[SPARK-7184] [SQL] enable codegen by default

Davies Liu · rxin · commit bc76a0f7506c · 2015-06-15T23:03:14.000-07:00
In order to have better performance out of box, this PR turn on codegen by default, then codegen can be tested by sql/test and hive/test. This PR also fix some corner cases for codegen. Before 1.5 release, we should re-visit this, turn it off if it's not stable or causing regressions. cc rxin JoshRosen Author: Davies Liu <davies@databricks.com> Closes apache#6726 from davies/enable_codegen and squashes the following commits: f3b25a5 [Davies Liu] fix warning 73750ea [Davies Liu] fix long overflow when compare 3017a47 [Davies Liu] Merge branch 'master' of github.com:apache/spark into enable_codegen a7d75da [Davies Liu] Merge branch 'master' of github.com:apache/spark into enable_codegen ff5b75a [Davies Liu] Merge branch 'master' of github.com:apache/spark into enable_codegen f4cf2c2 [Davies Liu] fix style 99fc139 [Davies Liu] Merge branch 'enable_codegen' of github.com:davies/spark into enable_codegen 91fc7a2 [Davies Liu] disable codegen for ScalaUDF 207e339 [Davies Liu] Update CodeGenerator.scala 44573a3 [Davies Liu] check thread safety of expression f3886fa [Davies Liu] don't inline primitiveTerm for null literal c8e7cd2 [Davies Liu] address comment a8618c9 [Davies Liu] enable codegen by default
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/BoundAttribute.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/BoundAttribute.scala
@@ -19,9 +19,9 @@ package org.apache.spark.sql.catalyst.expressions
 
 import org.apache.spark.Logging
 import org.apache.spark.sql.catalyst.errors.attachTree
-import org.apache.spark.sql.catalyst.expressions.codegen.{GeneratedExpressionCode, CodeGenContext}
+import org.apache.spark.sql.catalyst.expressions.codegen.{CodeGenContext, GeneratedExpressionCode}
+import org.apache.spark.sql.catalyst.trees
 import org.apache.spark.sql.types._
-import org.apache.spark.sql.catalyst.{InternalRow, trees}
 
 /**
  * A bound reference points to a specific slot in the input tuple, allowing the actual value
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/Expression.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/Expression.scala
@@ -60,6 +60,14 @@ abstract class Expression extends TreeNode[Expression] {
   /** Returns the result of evaluating this expression on a given input Row */
   def eval(input: InternalRow = null): Any
 
+  /**
+   * Return true if this expression is thread-safe, which means it could be used by multiple
+   * threads in the same time.
+   *
+   * An expression that is not thread-safe can not be cached and re-used, especially for codegen.
+   */
+  def isThreadSafe: Boolean = true
+
   /**
    * Returns an [[GeneratedExpressionCode]], which contains Java source code that
    * can be used to generate the result of evaluating the expression on an input row.
@@ -68,6 +76,9 @@ abstract class Expression extends TreeNode[Expression] {
    * @return [[GeneratedExpressionCode]]
    */
   def gen(ctx: CodeGenContext): GeneratedExpressionCode = {
+    if (!isThreadSafe) {
+      throw new Exception(s"$this is not thread-safe, can not be used in codegen")
+    }
     val isNull = ctx.freshName("isNull")
     val primitive = ctx.freshName("primitive")
     val ve = GeneratedExpressionCode("", isNull, primitive)
@@ -169,6 +180,7 @@ abstract class BinaryExpression extends Expression with trees.BinaryNode[Express
 
   override def toString: String = s"($left $symbol $right)"
 
+  override def isThreadSafe: Boolean = left.isThreadSafe && right.isThreadSafe
   /**
    * Short hand for generating binary evaluation code, which depends on two sub-evaluations of
    * the same type.  If either of the sub-expressions is null, the result of this computation
@@ -218,6 +230,7 @@ abstract class UnaryExpression extends Expression with trees.UnaryNode[Expressio
 
   override def foldable: Boolean = child.foldable
   override def nullable: Boolean = child.nullable
+  override def isThreadSafe: Boolean = child.isThreadSafe
 
