MMON Reports ORA-600 [6810] In Alert Log File

ORA-00600: internal error code, arguments: [6810], [162640], [168472]

Call Stack:

kdngnl kdnini2 keltinitseq keltgseq keltfill keltpost kelr_issue_alert 382 kelr_monitor_metric ksbcti ksbabs kebm_mmon_main


This issue is reported during MMON's alerting mechanism. Could not identify any known issue at this stage.

Bug 5088977 is related,but doesn't seems this is the cause.
Details:

MMON may dump in keltfill.

The workaround mentioned in the bug is helping.

Solution :

MMON is dumping the trace and objects accessed are related to MMON's alerting mechanism.

SYS.WRI$_ALERT_SEQUENCE
WRI$_ALERT_OUTSTANDING
WRI$_ALERT_THRESHOLD

These all are related to alerting mechanism and call stack also further confirm the same.

Workaround is to disable the MMON alerting functionality by setting the following:

If using init.ora:

_threshold_alerts_enable=0

If using spfile:

SQL> alter system set "_threshold_alerts_enable"=0 scope=spfile sid='*';

and restart the instance.

This disables alerting mechanism.
This should not have any impact to other normal functionality of the database.