Broken index?

Hi,

I am having a problem with duplicates appearing in a unique index and I
have no idea why. The database in question has a high number of inserts and
updates to a table (around 5000-10000 per hour) and occasionally duplicates
slip through. To provide some background, I have listed the properties of
the table and the index in question:

player_stats=> \d player
                                Table "player"
  Attribute   |     Type     |                    Modifier

--------------+--------------+-------------------------------------------------
 id           | integer      | not null default
nextval('player_serial'::text)
 name         | varchar(50)  | not null
 password     | varchar(50)  |
 icqnumber    | varchar(20)  |
 emailaddress | varchar(255) |
 flatname     | varchar(50)  |
Indices: player_flatname_idx,
         player_flatname_unique_idx,
         player_id_idx,
         player_name_key,
         player_pkey

player_stats=> \d player_name_key
 Index "player_name_key"
 Attribute |    Type
-----------+-------------
 name      | varchar(50)
unique btree

The attribute that appears to sometimes allow duplicates to be inserted is
'name' and only 'player_name_key' operates on this attribute.

I can't say how often these duplicates slip through, but it seems to only
happen *very* rarely, but is obviously completely mangling my data. Not
only that, but VACUUM ANALYZE is taking *days* to complete and I can only
assume this is due to these duplicates. The 'player' table contains around
180000 records, so if this fall of in performance when running vacuum can
be associated with this, I'd appreciate some feedback.

Anyway, I'd just like to know if anyone else has had this problem or if it
is a known bug. All the database operations are handled through the JDBC
driver and transactions are used to bundle these operations in to sets of
20 (maybe a potential problem here?).

I'd *really* appreciate some feedback as it is becoming a very annoying
problem. If you'd like to check the site out where it is used, go to
http://www.fragmeter.com.

Cheers!
--
Paul Green
Programmer

Jippii Midlands
85 London Road,
Leicester,
England,
LE2 0PF.
tel: 0116 2230662
fax: 0116 2221305

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