[web2py] Sending emails with background queue problem

[Florian Letsch]

I want to send emails using a background queue as described in the web2py book: 
http://web2py.com/books/default/chapter/29/8#Sending-messages-using-a-background-task

However, the queue only sends emails that have been in the database when I 
start the script. Database entries added lateron don't get picked up by the 
script. The only way I can achieve that is to add another db.commit() before 
the select(). I am sure this is not supposed to be necessary. Does anyone know 
why this is happening?

import time
while True:
    db.commit() # Only works if I add this line
    rows = db(db.queue.status=='pending').select()
    for row in rows:
        if mail.send(to=row.email,
            subject=row.subject,
            message=row.message):
            row.update_record(status='sent')
        else:
            row.update_record(status='failed')
        db.commit()
    time.sleep(60) # check every minute

--