I noticed in my daily database reports for the RAC 12c database that they were some invalid MATERIALIZED VIEWS in the SYSTEM schema.
Then a week later I started getting ORA 600 errors. Reviewing the dump I see the offending query, which referenced the materialized view in the alert log. Logged into Oracle support and found that it is a bug, but with earlier versions.
As always work with support, when attempting any custom solutions, your environment will have different variables. A workaround is too delete the reference in the AWR internal tables (TAKE A BACKUP FIRST) wri$_adv_sqla_fake_reg, then attempt to drop the MV if things go south, restore your change.
ORA 600 [ORA-00600: internal error code, arguments: [kglDeleteAllPinsOnObj1], [0x824916A10
========= Dump for incident 614380 (ORA 600 [kglDeleteAllPinsOnObj1]) ========
—– Beginning of Customized Incident Dump(s) —-
—– Current SQL Statement for this session (sql_id=7qraaqcuss9x9) —–
DROP MATERIALIZED VIEW “SYSTEM”.”MV$$_8E65A001C”
|SYSTEM||MATERIALIZ ED VIEW||MV$$_8E65A001C|
|SYSTEM||MATERIALIZ ED VIEW||MV$$_8E65A001B|