Oracle Database Express Edition (XE)

Running XE on Windows XP with the system timezone to GMT rebooted, restarted XE)

Oracle Database 10g Express Edition Release 10.2.0.1.0 - Product
PL/SQL Release 10.2.0.1.0 - Production
CORE 10.2.0.1.0 Production
TNS for 32-bit Windows: Version 10.2.0.1.0 - Production
NLSRTL Version 10.2.0.1.0 - Production


I'm getting incorrect and inconsistent results with current_timestamp and localtimestamp:

With SQL, localtimestamp computes the wrong offset (appears to use 1987-2006 DST rules):

-----
select
dbtimezone
, sessiontimezone
, current_timestamp
, current_timestamp + numtodsinterval(18,'day') as current_timestamp18
, localtimestamp
from dual;

+00:00
US/Eastern
17-MAR-10 10.27.17.376000000 AM US/EASTERN
04-APR-10 10.27.17.376000000 AM US/EASTERN
17-MAR-10 09.27.17.376000000 AM
-----

however, in PL/SQL, both current_timestamp and localtimestamp return the wrong hour value, and adding 18 to current_timestamp shows it is using 1987-2006 DST rules (1st sunday of april)/ note that this happens in straight PL/SQL and in embedded SQL (same results selecting from tables other than DUAL):

-----
begin
for r1 in (
select
dbtimezone
, sessiontimezone
, current_timestamp
, current_timestamp + numtodsinterval(18,'day') as current_timestamp18
, localtimestamp
from dual
)
loop
dbms_output.put_line('SQL dbtimezone = ' || r1.dbtimezone);
dbms_output.put_line('SQL sessiontimezone = ' || r1.sessiontimezone);
dbms_output.put_line('SQL current_timestamp = ' || r1.current_timestamp);
dbms_output.put_line('SQL current_timestamp +18 = ' || r1.current_timestamp18);
dbms_output.put_line('SQL localtimestamp = ' || r1.localtimestamp);
end loop;
dbms_output.put_line('dbtimezone = ' || dbtimezone);
dbms_output.put_line('sessiontimezone = ' || sessiontimezone);
dbms_output.put_line('systimestamp = ' || systimestamp);
dbms_output.put_line('current_timestamp = ' || current_timestamp);
dbms_output.put_line('current_timestamp +18 = ' || (current_timestamp + numtodsinterval(18,'day')));
dbms_output.put_line('localtimestamp = ' || localtimestamp);
end;
/

SQL dbtimezone = +00:00
SQL sessiontimezone = US/Eastern
SQL current_timestamp = 17-MAR-10 09.29.32.784000 AM US/EASTERN
SQL current_timestamp +18 = 04-APR-10 10.29.32.784000000 AM US/EASTERN
SQL localtimestamp = 17-MAR-10 09.29.32.784000 AM
dbtimezone = +00:00
sessiontimezone = US/Eastern
systimestamp = 17-MAR-10 02.29.32.784000000 PM +00:00
current_timestamp = 17-MAR-10 09.29.32.784000000 AM US/EASTERN
current_timestamp +18 = 04-APR-10 10.29.32.784000000 AM US/EASTERN
localtimestamp = 17-MAR-10 09.29.32.784000000 AM

dbtimezone = +00:00
sessiontimezone = US/Eastern
systimestamp = 17-MAR-10 02.16.21.366000000 PM +00:00
current_timestamp = 17-MAR-10 09.16.21.366000000 AM US/EASTERN
current_timestamp +18 = 04-APR-10 10.16.21.366000000 AM US/EASTERN
localtimestamp = 17-MAR-10 09.16.21.366000000 AM
-----

is this a known bug?
is there a patch or a work-around for XE?
are other datasbase versions affected?