Which Archive-Logs are to delete?

Hi folks,

I have a problem with an Oracle database (Version 8.1.5 NT) running in archive_log mode.

In order not to waste harddisk-memory, I want to delete archivelogs which are not needed for the recovery procedure.

The normal way was, I deleted my archive-logs, started the backup with

alter system switch logfile (which does an 'alter system checkpoint') alter tablespace xxx begin backup
copied the related datafile to my backup-destination finished the backup with alter tablespace xxx end backup.

Now it happend two times during some tests, that the recovery of my backup failed, because oracle did await an archivelog which had an 2 days EARLIER date
then the date when the backup was performed. For example the sequence_number of the first archivelog AFTER the backup was 120,
but Oracle requested an archivelog with the sequence number 117 (was written 2 days before
but deleted when the backup started => memory reasons). During the backup ALL datafiles where backed up!

How can this happen?? Why does oracle request this old archivelog? After performing
an 'alter system switch logfile' all transactions should be in the datafiles, or not??

OK, I could even store also the old archivelogs, but I do not understand why this
happend.

No I try to find out, which archive-logs are really necessarry for a successful recovery
of my backup-set by using this join:

SELECT A.SEQUENCE#
FROM V$LOG_HISTORY A, V$DATABASE B
WHERE A.FIRST_CHANGE# >= B.ARCHIVE_CHANGE#; Is this the correct way, has anybody experience or tips for an easier way to find
out, which archive-logs are possible to delete?

Every help is very welcome because this really is a serious problem for me

Thanx in advance
Frank Received on Fri Oct 06 2000 - 11:12:22 CDT