Oracle Application Performance Issue.

Please follow below steps:
1.Where more specific are you encounter performance issues. While login, accessing forms, jsp pages, etc?
2. Check  what performance issue means what is the expected time and what is normal time on this situation?
3. Check context file for investigation
4. How many concurrent users do you have at peak?

If uncertain, you could get a round about number using:

REM
REM SQL to count number of Apps users
REM Run as APPS user
REM
select 'Number of user sessions : ' || count( distinct session_id) How_many_user_sessions
from icx_sessions icx
where disabled_flag != 'Y'
and PSEUDO_FLAG = 'N'
and (last_connect + decode(FND_PROFILE.VALUE('ICX_SESSION_TIMEOUT'), NULL,limit_time, 0,limit_time,FND_PROFILE.VALUE('ICX_SESSION_TIMEOUT')/60)/24) > sysdate
and counter < limit_connects;
REM
REM END OF SQL
REM

5. How many web servers do you have? How many cpu's on each web server?

6. Check Below Script result.
 
monitor_jdbc_conn.sql - Script to monitor JDBC connections in Apps eBusiness Suite ( Doc ID 557194.1 ).

7. Check txk report with the following:

$ADPERLPRG $FND_TOP/patch/115/bin/TXKScript.pl -script=$FND_TOP/patch/115/bin/txkInventory.pl -txktop=$APPLTMP -outfile=$APPLTMP/Report_Inventory.html

8. How many users are connecting at peak?

9. What values you have defined for xms and xmx for jvm startup?

10. To check SGA size?

Example:

1. There is a delay while login to the oracle application, there is a delay in accessing forms and jsp pages.

2. As a DBA i am observing the performance issue while accessing the server using putty, For e.g. when i go to $AD_TOP directory and execute "du -sk *" normally it takes few seconds to output the result but currently it is taking so much time to output the result.

3. Check context file for investigation

4. Number of user sessions : 121

5. We don't have a webserver outside the Oracle EBS
# lsdev -Cc processor
proc0 Available 00-00 Processor
proc8 Available 00-08 Processor
proc16 Available 00-16 Processor

# bindprocessor -q
The available processors are: 0 1 2 3 4 5 6 7 8 9 10 11

# pmcycles -m
CPU 0 runs at 4116 MHz
CPU 1 runs at 4116 MHz
CPU 2 runs at 4116 MHz
CPU 3 runs at 4116 MHz
CPU 4 runs at 4116 MHz
CPU 5 runs at 4116 MHz
CPU 6 runs at 4116 MHz
CPU 7 runs at 4116 MHz
CPU 8 runs at 4116 MHz
CPU 9 runs at 4116 MHz
CPU 10 runs at 4116 MHz
CPU 11 runs at 4116 MHz

# prtconf -s
Processor Clock Speed: 4116 MHz

6. Check Below Script result.

monitor_jdbc_conn.sql

7. Check txk report.

$ TOP/patch/115/bin/txkInventory.pl -txktop=$APPLTMP -outfile=$APPLTMP/Report_Inventory.html <
Enter Apps password ?
*** ALL THE FOLLOWING FILES ARE REQUIRED FOR RESOLVING RUNTIME ERRORS
*** STDOUT = /prodappl/inst/apps/PROD_erpprodappl/logs/appl/rgf/TXK/txkInventory_Wed_Jun_29_16_25_45_2016_stdout.log

9. values you have defined for xms=256 and xmx=128 for jvm startup.

10. SGA Size 1G.

Solution:
Please review document : JVM: Guidelines to setup the Java Virtual Machine in Apps Ebusiness Suite 11i and R12 ( Doc ID 362851.1 ) and according with this please perform the following:

1. Please increase Xmx with 2048 and Xms with 2048
2. Please make sure that you are using no more than 1 oacore per 100 user, in case you are using more than 100 user you will need to add more oacores, for this please follow the bellow note:
Managing Configuration of Oracle HTTP Server and Web Application Services in Oracle E-Business Suite Release 12.2 ( Doc ID 1905593.1 )
3. Please make sure that you add the following parameter to the DBC file:
JDBC\:oracle.jdbc.maxCachedBufferSize=262144