Improve permissions endpoint query performance (baserow#5464)

Author: bram2w

backend/src/baserow/core/registries.py

@@ -1024,11 +1024,29 @@ def get_objects_in_scopes(self, scopes: List[Any]) -> Dict[Any, Any]:
                 parent_scope_types.add(object_scope_type)
 
         if parent_scopes:
-            query_result = list(
-                self.get_enhanced_queryset().filter(
-                    self.get_filter_for_scopes(parent_scopes)
+            scopes_by_type = defaultdict(list)
+            for scope in parent_scopes:
+                scopes_by_type[object_scope_type_registry.get_by_model(scope)].append(
+                    scope
                 )
+
+            enhanced_queryset = self.get_enhanced_queryset()
+            ordering = (
+                enhanced_queryset.query.order_by
+                or enhanced_queryset.model._meta.ordering
+            )
+
+            branches = [
+                enhanced_queryset.filter(
+                    self.get_filter_for_scope_type(scope_type, typed_scopes)
+                ).order_by()
+                for scope_type, typed_scopes in scopes_by_type.items()
+            ]
+            combined = (
+                branches[0] if len(branches) == 1 else branches[0].union(*branches[1:])
             )
+            combined = combined.order_by(*ordering)
+            query_result = list(combined)
 
             # We have all the objects in the queryset, but now we want to sort them
             # into buckets per original scope they are a child of.

changelog/entries/unreleased/bug/improve_permissions_endpoint_query_performance.json

@@ -0,0 +1,9 @@
+{
+  "type": "bug",
+  "message": "Improve permissions endpoint query performance by using union instead of OR.",
+  "issue_origin": "github",
+  "issue_number": null,
+  "domain": "database",
+  "bullet_points": [],
+  "created_at": "2026-06-03"
+}