Re: ORA-1578...block corrupted...error is normal...a block...had a NOLOGGING...operation performed against

  • From: BobMetelsky <bobmetelsky@xxxxxxxxxxx>
  • Date: Tue, 23 Aug 2005 08:59:14 -0400

Guys, Im have a problem getting the complete concept or NO LOGGING and recovery in my situation

ie

I have a large database running in no archive log
Im doing cold backups to tape
I plan to turn on ARCHIVE LOG

my question is will the segments/blocks created with NOLOGGING be a problem to recover *after* the NOLOGGING is turned on?

Logically Im thinking not but would appreciate a little more feedback .
Im afraid when I try to apply the archived logs there will be the possibility of flagged blocks being recognized as corrupt.


I've found an article which provides more information of the issue but not my case specifically
http://www.rittman.net/archives/cat_oracle_warehouse_builder.html


I guess my real question (mis understanding) is how does one "reset" the database/datafiles??
to sync up NOLOGGING operations?
This seems like it could be a management nightmare.



Thanks very much! bob


"Oracle error messages being what they are, do not highlight the correct cause of fault, but will identify some other error located close to where the real fault lies."

rjsearle@xxxxxxxxx wrote:
Hi Jared,
I understand and agree with all you have said.
I have begun departing from this recently after a recent nasty restore and recover that took us 3 weeks. Some of this delay was caused by successive failures of backup tapes. We had to go back 3 days as one tape each from the more recent backup sets failed. fortunately, the archivelogs were recovered. UNfortunately ALL online redos were lost, but that's another matter. One of these tapes failed on the second use. We completely restored from a backup set, then 24 hours later had to get some more files from the same backup set and one of the tapes had failed. rotten luck! This is an environment where all backups are verified and tapes are regularly.
This reminded me not to place too many eggs in the backup basket. If the most recent backup contained the first backup of the new segments created nologging and that tapeset fails then you are left in the same precarious situation.
The benefits to nologging are clear and inviting. i think we should remember the additional risks associated.
Russell


On 8/23/05, *Jared Still* <jkstill@xxxxxxxxx <mailto:jkstill@xxxxxxxxx>> wrote:


On 8/22/05, *Mercadante, Thomas F (LABOR)* < Thomas.Mercadante@xxxxxxxxxxxxxxxxx <mailto:Thomas.Mercadante@xxxxxxxxxxxxxxxxx>> wrote:

        I was thinking about this whole topic over the weekend.  It just
        affirms my feeling that using the NOLOGGING option needs to be
        used judiciously.  And I question how much time we are saving here.


Quite a bit of time actually. Try timing a bulk load operation with
and without logging.


        If the total time to reload using NOLOGGING and a total backup
        is less than a reload with LOGGING and no backup, then don't use
        it.


You don't need a complete database backup, just the datafiles
containing the nologging objects.


-- Jared Still
Certifiable Oracle DBA and Part Time Perl Evangelist



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