Re: LOG_BUFFER setting question

"Paul Brewer" <paul_at_paul.brewers.org.uk> schrieb im Newsbeitrag news:3de28833$1_3_at_mk-nntp-1.news.uk.worldonline.com...
> "Jan Gelbrich" <j_gelbrich_at_westfalen-blatt.de> wrote in message
> news:arte04$lmbbd$1_at_ID-152732.news.dfncis.de...
> > Hello, I would like to ask on more question:
> >
> > The 8i online CD says:
> > --------------------------
> > LOG_BUFFER
> > Parameter type: Integer
> > Parameter class: Static
> > Default value: Operating system specific. Maximum: 500K or 128K *
> > CPU_COUNT, whichever is greater
> > Range of values: Operating system dependent
> > --------------------------
> > We have 4CPU, so maximum is 524288 ?
> > Does it mean that the actual setting of 2097152 (2M) is a mistake ?
> > It was set as we found 'redo log space requests' from a script report,
> > and the script suggested to increase log_buffer (from 1M already).
> >
> > If 128k*CPU count is the maximal value, what can I do to decrease 'redo
> log
> > space requests' still occurring ?
> >
> > SQL> select substr(name,1,25) Name,
> > 2 substr(value,1,15) "VALUE (Near 0?)"
> > 3 from v$sysstat
> > 4 where name = 'redo log space requests'
> > 5 /
> >
> > NAME VALUE (Near 0?)
> > ------------------------- ---------------
> > redo log space requests 2988
> >
> > This definitely far beyond 0 and also increasing over the last months
...
> >
> > My system:
> > Oracle EE 8.1.7 on AIX 4.3.3 (4 CPU), C/S environment with 200 clients,
> but
> > only 10 active (avg) at the same time.
> > Oracle Forms&Reports Runtime Environment on clients.
> >
> > ThanX in advance,
> > Jan
> >
> How often are the logs switching?

In normal times, switches every 5-8 hours, on heavy duty times (once a day for a period of 1 hour) every minute sometimes. When I first realized this, I thought this is a mess, I should increase the redo log sizes (3 groups of 40M).
Then I saw the history of all switches over the last 2 years, its figures where almost constant: about 50 switches on weekdays and about 5 on weekends. Exceptions only at currency conversion to EUROs.

I admit that I am not satisfied with this situation, but unfortunately, I cannot do just what I would like to improve the db, because I am not the only one in the team ... would You, too, suggest to increase log group sizes ? And _then_
increase log_buffer - even if it would be over its recommended maximum of 500K then ?

Yours,
Jan Received on Tue Nov 26 2002 - 01:46:22 CST