ah yes - you're right ... I was more thinking about PMON/SMON/DBWR which I
guess will only open and close
their filedescriptors at database startup and shutdown
"Yong Huang" <yong321_at_yahoo.com> wrote in message
news:b3cb12d6.0203041026.42c7f846_at_posting.google.com...
> 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 Tue Mar 05 2002 - 12:49:26 CST
