Answers in-line Regards
Jonathan Lewis http://www.jlcomp.demon.co.uk The educated person is not the person who can answer the questions, but the person who can question the answers -- T. Schick Jr One-day tutorials: http://www.jlcomp.demon.co.uk/tutorial.html Three-day seminar: see http://www.jlcomp.demon.co.uk/seminar.html ____UK___November The Co-operative Oracle Users' FAQ http://www.jlcomp.demon.co.uk/faq/ind_faq.html ----- Original Message ----- To: "Multiple recipients of list ORACLE-L" <[EMAIL PROTECTED]> Sent: Wednesday, December 24, 2003 9:44 PM > It's been awhile since I've looked at flashback queries, and > I have a couple questions: > > * Given an SCN, is there any way to know for certain whether > a flashback query to that SCN is possible? Can a non-DBA > user determine this? > No, not without doing it. As a general principle, you can always be in a position where one querycan flash back to SCN = t1, but another query can't because the two queries require undo from different segments. > * Is there an easy way to determine how much undo data my > database is (hopefully) retaining? In other words, can I > easily determine how far back in the past I *can* go? > No. You could mess about with dumping segment header blocks and looking at the 'retention' table, which has a timestamp per extent of the most recent commit recorded against that extent. The highest (most recent) timestamp would be a valid bound for the earliest point in time that you could reach - but depending on luck, size of extents, etc. you might get some queries going a lot further back. > Yes, here it is Christmas eve, and I'm working away... > > Best regards, > > Jonathan Gennick --- Brighten the corner where you are > http://Gennick.com * 906.387.1698 * mailto:[EMAIL PROTECTED] > > Join the Oracle-article list and receive one > article on Oracle technologies per month by > email. To join, visit http://four.pairlist.net/mailman/listinfo/oracle-article, > or send email to [EMAIL PROTECTED] and > include the word "subscribe" in either the subject or body. > > -- > Please see the official ORACLE-L FAQ: http://www.orafaq.net > -- > Author: Jonathan Gennick > INET: [EMAIL PROTECTED] > > Fat City Network Services -- 858-538-5051 http://www.fatcity.com > San Diego, California -- Mailing list and web hosting services > --------------------------------------------------------------------- > To REMOVE yourself from this mailing list, send an E-Mail message > to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in > the message BODY, include a line containing: UNSUB ORACLE-L > (or the name of mailing list you want to be removed from). You may > also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Jonathan Lewis INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
