Скачать или смотреть How to determine elapsed time of a given process?

Using,
Oracle : dbms_utility.get_time
at the end of the code - you are dividing by 100 to get the duration of the procedure in seconds instead of hundredths of seconds.
set serveroutput on;
declare
s_time number;
e_time number;
t_time number;
begin
s_time := dbms_utility.get_time;
dbms_lock.sleep(3);
e_time := dbms_utility.get_time;

t_time := e_time-s_time;

dbms_output.put_line('Elapsed time '||t_time/100);

end;

Postgres : clock_timestamp() used to find time
substract the difference between start/end time to find elapsed time.
--postgres
do $$
declare
start_time time;
end_time time;
elapsed_time time;
begin
start_time := clock_timestamp();
raise notice 'start time %',start_time;
perform pg_sleep(3);
end_time := clock_timestamp();
raise notice 'end time %',end_time;
elapsed_time := end_time - start_time;
raise notice 'elapsed time %',elapsed_time;
end;
$$;