Enable and Disable the Trace on Listener in Oracle

Trace is enabled for listener to monitor the listener activity for connectivity issue. Suppose you connection is dropped automatic. then you need to identified the reason of dropped connection that’s why you need to enable trace on listener.

Enable the Trace on Listener
You set the trc level to 16 and then check where trace file is created and which directory location it is created.

LSNRCTL> show trc_level
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=EXTPROC1)))
LISTENER parameter "trc_level" set to off
The command completed successfully
LSNRCTL>
LSNRCTL> show trc_file
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=EXTPROC1)))
LISTENER parameter "trc_file" set to ora_2728_3016.trc
The command completed successfully
LSNRCTL>
LSNRCTL> show trc_directory
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=EXTPROC1)))
TNS-01153: Failed to process string: (DESCRIPTION=(TMP=)(VSNNUM=186647040)(ERR=0)(COMMAND=trc_directory)(TRCDIRNAME=D:\oraclexe\app\oracle\diag\tnslα_J♦

Change the Trace location and level in Listener

lsrnctl>set trc_directory
lsrnctl>set trc_file
lsrnctl>set trc_level

Enable the Trace on Listener
You set the trc level to 16 and then check where trace file is created and directory location

LSNRCTL> set trc_level 16
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=EXTPROC1)))
LISTENER parameter "trc_level" set to support
The command completed successfully
LSNRCTL>
LSNRCTL> show trc_file
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=EXTPROC1)))
LISTENER parameter "trc_file" set to ora_2728_3016.trc
The command completed successfully
LSNRCTL>
LSNRCTL> show trc_directory
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=EXTPROC1)))
TNS-01153: Failed to process string: (DESCRIPTION=(TMP=)(VSNNUM=186647040)(ERR=0)(COMMAND=trc_directory)(TRCDIRNAME=D:\oraclexe\app\oracle\diag\tnslα_J♦

Disable the Trace on Listener

LSNRCTL> set trc_level 0
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=EXTPROC1)))
LISTENER parameter "trc_level" set to off
The command completed successfully