   /**
    * Called by unary expressions to generate a code block that returns null if its parent returns
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/ScalaUdf.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/ScalaUdf.scala
@@ -958,4 +958,6 @@ case class ScalaUdf(function: AnyRef, dataType: DataType, children: Seq[Expressi
   private[this] val converter = CatalystTypeConverters.createToCatalystConverter(dataType)
   override def eval(input: InternalRow): Any = converter(f(input))
 
+  // TODO(davies): make ScalaUdf work with codegen
+  override def isThreadSafe: Boolean = false
 }
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/SortOrder.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/SortOrder.scala
@@ -18,7 +18,7 @@
 package org.apache.spark.sql.catalyst.expressions
 
 import org.apache.spark.sql.catalyst.errors.TreeNodeException
-import org.apache.spark.sql.catalyst.{InternalRow, trees}
+import org.apache.spark.sql.catalyst.trees
 import org.apache.spark.sql.types.DataType
 
 abstract sealed class SortDirection
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/arithmetic.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/arithmetic.scala
@@ -341,31 +341,29 @@ case class MaxOf(left: Expression, right: Expression) extends BinaryArithmetic {
   }
 
   override def genCode(ctx: CodeGenContext, ev: GeneratedExpressionCode): String = {
-    if (ctx.isNativeType(left.dataType)) {
-      val eval1 = left.gen(ctx)
-      val eval2 = right.gen(ctx)
-      eval1.code + eval2.code + s"""
-        boolean ${ev.isNull} = false;
-        ${ctx.javaType(left.dataType)} ${ev.primitive} =
-          ${ctx.defaultValue(left.dataType)};
-
-        if (${eval1.isNull}) {
-          ${ev.isNull} = ${eval2.isNull};
-          ${ev.primitive} = ${eval2.primitive};
-        } else if (${eval2.isNull}) {
-          ${ev.isNull} = ${eval1.isNull};
+    val eval1 = left.gen(ctx)
+    val eval2 = right.gen(ctx)
+    val compCode = ctx.genComp(dataType, eval1.primitive, eval2.primitive)
+
+    eval1.code + eval2.code + s"""
+      boolean ${ev.isNull} = false;
+      ${ctx.javaType(left.dataType)} ${ev.primitive} =
+        ${ctx.defaultValue(left.dataType)};
+
+      if (${eval1.isNull}) {
+        ${ev.isNull} = ${eval2.isNull};
+        ${ev.primitive} = ${eval2.primitive};
+      } else if (${eval2.isNull}) {
+        ${ev.isNull} = ${eval1.isNull};
+        ${ev.primitive} = ${eval1.primitive};
+      } else {
+        if ($compCode > 0) {
           ${ev.primitive} = ${eval1.primitive};
         } else {
-          if (${eval1.primitive} > ${eval2.primitive}) {
-            ${ev.primitive} = ${eval1.primitive};
-          } else {
-            ${ev.primitive} = ${eval2.primitive};
-          }
+          ${ev.primitive} = ${eval2.primitive};
         }
-      """
-    } else {
-      super.genCode(ctx, ev)
-    }
+      }
+    """
   }
   override def toString: String = s"MaxOf($left, $right)"
 }
@@ -395,33 +393,29 @@ case class MinOf(left: Expression, right: Expression) extends BinaryArithmetic {
   }
 
   override def genCode(ctx: CodeGenContext, ev: GeneratedExpressionCode): String = {
-    if (ctx.isNativeType(left.dataType)) {
-
-      val eval1 = left.gen(ctx)
-      val eval2 = right.gen(ctx)
-
-      eval1.code + eval2.code + s"""
-        boolean ${ev.isNull} = false;
-        ${ctx.javaType(left.dataType)} ${ev.primitive} =
-          ${ctx.defaultValue(left.dataType)};
+    val eval1 = left.gen(ctx)
+    val eval2 = right.gen(ctx)
+    val compCode = ctx.genComp(dataType, eval1.primitive, eval2.primitive)
 
