Performance of MIN() and MAX()

PGSQL 6.5.0, FreeBSD 3.2, Intel Pentium II 366MHz, 128 MB

The table below was filled with about 1,000,000 records. Then a bunch of
indexes was created and a VACUUM executed.

I was under impression that when max(<primary key>) is called, it should
just take the value from the index. I believe it should not do any kind of
scan. But, in fact, it scans the table.

select max(id) from ItemBars

takes well over 10 seconds to complete. It's almost instantaneous on MSSQL
or on Interbase. Something is clearly wrong. MAX() on the primary key should
not take so much time. Am I doing something wrong? Is it a known bug? If
it's a bug then it's a show stopper for us. How can I help fixing it?

CREATE TABLE ItemBars (       ID              SERIAL          PRIMARY KEY     ,       ItemID          INT
NOTNULL        ,       Interv          INT             NOT NULL        ,       StaTS           DATETIME        NOT NULL
      ,       EndTS           DATETIME        NOT NULL        ,       IsActive        BOOL            NOT NULL        ,
     Opn             FLOAT(7)        NOT NULL        ,       High            FLOAT(7)        NOT NULL        ,
Low            FLOAT(7)        NOT NULL        ,       Cls             FLOAT(7)        NOT NULL        ,       Vol
      INT             NOT NULL
 
);

Gene Sokolov.