''Part of DjangoSpecifications''

= Threading improvements in Django =

According to tickets #5632, #6950 and discussions http://groups.google.com/group/django-users/browse_frm/thread/a7d42475b66530bd, http://groups.google.com/group/django-developers/browse_thread/thread/fbcfa88c997d1bb3, at least the following components of Django are not entirely thread-safe:
 * django.template.loader
 * django.db.models
 * django.contrib.sessions

This specification outlines the changes that need to be implemented to solve these issues.

A related task is to identify other components not mentioned here that have threading issues.

See #1442 and http://groups.google.com/group/django-developers/browse_thread/thread/905f79e350525c95 for threading discussions.

== Globals ==

There are three types of globals:
 1. read-only globals that are never assigned to (THREAD-SAFE),
 1. globals assigned to in a function by using the `global` keyword (NOT THREAD-SAFE),
 1. global mutable data structures (lists and dictionaries, also instances) that are assigned to at module level but whose elements are modified in functions and that are accessed without using the `global` keyword (NOT THREAD-SAFE unless never modified).

We won't deal with read-only globals. `grep` in Django source finds the following other globals.

=== Globals accessed with the `global` keyword ===

{{{
$ grep -r '^[[:space:]]*global ' django/ | egrep -v '(\.svn|\.html|\.css|\.pyc|doctest)' | sort | uniq
}}}

yields the following results

{{{
django/contrib/sites/models.py:        global SITE_CACHE
django/core/management/__init__.py:    global _commands
django/template/context.py:    global _standard_context_processors
django/template/__init__.py:                    global invalid_var_format_string
django/template/loader.py:    global template_source_loaders
django/utils/translation/trans_real.py:    global _accepted
django/utils/translation/trans_real.py:    global _active
django/utils/translation/trans_real.py:    global _default, _active
django/utils/translation/trans_real.py:        global _translations
django/utils/translation/trans_real.py:    global _translations
}}}

=== Global dictionaries ===

=== Global lists ===