[SPARK-20341][SQL] Support BigInt's value that does not fit in long v…

…alue range

## What changes were proposed in this pull request?

This PR avoids an exception in the case where `scala.math.BigInt` has a value that does not fit into long value range (e.g. `Long.MAX_VALUE+1`). When we run the following code by using the current Spark, the following exception is thrown.

This PR keeps the value using `BigDecimal` if we detect such an overflow case by catching `ArithmeticException`.

Sample program:
```
case class BigIntWrapper(value:scala.math.BigInt)```
spark.createDataset(BigIntWrapper(scala.math.BigInt("10000000000000000002"))::Nil).show
```
Exception:
```
Error while encoding: java.lang.ArithmeticException: BigInteger out of long range
staticinvoke(class org.apache.spark.sql.types.Decimal$, DecimalType(38,0), apply, assertnotnull(assertnotnull(input[0, org.apache.spark.sql.BigIntWrapper, true])).value, true) AS value#0
java.lang.RuntimeException: Error while encoding: java.lang.ArithmeticException: BigInteger out of long range
staticinvoke(class org.apache.spark.sql.types.Decimal$, DecimalType(38,0), apply, assertnotnull(assertnotnull(input[0, org.apache.spark.sql.BigIntWrapper, true])).value, true) AS value#0
	at org.apache.spark.sql.catalyst.encoders.ExpressionEncoder.toRow(ExpressionEncoder.scala:290)
	at org.apache.spark.sql.SparkSession$$anonfun$2.apply(SparkSession.scala:454)
	at org.apache.spark.sql.SparkSession$$anonfun$2.apply(SparkSession.scala:454)
	at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:234)
	at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:234)
	at scala.collection.immutable.List.foreach(List.scala:381)
	at scala.collection.TraversableLike$class.map(TraversableLike.scala:234)
	at scala.collection.immutable.List.map(List.scala:285)
	at org.apache.spark.sql.SparkSession.createDataset(SparkSession.scala:454)
	at org.apache.spark.sql.Agg$$anonfun$18.apply$mcV$sp(MySuite.scala:192)
	at org.apache.spark.sql.Agg$$anonfun$18.apply(MySuite.scala:192)
	at org.apache.spark.sql.Agg$$anonfun$18.apply(MySuite.scala:192)
	at org.scalatest.Transformer$$anonfun$apply$1.apply$mcV$sp(Transformer.scala:22)
	at org.scalatest.OutcomeOf$class.outcomeOf(OutcomeOf.scala:85)
	at org.scalatest.OutcomeOf$.outcomeOf(OutcomeOf.scala:104)
	at org.scalatest.Transformer.apply(Transformer.scala:22)
	at org.scalatest.Transformer.apply(Transformer.scala:20)
	at org.scalatest.FunSuiteLike$$anon$1.apply(FunSuiteLike.scala:166)
	at org.apache.spark.SparkFunSuite.withFixture(SparkFunSuite.scala:68)
	at org.scalatest.FunSuiteLike$class.invokeWithFixture$1(FunSuiteLike.scala:163)
	at org.scalatest.FunSuiteLike$$anonfun$runTest$1.apply(FunSuiteLike.scala:175)
	at org.scalatest.FunSuiteLike$$anonfun$runTest$1.apply(FunSuiteLike.scala:175)
	at org.scalatest.SuperEngine.runTestImpl(Engine.scala:306)
	at org.scalatest.FunSuiteLike$class.runTest(FunSuiteLike.scala:175)
...
Caused by: java.lang.ArithmeticException: BigInteger out of long range
	at java.math.BigInteger.longValueExact(BigInteger.java:4531)
	at org.apache.spark.sql.types.Decimal.set(Decimal.scala:140)
	at org.apache.spark.sql.types.Decimal$.apply(Decimal.scala:434)
	at org.apache.spark.sql.types.Decimal.apply(Decimal.scala)
	at org.apache.spark.sql.catalyst.expressions.GeneratedClass$SpecificUnsafeProjection.apply(Unknown Source)
	at org.apache.spark.sql.catalyst.encoders.ExpressionEncoder.toRow(ExpressionEncoder.scala:287)
	... 59 more
```

## How was this patch tested?

Add new test suite into `DecimalSuite`

Author: Kazuaki Ishizaki <ishizaki@jp.ibm.com>

Closes #17684 from kiszk/SPARK-20341.

sql/catalyst/src/main/scala/org/apache/spark/sql/types/Decimal.scala

@@ -132,14 +132,22 @@ final class Decimal extends Ordered[Decimal] with Serializable {
   }
 
   /**
-   * Set this Decimal to the given BigInteger value. Will have precision 38 and scale 0.
+   * If the value is not in the range of long, convert it to BigDecimal and
+   * the precision and scale are based on the converted value.
+   *
+   * This code avoids BigDecimal object allocation as possible to improve runtime efficiency
    */
   def set(bigintval: BigInteger): Decimal = {
-    this.decimalVal = null
-    this.longVal = bigintval.longValueExact()
-    this._precision = DecimalType.MAX_PRECISION
-    this._scale = 0
-    this
+    try {
+      this.decimalVal = null
+      this.longVal = bigintval.longValueExact()
+      this._precision = DecimalType.MAX_PRECISION
+      this._scale = 0
+      this
+    } catch {
+      case _: ArithmeticException =>
+        set(BigDecimal(bigintval))
+    }
   }
 
   /**

sql/catalyst/src/test/scala/org/apache/spark/sql/types/DecimalSuite.scala

@@ -212,4 +212,10 @@ class DecimalSuite extends SparkFunSuite with PrivateMethodTester {
       }
     }
   }
+
+  test("SPARK-20341: support BigInt's value does not fit in long value range") {
+    val bigInt = scala.math.BigInt("9223372036854775808")
+    val decimal = Decimal.apply(bigInt)
+    assert(decimal.toJavaBigDecimal.unscaledValue.toString === "9223372036854775808")
+  }
 }