Re: Rollback Segment Too Old !!!!!!!

From: A. Bardeen <abardeen1_at_yahoo.com>
Date: Mon, 19 Nov 2001 10:49:53 -0800
Message-ID: <F001.003C8990.20011119090025@fatcity.com>

The ORA-1555 is a read consistency error. The information from the rollback segments needed to create a read-consistent view of the data is not available. Usually because the information has been overwritten or the extents containing this information have been deallocated (e.g. if optimal is set).

Until 9i, where you can use automatic undo to avoid these errors, the best way is to create dummy transcations in each of the online RBS's before starting the export and leave them uncomitted until the export completes. This will prevent the rollback segments from wrapping around and overwriting the extents that contained uncomitted transactions when the export began. Of course this means you're likely to generate a lot more rollback than usual so you'll need to monitor the space in the RBS tablespaces to avoid getting extent allocation errors.

Check Steve Adams' site for a set of scripts to assist you with this:
  http://www.ixora.com.au
    Scripts > Rollback Segments

HTH,

• Anita
  • Jackson Dumas <tjaros_at_webmail.co.za> wrote:
    >
    > Yeah
    >
    > I had a problem recently were I was exporting a
    > 45Gigg database, the
    > export will continue until at a end it will come up
    > with a warning
    > that export was completed successfully with warnings
    > because rollback
    > segment was too old. I increased the tablespace RBS
    > where the rollback
    > segments are residing and also created some more
    > rollback segments.
    > This did not work also, I had a problem similar to
    > this but this was
    > happening when the user was trying to delete some
    > records with a where
    > clause, it would come up with the error rollback
    > segment too old.
    > Can somebody give me an idea of how to go about this
    > problem, I would
    > appreciate you input dearly
    >
    > Thank you,
    >
    > Mtabaruka !!!!!
    >
    

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Author: A. Bardeen
  INET: abardeen1_at_yahoo.com

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Received on Mon Nov 19 2001 - 12:49:53 CST