The problem sums up to: I expect when committing that something like "saving a file" happens...everybody, and I mean everybody trying to access that file later would read the same thing. SQlite, MSSQL, Postgresql, Oracle adapters work this way, and I assume also mongo and couchdb. I tried to read the PEP for the DBAPI and saw no explicit references to what committing should do in reference to a multiprocess environment (i.e. if commit should "save" the changes and make them available for other processes). However, I'm not a python guru to rule that out, I'm just saying that from a DAL point of view having to commit before reading to see records changed/inserted by other processes is required ONLY from mysql.
On Tuesday, August 14, 2012 6:15:14 AM UTC+2, Massimo Di Pierro wrote: > > Should we change the settings in the Adapter? > > On Monday, 13 August 2012 17:21:09 UTC-5, Niphlod wrote: >> >> The most probable cause is the transaction isolation "problem" with mysql >> as explained in >> https://groups.google.com/d/msg/web2py/qLHP3iYz8Lo/Ly2wqK4qZZgJ >> >> I'm starting to think that it's the only adapter behaving differently. >> >> On Monday, August 13, 2012 11:46:11 PM UTC+2, Florian Letsch wrote: >>> >>> Yes, I am using mysql. >>> >>> I've accidentally posted this twice [0] on the group (sorry for that). >>> Anthony asked: >>> > How are emails added to the database -- does that happen within the >>> application, or also in a script? >>> >>> Emails are added to the database from within the application (a >>> controller function adds a confirmation email to the queue) >>> >>> [0] >>> https://groups.google.com/forum/?fromgroups#!topic/web2py/YT2jDMea6lU >>> >>> On Sunday, 12 August 2012 07:17:39 UTC+12, Massimo Di Pierro wrote: >>>> >>>> Are you using mysql? >>>> >>>> On Friday, 10 August 2012 23:11:03 UTC-5, Florian Letsch wrote: >>>>> >>>>> 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 >>>>> >>>>> --
