Oracle SQL Plan operation BITMAP CONVERSION TO ROWIDS

create table tq84_bm ( flg number(1) not null, val number, txt varchar2(50) ); create bitmap index tq84_bm_ix on tq84_bm(flg); explain plan for select val, txt from tq84_bm where flg = 1; select * from table(dbms_xplan.display(format=>'basic')); -- -- ---------------------------------------------------------- -- | 0 | SELECT STATEMENT | | -- | 1 | TABLE ACCESS BY INDEX ROWID BATCHED| TQ84_BM | -- | 2 | BITMAP CONVERSION TO ROWIDS | | -- | 3 | BITMAP INDEX SINGLE VALUE | TQ84_BM_IX | -- ----------------------------------------------------------

Not necessarily related to bitmap indexes

The BITMAP in the name of this operator is not necessarily related to bitmap indexes:

create table tq84_tab (
    id   number  (5),
    val  number  (3),
    txt  varchar2(5)
);

begin
   dbms_random.seed(42);
end;
/

insert into tq84_tab
select
   level,
   trunc(dbms_random.value (0, 1000)),
   dbms_random.string('a',5)
from
   dual connect by level <= 10000;   
    
create index tq84_tab_ix_val on tq84_tab(val);
create index tq84_tab_ix_txt on tq84_tab(txt);

begin
   dbms_stats.gather_table_stats(user, 'tq84_tab');
end;
/

explain plan for
   select
      *
   from
      tq84_tab
   where
      val =  974   or
      txt = 'knInl'
;

select * from table(dbms_xplan.display(format=>'basic'));
--
-- ---------------------------------------------------------------
-- | Id  | Operation                           | Name            |
-- ---------------------------------------------------------------
-- |   0 | SELECT STATEMENT                    |                 |
-- |   1 |  TABLE ACCESS BY INDEX ROWID BATCHED| TQ84_TAB        |
-- |   2 |   BITMAP CONVERSION TO ROWIDS       |                 |
-- |   3 |    BITMAP OR                        |                 |
-- |   4 |     BITMAP CONVERSION FROM ROWIDS   |                 |
-- |   5 |      INDEX RANGE SCAN               | TQ84_TAB_IX_VAL |
-- |   6 |     BITMAP CONVERSION FROM ROWIDS   |                 |
-- |   7 |      INDEX RANGE SCAN               | TQ84_TAB_IX_TXT |
-- ---------------------------------------------------------------

drop table tq84_tab;

Oracle SQL Plan operation BITMAP CONVERSION TO ROWIDS

Not necessarily related to bitmap indexes

See also