExpressions extends Rule[LogicalPlan] {
}
}
+/**
+ * Removes repetition from group expressions in [[Aggregate]], as they have no effect to the result
+ * but only makes the grouping key bigger.
+ */
+object RemoveRepetitionFromGroupExpressions extends Rule[LogicalPlan] {
+ def apply(plan: LogicalPlan): LogicalPlan = plan transform {
+ case a @ Aggregate(grouping, _, _) =>
+ val newGrouping = ExpressionSet(grouping).toSeq
+ a.copy(groupingExpressions = newGrouping)
+ }
+}
+
/**
* Computes the current date and time to make sure we return the same result in a single query.
*/
diff --git a/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/optimizer/AggregateOptimizeSuite.scala b/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/optimizer/AggregateOptimizeSuite.scala
index e458eb8a1d..c94dcb3354 100644
--- a/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/optimizer/AggregateOptimizeSuite.scala
+++ b/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/optimizer/AggregateOptimizeSuite.scala
@@ -17,6 +17,9 @@
package org.apache.spark.sql.catalyst.optimizer
+import org.apache.spark.sql.catalyst.SimpleCatalystConf
+import org.apache.spark.sql.catalyst.analysis.{Analyzer, EmptyFunctionRegistry}
+import org.apache.spark.sql.catalyst.catalog.{InMemoryCatalog, SessionCatalog}
import org.apache.spark.sql.catalyst.dsl.expressions._
import org.apache.spark.sql.catalyst.dsl.plans._
import org.apache.spark.sql.catalyst.expressions.Literal
@@ -25,10 +28,14 @@ import org.apache.spark.sql.catalyst.plans.logical.{LocalRelation, LogicalPlan}
import org.apache.spark.sql.catalyst.rules.RuleExecutor
class AggregateOptimizeSuite extends PlanTest {
+ val conf = new SimpleCatalystConf(caseSensitiveAnalysis = false)
+ val catalog = new SessionCatalog(new InMemoryCatalog, EmptyFunctionRegistry, conf)
+ val analyzer = new Analyzer(catalog, conf)
object Optimize extends RuleExecutor[LogicalPlan] {
val batches = Batch("Aggregate", FixedPoint(100),
- RemoveLiteralFromGroupExpressions) :: Nil
+ RemoveLiteralFromGroupExpressions,
+ RemoveRepetitionFromGroupExpressions) :: Nil
}
test("remove literals in grouping expression") {
@@ -42,4 +49,15 @@ class AggregateOptimizeSuite extends PlanTest {
comparePlans(optimized, correctAnswer)
}
+
+ test("remove repetition in grouping expression") {
+ val input = LocalRelation('a.int, 'b.int, 'c.int)
+
+ val query = input.groupBy('a + 1, 'b + 2, Literal(1) + 'A, Literal(2) + 'B)(sum('c))
+ val optimized = Optimize.execute(analyzer.execute(query))
+
+ val correctAnswer = analyzer.execute(input.groupBy('a + 1, 'b + 2)(sum('c)))
+
+ comparePlans(optimized, correctAnswer)
+ }
}
--
GitLab