Everyday at the same time, there is an OEM 12c alert for the 10g listener as below:
Host=racnode1.raccluster Target type=Listener Target name=LISTENER_racnode1.raccluster Message=TNS-12508. Please check log for details. Severity=Critical Event reported time=Dec 1, 2016 5:41:19 PM EST
Information in LISTENER.log :
01-DEC-2016 17:34:21 * version * 0 01-DEC-2016 17:34:21 * version * 0 01-DEC-2016 17:34:22 * 12508 TNS-12508: TNS:listener could not resolve the COMMAND given WARNING: Subscription for node down event still pending 01-DEC-2016 17:34:22 * (CONNECT_DATA=(CID=(PROGRAM=)(HOST=racnode1.raccluster)(USER=oracle))(COMMAND=status)(ARGUMENTS=64)(SERVICE=LISTENER)(VERSION=186647552)) * status * 0 01-DEC-2016 17:34:22 * log_directory * 0 01-DEC-2016 17:34:22 * trc_directory * 0
From LISTENER.log, most likely one command does not exist or failed while running against the 10g LISTENER. Some doc said it is trying to run “show oracle_home” which is not available for 10g listener. After this failing command, there are two successful commands against “log_directory” and “trc_directory”.
LSNRCTL> show oracle_home NL-00853: Message 853 not found; No message file for product=network, facility=NL [ show] [oracle_home] [ show]
After manually running “show oracle_home” against 10g LISTENER, I did NOT see “TNS-12508: TNS:listener could not resolve the COMMAND given” recorded in LISTENER.log as per Doc ID 1596633.1
Suppress the alerts by changing the default threshold for “TNS Errors” metric from:
“Upgrading the Database Plug-in to version 126.96.36.199 or higher” as per (Doc ID 1596633.1) is NOT working, since our database plug-in is 188.8.131.52 already.