Github user vdiravka commented on a diff in the pull request:
https://github.com/apache/drill/pull/656#discussion_r98358344
--- Diff:
exec/java-exec/src/main/java/org/apache/drill/exec/store/parquet/ParquetReaderUtility.java
---
@@ -323,18 +323,28 @@ public static DateCorruptionStatus
checkForCorruptDateValuesInStatistics(Parquet
* @param binaryTimeStampValue
* hive, impala timestamp values with nanoseconds precision
* are stored in parquet Binary as INT96 (12 constant bytes)
- *
+ * @param retainLocalTimezone
+ * parquet files don't keep local timeZone according to the
+ * <a
href="https://github.com/Parquet/parquet-format/blob/master/LogicalTypes.md#timestamp";>Parquet
spec</a>,
+ * but some tools (hive, for example) retain local timezone for
parquet files by default
+ * Note: Impala doesn't retain local timezone by default
* @return Unix Timestamp - the number of milliseconds since January 1,
1970, 00:00:00 GMT
* represented by @param binaryTimeStampValue .
*/
- public static long getDateTimeValueFromBinary(Binary
binaryTimeStampValue) {
+ public static long getDateTimeValueFromBinary(Binary
binaryTimeStampValue, boolean retainLocalTimezone) {
// This method represents binaryTimeStampValue as ByteBuffer, where
timestamp is stored as sum of
// julian day number (32-bit) and nanos of day (64-bit)
NanoTime nt = NanoTime.fromBinary(binaryTimeStampValue);
int julianDay = nt.getJulianDay();
long nanosOfDay = nt.getTimeOfDayNanos();
- return (julianDay - JULIAN_DAY_NUMBER_FOR_UNIX_EPOCH) *
DateTimeConstants.MILLIS_PER_DAY
+ long dateTime = (julianDay - JULIAN_DAY_NUMBER_FOR_UNIX_EPOCH) *
DateTimeConstants.MILLIS_PER_DAY
+ nanosOfDay / NANOS_PER_MILLISECOND;
+ if (retainLocalTimezone) {
+ return new org.joda.time.DateTime(dateTime,
org.joda.time.chrono.JulianChronology.getInstance())
+
.withZoneRetainFields(org.joda.time.DateTimeZone.UTC).getMillis();
--- End diff --
`withZoneRetainFields` method calculates the difference between local
timezone and UTC (parameter of that method) and returns original dateTime with
a shift of that difference. This approach is used frequently in drill code.
But thinking a little more on this I decided that it is possible to use
more simpler statement, without creating DateTime object.
`DateTimeZone.getDefault().convertUTCToLocal(dateTime)`. I think it's more
clear.
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