BUG #5738: btree index search bug

The following bug has been logged online:

Bug reference: 5738
Logged by: spche
Email address: spche(at)163(dot)com
PostgreSQL version: 9.01
Operating system: Winxp
Description: btree index search bug
Details:

create table a (a int);
create index a_a on a(a);

insert into a values(1);
insert into a values(2);

insert into a select * from a;
insert into a select * from a;
insert into a select * from a;
insert into a select * from a;
insert into a select * from a;
insert into a select * from a;
insert into a select * from a;
insert into a select * from a;
insert into a select * from a;
insert into a select * from a;
insert into a select * from a;
insert into a select * from a;

delete from a where a=3;

CREATE or replace FUNCTION aa() RETURNS integer AS $$
DECLARE
curs2 cursor for SELECT a FROM a where a=3;
rowv1 integer DEFAULT 0;
rowv2 integer DEFAULT 32;
cou1 integer DEFAULT 0;
BEGIN

insert into a values(3);
OPEN curs2;
FETCH curs2 INTO rowv1;

IF FOUND THEN
cou1 := cou1 + 1 ;
END IF;
insert into a values(3);
insert into a values(3);
insert into a values(3);
--update a set a=4 where a=3;

FETCH curs2 INTO rowv2;
IF FOUND THEN
cou1 := cou1 + 1 ;
END IF;

FETCH curs2 INTO rowv2;
IF FOUND THEN
cou1 := cou1 + 1 ;
END IF;

FETCH curs2 INTO rowv2;
IF FOUND THEN
cou1 := cou1 + 1 ;
END IF;

close curs2;
RETURN cou1;
END;
$$ LANGUAGE plpgsql;
select aa();

the result is 1; the index scan is not updated;
because static bool
_bt_readpage(IndexScanDesc scan, ScanDirection dir, OffsetNumber offnum)
copy a old version, and not update when new version come.