thanks a lot.
"gp" <gieppetto_at_tiscali.it> ha scritto nel messaggio
news:bvbagj$da9$1_at_carabinieri.cs.interbusiness.it...
> ok,
> excuse me;
>
> i have increased the log_buffer parameter because i have 'redo log space
> requests = 381'
> and i have read that the solution for this problem is to increase
> log_buffer;
> i have set nologging mode for my tablespaces to increase performance
because
> i have very lot transactions;
>
> thanks.
>
> "Howard J. Rogers" <hjr_at_dizwell.com> ha scritto nel messaggio
> news:4019193b$0$28870$afc38c87_at_news.optusnet.com.au...
> >
> > "gp" <gieppetto_at_tiscali.it> wrote in message
> > news:bvb2vl$ri1$1_at_carabinieri.cs.interbusiness.it...
> > > do you think that i must increase log_buffer parameter ?
> > > (now it is 16 MB)
> > > thanks.
> > > Ciao.
> >
> > Lord! The log_buffer should never, ever, ever need to be bigger than
1MB.
> > Ever.
> >
> > Well, except on those extremely rare occasions when maybe 3 or 4MB might
> be
> > in order. But those are extremely rare, so I'd prefer to make your life
> > easier by sticking with 'never, ever'.
> >
> > Really. The log_buffer is (or ought to be) tiny, because redo is tiny.
> > You're talking about a few hundred bytes at most being generated per row
> > modification, and with in-built cleansing mechanisms such as the flush
at
> > 1/3rd full, every commit and before DBWR to keep the persistence space
> > demands on the log buffer down to negligible levels. It's not like the
> > buffer cache, that deals with blocks of data in the multi-thousands of
> bytes
> > sizes, where blocks hang around for quite long times, where DBWR flushes
> > comparatively rarely and so on. Buffer Cache big, log buffer tiny.
> >
> > I suppose the real question is: what makes you think you might need a
log
> > buffer of 16MB, and what makes you do daft things like (attempt to) turn
> all
> > tablespaces into nologging mode? It wouldn't be because you are
suffering
> > from log buffer space wait events or something, would it? Because those
> are
> > not the cures for that particular problem.
> >
> > Tell you what: tell us why you thought you needed to do these things
> first,
> > and then we can have a go at explaining what the real cures are. But
16MB
> > for a log buffer is way, way too much.
> >
> > Regards
> > HJR
> > --
> > ------------------------------------
> > Oracle insights at www.dizwell.com
> > ------------------------------------
> >
> >
>
>
Received on Fri Jan 30 2004 - 03:32:56 CST
