Troubleshooitng the SQL Connectivity issues : Steps to start with

http://blogs.msdn.com/sql_protocols/archive/2008/04/30/steps-to-troubleshoot-connectivity-issues.aspx

SELECT FOR UPDATE and NOWAIT

SELECT FOR UPDATE[SFU in short] in Oracle lets you lock the records satisfied by the Where clause in advance.By default when you issue this command it will wait indefinitely for the locks.So if someone has already locked a record, you will never get the control back.
On the other hand if you include the optional keyword NOWAIT, the control will immediately come back to application, if the record is locked by some one else.

Oracle EnterpriseOne Support Assistant Tool

Oracle EnterpriseOne Support Assistant is a free tool that is used to gather the most commonly needed information in an automated manner for speedy diagnosis of the problem.Support Assistant makes use of predefined profiles, to gather the required general,specific information from the customer's environment.
Highlights:
SA can be run on a FAT client,Deployment server or a windows terminal server.
Support Assistant supports Xe,ERP 8.0,8.9,810,811,811SP1 and 812.
SA can also be used to view a created report.
SA has a built in table browser similar to UTB/DataBrowser.

Download the latest version of Support Assistant