Henry, I got aiostat from IBM Support when I bugged them about how to monitor AIO. Not sure if aiostat is readily available as a download from their Web site or in/for the newer versions of AIX. It works similar to vmstat and iostat, showing number of pending AIO requests at the time of sampling. Following is an example from one of our Servers, showing 10 samples at 1 sec interval. Ideally, the count should be 0 at all times. If it stays high (relative term) consistently then one needs to increase the number of configured AIO servers, or check the I/O subsystem for other problems... By default, aiostat must be run as 'root'.
HTH, - Kirti ibmRS50 [VS9XBP]# aiostat 1 10 AIO requestcount: 1 AIO requestcount: 0 AIO requestcount: 0 AIO requestcount: 1 AIO requestcount: 0 AIO requestcount: 2 AIO requestcount: 0 AIO requestcount: 3 AIO requestcount: 0 AIO requestcount: 0 -----Original Message----- Sent: Thursday, February 06, 2003 9:34 AM To: Multiple recipients of list ORACLE-L Kirti, I've been searching on the IBM site for aiostat without much luck. What kind of information does it give you? (if I'm going to convince my SA to call IBM about this I'll need a very good argument. I'm still working on getting the rights to use sar). Henry -----Original Message----- Kirti Sent: Wednesday, February 05, 2003 8:29 PM To: Multiple recipients of list ORACLE-L Jeff, If you see the SEQ# field in the v$session_wait view not incrementing, then something else, other than Oracle, is causing a hang up... On AIX, if you have AIO enabled, try running 'aiostat'. It will show if there are any pending AIO requests. The difficult part would be to relate those pending calls to your session. It is quite likely that a particular AIO server may show waits on I/O, if this hang up is IO related. You can try 'pstat' to find out AIO server processes and associated 'pid' to dig deeper. If you do not have 'aiostat', ring up IBM Support. It is a nice utility to have, and it is free. For those on AIX 5L, can you please check if 'aiostat' is available as a standard distribution? I was told by IBM Support that 'aiostat' was going to be available with AIX 5L. - Kirti -----Original Message----- Sent: Wednesday, February 05, 2003 3:20 PM To: Multiple recipients of list ORACLE-L It looks like your process really is stuck in a way that has nothing to do with the Oracle code directly. You might look at the CPU usage of your session and its shadow using an O/S utility, but I suspect it would show zero CPU. Perhaps truss (or the AIX equivalent) might show your process spinning on whatever call equates to 'has the async read completed yet'. You could try doing three processstate dumps with 5 second intervals to see if the processstate shows any changes which might give you a hint - but again I'd GUESS that you'll find nothing happening. Regards Jonathan Lewis http://www.jlcomp.demon.co.uk Coming soon one-day tutorials: Cost Based Optimisation Trouble-shooting and Tuning Indexing Strategies (see http://www.jlcomp.demon.co.uk/tutorial.html ) ____UK_______March 19th ____USA_(FL)_May 2nd Next Seminar dates: (see http://www.jlcomp.demon.co.uk/seminar.html ) ____USA_(CA, TX)_August The Co-operative Oracle Users' FAQ http://www.jlcomp.demon.co.uk/faq/ind_faq.html -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Deshpande, Kirti INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
