Re: wither the checkpoint?

From: Devinder Pal Singh <Devinder_Pal.Singh_at_pharma.novartis.com>
Date: Fri, 02 Apr 1999 14:27:40 -0500
Message-ID: <37051A2B.1C673ABD@pharma.novartis.com>

I think here we need to understand what happens when a checkpoint occures.
When a checkpoint happens either implicit or explicit, CKPT or LGWR signals the DBWR to flush the buffers to the datafiles, it then waits for it to finish, when DBWR finishes it signals LGWR or CKPT that it has finished, then LGWR or CKPT updates control file and datafile headers. I think this answers your question.

Jonathan Gennick wrote:

> I have an esoteric question on checkpoints that I need
> answered. The Oracle8 Backup & Recovery manual, under the
> heading "Managing Checkpoints", states the following:
>
> "A checkpoint identifies a redo log record such that all
>
> changes prior to the change pointed to by the checkpoint
>
> have been written to the datafiles by DBWn. "
>
> The way this sentence is written, it sounds as if the
> specific change pointed to by the checkpoint has NOT been
> written to the datafiles. Is that really true? Does anyone
> know for sure. Can anyone point me to a reliable reference
> that clarifies this?
>
> Jonathan
Received on Fri Apr 02 1999 - 13:27:40 CST