7.3.2 indexes in PL/PgSQL

I have select like that:

SELECT playerid FROM players WHERE nickname = 'qq' AND password = 'qqq';

query plan:

auction=# explain SELECT playerid FROM players WHERE nickname = 'qq' AND
password = 'qqq';
QUERY PLAN

--------------------------------------------------------------------------------------------------
Index Scan using nick_pass on players (cost=0.00..6.01 rows=1 width=4)
Index Cond: ((nickname = 'qq'::character varying) AND ("password" = 'qqq'::character varying))
(2 rows)

but in procedure on PL/PgSQL this select realy do sequense scan:

--- cut from create_session procedure ---
SELECT playerid INTO _playerid FROM players WHERE nickname = _nickname AND password = _passwd;
--- cut ---

Where i'm wrong? or that realy bug?

always thanks.

Diabolo.

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