Search notes:

DBMS_STATS.GATHER_SYSTEM_STATS

dbms_stats.gather_system_stats gathers system statistics. 
begin
   dmbs_stats.gather_system_stats (
      gathering_mode   => '…',  -- Default is 'NOWORKLOAD',
      interval         =>  … ,  -- an integer whose default is 60
      stattab          => '…',  -- default is null
      statid           => '…',  -- default is null
      statown          => '…'   -- default is null
   );
end;
/

Getting «no workload» stats

set serveroutput on
declare
   t0 date;
begin
   t0 := sysdate;
   dbms_stats.gather_system_stats;
   dbms_output.put_line('gethering stats took ' || round((sysdate - t0) * 86400) || ' seconds.');
end;
/
--
-- gethering stats took 28 seconds.

select
   pname,
   pval1
from
   sys.aux_stats$
where
   sname =   'SYSSTATS_MAIN' and
   pname in ('CPUSPEEDNW', 'IOSEEKTIM', 'IOTFRSPEED');

See also

aux_stats$
dbms_stats
MOS Note 470316.1

Index

Fatal error: Uncaught PDOException: SQLSTATE[HY000]: General error: 8 attempt to write a readonly database in /home/httpd/vhosts/renenyffenegger.ch/php/web-request-database.php:78 Stack trace: #0 /home/httpd/vhosts/renenyffenegger.ch/php/web-request-database.php(78): PDOStatement->execute(Array) #1 /home/httpd/vhosts/renenyffenegger.ch/php/web-request-database.php(30): insert_webrequest_('/notes/developm...', 1758199096, '216.73.216.150', 'Mozilla/5.0 App...', NULL) #2 /home/httpd/vhosts/renenyffenegger.ch/httpsdocs/notes/development/databases/Oracle/installed/packages/dbms/stats/api/nouns/stats/system/gather/index(78): insert_webrequest() #3 {main} thrown in /home/httpd/vhosts/renenyffenegger.ch/php/web-request-database.php on line 78