If you are getting this error every minutes or so
2021-06-29T03:06:00.070956+02:00
Exception [type: SIGSEGV, Invalid permissions for mapped object] [ADDR:0x18] [PC:0x10396E150, IPRA.$kkqjpdpvpd()+656] [flags: 0x0, count: 1]
Errors in file /app/oracle/diag/rdbms/uvd2dol/UVD2DOL/trace/UVD2DOL_ora_48562594.trc (incident=78750):
ORA-07445: exception encountered: core dump [kkqjpdpvpd()+656] [SIGSEGV] [ADDR:0x18] [PC:0x10396E150] [Invalid permissions for mapped object] []
Use ADRCI or Support Workbench to package the incident.
See Note 411.1 at My Oracle Support for error and packaging details.This error is because you have optimizer_features_enable set to 4 position instead of 3.
When setting this parameter on Oracle Database 18c or later, you must specify three numeric values separated by periods, such as 18.1.0 or 19.1.0.
Solution:
alter system set optimizer_features_enable=’19.1.0′;