Using DBMS_STATS to Gather Statistics

Collection of statistics on the database objects is very important for the performance of the database. DBMS_STATS package is used to collect these statistics.
To collect system statistics, use following procedure

SQL> exec dbms_stats.gather_system_stats

ORA-20005: object statistics are locked

Error “ORA-20005: object statistics are locked” means that table statistics are locked and hence stats can’t be gathered on this table. Stats are locked if we don’t want stats to be gathered on some or all of our tables.

Following example explains stats locking and unlocking process.

ORA-15410: Disks in disk group DISKGROUP_NAME do not have equal size

If you are trying to create a diskgroup (suppose diskgroup name is DATA) and you see errors as bellow

ORA-15018: diskgroup cannot be created ORA-15410: Disks in disk group DATA do not have equal size

following would be the reason of it.