Declare 

Cursor c1
SELECT /* CHOOSE */  <columns>   ----  ????? What hint to use ??????
FROM base_table a,   --- variable row count; anywhere from 1 to 4000
large_child_table b  --- about 50,000,000 records
WHERE a.person_id = b.person_id;  -- indexed join

Type c1_table_type     is table of c1%rowtype;
C1_table                      c1_table_type;

Begin

Open c1;
loop
  Fetch c1 bulk collect into c1_table limit 100;
  Exit when c1_table.first is null;

  Forall l_rec  c1_table.first .. c1_table.last

      Insert into other_table
     (   ......  )
     Values
     ( ........ )

    Commit;

End loop;
Close c1;

End;
/

   open c1;
   loop
       fetch c1 bulk collect into c1_table LIMIT 100 ;
       forall i in 1 .. c1.count SAVE EXCEPTIONS
            insert /+ append*/ into other_table 
                   values ( c1(i).colmun1, ...etc);
       end loop;

       exit when c1%notfound;
   end loop;
   close c1 ;

insert into other_table
SELECT <columns>   
FROM base_table a, 
large_child_table b
WHERE a.person_id = b.person_id;