Forgot to mention, also look at Metalink doc #73901.1
Suzy Vordos wrote:
>
> Questioned this myself after noticing 8i logswitch checkpoints taking a
> LONG time. There is a new parameter you might look at:
> fast_start_io_target. Also look at v$instance_recovery, it shows which
> parameter (log_checkpoint_timeout, log_checkpoint_interval,
> fast_start_io_target) takes priority for controlling checkpoints.
>
> I ended up setting both log_checkpoint_timeout and
> log_checkpoint_interval to zero. Then fiddled with fast_start_io_target
> until the checkpoint intervals seemed reasonable. Note that these
> checkpoints don't appear in alert.log, I dunno why.
>
> Still bewildered, but things appear to be working much better....
> suzy
>
> > "Koivu, Lisa" wrote:
> >
> > hello all,
> >
> > I've got LOG_CHECKPOINT_TIMEOUT set to 1800 (30 minutes) in one of my
> > databases. I also have LOG_CHECKPOINTS_TO_ALERT set to true.
> > However, every morning I look at the archive logs and I see that 1.
> > the logs haven't switched since the nightly batch quit and 2. there
> > are no checkpoints in the alert log since the log switch. This makes
> > me a little nervous.
> >
> > It seems that LOG_CHECKPOINT_TIMEOUT is not working. However, I find
> > this on metalink that kind of explains it.
> >
> > The parameter log_checkpoint_timeout has been re-interpreted. In prior
> > releases, every log_checkpoint_timeout seconds, Oracle started an
> > interval checkpoint. Starting with Oracle 8.1, log_checkpoint_timeout
> > will be interpreted to mean that the incremental checkpoint should be
> > at the log position where the tail of the log was
> > log_checkpoint_timeout seconds ago. In other words, the incremental
> > checkpoint should lag the tail of the log by no more than
> > log_checkpoint_timeout seconds worth of redo.
> >
> > I don't quite understand. Can someone paraphrase this? Does this
> > mean that every LOG_CHECKPOINT_TIMEOUT seconds it makes sure that
> > there is no redo that hasn't been written to disk that is more than
> > LOG_CHECKPOINT_TIMEOUT seconds old? In other words, it checks to see
> > if a checkpoint is necessary instead of just doing it?
> >
> > Thanks
> >
> > Lisa Rutland Koivu
> > Oracle Database Administrator
> > Qode.com
> > 4850 North State Road 7
> > Suite G104
> > Fort Lauderdale, FL 33319
> >
> > V: 954.484.3191, x174
> > F: 954.484.2933
> > C: 954.658.5849
> > http://www.qode.com
> >
> > "The information contained herein does not express the opinion or
> > position of Qode.com and cannot be attributed to or made binding upon
Received on Thu Jan 04 2001 - 15:20:18 CST
