duplicate primary key

Hello.

I'm a bit shocked. During import/export of our database we've found a
duplicate primary key.

# \d player

Table "public.player"
Column | Type |
Modifiers

--------------------+-----------------------------+------------------------------------------------------------------------------------------------------------
id | integer | not null default
nextval('player_id_seq'::regclass)
...
Indexes:
"pk_id" PRIMARY KEY, btree (id)
...

# select * from pg_indexes where indexname='pk_id';
schemaname | tablename | indexname | tablespace |
indexdef
------------+-----------+-----------+------------+------------------------------------------------------
public | player | pk_id | | CREATE UNIQUE INDEX
pk_id ON player USING btree (id)

# select * from pg_constraint where conname='pk_id';
-[ RECORD 1 ]-+------
conname | pk_id
connamespace | 2200
contype | p
condeferrable | f
condeferred | f
convalidated | t
conrelid | 18319
contypid | 0
conindid | 18640
confrelid | 0
confupdtype |
confdeltype |
confmatchtype |
conislocal | t
coninhcount | 0
connoinherit | t
conkey | {1}
confkey |
conpfeqop |
conppeqop |
conffeqop |
conexclop |
conbin |
consrc |

# select count(*) from player where id=122224875;
-[ RECORD 1 ]
count | 2

The records are identical, besides ctid,xmin,xmax

# select tableoid,ctid,id,xmin,xmax from player where id=122224875;
tableoid | ctid | id | xmin | xmax
----------+--------------+-----------+------------+------------
18319 | (9982129,2) | 122224875 | 3149449600 | 3152681810
18319 | (9976870,49) | 122224875 | 3149448769 | 3152328995

I don't understand how this could have happened....

--
Best regards,
Alexander Pyhalov, 3152328995
system administrator of Southern Federal University IT department