Setting timezone in 10g systimestamp/dbtimezone

Question

Using DB 10.2 and want to set the database time zone so that SYSTIMESTAMP stores a time zone as a region rather than h:m offset. I've issued the alter database required to set:
SQL> select dbtimezone from dual;
DBTIMEZONE
Australia/Melbourne
.. and restarted the database, but when I query SYSTIMESTAMP I still get:
SQL> select systimestamp,
2 extract(timezone_region from systimestamp),
3 extract(timezone_abbr from systimestamp) from dual;
SYSTIMESTAMP
EXTRACT(TIMEZONE_REGIONFROMSYSTIMESTAMP) EXTRACT(TI
20-DEC-07 11.44.19.187000 AM +11:00
UNKNOWN UNK
The +11:00 setting I imagine is coming from the OS (Windows Server 2003). The concepts manual implies that the DB setting should be used before the OS, but I get the impression from the Admin Guide, that it needs to be set when the DB is created or modified in the OS only.
Can someone explain how I get the timezone region into the SYSTIMESTAMP ?
Thanks,

Answer 1

systimestamp or sysdate always makes a os call to get system time stamp and showes in system timzone
There is timezone session variable which you will set for each session and database's time zone you set during the creation during the creation of db OR before creating a column timestamp with local time zone.
SQL> select sessiontimezone,dbtimezone from dual;
SESSIONTIMEZONE DBTIMEZONE
US/Eastern US/Central
(I am in eastern and my db in central for this test case)
SQL> select current_Timestamp,systimestamp from dual;
CURRENT_TIMESTAMP SYSTIMESTAMP
19-DEC-07 08.29.34.862000 PM US/EASTERN 19-DEC-07 07.29.34.862000 PM -06:00
(MY os in -6:00 time zone :))