[SPARK-6087][CORE] Provide actionable exception if Kryo buffer is not large enough

A simple try-catch wrapping KryoException to be more informative.

Author: Lev Khomich <levkhomich@gmail.com>

Closes #4947 from levkhomich/master and squashes the following commits:

0f7a947 [Lev Khomich] [SPARK-6087][CORE] Provide actionable exception if Kryo buffer is not large enough

core/src/main/scala/org/apache/spark/serializer/KryoSerializer.scala

@@ -158,7 +158,13 @@ private[spark] class KryoSerializerInstance(ks: KryoSerializer) extends Serializ
 
   override def serialize[T: ClassTag](t: T): ByteBuffer = {
     output.clear()
-    kryo.writeClassAndObject(output, t)
+    try {
+      kryo.writeClassAndObject(output, t)
+    } catch {
+      case e: KryoException if e.getMessage.startsWith("Buffer overflow") =>
+        throw new SparkException(s"Kryo serialization failed: ${e.getMessage}. To avoid this, " +
+          "increase spark.kryoserializer.buffer.max.mb value.")
+    }
     ByteBuffer.wrap(output.toBytes)
   }
 

core/src/test/scala/org/apache/spark/serializer/KryoSerializerSuite.scala

@@ -261,6 +261,20 @@ class KryoSerializerSuite extends FunSuite with SharedSparkContext {
       ser.serialize(HighlyCompressedMapStatus(BlockManagerId("exec-1", "host", 1234), blockSizes))
     }
   }
+
+  test("serialization buffer overflow reporting") {
+    import org.apache.spark.SparkException
+    val kryoBufferMaxProperty = "spark.kryoserializer.buffer.max.mb"
+
+    val largeObject = (1 to 1000000).toArray
+
+    val conf = new SparkConf(false)
+    conf.set(kryoBufferMaxProperty, "1")
+
+    val ser = new KryoSerializer(conf).newInstance()
+    val thrown = intercept[SparkException](ser.serialize(largeObject))
+    assert(thrown.getMessage.contains(kryoBufferMaxProperty))
+  }
 }