Flashback database log status

Question

My question are
- how come the oldest_flashback_scn is 0
- how come oldest_flashback_time is empty
And I can still do "as of" query
SQL> select * from v$version;
BANNER
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Prod
PL/SQL Release 10.2.0.1.0 - Production
CORE 10.2.0.1.0 Production
TNS for 32-bit Windows: Version 10.2.0.1.0 - Production
NLSRTL Version 10.2.0.1.0 - Production
SQL> select
2 OLDEST_FLASHBACK_SCN,
3 to_char(oldest_flashback_time,'Dy DD-Mon-YYYY HH24:MI:SS'),
4 RETENTION_TARGET,
5 FLASHBACK_SIZE,
6 ESTIMATED_FLASHBACK_SIZE
7 from v$flashback_database_log;
OLDEST_FLASHBACK_SCN TO_CHAR(OLDEST_FLASHBACK RETENTION_TARGET FLASHBACK_SIZE ESTIMATED_FLASHBACK_SIZE
0 15 151461888 67700736
SQL>
SQL> select count(*) from test1 as of scn 364263;
COUNT(*)
2097152

Answer 1

I've setup Flashback and was working properly. I meant to setup a very small size of flashback area and tried to make it to be filled then I get oldest flashback scn "0" from the view v$flashback_database_log. Can anyone explain this for me please?
OLDEST_FLASHBACK_SCN TO_CHAR(OLDEST_FLASHBACK
0
and it was like this
OLDEST_FLASHBACK_SCN TO_CHAR(OLDEST_FLASHBACK
545777 Thu 25-Mar-2010 16:56:27
Thanks gurus
Edited by: HenryLiu on 25/03/2010 15:16
Edited by: HenryLiu on 25/03/2010 15:21