perf(endpoint_manager): avoid double queryset evaluation in update_endpoint_status

Evaluate existing_finding_endpoint_status_list once into a list with
select_related("endpoint") before the two list comprehensions, preventing
a duplicate DB hit and N+1 endpoint lookups. Update expected performance
test counts to reflect the reduced query counts.

Author: valentijnscholten

dojo/importers/endpoint_manager.py

@@ -158,8 +158,11 @@ def update_endpoint_status(
         """Update the list of endpoints from the new finding with the list that is in the old finding"""
         # New endpoints are already added in serializers.py / views.py (see comment "# for existing findings: make sure endpoints are present or created")
         # So we only need to mitigate endpoints that are no longer present
-        existing_finding_endpoint_status_list = existing_finding.status_finding.exclude(
-            Q(false_positive=True) | Q(out_of_scope=True) | Q(risk_accepted=True),
+        # Evaluate the queryset once into a list to avoid double DB evaluation below
+        existing_finding_endpoint_status_list = list(
+            existing_finding.status_finding.exclude(
+                Q(false_positive=True) | Q(out_of_scope=True) | Q(risk_accepted=True),
+            ).select_related("endpoint"),
         )
         new_finding_endpoints_list = new_finding.unsaved_endpoints
         if new_finding.is_mitigated:

unittests/test_importers_performance.py

@@ -270,9 +270,9 @@ def test_import_reimport_reimport_performance_pghistory_async(self):
         self._import_reimport_performance(
             expected_num_queries1=295,
             expected_num_async_tasks1=6,
-            expected_num_queries2=267,
+            expected_num_queries2=232,
             expected_num_async_tasks2=17,
-            expected_num_queries3=154,
+            expected_num_queries3=114,
             expected_num_async_tasks3=16,
         )
 
@@ -292,9 +292,9 @@ def test_import_reimport_reimport_performance_pghistory_no_async(self):
         self._import_reimport_performance(
             expected_num_queries1=302,
             expected_num_async_tasks1=6,
-            expected_num_queries2=274,
+            expected_num_queries2=239,
             expected_num_async_tasks2=17,
-            expected_num_queries3=161,
+            expected_num_queries3=121,
             expected_num_async_tasks3=16,
         )
 
@@ -315,9 +315,9 @@ def test_import_reimport_reimport_performance_pghistory_no_async_with_product_gr
         self._import_reimport_performance(
             expected_num_queries1=309,
             expected_num_async_tasks1=8,
-            expected_num_queries2=281,
+            expected_num_queries2=246,
             expected_num_async_tasks2=19,
-            expected_num_queries3=165,
+            expected_num_queries3=125,
             expected_num_async_tasks3=18,
         )