Re: Rollback in recovery.

Hi !
 you may aware that redo log just conatains changes. rollback segment actually
contains before image of the record. so, at the time of recovery it needs both ,
rollback segments as well as redo logs. in this phase , rollback segments are used
to get the before image of the records which are not committed at the time of crash.
while , during rollforward , it gets all records which are committed, but not written
to the data file as you know that transaction is committed by writing to redo log
rather than data file.

I hope you have understood the complex mechanism of ORACLE recovery .

UDAY Guilherme Mesquita Chaves <chavesgm_at_br.homeshopping.com.br> wrote in article <334CDB06.5EE3_at_br.homeshopping.com.br>...
> I'd like to know if the rollback phase at recovery uses the rollback
> segments or the rollback stored at the log files, or even both. I'd like
> to know what happens at the rollback phase at recovery. I thank you in
> advance.
>
  Received on Fri Apr 11 1997 - 00:00:00 CDT