Addressing review comments

Author: sureshthalamati

external/docker-integration-tests/src/test/scala/org/apache/spark/sql/jdbc/PostgresIntegrationSuite.scala

@@ -61,6 +61,7 @@ class PostgresIntegrationSuite extends DockerJDBCIntegrationSuite {
     val df = sqlContext.read.jdbc(jdbcUrl, "bar", new Properties)
     val rows = df.collect().sortBy(_.toString())
     assert(rows.length == 2)
+    // Test the types, and values using the first row.
     val types = rows(0).toSeq.map(x => x.getClass)
     assert(types.length == 17)
     assert(classOf[String].isAssignableFrom(types(0)))
@@ -101,7 +102,7 @@ class PostgresIntegrationSuite extends DockerJDBCIntegrationSuite {
     assert(rows(0).getFloat(15) == 1.01f)
     assert(rows(0).getShort(16) == 1)
 
-    // Test reading null values.
+    // Test reading null values using the second row.
     assert(0.until(16).forall(rows(1).isNullAt(_)))
   }
 

sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/jdbc/JdbcUtils.scala

@@ -466,7 +466,7 @@ object JdbcUtils extends Logging {
 
       (rs: ResultSet, row: InternalRow, pos: Int) =>
         val array = nullSafeConvert[java.sql.Array](
-          rs.getArray(pos + 1),
+          input = rs.getArray(pos + 1),
           array => new GenericArrayData(elementConversion.apply(array.getArray)))
         row.update(pos, array)