App pool refresh issue

Application is not working if we do not refresh the app pool (in IIS).

Issue Background

When our ASP.NET application and database (Oracle SQL developer) was migrated to a new server, it started coming for the new app server and DB server before that in old database and application server, it was not starting up.

Our Investigation

We have started our investigation and created a logging table Before and after the Application Pool refresh in this procedure:

osspbs_dba.build_request_pkg.get_requests_sp(in_req_id => :in_req_id,
                                             in_site_id => :in_site_id,
                                             out_cur_requests => :out_cur_requests);

We found the it is throwing a database error while fetching the cursor

Ora-01861.

Later we have logged the parameter and found that when China user works the NLS_TERRITORY and NLS_LANGUAGE is logged in the database according to their session.

But after that when American user started working then NLS_TERRITORY and NLS_LANGUAGE still logging as CHINA and the error started showing up.

This issue is gone when we refresh the application pool on the application server.

Attaching the screen shot of logs:

1. At line number 15 REQ_ID - 65527 when I access it from my system after the issue came it is logging it as CHINA.
2. After the Application Pool refresh It is logging as American and working fine.
3. So in my investigation once this changes to CHINA then it is not changing for other users sessions who are based on America or other locations.

Note: connection pool size also increased in web.config.