bitmap index
说明:
set echo on
drop table t purge; create table t
( processed_flag varchar2(1)
);
create bitmap index
t_idx on t(processed_flag);
insert into t values ( 'N' );
declare
pragma autonomous_transaction;
begin
insert into t values ( 'N' );
commit;
end;
/
如果数据在一个回话里执行会出现锁死错误,所以尽量不要用 bitmap index