Optimizer Statistics Restore

dba_optstat_operations: start and end time for all DBMS_STATS operations
dba_tab_stats_history: history of table statistics modifications for the past 31 days. This means you can use DBMS_STATS.RESTORE to restore optimizer statistics up to 31 days
dba_scheduler_jobs

If you user ANALYZE command to collect statistics, these statistics information will not be stored in the data dictionary.

dbms_stats.restore_table_stats(,,timestamp)
dbms_stats.restore_schema_stats
dbms_stats.restore_database_stats
dbms_stats.restore_dictionary_stats
dbms_stats.restore_fixed_objects_stats
dbms_stats.restore_system_stats
dbms_stats.purge_stats();
dbms_stats.alter_stats_history_retention ();
dbms_stats.get_stats_history_availability