Re: Performance question: single datafile vs multiple datafiles

Why? If you watch your oracle process making system calls, you'll see it open and close datafiles when they're needed. Let's say you have a datafile called 'rarelyused01.dbf' and data of a table rarelyused is sure in this datafile. Find the shadow process on behalf of your sqlplus and run truss -t open -p [pid] (assuming Solaris). Go to sqlplus and type select * from rarelyused. You should see an open call made to this rarelyused01.dbf file. Verify by lsof -p [pid] -a -d [file descriptor], where the file descriptor is the return value of open(). lsof is a freeware program.

This only proves files are opened when they're used. To see inode lock effect needs much more careful planning.

Yong Huang
yong321_at_yahoo.com

"koert54" <koert54_at_nospam.com> wrote in message news:<%qwf8.211172$rt4.21544_at_afrodite.telenet-ops.be>...
> > Suppose the file is opened and closed very frequently
>
> only if shutdown and startup your database very frequently :-)
>
>
> "Yong Huang" <yong321_at_yahoo.com> wrote in message
> news:b3cb12d6.0202280942.5acc0ecb_at_posting.google.com...
> > If there's only one physical disk, the difference is very small.
> > Suppose the file is opened and closed very frequently, further suppose
> > it's written a lot (not mostly for read), splitting into multiple
> > files helps to reduce inode locks.
> >
> > Yong Huang
> > yong321_at_yahoo.com
Received on Mon Mar 04 2002 - 12:26:14 CST