-        if (${eval1.isNull}) {
-          ${ev.isNull} = ${eval2.isNull};
-          ${ev.primitive} = ${eval2.primitive};
-        } else if (${eval2.isNull}) {
-          ${ev.isNull} = ${eval1.isNull};
+    eval1.code + eval2.code + s"""
+      boolean ${ev.isNull} = false;
+      ${ctx.javaType(left.dataType)} ${ev.primitive} =
+        ${ctx.defaultValue(left.dataType)};
+
+      if (${eval1.isNull}) {
+        ${ev.isNull} = ${eval2.isNull};
+        ${ev.primitive} = ${eval2.primitive};
+      } else if (${eval2.isNull}) {
+        ${ev.isNull} = ${eval1.isNull};
+        ${ev.primitive} = ${eval1.primitive};
+      } else {
+        if ($compCode < 0) {
           ${ev.primitive} = ${eval1.primitive};
         } else {
-          if (${eval1.primitive} < ${eval2.primitive}) {
-            ${ev.primitive} = ${eval1.primitive};
-          } else {
-            ${ev.primitive} = ${eval2.primitive};
-          }
+          ${ev.primitive} = ${eval2.primitive};
         }
-      """
-    } else {
-      super.genCode(ctx, ev)
-    }
+      }
+    """
   }
 
   override def toString: String = s"MinOf($left, $right)"
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/codegen/CodeGenerator.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/codegen/CodeGenerator.scala
@@ -24,7 +24,6 @@ import com.google.common.cache.{CacheBuilder, CacheLoader}
 import org.codehaus.janino.ClassBodyEvaluator
 
 import org.apache.spark.Logging
-import org.apache.spark.sql.catalyst
 import org.apache.spark.sql.catalyst.expressions._
 import org.apache.spark.sql.types._
 import org.apache.spark.unsafe.types.UTF8String
@@ -176,9 +175,8 @@ class CodeGenContext {
    * Generate code for compare expression in Java
    */
   def genComp(dataType: DataType, c1: String, c2: String): String = dataType match {
-    // Use signum() to keep any small difference bwteen float/double
-    case FloatType | DoubleType => s"(int)java.lang.Math.signum($c1 - $c2)"
-    case dt: DataType if isPrimitiveType(dt) => s"(int)($c1 - $c2)"
+    // use c1 - c2 may overflow
+    case dt: DataType if isPrimitiveType(dt) => s"(int)($c1 > $c2 ? 1 : $c1 < $c2 ? -1 : 0)"
     case BinaryType => s"org.apache.spark.sql.catalyst.util.TypeUtils.compareBinary($c1, $c2)"
     case other => s"$c1.compare($c2)"
   }
@@ -266,7 +264,7 @@ abstract class CodeGenerator[InType <: AnyRef, OutType <: AnyRef] extends Loggin
    * weak keys/values and thus does not respond to memory pressure.
    */
   protected val cache = CacheBuilder.newBuilder()
-    .maximumSize(1000)
+    .maximumSize(100)
     .build(
       new CacheLoader[InType, OutType]() {
         override def load(in: InType): OutType = {
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/namedExpressions.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/namedExpressions.scala
@@ -117,6 +117,8 @@ case class Alias(child: Expression, name: String)(
 
   override def eval(input: InternalRow): Any = child.eval(input)
 
