Re: log buffer space

I'm sorry, I've missed whether this is a production database in archive log mode or not. If it is, log switches twice per hour may be too few. You should find out what your data loss tolerance is for this instance and adjust your redo log setup to accomodate that. I agree, 50 per hour is a bit much, but there are databases where 30 minutes of data lost could be quite hurtful.

>>> orarup_at_hotmail.com 03/14/03 05:29PM >>>
Well, there lies your problem. I suggest you do the following in this order of priority and see if they resolved the problem.

(1) Log buffer of 320K is definitely small. Make it 4 MB (or at least 3MB) if you have enough memory.
(2) Your log switching is 50 per hour?!! That's a little too much. Are you sure it's that high? If so, you need to bring it down to about 2 per hour. If 50/hr is your average rate of switch, then you need to size the logfiles at least 25 times current size to achieve the 2 per hour rate. Make your logs 500M each, again if you have enough disk space. (3) If possible, try to move the redo logs to non-RAID disks, preferably local (direct attached).

HTH. Arup Nanda

• Original Message ----- To: "Multiple recipients of list ORACLE-L" <ORACLE-L_at_fatcity.com> Sent: Friday, March 14, 2003 5:34 PM

> log buffer is 320 K and log files are 30M approx. there are about 50 log
> switch /hr .
>
> -ak
>
>
> ----- Original Message -----
> To: "Multiple recipients of list ORACLE-L" <ORACLE-L_at_fatcity.com>
> Sent: Friday, March 14, 2003 9:29 AM
>
>
> > AK,
> >
> > Could you provide the redo log sizes and the log_buffers parameters,
> please.
> > Also let us know the log switch frequency, too.
> >
> > Thanks.
> >
> > Arup
> >
> > ----- Original Message -----
> > To: "Multiple recipients of list ORACLE-L" <ORACLE-L_at_fatcity.com>
> > Sent: Friday, March 14, 2003 11:14 AM
> >
> >
> > > Do you guys think , adding more log file can help ? I think it should
> not
> > ,
> > > cuz any way logwriter is going to write in one datafile at a time ,
> > correct
> > > ?
> > >
> > > -ak
> > >
> > >
> > > ----- Original Message -----
> > > To: "Multiple recipients of list ORACLE-L" <ORACLE-L_at_fatcity.com>
> > > Sent: Friday, March 14, 2003 4:32 AM
> > >
> > >
> > > > Arup:
> > > >
> > > > <NO FLAMES>
> > > > The second condition is not quite true. It is 2/3 full in the
current
> > > > versions.
> > > > </NO FLAMES>
> > > >
> > > > It is very easy to test with the event 10046^8.
> > > >
> > > > KG
> > > >
> > > >
> > > > --- Arup Nanda <orarup_at_hotmail.com> wrote:
> > > > > AK,
> > > > >
> > > > > If the log buffer is at least 4MB, then increasing it will not
help,
> > > > > rather it may hurt. The log buffer is flushed when any of the the
> > > > > follwoing occur
> > > > > (i) 1 MB is filled up
> > > > > (2) 1/3rd is filled up
> > > > > (3) every 3 seconds
> > > > > (4) when a checkpoint occurs
> > > > > (5) when a commit occurs.
> > > > >
> > > > > Therefore, see if any of these could be the problem. It's easy to
> > > > > check #s 4 and 3.
> > > > >
> > > > > As Kirti suggested, the problem could be due to the redo logs
being
> > > > > on a busy disk, or even a slow one.
> > > > >
> > > > > HTH.
> > > > >
> > > > > Arup
> > > > > ----- Original Message -----
> > > > > From: Deshpande, Kirti
> > > > > To: Multiple recipients of list ORACLE-L
> > > > > Sent: Thursday, March 13, 2003 8:13 PM
> > > > > Subject: RE: log buffer space
> > > > >
> > > > >
> > > > > Increasing log_buffer size is an option, if it is really small.
> > > > > I would also check if the redo logs are on a busy disk. If so,
try
> > > > > moving those (or other busy data files on the same disk) to other
> > > > > not-so-busy disks.
> > > > >
> > > > > - Kirti
> > > >
> > > >
> > > > =====
> > > > Have a nice day !!
> > > > ------------------------------------------------------------
> > > > Best Regards,
> > > > K Gopalakrishnan,
> > > > Bangalore, INDIA.
> > > > --
> > > > Please see the official ORACLE-L FAQ: http://www.orafaq.net
> > > > --
> > > > Author: K Gopalakrishnan
> > > > INET: kaygopal_at_yahoo.com
> > > >
> > > > Fat City Network Services -- 858-538-5051 http://www.fatcity.com
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-- 
Author: Arup Nanda
  INET: orarup_at_hotmail.com 

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