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Home -> Community -> Mailing Lists -> Oracle-L -> Re: Undo Retention of 5 days; anyone?
Arup
Here is small cut out from one of the Oracle Openworld presentation title"
ORACLE DATABASE 10 g TIME NAVIGATION: HUMAN ERROR CORRECTION" by Tammy
Bednar from Oracle
"New in Oracle Database10g is the ability to query data in the past for more than 5 days if the UNDO_RETENTION is set for greater then 5 days. Oracle will maintain the undo for that period of time as long as the Undo Tablespace datafiles are allocated enough disk space"
Now I am surprised with the result mentioned by one of the expert in
earlier email in the list that he tested it with more than 5 days. The
only exception I can count is
-->either if the database is down for few days and then in that case
SMON_SCN_TIME can have timestamp for more than 5 days
OR
--> If the SCN flashback method is used and not the Timestamp.
Also the Timestamp Mapping to SMON_SCN_TIME are been referred at lot of places like here is one of the presentation link http://www.aoug.at/Files/doag2003_x.pdf
Also this is been mentioned by Kirti in one of his presentaion slide named " Back to th past with Oracle 9i Flashback query"
Thanks
Indy Johal
Manager, Database Administration
PR Newswire
indy_johal_at_prnewswire.com
http://www.prnewswire.com
(201) 946-5687 [W]
(201) 400-3960 [M]
"We tell your story to the world."
"Arup Nanda" <orarup_at_hotmail.com>
Sent by: oracle-l-bounce_at_freelists.org
02/12/2004 10:16 PM
Please respond to oracle-l
To: <oracle-l_at_freelists.org>
cc:
Subject: Re: Undo Retention of 5 days; anyone?
Indy,
Thanks for the update on the SCN time limitation. I wasn't thinking about
that. If you do find some information on that limitation, I'll appreciate
if
you could please share that with me.
The theretical limit of undo_retention is some 136 years!
Thanks.
Arup
> Arup
> If I am correct, can we go beyond 5 days of Flashback recovery using
> Timestamp method in Oracle 9i. I know somebody referred earlier in the
> mail that he recover the data which is older than 15 days. I know that
> some documentation says that it is not possible as timestamp mapping to
> SCN is maintained in SMON_SCN_TIME for only 5 days. I am not having any
> configuration to test it so thought I can check with you.
>
> Thanks
>
> Indy Johal
> http://www.prnewswire.com
>
> (201) 946-5687 [W]
> (201) 400-3960 [M]
>
> "We tell your story to the world."
>
>
>
>
> "Arup Nanda" <orarup_at_hotmail.com>
> Sent by: oracle-l-bounce_at_freelists.org
> 02/12/2004 12:42 AM
> Please respond to oracle-l
>
>
> To: <oracle-l_at_freelists.org>
> cc:
> Subject: Undo Retention of 5 days; anyone?
>
>
> List,
> I have a very unusual request from users to have UNDO_RETENTION set to 5
> days. Normally I set to about 5 hours, not days. Don't ask why. They
have
> inherited a bad design that requires flashing back to 5 days ago and,
no,
> they can't redesign it.
>
> I'm curious if anyone has actually done it, i.e setting it to a very
high
> value. Any input will be highly appreciated.
>
> Thanks a lot in advance.
>
> Arup
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-- Archives are at http://www.freelists.org/archives/oracle-l/ FAQ is at http://www.freelists.org/help/fom-serve/cache/1.html ----------------------------------------------------------------- ---------------------------------------------------------------- Please see the official ORACLE-L FAQ: http://www.orafaq.com ---------------------------------------------------------------- To unsubscribe send email to: oracle-l-request_at_freelists.org put 'unsubscribe' in the subject line. -- Archives are at http://www.freelists.org/archives/oracle-l/ FAQ is at http://www.freelists.org/help/fom-serve/cache/1.html -----------------------------------------------------------------Received on Fri Feb 13 2004 - 10:03:27 CST
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