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

  • From: "Mercadante, Thomas F (LABOR)" <Thomas.Mercadante@xxxxxxxxxxxxxxxxx>
  • To: <bobmetelsky@xxxxxxxxxxx>
  • Date: Tue, 23 Aug 2005 09:27:23 -0400

Bob,

If you are running in NOARCHIVELOG mode, you *always* have to backup
your database daily to be able to recover it to when you backed it up -
you do not get any recovery option other than that.

If you are running in NOARCHIVELOG mode and you turn logging on, you
must perform a backup immediately to be able to perform point in time
reovery from that point forward.

The CREATE TABLE/INDEX.. NOLOGGING option simply creates the object
without producing redo log information.  If you create an object in this
way, you *have to* backup the database immediately afterward to be able
to recover the object you created.

And to answer your question, if you create an object with NOLOGGING but
then back the database up, it will be recovered if you restore the
database to that point in time.  The problem that started this topic was
that a backup was taken of the database, an object was created with the
NOLOGGING option, and then a restore was attempted.  Since the NOLOGGING
option did not create any REDO/Archivelog information, the object could
not be restored and was left invalid.

So the lesson learned here is to either create an object in the normal
way (with archiving enabled) or use the NOLOGGING option and always
schedule a backup to protect what you just created.

Hope this helps.

Tom

-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of BobMetelsky
Sent: Tuesday, August 23, 2005 8:59 AM
Cc: oracle-l@xxxxxxxxxxxxx
Subject: Re: ORA-1578...block corrupted...error is normal...a
block...had a NOLOGGING...operation performed against

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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