How reliable is v$datafile.last_change table information? (working with R/O tablespaces)

Hi

I'm currently working on extending our hot-backup shell-script and need some input regarding handeling READ ONLY tablespaces. Hope you can/will help!

In my solution I check v$datafile.last_change# before and after I copy the datafiles to ensure that the datafiles hasn't changes while I copied the file w/o setting the tablespace "alter tablespace begin/end backup" (I only copies files which needs to be copied). This works file, but I'm still a bit concerned about the validity of the information retreived from v$datafile. In case of a shutdown abort or a freaky instance failure, maby?!? - Can I be sure that the SCN found in v$datafile is valid compared to the SCN in the datafile header???? V$datafile reads the information from the controlfile, so can situations occur, where the SCN represented in the controlfile (v$datafile.last_change#) is different from the SCN in the datafile on read only tablespaces?? I would think that Oracle has it all under control, but I hate to be the guy who has to tell a client 5 a.m that he has lost 15GB of data in his productionsystem due to a slight misunderstanding in the backup procudure.

Regards
Lehmann Received on Mon Sep 11 2000 - 06:27:23 CDT