Async IO on Oracle 9.2.0.5

Hi

We are trying to figure if oracle is indeed using async io

there are two articles/notes i referred to in the process and of course the metalink. We did relink the Oracle kernel

1. http://download-east.oracle.com/oowsf2004/1449_wp.pdf See page 14
2. http://www.grabinar.com/simon/aio.html

i am still not sure if the server is doing async io and the other issue is when we run quries on the DB i see a lot of Io waits Checks we have done. The OS is enabled with async io looks like its the threaded aysnc io since kernel io is only in 2.6 + we are using

Linux extapp1 2.4.21-27.ELsmp #1 SMP Wed Dec 1 21:59:02 EST 2004 i686 i686 i386 GNU/Linux

Oracle 9.2.0.5 with the aio related patches

nm $ORACLE_HOME/bin/oracle | grep io_getevent

         U io_getevents@@LIBAIO_0.1

ran a sql query which dd full table scans and trace the pid with
strace -p pid

Among other systems calls you will see either: a. synchronous calls

          read(3, "783|37567799|213483944|2004-10-1"..., 4096) = 4096 b. asynchronous calls

     io_submit(0xb6a93000, 0x1, 0xbfff236c) = 1
     io_submit(0xb6a93000, 0x1, 0xbfff236c) = 1
     io_getevents(0xb6a93000, 0x1, 0x400, 0xbffeb794,

i am only seeing case a. read

On lthe linux box
rpm -q --whatprovides libaio
libaio-0.3.96-5

and its enabled
Oops i forgot Oracle is also enabled with the asynch io parameters filesystemio_options=asynch
disk_asynch_io=true

is this a fair test to confirm aio is happening or is there any other definitive method to confirm if we are indeed using asynch io

thanks for any help

regds
Kris Received on Thu Jun 30 2005 - 14:36:36 CDT