Physical reads are the number of times Oracle actually did a read from disk.
Physical block reads are the number of times that Oracle actually did a
BLOCK read from disk.
Physical reads< Physical block reads
eg when doing a full table scan Oracle may read multiple blocks in one read
and hence that is one physical read (multi block read) and many physical
block reads.
This is a useful statistic to know if it is just reading random blocks or it
is reading sequential blocks. (a full table scan for exampl)
Jim
"Jayaraman Ashok" <ashok_jayaraman_at_yahoo.com> 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 Thu Sep 26 2002 - 09:40:00 CDT
