[SQL] Improve Speed of InsertIntoHiveTable

Author: Michael Armbrust <michael@databricks.com>

Closes #1130 from marmbrus/noFunctional and squashes the following commits:

ccdb68c [Michael Armbrust] Remove functional programming and Array allocations from fast path in InsertIntoHiveTable.

sql/hive/src/main/scala/org/apache/spark/sql/hive/execution/hiveOperators.scala

@@ -371,12 +371,18 @@ case class InsertIntoHiveTable(
           ObjectInspectorCopyOption.JAVA)
         .asInstanceOf[StructObjectInspector]
 
+
+      val fieldOIs = standardOI.getAllStructFieldRefs.map(_.getFieldObjectInspector).toArray
+      val outputData = new Array[Any](fieldOIs.length)
       iter.map { row =>
-        // Casts Strings to HiveVarchars when necessary.
-        val fieldOIs = standardOI.getAllStructFieldRefs.map(_.getFieldObjectInspector)
-        val mappedRow = row.zip(fieldOIs).map(wrap)
+        var i = 0
+        while (i < row.length) {
+          // Casts Strings to HiveVarchars when necessary.
+          outputData(i) = wrap(row(i), fieldOIs(i))
+          i += 1
+        }
 
-        serializer.serialize(mappedRow.toArray, standardOI)
+        serializer.serialize(outputData, standardOI)
       }
     }