Oracle CPU usage on web application

Question

I have a Dell desktop running Windows XP professional. (pentium 4, 2gb ram) This desktop is being used for a web app that does employee time cards. A contractor did this for the company and we are not proficient with Oracle, so we need some assistance!
The web application uses asp.net for the site and the database is oracle 11g.
So the various problems are:
1. The system will work flawlessly for a few days; once even a week! Lately, it has not been that good. There are four services related to oracle - two of them are sometimes having problems starting.. (status says "starting" then it will time out, then try to start again.) We have been rebooting the system multiple times just to get things working again so people can login.
services are as follows:
ORACLEDBConsole-timeentry - problems starting lately.
Oraclejobscheduler-timeentry - not currently set to start automatically
OracleoraDb11g_homeTNSlistener - usually starts fine
OracleServicetimeentry - have had problems starting sometimes, working good for now.
2. A few days ago I logged on to the machine and checked running processes. Oracle was consuming 100% cpu, and lots of memory. (~512mb) Also, there were many instances of TNSPing.exe running consuming resources as well.
3. Lately it doesn't work for over a day. We have to reboot every morning, and Oracle will not "crash" but does stay at 40-50% cpu usage. We think there is something going wrong with oracle services/oracle in general but have no idea where to look for a solution. There are no error messages or clues to what is going on!
Thanks in advance for your help!
-Ryan

Answer 1

The excessive cpu usage in oracle is usually caused by code that does not use bind variables.
eg your sql string is passed as follows:
select * from customer where customer_number = '12345';
Your code should be passing:
select * from customer where customer_number = :BV1;
BV1 is a placeholder for a bind variable. Whatever language you use you need to associate a value with BV1. All the languages are capable of using bind variables, and once you know how, its easier than the usual :
'select * from customer where customer_number = '||customer_number;
If you're on oracle 8.1.7. then you can set the cursor_sharing parameter to force.
You will add this to your init.ora file and then restart the database.
I highly recommend you look at http://asktom.oracle.com as there is a wealth of useful information there, including how to determine whether your database is using bind variables.
Note: We run a web app server here with a database and 2 gb is easily sufficient. We are a development environment so dont get a lot of users. I have had the guys here recode there java code to use bind variables and we got a lot of performance improvement.