Re: Physical block reads difference

Hi David,

I think the original poster got it right (in a wrong sort of way).

The number of 'Physical Reads' from v$sysstat should be very very close to the sum of phyblkrd from v$filestat (as he stated) and v$tempstat (which he forgot). They all record the number of *blocks* physically read from disk.

I've only got access to my play DB at home and my figures are 1 off (for which I forgive Oracle and for which I won't lose too much sleep).

Cheers

Richard
"David Fitzjarrell" <oratune_at_msn.com> wrote in message news:32d39fb1.0209260955.2d7185a2_at_posting.google.com...
> Had you looked further into the view you would have also seen PHYRDS,
> reporting physical reads, along with PHYBLKRDS, and you would have
> noticed the difference between the values there. As such, PHYBLKRDS
> is NOT the same as PHYRDS.
>
> Since a single physical read may span more than one physical block,
> just as a physical write may write multiple blocks in a single
> request, it's not surprising that PHYBLKRDS exceeds the value for
> PHYRDS.
>
> David Fitzjarrell
>
> ashok_jayaraman_at_yahoo.com (Jayaraman Ashok) wrote in message
news:<7ca2852.0209260221.37be8227_at_posting.google.com>...
> > Hi
> > I queried the v$sysstat for getting the 'physical reads' on the
> > database. I believe this is the number of physical block reads. Now
> > querying the sum(phyblkrds) in v$filestat, shouldn't the value be the
> > same? I think both the statsistics are one and the same. But then why
> > the difference? Kindly explain.
> >
> > Cheers,
> > Ashok
Received on Fri Sep 27 2002 - 08:33:27 CDT