1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
|
Performance guidelines
======================
The translations of each model is stored in a separate table.
In some cases, this may cause in N-query issue.
*django-parler* offers two ways to handle the performance of the dabase.
Caching
-------
All translated contents is cached by default.
Hence, when an object is read again, no query is performed.
This works out of the box when the project uses a proper caching:
.. code-block:: python
CACHES = {
'default': {
'BACKEND': 'django.core.cache.backends.memcached.MemcachedCache',
'KEY_PREFIX': 'mysite.production', # Change this
'LOCATION': '127.0.0.1:11211',
'TIMEOUT': 24*3600
},
}
You have to make sure your project has the proper backend support available::
pip install python-memcached
Now, the translation table only has to be read once per day.
Query prefetching
-----------------
By using :func:`~django.db.models.query.QuerySet.prefetch_related`,
all translations can be fetched in a single query:
.. code-block:: python
object_list = MyModel.objects.prefetch_related('translations')
for obj in object_list:
print obj.title # reads translated title from the prefetched queryset
Note that the prefetch reads the information of all languages,
not just the currently active language.
When you display translated objects in a form, e.g. a select list, you can prefetch the queryset too:
.. code-block:: python
class MyModelAdminForm(TranslatableModelForm):
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
self.fields['some_field'].queryset = self.fields['some_field'].queryset.prefetch_related('translations')
|
