Jeremy, Thank-you for some more good tips. The end of the error message is:
> > Can't pickle : it's not the same object as > > psycopg2.tz.FixedOffsetTimezone I am pretty sure there is nothing after that. I will check into the sqlalchemy datetime wrt pickling. The error appears to occur 50% of the time, but maybe the session only gets pickled 50% of the time, and the pickling is failing all the time. If it is expecting a psycopg2 datetime, but I am providing a sqlalchemy datetime - don't know why it would be expecting the psycopg datetime in the first place. Thank-you for straightening me out on my misinterpretation of the trace. I see what you mean. I may temporarily remove the update_date and see if the problem goes away - an confirmation that this is where the problem is. On Apr 5, 3:59 pm, "Jeremy Dunck" <[EMAIL PROTECTED]> wrote: > On 4/5/07, paceman <[EMAIL PROTECTED]> wrote: > > > One is an update_date > > that comes from > > a postgresql database > > Yes, the original error reported is: > > > > "/var/lib/python-support/python2.4/django/contrib/sessions/models.py", > > > line 10, in encode pickled = pickle.dumps(session_dict) PicklingError: > > > Can't pickle : it's not the same object as > > > psycopg2.tz.FixedOffsetTimezone > > Which suggests that it has something to do with psycopg2. :) > Unfortunately, it looks like part of your error message was eaten. > There should be something just after "Can't pickle". Can you send > that again? > > Anyway, the datetimes returned by psycopg2 are a subclass defined in > psycopg2. The python docs actually have a specific admonition about > pickling tzinfo:http://www.python.org/doc/2.3.5/lib/datetime-tzinfo.html > > psycopg2's tzinfo subclass implements this. > > Is it possible that the tzinfo attached to the datetime you're storing > in the session is not picklable? > > >>> import psycopg2 > >>> c=psycopg2.connect("dbname=sekrit") > >>> cur = c.cursor() > >>> cur.execute('select current_timestamp') > >>> r = cur.fet > >>> r = cur.fetchone() > >>> r > > (datetime.datetime(2007, 4, 5, 14, 46, 57, 754021, > tzinfo=<psycopg2.tz.FixedOffsetTimezone object at 0xb776bfcc>),) > > >>> import pickle > >>> pickle.dumps(r) > > "(cdatetime\ndatetime\np0\n(S'\\x07\\xd7\\x04\\x05\\x0e.9\\x0b\\x81e'\np1\ncpsycopg2.tz\nFixedOffsetTimezone\np2\n(tRp3\n(dp4\nS'_offset'\np5\ncdatetime\ntimedelta\np6\n(I-1\nI68400\nI0\ntp7\nRp8\nsbtp9\nRp10\ntp11\n." > > > What throws me off, is the pickling error seems to be complaining > > about the Session cookie name which > > is a datetime that django takes care of - not me. > > No, that's one line in the stack trace, but it's not the line with the > error. That line forces pickling of the session object, which is > where the problem is. It has nothing to do with the cookie. :) > > > I thought I was using straightforward django technique, except for > > using sqlalchemy to access > > my database tables. > > Hmm, I have no idea how SQLAlchemy is constructing its datetime > instances. It would probably be worth looking at, since using > SQLAlchemy is probably fairly unusual with Django+psycopg2. > > -Jeremy --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-users@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/django-users?hl=en -~----------~----~----~----~------~----~------~--~---
