Re: design question, use of partitioned tables?

"Tanel Poder" <tanel@@peldik.com> wrote in message news:3f33a7ae$1_1_at_news.estpak.ee...

> > > Another thing, triggered by what Tanel said and ixora: the control
> > > files seem to get some considerable I/O during a load of a lob.
> > > Certainly V$SYSTEM_EVENT showed that.
> > I can affirm this. On the development box where I performed only the
> > load (no other DB activity) V$SYSTEM_EVENT shows:
> > total_waits for following parameters:
> > control file sequential read 2429
> > control file parallel write 2893
> > Instance was freshly started this morning.
>
> This is probably because CKPT visits controlfiles every 3 seconds to record
> incremental checkpoint there.
>

I don't think it's just that. In my system, the deltas for these two consistently largely exceed the deltas for the direct read (lob) and direct write (lob) counters. During the load, of course. It's not even a small number: we're talking a LOT more. Controlfile I/O is definitely a bottleneck if NOLOGGING and loading lobs. With LOGGING, I get "normal" numbers on these counters and much better performance. Probably because my redo logs are as fast as they can get in this system and they are the bottleneck with LOGGING.

--
Cheers
Nuno Souto
wizofoz2k_at_yahoo.com.au.nospam