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Home -> Community -> Mailing Lists -> Oracle-L -> RE: How much time can save using _disable_logging on 10g
Just go all the way with it.
Some of this information was given to me by friends on this list.
I believe Connor gave me this info on "_wait_for_sync".
Who ever did it (correctly) came with a strong warning.
PS I did not test "_wait_for_sync".
Set init.ora parameter _disable_logging = TRUE (Warning, this could be
dangerous and unrecoverable in failure.
Backup immediately after import - * Redo records (to disk) will NOT be
generated (redo WAS generated in the log buffer.) [Even with
_disable_logging you still "switch" logs when they get "full"])
Set init.ora parameter _wait_for_sync = FALSE (Warning, this could be
dangerous and unrecoverable in failure.
Backup immediately after import - _wait_for_sync: Wait_for_sync is an
oracle generic parameter which, when set to false, will allow the system
to complete commits without waiting for the redo-log buffer flushes to
complete.)
Make redo logs enormous; 500MB, 1GB, etc.
Chris Marquez
Oracle DBA
-----Original Message-----
From: Marquez, Chris
Sent: Tuesday, October 11, 2005 12:29 PM
To: 'Juan Carlos Reyes Pacheco'
Cc: mcdonald.connor_at_gmail.com; oracle-l_at_freelists.org
Subject: RE: How much time can save using _disable_logging on 10g
>>Can you tell me please how much time you saved
I had to dig through my notes...I don't have a memory for this stuff ...that's why I take notes.
This is from my own email to my co-workers;
>> I was able to load theses TABLEs in about 24 to 32 minutes.
>> Below are my EXPort and IMPort parameters.
>> Also, I tried using the Oracle parameter; "_disable_logging = TRUE"
>> ...it seemed to have a 15% - 25% time improvement...18 minutes.
hth
Chris Marquez
Oracle DBA
-----Original Message-----
From: Juan Carlos Reyes Pacheco [mailto:juancarlosreyesp_at_gmail.com]
Sent: Tuesday, October 11, 2005 12:07 PM
To: Marquez, Chris
Cc: mcdonald.connor_at_gmail.com; oracle-l_at_freelists.org
Subject: Re: How much time can save using _disable_logging on 10g
Thanks Chris, I agree with you, a simple shutdown immediate crashed my test database too, but anyway is interesting to know its limitations.
Can you tell me please how much time you saved :) only for statistics. when migrating.
Thanks in Advance.
On 10/11/05, Marquez, Chris <cmarquez_at_collegeboard.org> wrote:
> > > > >>shutdown abort with _disable_logging and you'll see some interesting > consequences > > Ahhhh yes we conversed on this topic a while back. I used_disable_logging
> for migration purposes after a lot of TEST my process. > I kept wondering why my test db was crashing hard...we had some disk > issue at the time, so that seemed the culprit. > Turns out I kept leaving my TEST db up with _disable_logging enabled > during server reboots...it did not come back happily > > A great and very, very challenging recovery filled with undocumented > parameters that rendered my TEST database un-supported. > I was able to recover sometimes, but others not. > Think I was "bumping scn's" and allowing reset log corruption. > You have not lived until you have recovered a database thisway...nasty!
> :o) > Also, learned and documented the "clean way" to stop using > _disable_logging and put my db back in archive log mode. > > > Sorry, "yes" _disable_logging saved time during my migration (at the > risk of loosing it all on the *new* server, but not on the oldserver).
> > Chris Marquez > Oracle DBA > > ________________________________ > From: oracle-l-bounce_at_freelists.org > [mailto:oracle-l-bounce_at_freelists.org] > On Behalf Of Connor McDonald > Sent: Monday, October 10, 2005 11:08 AM > To: oracle-l_at_freelists.org > Subject: Re: How much time can save using _disable_logging on 10g > > > shutdown immediate is still a clean shutdown. > > Try shutdown abort with _disable_logging and you'll see some > interesting consequences > > hth > connor > > > > -- > Connor McDonald > =========================== > email: connor_mcdonald_at_yahoo.com > web: http://www.oracledba.co.uk > > "Semper in excremento, sole profundum qui variat"
-- Oracle Certified Profesional 9i 10g Orace Certified Professional Developer 6i 8 years of experience in Oracle 7,8i,9i,10g and developer 6i -- http://www.freelists.org/webpage/oracle-lReceived on Tue Oct 11 2005 - 12:06:13 CDT
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