Re: Hot Backup - Need for Rollback Segs

From: Jonathan Lewis <Jonathan_at_jlcomp.demon.co.uk>
Date: 1995/08/11
Message-ID: <808130534snz_at_jlcomp.demon.co.uk>#1/1


In article <40dai4$1hl_at_engineer.mrg.uswest.com>

           LNudelm_at_unotes1.mnet.uswest.com "Larry Nudelman" writes:

: I can't see restoring a RB tablespace from
: the hot back up if the OS file gets hit.
:
: and space. Any comments on if I can / should exclude them.
:

Recovery works by applying physical changes to the database files that have been recorded in the (archived) redo logs. The final stage to the recovery is to reverse out the changes which are due to transactions that have not been committed, i.e. to use the rollback segments to roll back some of the changes applied during recovery. That is why you have to backup and recover the rollback segments.

: The rbs tablespace is about one-fourth the size of the entire database

It is possible that this rather extreme size is a hang-up from Version 6 days. If you are on Version 7, you may find that you can take advantage of the 'optimal size' feature of rollback segments to reduce the total filesize needed.

-- 
Jonathan Lewis
Received on Fri Aug 11 1995 - 00:00:00 CEST

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