RE: AIX 4.3.3 / 8.1.7 & Timed Statistics & Tuning Question

Lisa,  

Be aware that AIX uses the memory for File system caching, and as much as it can. So don't be surprised by low values in 'fremem' in vmstat. What you do need to watch out is the 'pi' (page in) column which can indicate paging in.. Large values in 'po', when you are seeing lots of physical file I/O shouldn't worry you. I believe there is a separate 'Oracle tuning for AIX' article somewhere on the web. Try searching for this stuff in 'http://www.redbooks.ibm.com' (this should be free for all).  

John Kanagaraj
Oracle Applications DBA
DBSoft Inc
(W): 408-970-7002

I don't know what the future holds for me, but I do know who holds my future!

• The opinions and statements above are entirely my own and not those of my employer or clients **

-----Original Message-----

Sent: Thursday, February 06, 2003 9:50 AM To: Multiple recipients of list ORACLE-L

Hi Henry,  

OS isn't paging when I've looked. But with the memory this low it seems to me paging could happen pretty darn quick.  

There are a couple of logins that can run reports. These aren't big databases but as you know a L-user firing cartesian joins could cause everything to suffer.  

App servers and db's are brought down daily for backups (gonna change that too...). I'm amazed that one of the financials apps maintains 80 connections to one database.  

I'm going to turn on timed_statistics, install statspack and start watching. Yea, that and 50 other things.  

Monkey, dingbat, doorknob, dogbone, diaper, database. It's all the same to me... gotta pay the mortgage, gotta pay the mortgage...  

Thanks Henry, Ed and Scott, and everyone that replied.

-----Original Message-----

Sent: Thursday, February 06, 2003 10:50 AM To: Multiple recipients of list ORACLE-L

Lisa,  

When I first got to URI (8.1.7 4.3.3) timed_statistics were also set to false. I changed them to true and have had no problems with it.  

I have also found that a lot of PeopleSoft setups aren't installed by experienced Dingbat Administrators (when the switch from monkey to dingbat?) so the SGA and other parameters can be funky (for a small dev db we had a 20M log_buffer). Given that, my feeling on whether to change your SGA is 'it depends'.  

Is there any paging on the OS? How often do you restart your application server processes? They can continue to gobble up additional memory (you can monitor this with ps). There is a way to recycle them (some config file parameters. I'd have to look them up) if this is a problem. Also, if user load will grow, new app servers might be spawned, using up additional memory.  

How does your db performance look? (of course that'll be easier to tell after turning on timed_statistics). Any users connecting to the database outside of PeopleSoft? What is their sort_area_size, ...?  

HTH.   Henry
no clever moniker

-----Original Message-----

Sent: Thursday, February 06, 2003 9:24 AM To: Multiple recipients of list ORACLE-L

Good morning everyone -

Quick poll for those of you on 8.1.7 and AIX 4.3.3:

Do you have TIMED_STATISTICS = true? Have you encountered any problems with it?

The databases I inherited have this set false all over the place, hence my tuning efforts are really limited. However I don't want to change it without checking around first.

And a tuning question:

This environment (peoplesoft) is very very low on memory. When the app servers and databases are up there's less than 50MB of memory free. Adding hardware is not a choice here.

The databases have 100MB set for the SGA. It really looks like not much thought went into some of the parm settings.

What I've read about tuning says that you must have a goal in mind. Well, afaik nothing is "broken", nothing is suffering - then again, no one really paid much attention to Oracle. It was up, fine, move on. Am I on the wrong path if my goal for tuning is to figure out if I can reduce the size of the SGA and redo logs without adversely affecting performance?

Any comments are appreciated. Thanks everyone

Lisa Koivu
Oracle Dingbat Administrator
Fairfield Resorts, Inc.
5259 Coconut Creek Parkway
Ft. Lauderdale, FL, USA 33063
Office: 954-935-4117
Fax: 954-935-3639
Cell: 954-683-4459

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