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[SPARK-13242] [SQL] Generate one method per when clause #11221

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[SPARK-13242] [SQL] Generate one method per when clause #11221

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4dbdf6e
Add test case
joehalliwell Feb 9, 2016
2b59453
Split when clauses into separate methods
joehalliwell Feb 16, 2016
57c78a7
Smoketest generated code
joehalliwell Feb 16, 2016
ddc54f5
Remove some cruft
joehalliwell Feb 16, 2016
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84 changes: 57 additions & 27 deletions ...yst/src/main/scala/org/apache/spark/sql/catalyst/expressions/conditionalExpressions.scala
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Original file line number Diff line number Diff line change
Expand Up @@ -139,54 +139,84 @@ case class CaseWhen(branches: Seq[(Expression, Expression)], elseValue: Option[E
override def genCode(ctx: CodegenContext, ev: ExprCode): String = {
// Generate code that looks like:
//
// condA = ...
// if (condA) {
// valueA
// } else {
// def when_0 {
// condA = ...
// if (condA) {
// valueA
// return true
// }
// return false
// }
//
// def when_1 {
// condB = ...
// if (condB) {
// valueB
// } else {
// condC = ...
// if (condC) {
// valueC
// } else {
// elseValue
// }
// return true
// }
// return false
// }
//
// def when_2 {
// elseValue
// return true
// }
//
// if (when_0()) {} else { if (when_1()) {} else { if (when_2()) {} else { }}}

val isNull = ctx.freshName("isNull")
val value = ctx.freshName("value")

ctx.addMutableState("boolean", isNull, s"boolean ${isNull} = true;")
ctx.addMutableState(ctx.javaType(dataType), value,
s"${ctx.javaType(dataType)} ${value} = ${ctx.defaultValue(dataType)};")

def addCase(body: String) = {
val name = ctx.freshName("when_")
val code = s"""
public boolean ${name}(InternalRow ${ctx.INPUT_ROW}) {
${body}
}"""
ctx.addNewFunction(name, code)
name
}

val cases = branches.map { case (condExpr, valueExpr) =>
val cond = condExpr.gen(ctx)
val res = valueExpr.gen(ctx)
s"""
${cond.code}
if (!${cond.isNull} && ${cond.value}) {
${res.code}
${ev.isNull} = ${res.isNull};
${ev.value} = ${res.value};
${isNull} = ${res.isNull};
${value} = ${res.value};
return true;
}
return false;
"""
}

var generatedCode = cases.mkString("", "\nelse {\n", "\nelse {\n")

elseValue.foreach { elseExpr =>
val elseCase = elseValue.map { elseExpr =>
val res = elseExpr.gen(ctx)
generatedCode +=
s"""
${res.code}
${ev.isNull} = ${res.isNull};
${ev.value} = ${res.value};
"""
s"""
${res.code}
${isNull} = ${res.isNull};
${value} = ${res.value};
return true;
"""
}

generatedCode += "}\n" * cases.size
val names = (cases ++ elseCase).map(c => addCase(c))
val calls = names
.map(fn => s"if (${fn}(${ctx.INPUT_ROW})) { } else { ").mkString("", "", "}" * names.size)

s"""
boolean ${ev.isNull} = true;
${ctx.javaType(dataType)} ${ev.value} = ${ctx.defaultValue(dataType)};
$generatedCode
"""
${isNull} = true;
${value} = ${ctx.defaultValue(dataType)};
$calls
boolean ${ev.isNull} = ${isNull};
${ctx.javaType(dataType)} ${ev.value} = ${value};
"""
}

override def toString: String = {
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21 changes: 21 additions & 0 deletions ...talyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/CodeGenerationSuite.scala
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Original file line number Diff line number Diff line change
Expand Up @@ -58,6 +58,27 @@ class CodeGenerationSuite extends SparkFunSuite with ExpressionEvalHelper {
}
}


test("SPARK-13242: split when clauses") {
val cases = 50
val clauses = 20

// Generate an individual case
def generateCase(n: Int): (Expression, Expression) = {
val condition = (1 to clauses)
.map(c => EqualTo(BoundReference(0, StringType, false), Literal(s"$c:$n")))
.reduceLeft[Expression]((l, r) => Or(l, r))
(condition, Literal(n))
}

val expression = CaseWhen((1 to cases).map(generateCase(_)))
val plan = GenerateMutableProjection.generate(Seq(expression))()
val input = new GenericMutableRow(Array[Any](UTF8String.fromString(s"${clauses}:${cases}")))
val actual = plan(input).toSeq(Seq(expression.dataType))

assert(actual(0) == cases)
}

test("test generated safe and unsafe projection") {
val schema = new StructType(Array(
StructField("a", StringType, true),
Expand Down