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[SPARK-21845] [SQL] Make codegen fallback of expressions configurable #19062

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[SPARK-21845] [SQL] Make codegen fallback of expressions configurable #19062

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9f3a1cd
fix.
gatorsmile Aug 26, 2017
26dcbd6
fix
gatorsmile Aug 29, 2017
4f39a52
fix
gatorsmile Aug 29, 2017
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6 changes: 3 additions & 3 deletions sql/catalyst/src/main/scala/org/apache/spark/sql/internal/SQLConf.scala
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Original file line number Diff line number Diff line change
Expand Up @@ -551,9 +551,9 @@ object SQLConf {
.intConf
.createWithDefault(100)

val WHOLESTAGE_FALLBACK = buildConf("spark.sql.codegen.fallback")
val CODEGEN_FALLBACK = buildConf("spark.sql.codegen.fallback")
.internal()
.doc("When true, whole stage codegen could be temporary disabled for the part of query that" +
.doc("When true, (whole stage) codegen could be temporary disabled for the part of query that" +
" fail to compile generated code")
.booleanConf
.createWithDefault(true)
Expand Down Expand Up @@ -1041,7 +1041,7 @@ class SQLConf extends Serializable with Logging {

def wholeStageMaxNumFields: Int = getConf(WHOLESTAGE_MAX_NUM_FIELDS)

def wholeStageFallback: Boolean = getConf(WHOLESTAGE_FALLBACK)
def codegenFallback: Boolean = getConf(CODEGEN_FALLBACK)

def maxCaseBranchesForCodegen: Int = getConf(MAX_CASES_BRANCHES)

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15 changes: 5 additions & 10 deletions sql/core/src/main/scala/org/apache/spark/sql/execution/SparkPlan.scala
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Expand Up @@ -56,14 +56,10 @@ abstract class SparkPlan extends QueryPlan[SparkPlan] with Logging with Serializ

protected def sparkContext = sqlContext.sparkContext

// sqlContext will be null when we are being deserialized on the slaves. In this instance
// the value of subexpressionEliminationEnabled will be set by the deserializer after the
// constructor has run.
val subexpressionEliminationEnabled: Boolean = if (sqlContext != null) {
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@gatorsmile gatorsmile Aug 29, 2017 •
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cc @marmbrus @cloud-fan Does this sound OK? Currently, our codebase does not check nullability in most places. This value will be always not null when we initialize the value.

sqlContext.conf.subexpressionEliminationEnabled
} else {
false
}
// whether we should fallback when hitting compilation errors caused by codegen
private val codeGenFallBack = sqlContext.conf.codegenFallback

protected val subexpressionEliminationEnabled = sqlContext.conf.subexpressionEliminationEnabled

/** Overridden make copy also propagates sqlContext to copied plan. */
override def makeCopy(newArgs: Array[AnyRef]): SparkPlan = {
Expand Down Expand Up @@ -370,8 +366,7 @@ abstract class SparkPlan extends QueryPlan[SparkPlan] with Logging with Serializ
try {
GeneratePredicate.generate(expression, inputSchema)
} catch {
case e @ (_: JaninoRuntimeException | _: CompileException)
if sqlContext == null || sqlContext.conf.wholeStageFallback =>
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@gatorsmile gatorsmile Aug 26, 2017

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Because sqlContext is always null when running it in executors, and thus, this always return true.

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@maropu maropu Aug 28, 2017

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Better to put this comment in https://github.com/apache/spark/pull/19062/files#diff-b9f96d092fb3fea76bcf75e016799678R57?

