⚡️(backend) improve trashbin endpoint performance (#1495)

The trashbin endpoint is slow. To filter documents the user has owner
access, we use a subquery to compute the roles and then filter on this
subquery. This is very slow. To improve it, we use the same way to
filter children used in the tree endpoint. First we look for all highest
ancestors the user has access on with the owner role. Then we create one
queryset filtering on all the docs starting by the given path and are
deleted.

Author: lunika

CHANGELOG.md

@@ -12,6 +12,10 @@ and this project adheres to
   - ♿ add missing aria-label to add sub-doc button for accessib… #1480
   - ♿ add missing aria-label to more options button on sub-docs #1481
 
+### Fixed
+
+- ⚡️(backend) improve trashbin endpoint performance
+
 ## [3.8.0] - 2025-10-14
 
 ### Added

src/backend/core/api/viewsets.py

@@ -623,12 +623,29 @@ def trashbin(self, request, *args, **kwargs):
         The selected documents are those deleted within the cutoff period defined in the
         settings (see TRASHBIN_CUTOFF_DAYS), before they are considered permanently deleted.
         """
+
+        if not request.user.is_authenticated:
+            return self.get_response_for_queryset(self.queryset.none())
+
+        access_documents_paths = (
+            models.DocumentAccess.objects.select_related("document")
+            .filter(
+                db.Q(user=self.request.user) | db.Q(team__in=self.request.user.teams),
+                role=models.RoleChoices.OWNER,
+            )
+            .values_list("document__path", flat=True)
+        )
+
+        children_clause = db.Q()
+        for path in access_documents_paths:
+            children_clause |= db.Q(path__startswith=path)
+
         queryset = self.queryset.filter(
+            children_clause,
             deleted_at__isnull=False,
             deleted_at__gte=models.get_trashbin_cutoff(),
         )
         queryset = queryset.annotate_user_roles(self.request.user)
-        queryset = queryset.filter(user_roles__contains=[models.RoleChoices.OWNER])
 
         return self.get_response_for_queryset(queryset)
 

src/backend/core/tests/documents/test_api_documents_trashbin.py

@@ -166,10 +166,10 @@ def test_api_documents_trashbin_authenticated_direct(django_assert_num_queries):
 
     expected_ids = {str(document1.id), str(document2.id), str(document3.id)}
 
-    with django_assert_num_queries(10):
+    with django_assert_num_queries(11):
         response = client.get("/api/v1.0/documents/trashbin/")
 
-    with django_assert_num_queries(4):
+    with django_assert_num_queries(5):
         response = client.get("/api/v1.0/documents/trashbin/")
 
     assert response.status_code == 200
@@ -208,10 +208,10 @@ def test_api_documents_trashbin_authenticated_via_team(
 
     expected_ids = {str(deleted_document_team1.id), str(deleted_document_team2.id)}
 
-    with django_assert_num_queries(7):
+    with django_assert_num_queries(8):
         response = client.get("/api/v1.0/documents/trashbin/")
 
-    with django_assert_num_queries(3):
+    with django_assert_num_queries(4):
         response = client.get("/api/v1.0/documents/trashbin/")
 
     assert response.status_code == 200