Why not have a "user.membership_exp_date" field. If a user signs up on day 0, the membership_exp_date could be set to now() + 5 days.
This will let you query the results in real-time. No cron job needed. On Thu, Jul 15, 2010 at 12:27 PM, Continuation <selforgani...@gmail.com>wrote: > I have groups that users can join. > > The difference between this and "normal" groups is that membership is > temporary - a user decides on joining to be a member for 5 days, a > week, 2 weeks, etc (choices are pre-defined). Or potentially all > memberships could be set to be of the same length - say a week - if > that makes thing simpler. > > I'd like to have a running tally of the number of members of each > group. The number doesn't need to be accurate up to the last second. > But it can't be *too* out of date either - say, should be updated once > a day. > > The "obvious" way to calculate the number of members seems to be > running a cron job, say daily, and go through every member of every > group one by one. If a membership has expired, remove that member > from the group and decrement the group's membership count by 1. > > That approach seems very inefficient and not very scalable. With a > large number of groups, it could take forever. > > Can you think of a better way to do this? The membership counts do > not need to be accurate to the latest second. It can be approximate > and (slightly) out of date. Also if it makes a difference all > memberships can be set to be of the same length, say a week. > > -- > You received this message because you are subscribed to the Google Groups > "Django users" group. > To post to this group, send email to django-us...@googlegroups.com. > To unsubscribe from this group, send email to > django-users+unsubscr...@googlegroups.com<django-users%2bunsubscr...@googlegroups.com> > . > For more options, visit this group at > http://groups.google.com/group/django-users?hl=en. > > -- Greg Pelly CEO / CTO, Munchly Inc. -- You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-us...@googlegroups.com. To unsubscribe from this group, send email to django-users+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/django-users?hl=en.
