SCN tied to the time stamp while doing recovery

Giganews Newsgroups
Subject: SCN tied to the time stamp while doing recovery
Posted by:  lambu9…
Date: 29 Jan 2005

Hi all,

I was reading Backup and Recovery Handbook 8i (By Rama Velpuri) and
I came across an interesting scenario in the case study.


Time change from 2am in the morning back to 1am during day light
savings time change. In the database, a mistake was made at 1:55am
*after* the day light savings adjustment is made. Or even a crash/media
failure can occur around that time.

When trying to recover we could easily end up recovering till the
1:54am *before* the time change. In other words we lose more than an
hour's worth of transactions. This happens because apparently the SCN
is tied to the time stamp in the log files.

1) Has anything changed in 9i to prevent such a scenario?
2) How do large companies that have hundreds/thousands of
transactions per hour handle this situation currently? Do they really
lose all the data?
3) Has any one really come across this scenario or is it too remote
to bother about? (Murphy wouldnt think so)
Thanks a lot to every one, as always,