Re: What is the purpose of segment level checkpoint before DROP/TRUNCATE of a table?
From: Tanel Poder <tanel_at_tanelpoder.com>
Date: Wed, 6 Jul 2011 11:59:08 +0300
Message-ID: <CAMHX9JK8E8mP5SNqxX9MGK=U0+y80Y27RcOi_LNOGNg0v3-CxA_at_mail.gmail.com>
I started writing a reply here, but thought others would benefit from it as well, so turned the answer into a blog entry:
Date: Wed, 6 Jul 2011 11:59:08 +0300
Message-ID: <CAMHX9JK8E8mP5SNqxX9MGK=U0+y80Y27RcOi_LNOGNg0v3-CxA_at_mail.gmail.com>
I started writing a reply here, but thought others would benefit from it as well, so turned the answer into a blog entry:
This is just my reasoning, there may be other, more fundmental reasons behind it.
-- Tanel Poder http://blog.tanelpoder.com On Wed, Jul 6, 2011 at 4:30 AM, Paresh Yadav <yparesh_at_gmail.com> wrote:Received on Wed Jul 06 2011 - 03:59:08 CDT
> Hi,
>
> What is the purpose of segment level checkpoint before DROP/TRUNCATE of a
> table? I have tried to find this since quite some time, Only thing I have
> found is that it is required for recoverability, specifically point in time
> recovery amongst many other things. I have read about it on so many sites
> (as far as I remember Jonathan Lewis, Tom Kyte etc.). I recently saw an
> awesome article on check points by Harald Van Breederode titled "What's the
> Point of Oracle Checkpoints?". How does it help in recoverability? I
> thought about point-in-time recovery. All the information to recover dirty
> buffers for committed transactions should be in the redo stream (redo log
> and/or archived log) so why do a checkpoint at the object level before
> truncat//drop? Is it to shorten MTTR etc.? An explanation will be very much
> appreciated. Any pointers to other resources that I can read in this matter?
>
> --
> Thanks
> Paresh
> 416-688-1003
>
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