BUG #2050: Bad plan by using of LIKE

The following bug has been logged online:

Bug reference:      2050
Logged by:          Johannes
Email address:      postgres@arltus.de
PostgreSQL version: 8.0.3
Operating system:   i686-pc-linux-gnu, compiled by GCC i686-pc-linux-gnu-gcc
(GCC) 3.3.5-20050130 (Gentoo 3.3.5.20050130-r1, ssp-3.3.5.20050130-1,
pie-8.7.7.1
Description:        Bad plan by using of LIKE
Details:

I use this table:
CREATE TABLE content (
    title character(64) NOT NULL,
    content_htm character(128) NOT NULL,
    id serial NOT NULL
);
ALTER TABLE ONLY content ADD CONSTRAINT p_key PRIMARY KEY (id);
CREATE INDEX idx1 ON content USING btree (title);

I have filling this with 1000000 rows by dbmonster and use this statement,
after analyze und reindex:

SELECT title FROM content WHERE title LIKE 'teane%';

It uses to long time, I compare this with sybase
and I was disappointed, but explain shows the reason.


EXPLAIN SELECT title FROM content WHERE title LIKE 'teane%';
Seq Scan on content  (cost=0.00..75647.59 rows=1 width=68)
   Filter: (title ~~ 'teane%'::text)

Now I change this SQL to:
SELECT title FROM content WHERE title >= 'teane' AND title < 'teanez';

I think it means the same but it works very fast by using my index.
(1600 ms up to 2 ms !! sybase uses 4 ms)

Explain shows the reason:

EXPLAIN SELECT title FROM content WHERE title >= 'teane' AND title <
'teanez';
 Index Scan using idx1 on content  (cost=0.00..4.02 rows=1 width=68)
   Index Cond: ((title >= 'teane'::bpchar) AND (title < 'teanez'::bpchar))

I'am not sure is this a bug or not, but without some modifications in the
postgres.conf the difference are more significant ( 22.530 ms ! to 2 ms).