Hello again,
It seems that db.commit() is necessary to get the query to reflect the
changed state of the database for some reason.
The simple code at the end of this message illustrates the problem.
Starting two ipython sessions, and running side1() in one, and then
side2() in the other, if the db.commit() line in the side1 loop is
removed, it will loop forever even though the database is actually
updated by side2.
This work around works, but I'd like to understand what's going on.
Thanks,
G
======== dbtest.py =======
from gluon import *
import time
db = DAL('mysql://web2py:web2py@localhost:33306/web2py',
folder = '/home/dl/trunkw2p/web2py/applications/
devel/databases')
db.define_table(
'test',
Field('status',requires=IS_NOT_EMPTY()))
def side1():
id = db.test.insert(status='queued')
db.commit()
query = (db.test.id == id) & ((db.test.status == 'start') |
(db.test.status == 'queued'))
while db(query).count():
print "query", [str(x) for x in db(query).select()]
db.commit() # !!! Comment out this line and this while loop
will never exit
time.sleep(0.1)
print "done"
def side2():
id = db(db.test.id>0).select().last().id
print "found id",id
time.sleep(5)
db(db.test.id == id).update(status='start')
db.commit()
print "finishing"
time.sleep(5)
db(db.test.id == id).update(status='done')
db.commit()
print "finished"
