A more robust version of the django 'cleanup' command, which requires less effort from the transaction handler of your database.

cleanup_nocrash.py

from datetime import datetime, timedelta

from django.core.management.base import NoArgsCommand
from django.contrib.sessions.models import Session
from django.db.transaction import commit

class Command(NoArgsCommand):
    def handle_noargs(self, **options):
        """ the conventional django cleanup method crashes when there's a few million records in django_sessions
            so, do this without crashing.
        """
        yesterday = datetime.today() - timedelta(days=2)
        count = 0
        oldest = Session.objects.all().order_by('expire_date')[:1]
        if oldest:
            oldest = oldest[0]
            old_date = oldest.expire_date

            while old_date < yesterday:
                sessions = Session.objects.filter(expire_date__lt=old_date)
                count += sessions.count()
                if sessions.count() > 10000:
                    pks = sessions.values_list('session_key', flat=True)
                    for i in xrange(0,len(pks),10000):
                        chunk = pks[i:i+10000]
                        Session.objects.filter(session_key__in=chunk).delete()
                        commit()
                else:
                    sessions.delete()
                    commit()    # this is the key. circumventing django's desire to do this in a single transaction
                old_date += timedelta(days=1)

            print 'All done!'
            print count, "records deleted"