Re: DWBR and dirty buffers

Notes in-line

Regards

Jonathan Lewis

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"Noons" <wizofoz2k_at_yahoo.com.au> wrote in message news:421fbd0f$0$21871$5a62ac22_at_per-qv1-newsreader-01.iinet.net.au...
> Jonathan Lewis apparently said,on my timestamp of 25/02/2005 6:03 PM:
>
>> You may find that a few blocks seem to stay as
>> xcur - check the objd (data object id) for these,
>> it will probably be about 4 billion - meaning it's
>> from a rollback segment. There's always a little
>> background activity going on which means that
>> a few more blocks will be dirtied even as the
>> checkpoint is running.
>
> Ah yes, this could well explain it. I'll monitor
> for this and see if it is consistent.
>
>

It might be easiest to report the objd column from v$bh - values around 4 billion are rollback segments, values between 4 million and 4 billion are temp tables. Values less than about 5000 are probably data dictionary or other SYS tables.

If that's not the answer, it may be a specific RAC thing, and I would take it up with Oracle - after all, it's a bit of a threat to recovery if you XCUR dirty blocks that never get cleaned. In principle it means you could overwrite a log file that should not have been overwritten. Received on Sat Feb 26 2005 - 03:03:54 CST