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@sameeragarwal sameeragarwal Aug 29, 2017

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Removing the null check here makes sense although this means existing spark jobs that were previously switching to the non-codegen version even with sqlContext.conf.wholeStageFallback = false will now start failing at runtime (perhaps, rightly so). Might be worth calling this out in the 2.3 release notes and/or the migration guide.

case _ @ (_: JaninoRuntimeException | _: CompileException) if codeGenFallBack =>
genInterpretedPredicate(expression, inputSchema)
}
}
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2 changes: 1 addition & 1 deletion sql/core/src/main/scala/org/apache/spark/sql/execution/WholeStageCodegenExec.scala
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Expand Up @@ -382,7 +382,7 @@ case class WholeStageCodegenExec(child: SparkPlan) extends UnaryExecNode with Co
try {
CodeGenerator.compile(cleanedSource)
} catch {
case e: Exception if !Utils.isTesting && sqlContext.conf.wholeStageFallback =>
case _: Exception if !Utils.isTesting && sqlContext.conf.codegenFallback =>
// We should already saw the error message
logWarning(s"Whole-stage codegen disabled for this plan:\n $treeString")
return child.execute()
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2 changes: 1 addition & 1 deletion sql/core/src/test/scala/org/apache/spark/sql/DataFrameFunctionsSuite.scala
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Expand Up @@ -422,7 +422,7 @@ class DataFrameFunctionsSuite extends QueryTest with SharedSQLContext {
v
}
withSQLConf(
(SQLConf.WHOLESTAGE_FALLBACK.key, codegenFallback.toString),
(SQLConf.CODEGEN_FALLBACK.key, codegenFallback.toString),
(SQLConf.WHOLESTAGE_CODEGEN_ENABLED.key, wholeStage.toString)) {
val df = spark.range(0, 4, 1, 4).withColumn("c", c)
val rows = df.collect()
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12 changes: 11 additions & 1 deletion sql/core/src/test/scala/org/apache/spark/sql/DataFrameSuite.scala
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Expand Up @@ -2011,7 +2011,17 @@ class DataFrameSuite extends QueryTest with SharedSQLContext {

val filter = (0 until N)
.foldLeft(lit(false))((e, index) => e.or(df.col(df.columns(index)) =!= "string"))
df.filter(filter).count

withSQLConf(SQLConf.CODEGEN_FALLBACK.key -> "true") {
df.filter(filter).count()
}

withSQLConf(SQLConf.CODEGEN_FALLBACK.key -> "false") {
val e = intercept[SparkException] {
df.filter(filter).count()
}.getMessage
assert(e.contains("grows beyond 64 KB"))
}
}

test("SPARK-20897: cached self-join should not fail") {
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2 changes: 2 additions & 0 deletions sql/core/src/test/scala/org/apache/spark/sql/test/SharedSQLContext.scala
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Expand Up @@ -24,6 +24,7 @@ import org.scalatest.concurrent.Eventually

import org.apache.spark.{DebugFilesystem, SparkConf}
import org.apache.spark.sql.{SparkSession, SQLContext}
import org.apache.spark.sql.internal.SQLConf

/**
* Helper trait for SQL test suites where all tests share a single [[TestSparkSession]].
Expand All @@ -34,6 +35,7 @@ trait SharedSQLContext extends SQLTestUtils with BeforeAndAfterEach with Eventua
new SparkConf()
.set("spark.hadoop.fs.file.impl", classOf[DebugFilesystem].getName)
.set("spark.unsafe.exceptionOnMemoryLeak", "true")
.set(SQLConf.CODEGEN_FALLBACK.key, "false")
}

/**
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1 change: 1 addition & 0 deletions sql/hive/src/main/scala/org/apache/spark/sql/hive/test/TestHive.scala
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Expand Up @@ -51,6 +51,7 @@ object TestHive
"TestSQLContext",
new SparkConf()
.set("spark.sql.test", "")
.set(SQLConf.CODEGEN_FALLBACK.key, "false")
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@gatorsmile gatorsmile Aug 26, 2017

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Turn it false to ensure it does not hide the actual bugs of our expression codegen that causes compilation falure.

.set("spark.sql.hive.metastore.barrierPrefixes",
"org.apache.spark.sql.hive.execution.PairSerDe")
.set("spark.sql.warehouse.dir", TestHiveContext.makeWarehouseDir().toURI.getPath)
Expand Down