Re: Shutdown Abort - Not a Good Idea, Right?

On Wed, 21 Apr 1999, Kelly Young wrote:
>
> You are correct. Shutdown/immediate is better than shutdown/abort.

"Better" seems a bit subjective. There is nothing wrong with shutdown abort. In fact, shutdown abort is real good! Come to think of it, shutdown abort is GRRRRREAT! It gets the database down fast, and you still have the database file in a known state (as of the last checkpoint). When the instance comes back up, it automatically recovers all the transactions that were committed since the last checkpoint. Shutdown abort minimizes downtime because during subsequent crash recovery, the rollback of uncommitted transactions is deferred until after the database is open and functioning.

For cold backups, it might be unwise to use shutdown abort, because it would necessitate copying the online redologs in addition to the rest of the database. But most people who do cold backups seem to back those up anyway.

When I use shutdown abort (and I use it all the time), I issue "alter system checkpoint;" right before I do it. This technique minimizes downtime, because there is much less redo to apply during crash recovery.

There is one situation that I can think of that would be inappropriate for shutdown abort. If you are upgrading versions (8.0.4 -> 8.0.5), there can be a change in redo logging format. To open a new redo thread upon first instantiation under the new version, an immediate, transactional or normal shutdown would be required. If you were careful to set COMPATIBLE=<your previous version>, however, you would not encounter such an issue.

--
Jeremiah Wilton http://www.wolfenet.com/~jeremiah

> M. Bhatti wrote:
> >
> > Question is, I thought shutdown abort should not be used except in
> > extreme conditions ie when a db instance
> > cannot be shutdown normal/immediate.
> >
> > So, I assume that:
> > This is bad idea right (shutdown abort)?
> > What can happen to the db?
Received on Wed Apr 21 1999 - 14:52:09 CDT