table size is bigger than expected

Hey,

I'm a new user of PostgreSQL. I found one of my tables is taking unexpectedly large space:

select pg_size_pretty(pg_relation_size('archive_files'));
pg_size_pretty
----------------
1113 MB
The structure of this table is like:
Column | Type | Modifiers
------------+-------------------+-----------
archive_id | integer | not null
dir_no | integer | not null
fname | character varying | not null
type | smallint | not null
size | bigint | not null
mod_date | integer | not null
blocks | bigint | not null
blk_offset | bigint | not null

the field "fname" stores file names without any directory names. In our case, each record is expected to take around 300 bytes.

However, this table contains 934829 records, which means each record takes about 1.2KB.

I did vaccum, reindex, the size is still the same. Is there anything else that I can do?

Thanks!

John