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Posted to commits@spark.apache.org by ya...@apache.org on 2024/04/19 02:54:09 UTC
(spark) branch branch-3.4 updated: [SPARK-47897][SQL][3.5] Fix ExpressionSet performance regression in scala 2.12
This is an automated email from the ASF dual-hosted git repository.
yao pushed a commit to branch branch-3.4
in repository https://gitbox.apache.org/repos/asf/spark.git
The following commit(s) were added to refs/heads/branch-3.4 by this push:
new bcaf61b975d6 [SPARK-47897][SQL][3.5] Fix ExpressionSet performance regression in scala 2.12
bcaf61b975d6 is described below
commit bcaf61b975d6e24222e483597eb2232aff822a98
Author: Zhen Wang <64...@qq.com>
AuthorDate: Fri Apr 19 10:53:16 2024 +0800
[SPARK-47897][SQL][3.5] Fix ExpressionSet performance regression in scala 2.12
### What changes were proposed in this pull request?
Fix `ExpressionSet` performance regression in scala 2.12.
### Why are the changes needed?
The implementation of the `SetLike.++` method in scala 2.12 is to iteratively execute the `+` method. The `ExpressionSet.+` method first clones a new object and then adds element, which is very expensive.
https://github.com/scala/scala/blob/ceaf7e68ac93e9bbe8642d06164714b2de709c27/src/library/scala/collection/SetLike.scala#L186
After https://github.com/apache/spark/pull/36121, the `++` and `--` methods in ExpressionSet of scala 2.12 were removed, causing performance regression.
### Does this PR introduce _any_ user-facing change?
### How was this patch tested?
Benchmark code:
```
object TestBenchmark {
def main(args: Array[String]): Unit = {
val count = 300
val benchmark = new Benchmark("Test ExpressionSetV2 ++ ", count)
val aUpper = AttributeReference("A", IntegerType)(exprId = ExprId(1))
var initialSet = ExpressionSet((0 until 300).map(i => aUpper + i))
val setToAddWithSameDeterministicExpression = ExpressionSet((0 until 300).map(i => aUpper + i))
benchmark.addCase("Test ++", 10) { _: Int =>
for (_ <- 0L until count) {
initialSet ++= setToAddWithSameDeterministicExpression
}
}
benchmark.run()
}
}
```
before this change:
```
OpenJDK 64-Bit Server VM 1.8.0_222-b10 on Linux 3.10.0-957.el7.x86_64
Intel Core Processor (Skylake, IBRS)
Test ExpressionSetV2 ++ : Best Time(ms) Avg Time(ms) Stdev(ms) Rate(M/s) Per Row(ns) Relative
------------------------------------------------------------------------------------------------------------------------
Test ++ 1577 1691 61 0.0 5255516.0 1.0X
```
after this change:
```
OpenJDK 64-Bit Server VM 1.8.0_222-b10 on Linux 3.10.0-957.el7.x86_64
Intel Core Processor (Skylake, IBRS)
Test ExpressionSetV2 ++ : Best Time(ms) Avg Time(ms) Stdev(ms) Rate(M/s) Per Row(ns) Relative
------------------------------------------------------------------------------------------------------------------------
Test ++ 14 14 0 0.0 45395.2 1.0X
```
### Was this patch authored or co-authored using generative AI tooling?
No
Closes #46114 from wForget/SPARK-47897.
Authored-by: Zhen Wang <64...@qq.com>
Signed-off-by: Kent Yao <ya...@apache.org>
(cherry picked from commit afd99d19a2b85dda2245d3557506d1090187c5f4)
Signed-off-by: Kent Yao <ya...@apache.org>
---
.../sql/catalyst/expressions/ExpressionSet.scala | 21 ++++++++++++++++++++-
1 file changed, 20 insertions(+), 1 deletion(-)
diff --git a/sql/catalyst/src/main/scala-2.12/org/apache/spark/sql/catalyst/expressions/ExpressionSet.scala b/sql/catalyst/src/main/scala-2.12/org/apache/spark/sql/catalyst/expressions/ExpressionSet.scala
index 3e545f745bae..c18679330f3a 100644
--- a/sql/catalyst/src/main/scala-2.12/org/apache/spark/sql/catalyst/expressions/ExpressionSet.scala
+++ b/sql/catalyst/src/main/scala-2.12/org/apache/spark/sql/catalyst/expressions/ExpressionSet.scala
@@ -17,7 +17,7 @@
package org.apache.spark.sql.catalyst.expressions
-import scala.collection.mutable
+import scala.collection.{mutable, GenTraversableOnce}
import scala.collection.mutable.ArrayBuffer
object ExpressionSet {
@@ -108,12 +108,31 @@ class ExpressionSet protected(
newSet
}
+ /**
+ * SPARK-47897: In Scala 2.12, the `SetLike.++` method iteratively calls `+` method.
+ * `ExpressionSet.+` is expensive, so we override `++`.
+ */
+ override def ++(elems: GenTraversableOnce[Expression]): ExpressionSet = {
+ val newSet = clone()
+ elems.foreach(newSet.add)
+ newSet
+ }
+
override def -(elem: Expression): ExpressionSet = {
val newSet = clone()
newSet.remove(elem)
newSet
}
+ /**
+ * SPARK-47897: We need to override `--` like `++`.
+ */
+ override def --(elems: GenTraversableOnce[Expression]): ExpressionSet = {
+ val newSet = clone()
+ elems.foreach(newSet.remove)
+ newSet
+ }
+
def map(f: Expression => Expression): ExpressionSet = {
val newSet = new ExpressionSet()
this.iterator.foreach(elem => newSet.add(f(elem)))
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