+  override def isThreadSafe: Boolean = child.isThreadSafe
+
   override def gen(ctx: CodeGenContext): GeneratedExpressionCode = child.gen(ctx)
 
   override def dataType: DataType = child.dataType
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/nullFunctions.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/nullFunctions.scala
@@ -19,7 +19,6 @@ package org.apache.spark.sql.catalyst.expressions
 
 import org.apache.spark.sql.catalyst.analysis.UnresolvedException
 import org.apache.spark.sql.catalyst.expressions.codegen.{CodeGenContext, GeneratedExpressionCode}
-import org.apache.spark.sql.catalyst.trees
 import org.apache.spark.sql.types.DataType
 
 case class Coalesce(children: Seq[Expression]) extends Expression {
@@ -53,6 +52,8 @@ case class Coalesce(children: Seq[Expression]) extends Expression {
     result
   }
 
+  override def isThreadSafe: Boolean = children.forall(_.isThreadSafe)
+
   override def genCode(ctx: CodeGenContext, ev: GeneratedExpressionCode): String = {
     s"""
       boolean ${ev.isNull} = true;
@@ -73,7 +74,7 @@ case class Coalesce(children: Seq[Expression]) extends Expression {
   }
 }
 
-case class IsNull(child: Expression) extends Predicate with trees.UnaryNode[Expression] {
+case class IsNull(child: Expression) extends UnaryExpression with Predicate {
   override def foldable: Boolean = child.foldable
   override def nullable: Boolean = false
 
@@ -91,7 +92,7 @@ case class IsNull(child: Expression) extends Predicate with trees.UnaryNode[Expr
   override def toString: String = s"IS NULL $child"
 }
 
-case class IsNotNull(child: Expression) extends Predicate with trees.UnaryNode[Expression] {
+case class IsNotNull(child: Expression) extends UnaryExpression with Predicate {
   override def foldable: Boolean = child.foldable
   override def nullable: Boolean = false
   override def toString: String = s"IS NOT NULL $child"
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/windowExpressions.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/windowExpressions.scala
@@ -19,8 +19,7 @@ package org.apache.spark.sql.catalyst.expressions
 
 import org.apache.spark.sql.catalyst.analysis.UnresolvedException
 import org.apache.spark.sql.catalyst.errors.TreeNodeException
-import org.apache.spark.sql.catalyst.expressions._
-import org.apache.spark.sql.types.{NumericType, DataType}
+import org.apache.spark.sql.types.{DataType, NumericType}
 
 /**
  * The trait of the Window Specification (specified in the OVER clause or WINDOW clause) for
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/plans/logical/LocalRelation.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/plans/logical/LocalRelation.scala
@@ -18,7 +18,7 @@
 package org.apache.spark.sql.catalyst.plans.logical
 
 import org.apache.spark.sql.catalyst.expressions.Attribute
-import org.apache.spark.sql.catalyst.{InternalRow, CatalystTypeConverters, analysis}
+import org.apache.spark.sql.catalyst.{CatalystTypeConverters, InternalRow, analysis}
 import org.apache.spark.sql.types.{StructField, StructType}
 
 object LocalRelation {
diff --git a/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/ScalaReflectionSuite.scala b/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/ScalaReflectionSuite.scala
@@ -21,7 +21,6 @@ import java.math.BigInteger
 import java.sql.{Date, Timestamp}
 
 import org.apache.spark.SparkFunSuite
-import org.apache.spark.sql.catalyst.InternalRow
 import org.apache.spark.sql.types._
 
 case class PrimitiveData(
@@ -75,7 +74,7 @@ case class MultipleConstructorsData(a: Int, b: String, c: Double) {
 }
 
 class ScalaReflectionSuite extends SparkFunSuite {
-  import ScalaReflection._
+  import org.apache.spark.sql.catalyst.ScalaReflection._
 
   test("primitive data") {
     val schema = schemaFor[PrimitiveData]
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/SQLConf.scala b/sql/core/src/main/scala/org/apache/spark/sql/SQLConf.scala
@@ -171,15 +171,11 @@ private[sql] class SQLConf extends Serializable with CatalystConf {
   private[spark] def sortMergeJoinEnabled: Boolean = getConf(SORTMERGE_JOIN, "false").toBoolean
 
