Rollback Question

I am studying for the Architecture and Administration exam and I want to make sure I have this correct. You have the Redo Log Buffer which holds the Rollback Segments which are written to the Redo Log Files by the LGWR process. Then when they hit a certain mark, which is determined in your parameter file, a log switch occurs. Is this correct? Do you have anything else in the Redo Log Buffer?

When the redo logs fills up or when the check point time is reached, thats when the log switch occours. Which ever comes the first.

Good luck.
Sam

Redo log buffers do not hold rollback segments, they are different structures. Redo log buffers are written to redo log files when:

- buffers are 1/3 filled
- every three seconds
- a DBWn proccess writes modified buffers to disk

,what happens first.

Log switch occurs when a redo log group is filled, or enforced manually if needed by ALTER DATABASE SWITCH LOGFILE. I think the initialization parameter you were talking about is LOG_BUFFER, it is related to writing from redo log buffers to redo log files, not log switch.

Yesterday there was a thread about the difference between redo log files and rollback segments. Maybe you should look at it.




Adriano.

Check this thread,

http://dbasupport.com/forums/showthr...?threadid=7651

Thanks for your link sambavan it helped.