[SPARK-18091][SQL] Deep if expressions cause Generated SpecificUnsafeProjection code to exceed JVM code size limit

## What changes were proposed in this pull request?

Fix for SPARK-18091 which is a bug related to large if expressions causing generated SpecificUnsafeProjection code to exceed JVM code size limit.

This PR changes if expression's code generation to place its predicate, true value and false value expressions' generated code in separate methods in context so as to never generate too long combined code.
## How was this patch tested?

Added a unit test and also tested manually with the application (having transformations similar to the unit test) which caused the issue to be identified in the first place.

Author: Kapil Singh <kapsingh@adobe.com>

Closes #15620 from kapilsingh5050/SPARK-18091-IfCodegenFix.
This commit is contained in:
Kapil Singh 2016-12-04 17:16:40 +08:00 committed by Wenchen Fan
parent edb0ad9d48
commit e463678b19
2 changed files with 90 additions and 13 deletions

View file

@ -64,19 +64,75 @@ case class If(predicate: Expression, trueValue: Expression, falseValue: Expressi
val trueEval = trueValue.genCode(ctx)
val falseEval = falseValue.genCode(ctx)
ev.copy(code = s"""
${condEval.code}
boolean ${ev.isNull} = false;
${ctx.javaType(dataType)} ${ev.value} = ${ctx.defaultValue(dataType)};
if (!${condEval.isNull} && ${condEval.value}) {
${trueEval.code}
${ev.isNull} = ${trueEval.isNull};
${ev.value} = ${trueEval.value};
} else {
${falseEval.code}
${ev.isNull} = ${falseEval.isNull};
${ev.value} = ${falseEval.value};
}""")
// place generated code of condition, true value and false value in separate methods if
// their code combined is large
val combinedLength = condEval.code.length + trueEval.code.length + falseEval.code.length
val generatedCode = if (combinedLength > 1024 &&
// Split these expressions only if they are created from a row object
(ctx.INPUT_ROW != null && ctx.currentVars == null)) {
val (condFuncName, condGlobalIsNull, condGlobalValue) =
createAndAddFunction(ctx, condEval, predicate.dataType, "evalIfCondExpr")
val (trueFuncName, trueGlobalIsNull, trueGlobalValue) =
createAndAddFunction(ctx, trueEval, trueValue.dataType, "evalIfTrueExpr")
val (falseFuncName, falseGlobalIsNull, falseGlobalValue) =
createAndAddFunction(ctx, falseEval, falseValue.dataType, "evalIfFalseExpr")
s"""
$condFuncName(${ctx.INPUT_ROW});
boolean ${ev.isNull} = false;
${ctx.javaType(dataType)} ${ev.value} = ${ctx.defaultValue(dataType)};
if (!$condGlobalIsNull && $condGlobalValue) {
$trueFuncName(${ctx.INPUT_ROW});
${ev.isNull} = $trueGlobalIsNull;
${ev.value} = $trueGlobalValue;
} else {
$falseFuncName(${ctx.INPUT_ROW});
${ev.isNull} = $falseGlobalIsNull;
${ev.value} = $falseGlobalValue;
}
"""
}
else {
s"""
${condEval.code}
boolean ${ev.isNull} = false;
${ctx.javaType(dataType)} ${ev.value} = ${ctx.defaultValue(dataType)};
if (!${condEval.isNull} && ${condEval.value}) {
${trueEval.code}
${ev.isNull} = ${trueEval.isNull};
${ev.value} = ${trueEval.value};
} else {
${falseEval.code}
${ev.isNull} = ${falseEval.isNull};
${ev.value} = ${falseEval.value};
}
"""
}
ev.copy(code = generatedCode)
}
private def createAndAddFunction(
ctx: CodegenContext,
ev: ExprCode,
dataType: DataType,
baseFuncName: String): (String, String, String) = {
val globalIsNull = ctx.freshName("isNull")
ctx.addMutableState("boolean", globalIsNull, s"$globalIsNull = false;")
val globalValue = ctx.freshName("value")
ctx.addMutableState(ctx.javaType(dataType), globalValue,
s"$globalValue = ${ctx.defaultValue(dataType)};")
val funcName = ctx.freshName(baseFuncName)
val funcBody =
s"""
|private void $funcName(InternalRow ${ctx.INPUT_ROW}) {
| ${ev.code.trim}
| $globalIsNull = ${ev.isNull};
| $globalValue = ${ev.value};
|}
""".stripMargin
ctx.addNewFunction(funcName, funcBody)
(funcName, globalIsNull, globalValue)
}
override def toString: String = s"if ($predicate) $trueValue else $falseValue"

View file

@ -97,6 +97,27 @@ class CodeGenerationSuite extends SparkFunSuite with ExpressionEvalHelper {
assert(actual(0) == cases)
}
test("SPARK-18091: split large if expressions into blocks due to JVM code size limit") {
val inStr = "StringForTesting"
val row = create_row(inStr)
val inputStrAttr = 'a.string.at(0)
var strExpr: Expression = inputStrAttr
for (_ <- 1 to 13) {
strExpr = If(EqualTo(Decode(Encode(strExpr, "utf-8"), "utf-8"), inputStrAttr),
strExpr, strExpr)
}
val expressions = Seq(strExpr)
val plan = GenerateUnsafeProjection.generate(expressions, true)
val actual = plan(row).toSeq(expressions.map(_.dataType))
val expected = Seq(UTF8String.fromString(inStr))
if (!checkResult(actual, expected)) {
fail(s"Incorrect Evaluation: expressions: $expressions, actual: $actual, expected: $expected")
}
}
test("SPARK-14793: split wide array creation into blocks due to JVM code size limit") {
val length = 5000
val expressions = Seq(CreateArray(List.fill(length)(EqualTo(Literal(1), Literal(1)))))