In-memory per-instance cache, scalability problem about django-page-cms HOT 10 CLOSED

Hi,

"Problem. Every content-item ever fetched stays in that dict until Page class is unloaded (forked process dies)"

For me every Page instance should be garbage collected after the view as been executed. The cache dict should be GC as well isn't it?

from django-page-cms.

The dict we are talking about is the class attribute. It will be there until class is unloaded, this isn't implemented in standard CPython as far as I know...

from django-page-cms.

Well then it's a bug that need to be fixed. This cache dict are supposed to be by instance only: data attributes, not class attribute. This is a programmatic error that will certainly create some weird bugs.

from django-page-cms.

Here is the fix for the issue:

http://github.com/batiste/django-page-cms/commit/bd5af3a430c8b2b8f7478a73eb77df8a4c2118a5

The goal of the cache was only to save some hits on the database/memcached on the instance level, like to avoid to hit the database if the user do that:

{{ page.title }} {{ page.title }} {{ page.title }}

What do you think?

from django-page-cms.

Yes, this should fix it. Thanks!

from django-page-cms.

Fixed

from django-page-cms.

Sorry for joining in late...

the issue was non-existent.

As a matter of fact you were declaring the class attributes
but you were always using instance attributes:

in managers.py in method get_content() (around line 215):

       if page._content_dict is None:
            page._content_dict = dict()
        if page._content_dict.get(key, None):
            content_dict = page._content_dict.get(key)
        else:
            content_dict = cache.get(key)

"page" is a Page instance and the first assignment overrides the class attribute.

from django-page-cms.

Are you saying that everything is ok? I don't quite remember everything.

from django-page-cms.

everything was OK even before the fix.

The fix just makes it easyer to understand that you're using an instance attribute. And that's good.

by the way, I like this cms, we're using it for our website and I'll be posting some pull requests shortly. Thanks!

from django-page-cms.

Nice. I am waiting to see some contributions. Cheers.

from django-page-cms.