Conversion mapping is losing time zone data during daylight saving time

Question

We have a problem with conversion of Calendars to timestamp with timezone for the last hour of Daylight Saving Time (e.g. 01:00 EDT - 01:59 EDT) where it is being interpreted as Standard Time which is in reality 60 minutes later.
We've written a JUnit test case that runs directly against TopLink to avoid any issues with WAS and its connection pooling.
The Calendar theDateTime comes from an object called TimeEntry which is mapped to a TIMESTAMP WITH TIMEZONE field using conversion mapping with Data Type TIMESTAMPTZ (oracle.sql) and Attribute Type Calendar (java.util).
We are using:
Oracle TopLink - 10g Release 3 (10.1.3.0.0) (Build Patch for Bugs 5145690 and 5156075)
Oracle9i Enterprise Edition Release 9.2.0.7.0 - 64bit Production
Oracle JDBC driver Version: 10.2.0.1.0
platform=>Oracle9Platform
Execute this Java:
SimpleDateFormat format = new SimpleDateFormat("MM/dd/yyyy HH:mm z");
TimeZone tzEasternRegion = TimeZone.getTimeZone("US/Eastern");
Calendar theDateTime = Calendar.getInstance(tzEasternRegion);
theDateTime.setTime(format.parse("10/29/2006 01:00 EDT"));
Persist to the database and execute this SQL:
SELECT the_date_time, EXTRACT(TIMEZONE_REGION FROM the_date_time), EXTRACT(TIMEZONE_ABBR FROM the_date_time), EXTRACT(TIMEZONE_HOUR FROM the_date_time)
FROM time_table WHERE time_table_id=1
This provides the following results:
THE_DATE_TIME EXTRACT(TIMEZONE_REGION FROM the_date_time) EXTRACT(TIMEZONE_ABBR FROM the_date_time) EXTRACT(TIMEZONE_HOUR FROM the_date_time)
29-OCT-06 01.00.00.000000 AM US/EASTERN US/Eastern EST -5
The wrong time zone is in the database. It should be EDT -4. Let's test the SQL that should be generated by TopLink. It should look like the following.
Execute this SQL:
UPDATE time_table SET the_date_time = TO_TIMESTAMP_TZ('10/29/2006 01:00 US/Eastern','mm/dd/yyyy HH24:MI TZR') WHERE (time_table_id=1)
SELECT the_date_time, EXTRACT(TIMEZONE_REGION FROM the_date_time), EXTRACT(TIMEZONE_ABBR FROM the_date_time), EXTRACT(TIMEZONE_HOUR FROM the_date_time)
FROM time_table WHERE time_table_id=1
This provides the same results:
THE_DATE_TIME EXTRACT(TIMEZONE_REGION FROM the_date_time) EXTRACT(TIMEZONE_ABBR FROM the_date_time) EXTRACT(TIMEZONE_HOUR FROM the_date_time)
29-OCT-06 01.00.00.000000 AM US/EASTERN US/Eastern EST -5
Now, execute this SQL:
UPDATE time_table SET the_date_time = TO_TIMESTAMP_TZ('10/29/2006 01:00 EDT US/Eastern','mm/dd/yyyy HH24:MI TZD TZR') WHERE (time_table_id=1)
SELECT the_date_time, EXTRACT(TIMEZONE_REGION FROM the_date_time), EXTRACT(TIMEZONE_ABBR FROM the_date_time), EXTRACT(TIMEZONE_HOUR FROM the_date_time)
FROM time_table WHERE time_table_id=1
This provides better results:
THE_DATE_TIME EXTRACT(TIMEZONE_REGION FROM the_date_time) EXTRACT(TIMEZONE_ABBR FROM the_date_time) EXTRACT(TIMEZONE_HOUR FROM the_date_time)
29-OCT-06 01.00.00.000000 AM US/EASTERN US/Eastern EDT -4
The correct time zone is now in the database. Let's test reading this with the following Java:
System.out.println("cal= " + theDateTime);
System.out.println("date= " + theDateTime.getTime());
System.out.println("millis= " + theDateTime.getTimeInMillis());
System.out.println("zone= " + theDateTime.getTimeZone());
This provides the following results:
cal= java.util.GregorianCalendar[...]
date= Sun Oct 29 01:00:00 EST 2006
millis= 1162101600000
zone= sun.util.calendar.ZoneInfo[id="US/Eastern",...]
The TimeZone object is correct since we are using the US/Eastern regional time zone, but the millis are wrong which makes the time EST instead of EDT. The millis should be 1162098000000.
The conversion from java.util.Calendar to TIMESTAMPTZ loses the actual offset when setting to a regional time zone. It can maintain this info by specifying it explicitly.
The conversion from TIMSTAMPTZ to java.util.Calendar also loses the actual offset even if the correct offset is in the database.
Has anyone else encountered this conversion problem? It appears to be a conversion problem in both directions. I know that the Calendar is lenient by default and will assume Standard Time if time is entered during the repeated 1 o'clock hour at the end of Daylight Saving Time, but the Calendars we are using are explicit in their time, so this would be classified as data corruption.
Nik

Answer 1

Opened an SR. Looks like there is a problem with conversion either in TopLink or in JDBC.