Some time ago Webfaction notified me "Memory usage over your limit" (80MB) It's taken me ages to find this darn memory leak! It was one short line that didn't even add functionality to my users.
I have 2000 items (cars) in a database table, which my users can search through. After the webfaction memory warning, I optimised the code so that my pagination was in place so that in theory only 10 items were loaded into memory per page view. But still my memory usage was massive. Anyway today I notice the line: msg =cgi.escape(str(len(cars)))+'<br>\n' # which stores a debugging message for me That line was between these two lines (spread out by other stuff and comments): cars = Car.objects.filter(...) #upto 2000 items msg =... len(cars) # can you see the massive memory use here? paginator = Paginator(cars, per_page=10) As you all know Django has been well designed to be lazy at executing database queries, this is how the Paginator can take a queryset representing all 2000 items, and return just 10 having loaded only those 10 into memory. So what's wrong with len(cars)? Well, it forces the db query to be executed in full (before the Paginator line) and loaded into memory. This caused massive memory use and made me go over my limit. If I'd wanted the total number of cars, or number of results, I should've done Car.objects.filter(...).count() which actually executes a SELECT COUNT(*) which returns a single number, rather than, in essence, a huge list. Maybe this post will help someone else also one thing I don't understand: Why wasn't the memory returned to me after each page view? Why was an apache off/on necessary to clear memory? And is there anything I can do to help clear memory that been used, but not returned to the system? --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
