Queries with timestamp II

Hi all,

  First of all thanks to Josh and Richard for their replies. What I have
done to test
their indications is the following. I have created a new table identical to
STATISTICS,
and an index over the TIMESTAMP_IN field.

CREATE TABLE STATISTICS2
(
  STATISTIC_ID    NUMERIC(10) NOT NULL DEFAULT
                  NEXTVAL('STATISTIC_ID_SEQ')
                  CONSTRAINT pk_st_statistic2_id PRIMARY KEY,
  TIMESTAMP_IN    TIMESTAMP,
  VALUE           NUMERIC(10)
);

CREATE INDEX i_stats2_tin ON STATISTICS2(TIMESTAMP_IN);

After that I inserted the data from STATISTICS and vacuumed the DB:

  INSERT INTO STATISTICS2 ( SELECT * FROM STATISTICS );
  vacuumdb -f -z -d test

once the vacuum has finished I do the following query

explain analyze select * from statistics2 where timestamp_in <
to_timestamp( '20031201', 'YYYYMMDD' );
NOTICE:  QUERY PLAN:

Seq Scan on statistics2  (cost=0.00..638.00 rows=9289 width=35) (actual
time=0.41..688.34 rows=27867 loops=1)
Total runtime: 730.82 msec

That query is not using the index. Anybody knows what I'm doing wrong?

Thank you very much

--
Arnau