Dica Oracle - Quando iniciou e terminou a coleta de estatísticas?

Na DBA_OPTSTAT_OPERATIONS é mantido um histórico de todas as operações executadas utilizando a DBMS_STATS, logo, é possível identificar o inicio e fim de varias operações como:

• gather_table_stats;

• lock_schema_stats;

• gather_fixed_objects_stats;

• gather_system_stats;

• gather_schema_stats;

• gather_dictionary_stats;

• set_system_stats;

• delete_table_stats;

• entre outros.

select operation,
       target,
       to_char(start_time, 'dd/mm/yyyy hh24:mi:ss') start_time,
       to_char(end_time, 'dd/mm/yyyy hh24:mi:ss') end_time
  from DBA_OPTSTAT_OPERATIONS
 where operation = 'gather_system_stats';

OPERATION                      TARGET                         START_TIME          END_TIME
------------------------------ ------------------------------ ------------------- -------------------
gather_system_stats                                           16/10/2017 14:17:21 16/10/2017 14:17:21
gather_system_stats           

select operation,
       target,
       to_char(start_time, 'dd/mm/yyyy hh24:mi:ss') start_time,
       to_char(end_time, 'dd/mm/yyyy hh24:mi:ss') end_time
  from DBA_OPTSTAT_OPERATIONS
 where operation = 'gather_schema_stats';

OPERATION                      TARGET                         START_TIME          END_TIME
------------------------------ ------------------------------ ------------------- -------------------
gather_schema_stats            SCHEMA1                        19/10/2017 00:02:05 19/10/2017 00:22:28
gather_schema_stats            SCHEMA2                        19/10/2017 00:22:28 19/10/2017 00:22:28
gather_schema_stats            SCHEMA3                        19/10/2017 00:22:28 19/10/2017 00:22:28
gather_schema_stats            SCHEMA4                        19/10/2017 00:22:28 19/10/2017 00:22:28
gather_schema_stats            SCHEMA5                        19/10/2017 00:22:34 19/10/2017 00:23:02

select operation,
       target,
       to_char(start_time, 'dd/mm/yyyy hh24:mi:ss') start_time,
       to_char(end_time, 'dd/mm/yyyy hh24:mi:ss') end_time
  from DBA_OPTSTAT_OPERATIONS
 where operation = 'gather_table_stats' and target like '%TABLE1%';

OPERATION                      TARGET                         START_TIME          END_TIME
------------------------------ ------------------------------ ------------------- -------------------
gather_table_stats             SCHEMA1.TABLE1                 24/09/2017 07:36:07 24/09/2017 08:13:19
gather_table_stats             SCHEMA1.TABLE1                 01/10/2017 06:53:58 01/10/2017 07:28:15
gather_table_stats             SCHEMA1.TABLE1                 08/10/2017 07:06:55 08/10/2017 07:41:41

select dbms_stats.get_stats_history_retention from dual;

GET_STATS_HISTORY_RETENTION
---------------------------
                         31

exec dbms_stats.alter_stats_history_retention(10);

PL/SQL procedure successfully completed.

select dbms_stats.get_stats_history_retention from dual;

GET_STATS_HISTORY_RETENTION
---------------------------
                         10