LGWR & Checkpoints Quick Q

From: gl <jogret_at_hotmail.com>
Date: Tue, 12 Mar 2002 16:33:11 -0500
Message-ID: <3c8e6f6d$1@hp176.detroit.deco.com>

I'm reading the concepts manual (8.1.6) about LGWR and checkpoints and I'm getting a little confused:

LGWR:
Besides writing commited records, LGWR will write redo log buffers every 3 sec., 1/3 redo log buffer full, and when DBWn writes dirty blocks to disk (checkpoint). Are these writes un-commited data? If so, isn't that the job of rollback segments?

CKPT:
Checkpoint is updating datafile headers as to the most recent checkpoint. Is this based on time (it couldn't be based on SCN)?

Is there any other source I can use other than the concepts manual to find out more info. on CKPT and LGWR processing?

Thanks in advance. Received on Tue Mar 12 2002 - 15:33:11 CST