id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
35405	Use @cached_property for FieldCacheMixin cache key	Adam Johnson	Adam Johnson	"`FieldCacheMixin` is used by related fields to track their cached values. Its existing design means calling `get_cache_name()` for each operation, even though that value doesn’t change. Changing `get_cache_name()` into a cached property can thus save a bunch of small but useless function calls working with related fields.

I profiled this change by using cProfile on a selection of tests using related fields:

{{{
$ python -m cProfile -s cumtime -o profile runtests.py --parallel 1 foreign_object *relat*
...
Found 399 test(s).
...
}}}

Before, there were 12,520 function calls:

{{{
$ python -m pstats profile <<< 'sort cumtime
stats 10000' | rg get_cache_name
    11193    0.001    0.000    0.001    0.000 /Users/chainz/Documents/Projects/django/django/db/models/fields/related.py:512(get_cache_name)
      712    0.000    0.000    0.000    0.000 /Users/chainz/Documents/Projects/django/django/db/models/fields/reverse_related.py:251(get_cache_name)
      615    0.000    0.000    0.000    0.000 /Users/chainz/Documents/Projects/django/django/contrib/contenttypes/fields.py:143(get_cache_name)
}}}

After, there are just 227 calls (should be one per related field):

{{{
$ python -m pstats profile <<< 'sort cumtime
stats 10000' | rg cache_name
      172    0.000    0.000    0.000    0.000 /Users/chainz/Documents/Projects/django/django/db/models/fields/related.py:512(cache_name)
       34    0.000    0.000    0.000    0.000 /Users/chainz/Documents/Projects/django/django/db/models/fields/reverse_related.py:251(cache_name)
       21    0.000    0.000    0.000    0.000 /Users/chainz/Documents/Projects/django/django/contrib/contenttypes/fields.py:143(cache_name)
}}}

The time saving is minimal here. It may be notable when working with a lot of model instances."	Cleanup/optimization	closed	Database layer (models, ORM)	dev	Normal	fixed			Ready for checkin	1	0	0	0	0	0