Re: transaction and rollback segment

From: Trifon Anguelov <trifona_at_pacbell.net>
Date: Mon, 15 Oct 2001 00:58:20 GMT
Message-ID: <Mwqy7.893$I7.190003211@newssvr14.news.prodigy.com>

"stef p." <stef_pellegrino_at_hotmail.com> wrote in message news:9qcb9k$fjk$1_at_wanadoo.fr...
> Hi,
> Just a little question
>
> When I'm in a transaction, where are written all my updated/inserted datas
?
> before the commit or rollback ...
> in the rollback segment I suppose ?
>
>
> thanx...
>
>
>
>
>

Stef,

All modified data blocks are writen into the data buffer cache and then DBWR is writing them to the disk.

Rollback segments are keeping the old data blocks before updates or deletes, so in case the transaction does not commit the before update image could be restored. When doing inserts, no data is kept in the rollback segments simply because nothing has to be restored in case the transaction fails. The inserted data is lost and the before data image is in sync.

Hope that helps.

Trifon Anguelov
Senior Oracle DBA

http://www.dbaclikc.com Received on Sun Oct 14 2001 - 19:58:20 CDT