Q Why u need GUEST/ORACLE To connect to database?
The GUEST user account is used in the application internally ( it is an application user). One of the major needs of this account is when there is a need to decrypt the APPS password (which is stored in an encrypted format in the apps tables). In order to decrypt the APPS password, the GUEST username/password is used to accomplish this task (using "Guest User Password" profile option).
GUEST account is used to obtain the decrypted value of the apps password for internal processes (i.e. when there is a need to connect as apps internally).
when the account gets locked/end-dated then you will see a blank page when you try to login to the instance.In that scenario you will have to correct this situation from the back-end as you will not be able to login to the application.
You will not find much details about the GUEST account documented anywhere ( may be coz of security reasons).
Key points :
s_guest_user is GUEST and s_guest_pwd is EXPORT in adconfig xml file.
select fnd_web_sec.validate_login('GUEST','ORACLE') FROM DUAL; ( to validate if guest user is corrrect)
select fnd_profile.value('GUEST_USER_PWD') from dual; (to find the current guest user password)
Check the GUEST/ORACLE password is present in DBC file at $FND_TOP/secure directory as well as at $FND_TOP/secure/SID_hostname directory.
Q What is the purpose of JSERV?
R12 uses version 10g of the Oracle Application Server, which does not have or use jserv
Q How to increase the performance of Apache?
Oracle HTTP Server uses directives in httpd.conf. This configuration file specifies the maximum number of HTTP requests that can be processed simultaneously, logging details, and certain limits and time outs.
The parameters defined in this file can be tweaked, which will impact the performance of http (apache) server.
for example :
1) KeepAlive option should be used judiciously along with MaxClients directive. KeepAlive option would tie a worker thread to an established connection until it times out or the number of requests reaches the limit specified by MaxKeepAliveRequests. This means that the connections or users in the ListenBacklog queue would be starving for a worker until the worker is relinquished by the keep-alive user. The starvation for resources happens on the KeepAlive user load with user population consistently higher than that specified in the MaxClients.
2) Increasing MaxClients may impact performance in the following ways:
A high number of MaxClients can overload the system resources and may lead to poor performance.
For a high user population with fewer requests, consider increasing the MaxClients to support KeepAlive connections to avoid starvation. Note that this can impact overall performance if the user concurrency increases. System performance is impacted by increased concurrency and can possibly cause the system to fail.
To avoid potential performance issues, values for any parameters should be set only after considering the nature of the workload and the system capacity.
Q Tell me some issues with Apache?
There can be many Apache issues. Some issues can be:
1) Apache process crashes and not able to come up.
One reason can be huge log file of above 2 gb because of which Apache process is unable to write to it coz of OS limitations.
2) sometimes clone/ install issues can also cause problem with Apache, example
After clonning (or installing) an Oracle Applications Release 12.0 or 12.1 instance on Linux 5, an error may occur while starting up the Apache service. The error would be this:
...
You are running adapcctl.sh version 120.6.12000000.4
Starting OPMN managed Oracle HTTP Server (OHS) instance ...
adapcctl.sh: exiting with status 204
...
Review the HTTP log file. The error is very clear about the missing soft link. It would show this error:
...
<physical Path>/10.1.3/Apache/Apache/bin/apachectl startssl: execing httpd
<physical Path>/10.1.3/Apache/Apache/bin/httpd: error while loading shared
libraries: libdb.so.2: cannot open shared object file: No such file or directory
...
Soft link libdb.so.2 is missing.
As the unix root user, create a soft link as follows:
ln -s /usr/lib/libgdbm.so.2.0.0 /usr/lib/libdb.so.2
3)
Q What is the difference between applsys, applysyspub and apps users?
FND_UNSUCCESSFUL_LOGINS
FND_SESSIONS
FND_PRODUCT_INSTALLATIONS
FND_PRODUCT_GROUPS
FND_MESSAGES
FND_LANGUAGES_TL
FND_APPLICATION_TL
FND_APPLICATION_VL
FND_LANGUAGES_VL
FND_SIGNON
FND_PUB_MESSAGE
FND_WEBFILEPUB
FND_DISCONNECTED
FND_MESSAGE
FND_SECURITY_PKG
FND_LOOKUPS
Q Why u need httpd.pid?why u need to clear that?
