Don't count users when CMS_RAW_ID_USERS=True

When using CMS_RAW_ID_USERS=True on a Postgres database with many users,
counting the users is slow and will always yield the same result.

Only count users when using an integer value as a threshold and reuse
the same logic for both PagePermissionInlineAdmin and
GlobalPagePermissionAdmin.

CHANGELOG.rst

@@ -6,6 +6,8 @@ Changelog
 unreleased
 ==========
 
+* Improved performance when using CMS_RAW_ID_USERS=True on a Postgres DB with many users
+
 3.9.0 (2021-06-30)
 ==================
 

cms/admin/permissionadmin.py

@@ -29,6 +29,29 @@ class TabularInline(admin.TabularInline):
     pass
 
 
+def users_exceed_threshold():
+    """
+    Check if the number of users exceed the configured threshold. Only bother
+    counting the users when using an integer threshold, otherwise return the
+    value of the setting to avoid a potentially expensive DB query.
+    """
+    threshold = get_cms_setting('RAW_ID_USERS')
+
+    # Don't bother counting the users when not using an integer threshold
+    if threshold is True or threshold is False:
+        return threshold
+
+    # Given a fresh django-cms install and a django settings with the
+    # CMS_RAW_ID_USERS = CMS_PERMISSION = True
+    # django throws an OperationalError when running
+    # ./manage migrate
+    # because auth_user doesn't exists yet
+    try:
+        return get_user_model().objects.count() > threshold
+    except OperationalError:
+        return False
+
+
 class PagePermissionInlineAdmin(TabularInline):
     model = PagePermission
     # use special form, so we can override of user and group field
@@ -52,19 +75,7 @@ def has_add_permission(self, request, obj=None):
     @classproperty
     def raw_id_fields(cls):
         # Dynamically set raw_id_fields based on settings
-        threshold = get_cms_setting('RAW_ID_USERS')
-
-        # Given a fresh django-cms install and a django settings with the
-        # CMS_RAW_ID_USERS = CMS_PERMISSION = True
-        # django throws an OperationalError when running
-        # ./manage migrate
-        # because auth_user doesn't exists yet
-        try:
-            threshold = threshold and get_user_model().objects.count() > threshold
-        except OperationalError:
-            threshold = False
-
-        return ['user'] if threshold else []
+        return ['user'] if users_exceed_threshold() else []
 
     def get_queryset(self, request):
         """
@@ -133,13 +144,8 @@ class GlobalPagePermissionAdmin(admin.ModelAdmin):
     list_filter.append('can_change_advanced_settings')
 
     def get_list_filter(self, request):
-        threshold = get_cms_setting('RAW_ID_USERS')
-        try:
-            threshold = threshold and get_user_model().objects.count() > threshold
-        except OperationalError:
-            threshold = False
         filter_copy = deepcopy(self.list_filter)
-        if threshold:
+        if users_exceed_threshold():
             filter_copy.remove('user')
         return filter_copy
 
@@ -158,19 +164,7 @@ def has_delete_permission(self, request, obj=None):
     @classproperty
     def raw_id_fields(cls):
         # Dynamically set raw_id_fields based on settings
-        threshold = get_cms_setting('RAW_ID_USERS')
-
-        # Given a fresh django-cms install and a django settings with the
-        # CMS_RAW_ID_USERS = CMS_PERMISSION = True
-        # django throws an OperationalError when running
-        # ./manage migrate
-        # because auth_user doesn't exists yet
-        try:
-            threshold = threshold and get_user_model().objects.count() > threshold
-        except OperationalError:
-            threshold = False
-
-        return ['user'] if threshold else []
+        return ['user'] if users_exceed_threshold() else []
 
 
 if get_cms_setting('PERMISSION'):

cms/tests/test_admin.py

@@ -18,6 +18,7 @@
 from cms import api
 from cms.api import create_page, create_title, add_plugin, publish_page
 from cms.admin.pageadmin import PageAdmin
+from cms.admin.permissionadmin import GlobalPagePermissionAdmin, PagePermissionInlineAdmin
 from cms.constants import TEMPLATE_INHERITANCE_MAGIC
 from cms.models import StaticPlaceholder
 from cms.models.pagemodel import Page, PageType
@@ -1385,3 +1386,54 @@ def test_move_node(self):
         #       ⊢ Beta
         #   ⊢ Delta
         #       ⊢ Gamma
+
+
+class AdminPerformanceTests(AdminTestsBase):
+
+    def test_raw_id_threshold_page_permission_inline_admin(self):
+        """
+        Only count users when using an integer value as threshold for
+        CMS_RAW_ID_USERS.
+        """
+        with self.settings(CMS_RAW_ID_USERS=1):
+            with self.assertNumQueries(1):
+                self.assertEqual(PagePermissionInlineAdmin.raw_id_fields, [])
+
+        # Create users to check if threshold is honored
+        self._get_guys()
+
+        with self.settings(CMS_RAW_ID_USERS=False):
+            with self.assertNumQueries(0):
+                self.assertEqual(PagePermissionInlineAdmin.raw_id_fields, [])
+
+        with self.settings(CMS_RAW_ID_USERS=True):
+            with self.assertNumQueries(0):
+                self.assertEqual(PagePermissionInlineAdmin.raw_id_fields, ['user'])
+
+        with self.settings(CMS_RAW_ID_USERS=1):
+            with self.assertNumQueries(1):
+                self.assertEqual(PagePermissionInlineAdmin.raw_id_fields, ['user'])
+
+    def test_raw_id_threshold_global_page_permission_admin(self):
+        """
+        Only count users when using an integer value as threshold for
+        CMS_RAW_ID_USERS.
+        """
+        with self.settings(CMS_RAW_ID_USERS=1):
+            with self.assertNumQueries(1):
+                self.assertEqual(GlobalPagePermissionAdmin.raw_id_fields, [])
+
+        # Create users to check if threshold is honored
+        self._get_guys()
+
+        with self.settings(CMS_RAW_ID_USERS=False):
+            with self.assertNumQueries(0):
+                self.assertEqual(GlobalPagePermissionAdmin.raw_id_fields, [])
+
+        with self.settings(CMS_RAW_ID_USERS=True):
+            with self.assertNumQueries(0):
+                self.assertEqual(GlobalPagePermissionAdmin.raw_id_fields, ['user'])
+
+        with self.settings(CMS_RAW_ID_USERS=1):
+            with self.assertNumQueries(1):
+                self.assertEqual(GlobalPagePermissionAdmin.raw_id_fields, ['user'])