Note 805586.1 Troubleshooting Session Administration (Doc ID 805586.1)
Note 822527.1 How To Find Where The Memory Is Growing For A Process (Doc ID 822527.1)
Note 273646.1 How to diagnose the high CPU utilization of ORACLE.EXE in Windows environment
Note 728539.1 Find Blocking Sessions In SQLPLUS
Note 61552.1 Troubleshooting Oracle Database Hanging Issues for versions from 7 to 9--Exhaustive
Note 164760.1 Detecting and Resolving Locking Conflicts using TopSessions