if you are a DBA, then you must have faced “ORA-00600” error. This is a generic error that potentially represent a defect and you will need to contact Oracle Support for help to fix the faced problem.
The error can be found in “alert.log” file , however there are different severity levels of ORA-600….. to find out you can use the very useful view: V$diag_alert_ext
The view has a column called “message_level” that indicates the severity level as shown below:
1 : CRITICAL: critical errors
2 : SEVERE: severe errors
8 : IMPORTANT: important message
16 : NORMAL: normal message
In a production system you will need monitor and check if either severity “1” or “2” is being thrown in the alert log file. So, basically this useful view provides more detailed information about the error…. having ORA-600 with severity level “16” is normal message alert and can be ignored.
*** This query will catch ORA-600 with severity level 1
SQL> select originating_timestamp,detailed_location,message_level,message_text,problem_key from V$diag_alert_ext where message_level=1 and message_text like’%ORA-00600%’ order by originating_timestamp desc;
one of the databases i am supporting ( on version 12cR1 126.96.36.199) was throwing ORA-600 in the alert log:
Archived Log entry 94742 added for thread 1 sequence 48014 ID 0x6a20c315 dest 2:
Errors in file /oracle/orcl12/diag/rdbms/orcl12/orcl12/trace/orcl12_j003_115141.trc (incident=582200):
ORA-00600: internal error code, arguments: [qerixAddNotNullStopKeyPredicate:1], , , , , , , , , , , 
Incident details in: /oraclex/orcl12/diag/rdbms/orcl12/orcl12/incident/incdir_582200/orcl12_j003_115141_i582200.trc
Non critical error ORA-48913 caught while writing to trace file “/oraclex/orcl12/diag/rdbms/orcl12/orcl12/incident/incdir_582200/orcl12_j003_115141_i582200.trc”
Error message: ORA-48913: Writing into trace file failed, file size limit  reached
if this error is infrequent then you can ignore, otherwise as a workaround is to disable the Automatic SQL Tuning Tasks by executing the following:
client_name => ‘sql tuning advisor’,
operation => NULL,
window_name => NULL );
As a consequence, this will disable all automatic SQL tuning tasks but you can still perform “on-demand” SQL tuning to get advice on tuning specific SQL statements.