Oracle hint: OPT_ESTIMATE

Influence assumed number of rows

create table tq84_opt_est (
    num    number,
    txt    varchar2(10)
);

explain plan for
select
/*+
    opt_estimate(table tq84_opt_est rows=12345)
*/
    num,
    txt
from
    tq84_opt_est;

select * from table(dbms_xplan.display(format=>'basic +rows'));
--
-- --------------------------------------------------
-- | Id  | Operation         | Name         | Rows  |
-- --------------------------------------------------
-- |   0 | SELECT STATEMENT  |              | 12345 |
-- |   1 |  TABLE ACCESS FULL| TQ84_OPT_EST | 12345 |
-- --------------------------------------------------

drop   table tq84_opt_est;

See also