Re: Redo log and rollback segment question

Hi! Oracle creates a snapshot of data that is currently being modified in the rollback segments. Users who need to read the data being modified are pointed to the rollback segments until the transaction that is modifying the data commits. Rollback segments also provide a way to rollback operator errors. SQL Server has no such mechanism - so users in sql server have to wait for the transaction modifying the data to finish. Locking problems in SQL Server stem mainly from this.
Redo logs are just like the Transaction log in SQL Server - but you can have any number of redo logs/groups in Oracle. If you run an Oracle DB in ARCHIVELOG mode, the filled up redo logs are automatically archived for use in future recovery.
hope that clarifies it a little
Regards
Venkat

aa wrote in message <6cte9q$lfb$1_at_news.interlog.com>...
>Can someone please explain the difference between Redo log and Rollback
>segments?
>
>What is the difference between creating the rollback segments under the
>System tablespace and a user defined tablespace?
>
>For those experienced in SQL Server, how does the Redo log and rollback
>segments compare to SQL Server's log? We have to periodically truncate the
>SQL Server log. Do we have to do the same to Redo log and rollback
 segments?
>
>Thanks for clearing this up for me.
>
>
Received on Tue Feb 24 1998 - 00:00:00 CST