Diff between physical reads and physical reads direct
- From: Database Admin <dba@xxxxxxxxxxx>
- To: <oracle-l@xxxxxxxxxxxxx>
- Date: Fri, 2 Apr 2004 15:56:21 +0530 (IST)
Hi All,
I was going through Oracle Doc's and certain things just stuck me ,I am
jotting them down plz let me knw your opinions on these
1) What is the difference between physical reads and physical reads (direct)
2) There exists a OS cache on all the servers now when Oracle requires a
block it first check its own Cache (Buffer) now if it fails to find it
there it asks for a disk read ,My question is what if that particular
piece of data exists in OS cache.In such a scenario
a) is such a situation possible?.
b) If yes then How does Oracle keep track b'coz to it there was a PIO
whereas in reality it was a LIO.
c)Does the system wide stats take care of this.
3)Does Oracle keep LOB's in Buffer cache or they are allways disk read.i.e
PIO.
Thanks a mil
Deep
----------------------------------------------------------------
Please see the official ORACLE-L FAQ: http://www.orafaq.com
----------------------------------------------------------------
To unsubscribe send email to: oracle-l-request@xxxxxxxxxxxxx
put 'unsubscribe' in the subject line.
--
Archives are at //www.freelists.org/archives/oracle-l/
FAQ is at //www.freelists.org/help/fom-serve/cache/1.html
-----------------------------------------------------------------
Other related posts:
- » Diff between physical reads and physical reads direct