   /**
-   * When set to true, Spark SQL will use the Scala compiler at runtime to generate custom bytecode
+   * When set to true, Spark SQL will use the Janino at runtime to generate custom bytecode
    * that evaluates expressions found in queries.  In general this custom code runs much faster
-   * than interpreted evaluation, but there are significant start-up costs due to compilation.
-   * As a result codegen is only beneficial when queries run for a long time, or when the same
-   * expressions are used multiple times.
-   *
-   * Defaults to false as this feature is currently experimental.
+   * than interpreted evaluation, but there are some start-up costs (5-10ms) due to compilation.
    */
-  private[spark] def codegenEnabled: Boolean = getConf(CODEGEN_ENABLED, "false").toBoolean
+  private[spark] def codegenEnabled: Boolean = getConf(CODEGEN_ENABLED, "true").toBoolean
 
   /**
    * caseSensitive analysis true by default
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/SQLContext.scala b/sql/core/src/main/scala/org/apache/spark/sql/SQLContext.scala
@@ -31,14 +31,13 @@ import org.apache.spark.SparkContext
 import org.apache.spark.annotation.{DeveloperApi, Experimental}
 import org.apache.spark.api.java.{JavaRDD, JavaSparkContext}
 import org.apache.spark.rdd.RDD
-import org.apache.spark.sql.catalyst.{InternalRow, _}
 import org.apache.spark.sql.catalyst.analysis._
-import org.apache.spark.sql.catalyst.expressions._
 import org.apache.spark.sql.catalyst.errors.DialectException
+import org.apache.spark.sql.catalyst.expressions._
 import org.apache.spark.sql.catalyst.optimizer.{DefaultOptimizer, Optimizer}
 import org.apache.spark.sql.catalyst.plans.logical.{LocalRelation, LogicalPlan}
 import org.apache.spark.sql.catalyst.rules.RuleExecutor
-import org.apache.spark.sql.catalyst.ParserDialect
+import org.apache.spark.sql.catalyst.{InternalRow, ParserDialect, _}
 import org.apache.spark.sql.execution.{Filter, _}
 import org.apache.spark.sql.sources._
 import org.apache.spark.sql.types._
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/columnar/ColumnBuilder.scala b/sql/core/src/main/scala/org/apache/spark/sql/columnar/ColumnBuilder.scala
@@ -18,6 +18,7 @@
 package org.apache.spark.sql.columnar
 
 import java.nio.{ByteBuffer, ByteOrder}
+
 import org.apache.spark.sql.catalyst.InternalRow
 import org.apache.spark.sql.columnar.ColumnBuilder._
 import org.apache.spark.sql.columnar.compression.{AllCompressionSchemes, CompressibleColumnBuilder}
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/execution/SparkPlan.scala b/sql/core/src/main/scala/org/apache/spark/sql/execution/SparkPlan.scala
@@ -156,7 +156,7 @@ abstract class SparkPlan extends QueryPlan[SparkPlan] with Logging with Serializ
       expressions: Seq[Expression], inputSchema: Seq[Attribute]): Projection = {
     log.debug(
       s"Creating Projection: $expressions, inputSchema: $inputSchema, codegen:$codegenEnabled")
-    if (codegenEnabled) {
+    if (codegenEnabled && expressions.forall(_.isThreadSafe)) {
       GenerateProjection.generate(expressions, inputSchema)
     } else {
       new InterpretedProjection(expressions, inputSchema)
@@ -168,7 +168,8 @@ abstract class SparkPlan extends QueryPlan[SparkPlan] with Logging with Serializ
       inputSchema: Seq[Attribute]): () => MutableProjection = {
     log.debug(
       s"Creating MutableProj: $expressions, inputSchema: $inputSchema, codegen:$codegenEnabled")
-    if(codegenEnabled) {
+    if(codegenEnabled && expressions.forall(_.isThreadSafe)) {
+
       GenerateMutableProjection.generate(expressions, inputSchema)
     } else {
       () => new InterpretedMutableProjection(expressions, inputSchema)
@@ -178,7 +179,7 @@ abstract class SparkPlan extends QueryPlan[SparkPlan] with Logging with Serializ
 
