Locking issue

Hi everyone,

I am running 'PostgreSQL 9.1.4, compiled by Visual
C++ build 1500, 64-bit' on a Windows Server and I am having some Locking
issues. Maybe anyone can let me know what is wrong with my example:

Imagine that we have two tables (t_users and t_records)

t_users contains 1 row per each user

t_records is a regular transactional table which contains a
field userid with the user that created/updated the row.

CREATE TABLE
t_users(userid VARCHAR(10),

loginattempts INTEGER,

CONSTRAINT pk_t_users PRIMARY KEY (userid));

CREATE TABLE
t_records(recordid INTEGER,

description VARCHAR(100),

userid VARCHAR(10)

REFERENCES
t_users(userid) MATCH SIMPLE

ON UPDATE NO ACTION ON DELETE NO ACTION);

INSERT INTO t_users (userid,
loginattempts) VALUES ('andrew',0);

The user logs in and starts a
background process that contains a long TRANSACTION which
updates/inserts rows in t_records with the user's
id. This process keeps the transaction
open for 1 hour while it works with code like:

/* Session #1 */

BEGIN TRANSACTION

/* Big loop */

INSERT INTO t_records (recordid,
description, userid) VALUES (1,'Record #1','andrew');

/*… SOME CODE HERE */

/*.... */

/* Once the loop ends, it will COMMIT/ROLLBACK the transaction */

ROLLBACK
/ COMMIT

/* END of Session #1 */

The user logs out and then tries
to log back in after 30 minutes. The login hangs because we are not be able to update records on t_user (for
userids used on Session#1 ) until the transaction on Session#1 is done:

/* SESSION #2 */

UPDATE t_users SET
loginattempts = 1 WHERE userid = 'andrew'

/*END SESSION #2*/

Any comments or feedback will be appreciated.
Regards,
Andrew Jaimes