Consider below tracing on Client and Server Side to capture any database errors, especially if you donot see any errors on DB alert logs and application team is complaining of database related timeouts in their application logs
1. Remove all entrees for TRACE_ from the client SQLNET.ORA
2. Place the below in the Client SQLNET.ORA making sure you change the file path for TRACE_DIRECTORY_CLIENT= to a location your user can write too.
TRACE_UNIQUE_CLIENT = ON
TRACE_LEVEL_CLIENT=16
TRACE_TIMESTAMP_CLIENT=TRUE
TRACE_DIRECTORY_CLIENT=/home/oracle/client_trace
TRACE_FILE_CLIENT=CL.trc
DIAG_ADR_ENABLED=OFF #<===Use this only for 11g and newer clients
3. Make sure to turn on SERVER side TRACE here on the Database side, Making sure you change the file path for TRACE_DIRECTORY_SERVER= to a location your user can write too.
Place the below in the Server side sqlnet.ora
TRACE_UNIQUE_SERVER = ON
TRACE_LEVEL_SERVER=16
TRACE_TIMESTAMP_SERVER=TRUE
TRACE_DIRECTORY_SERVER=/Path here/
TRACE_FILE_SERVER=SR.trc
DIAG_ADR_ENABLED=OFF #<===Use this only for 11g and newer clients
4. Review the DOC how to ID matching client to server trace and extract the trace files outlined (Only for concerned clients having the issue).
How to Match Oracle Net Client and Server Trace Files ( Doc ID 374116.1)
Orama.blog 