Re: Archive mode

"Brad" <someone_at_nowhere.com> wrote:

>We have an Oracle Workgroup Server running on WinNT 4.0. I need to set it
>up in archive mode so that I can do a partial backup of the database once a
>week. I can get it to show that it will automatically archive, but it
>still says the database is in NO ARCHIVELOG mode. Any ideas?
>
>Brad

Hi,

all the responses to this thread are correct, but no-one seems to be explaining the difference between changing the init.ora parameters and executing an ALTER DATABASE ARCHIVELOG statement. They DON'T do the same thing, They're both needed and the difference is this:

The ALTER DATABASE ARCHIVELOG statement tells the database that you intend your redo logs to be archived, and prevents it from overwriting a redo log which hasn't been archived. But it DOESN'T actually cause the logs to be archived. You must either do that manually or automatically. If you issue an ALTER DATABASE ARCHIVELOG statement and then don't actually archive off your filled redo logs, your database fill finally lock, complaining that it can't continue until an old redo log is archived off so that it can overwrite it.

Since manually archiving redo logs is a chore, it's better for this to be done automatically. You do this by making the init.ora parameter changes. This causes the database to spawn an ARCH process which automatically archives the redo logs when they become full. The init.ora parameters also specify the directory and format of filename to use for the archived off copies of the redo logs. If you set up your init.ora parameters with log_archive_start = true, but haven't issued an ALTER DATABASE ARCHIVELOG statement, it won't do any harm, but it won't do any good either: the database will just cycle round your online redo logs, overwriting them when they become full, and they won't be archived.

HTH, Dave.

-- 

To reply by email, remove the "no-spam" bit from my email address.