   protected def newPredicate(
       expression: Expression, inputSchema: Seq[Attribute]): (InternalRow) => Boolean = {
-    if (codegenEnabled) {
+    if (codegenEnabled && expression.isThreadSafe) {
       GeneratePredicate.generate(expression, inputSchema)
     } else {
       InterpretedPredicate.create(expression, inputSchema)
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/execution/expressions/MonotonicallyIncreasingID.scala b/sql/core/src/main/scala/org/apache/spark/sql/execution/expressions/MonotonicallyIncreasingID.scala
@@ -48,4 +48,6 @@ private[sql] case class MonotonicallyIncreasingID() extends LeafExpression {
     count += 1
     (TaskContext.get().partitionId().toLong << 33) + currentCount
   }
+
+  override def isThreadSafe: Boolean = false
 }
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/execution/joins/BroadcastLeftSemiJoinHash.scala b/sql/core/src/main/scala/org/apache/spark/sql/execution/joins/BroadcastLeftSemiJoinHash.scala
@@ -50,7 +50,8 @@ case class BroadcastLeftSemiJoinHash(
       if (!rowKey.anyNull) {
         val keyExists = hashSet.contains(rowKey)
         if (!keyExists) {
-          hashSet.add(rowKey)
+          // rowKey may be not serializable (from codegen)
+          hashSet.add(rowKey.copy())
         }
       }
     }
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/parquet/newParquet.scala b/sql/core/src/main/scala/org/apache/spark/sql/parquet/newParquet.scala
@@ -34,16 +34,16 @@ import org.apache.parquet.hadoop._
 import org.apache.parquet.hadoop.metadata.CompressionCodecName
 import org.apache.parquet.hadoop.util.ContextUtil
 
-import org.apache.spark.sql.catalyst.InternalRow
-import org.apache.spark.{Partition => SparkPartition, SerializableWritable, Logging, SparkException}
 import org.apache.spark.broadcast.Broadcast
 import org.apache.spark.deploy.SparkHadoopUtil
-import org.apache.spark.rdd.RDD._
 import org.apache.spark.rdd.RDD
+import org.apache.spark.rdd.RDD._
 import org.apache.spark.sql._
+import org.apache.spark.sql.catalyst.InternalRow
 import org.apache.spark.sql.sources._
 import org.apache.spark.sql.types.{DataType, StructType}
 import org.apache.spark.util.Utils
+import org.apache.spark.{Logging, SerializableWritable, SparkException, Partition => SparkPartition}
 
 private[sql] class DefaultSource extends HadoopFsRelationProvider {
   override def createRelation(
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/sources/commands.scala b/sql/core/src/main/scala/org/apache/spark/sql/sources/commands.scala
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/sources/interfaces.scala b/sql/core/src/main/scala/org/apache/spark/sql/sources/interfaces.scala
diff --git a/sql/hive/src/main/scala/org/apache/spark/sql/hive/hiveUdfs.scala b/sql/hive/src/main/scala/org/apache/spark/sql/hive/hiveUdfs.scala

Original file line number	Diff line number	Diff line change
`@@ -958,4 +958,6 @@ case class ScalaUdf(function: AnyRef, dataType: DataType, children: Seq[Expressi`
`958`	`958`	`private[this] val converter = CatalystTypeConverters.createToCatalystConverter(dataType)`
`959`	`959`	`override def eval(input: InternalRow): Any = converter(f(input))`
`960`	`960`
	`961`	`+ // TODO(davies): make ScalaUdf work with codegen`
	`962`	`+ override def isThreadSafe: Boolean = false`
`961`	`963`	`}`