Re: Snapshot Logs Explanation Needed

From: A. Bardeen <abardeen1_at_yahoo.com>
Date: Thu, 31 May 2001 04:48:48 -0700
Message-ID: <F001.0031553D.20010531045104@fatcity.com>

Tracy,

You may know that there were no modifications to the master table made from the time the snapshot log was dropped until it was recreated, but Oracle can't take that chance, otherwise data could get out of sync. That's why you have to either recreate your snapshot or do a complete refresh if the snapshot log is recreated.

To avoid recreating the snapshots I would ask why you need to reorg your master tables (i.e. what do you hope to accomplish by this)? If you're doing it for defragmentation reasons, I suggest you check out the excellent white paper "How to stop defragmenting and start living..." to see if this is really necessary.

http://www.vampired.net/articles/files/stopfrag.zip

HTH,

• Anita
  • Tracy Rahmlow <Tracy.Rahmlow_at_aexp.com> wrote:
    > I would like to reorg many tables which have
    > snapshots associated with them. I
    > understand that if the master table is dropped the
    > snapshot log is also
    > dropped. When a log is dropped, oracle states that
    > you need to do a complete
    > refresh of the affected snapshot. My question is
    > why? If you do not allow
    > users to access the database with the master table,
    > then you should not have
    > any transactions that would be lost. Why can't you
    > create a new log and
    > continue to do a fast refresh? I am trying to
    > avoid having to recreate all
    > the snapshots due to the size and number that we
    > have. Any thoughts? Thanks
    >
    >
    > --
    > Please see the official ORACLE-L FAQ:
    > http://www.orafaq.com
    > --
    > Author: Tracy Rahmlow
    > INET: Tracy.Rahmlow_at_aexp.com
    >
    > Fat City Network Services -- (858) 538-5051 FAX:
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-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.com
-- 
Author: A. Bardeen
  INET: abardeen1_at_yahoo.com

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Received on Thu May 31 2001 - 06:48:48 CDT