One of the most frustrating issues for any DBA or application owner is the dreaded "hung session" — a database connection that appears active but is actually dead due to a network failure, firewall timeout, or client crash.
lsnrctl reload Or for a clean start:
lsnrctl stop lsnrctl start Check an active session’s DCD setting: expire_time sqlnet.ora 19c
The value is in . A setting of 10 means the server will send a probe every 10 minutes. 3. Restart Listener (Not Required, but Recommended) Actually, sqlnet.ora changes take effect for new connections only . Existing sessions will not inherit the new setting. One of the most frustrating issues for any
To be safe: