[SPARK-11817][SQL] Truncating the fractional seconds to prevent inserting a NULL

JIRA: https://issues.apache.org/jira/browse/SPARK-11817

Instead of return None, we should truncate the fractional seconds to prevent inserting NULL.

Author: Liang-Chi Hsieh <viirya@appier.com>

Closes #9834 from viirya/truncate-fractional-sec.

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/util/DateTimeUtils.scala

@@ -327,6 +327,11 @@ object DateTimeUtils {
       return None
     }
 
+    // Instead of return None, we truncate the fractional seconds to prevent inserting NULL
+    if (segments(6) > 999999) {
+      segments(6) = segments(6).toString.take(6).toInt
+    }
+
     if (segments(3) < 0 || segments(3) > 23 || segments(4) < 0 || segments(4) > 59 ||
         segments(5) < 0 || segments(5) > 59 || segments(6) < 0 || segments(6) > 999999 ||
         segments(7) < 0 || segments(7) > 23 || segments(8) < 0 || segments(8) > 59) {

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/util/DateTimeUtilsSuite.scala

@@ -343,6 +343,14 @@ class DateTimeUtilsSuite extends SparkFunSuite {
       UTF8String.fromString("2015-03-18T12:03.17-0:70")).isEmpty)
     assert(stringToTimestamp(
       UTF8String.fromString("2015-03-18T12:03.17-1:0:0")).isEmpty)
+
+    // Truncating the fractional seconds
+    c = Calendar.getInstance(TimeZone.getTimeZone("GMT+00:00"))
+    c.set(2015, 2, 18, 12, 3, 17)
+    c.set(Calendar.MILLISECOND, 0)
+    assert(stringToTimestamp(
+      UTF8String.fromString("2015-03-18T12:03:17.123456789+0:00")).get ===
+        c.getTimeInMillis * 1000 + 123456)
   }
 
   test("hours") {