Q What is JVM?
Q How do you increase the jvm size?
Q If One dba can launch the forms and another unable to launch the forms?what will be the issue?
Q How to set trace at forms level?
Q If u have Concurrent request with pending -standby how do your troubleshoot?
Q If you have long pending requests and system become slow.what you do?
Q If you lost http.conf file, without running autoconfig to create all files,I want to generate only http.conf individually?
Q How autoconfig works?
Q what Concurrent Tables that will cleanup when u run cmclean.sql?
Q PCP configuration ?What is the prinical behind it? how do u configure?
Q What is diff between distributed AD and Shared Appltop? what happens when u apply patch and disturbuted AD and Shared Appltop?
Q What happen if you Miss Pre-Req patch and apply main patch and how to do continue?
Q How to do u skip a worker
Q How to u recover if u lost a single file.
Q Explain how Dataguard works? what is the prinicipal behide that?
Q what are different Session waits?
Q How do you check Blocking sessions?
Q Have u come across ora-600 errors?what is the cause of errors?
Q What are the different Events?
Q What are system stat event Stand for?
Q What is the main purpose of maintanence Mode?
Q What if Apache is up when Maintanence Mode is up?
Q What is heapsize?
Q Issues u faced with concurrent Managers?
Q What is the script u used to clean the FND_NODES of the production Entries on non-Prod Entries.
Q How you mount the production Snap to target without putting the prod in begin backup mode?
Q How to check port Availability?
Q How do you Save time while doing patching?
Q What is the purpose of Defaults File?
Q Where do your increase the processes for a concurrent Manager?
Q Wait Events? Different Wait events u have come across and what all the solution u have given to them?
Q Have u worked on workflow issues?
Q In Rac How do you do patching?
Q How do you check for conflicts with database patching?
Q What is the purpose of APPS,APPLSYS,APPLSYSPUB,At the login?
Q What happens when u put in database in begin backupmode?
Q why more redos are generated?
Q Is the Datafile Will update when headers are freeze?
Q what actions can perfom on datafiles when headers are freeze?
Q If you have 10 archive logs, How to find how many archives are required to complete the recovery?
Q Rac Complete Configuration with prereq steps?
Q What is Voting disk and OCR File?
Q How u will take ocr Backup if u lost?
Q How to check the node connectivy? what is the script used for?
Q What are the advantages of ASM?
Q Why we use raw devices in ASM? can we use any other strorage?
Q How to add redo logs in ASM?
Q How many Undo required in RAC?
Q Benefits of RMAN Backups
Q Have u clone RAC to Non RAC?
Q Clone of RAC to RAC..Tell me the difference?
Q Patching on Disturbuted AD?
Q Tellme some workflow background process?
Q How to generate DBC file?
Q For Discoverer What is required to set the profile?
Q what all the ad utilities you used ?
Q What are the different Status of Worker?
Q You know about the wait events?
Q Let me different Ad options?
Q What is the use of DBC File and Tnsnames.ora? what is the difference here...both used for connectivy?
Q PCP Concepts ..how to implement?
Q where do you increase the process for a concurrent Manager for standard manager?
Q Let me know the Major difference for 11i and R12?
Q Upgrade process 11.5.9 to R12?
Q How to you licence a product?what is the purpose of adsplice?what is the difference of the both?
Q Have u applied HRMS or Legislative Patches?
Q What exactly happens when any user connect to database?
Q What is $TWO_TASK
Q You do Rman Clones? How?
Q How to do save customizations, What u run autoconfig?
Q How to configure JVM?
Q Have u faced any performance issues After upgrade?
Q what are the services running in R12(1st node - CM and DB and 2nd node - web and forms
Q Custom_code Creation Steps
Q What are the things that can be done on OAM?
Q Mention some Workflow Tables?
Q why u rebuild workflow tables ?and How?
Q 10g Discoverer can be configured on 11?