create table user.table_old
(
  id                 number(21)                 not null,
  name               varchar2(1000 char)        not null,
  date_main          date                       not null
);

create table user.table_new
(
  id                 number(21)                 not null,
  name               varchar2(1000 char)        not null,
  date_main          date                       not null
)
partition by range (date_main)
interval (numtodsinterval(3, 'day')) 
(
partition p1 values less than (to_date(' 2010-01-01 00:00:00', 'syyyy-mm-dd hh24:mi:ss', 'nls_calendar=gregorian'))
);

insert into user.table_new (id, name, date_main)
    select id, name, date_main
    from user.table_old
    where date_main >= trunc(sysdate-7);
commit;

begin
for i in ( select id, name, date_main
           from user.table_old
           where date_main > trunc(sysdate-7) ) loop
               insert into user.table_new (id, name, date_main)
               values (i.id, i.name, i.date_main)
               commit;
               sleep(1/500);
           end loop;
end;
/

select count(id)
from user.table_old
where date_main >= trunc(sysdate-7)