Batch plan saves reduce RDS CPU during bulk modelling runs 🟪

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

applications/modelling_e2e/handler.py

@@ -93,6 +93,7 @@ from repositories.comparable_properties.epc_comparable_properties_repository imp
     SkippedCohortCert,
 )
 from repositories.epc.epc_postgres_repository import EpcPostgresRepository, EpcSaveRequest
+from repositories.plan.plan_repository import PlanSaveRequest
 from repositories.geospatial.geospatial_s3_repository import (
     GeospatialS3Repository,
     ParquetReader,
@@ -201,6 +202,17 @@ def _flush_writes(engine: Engine, writes: list[_PropertyWrite]) -> None:
             uow.epc.save_batch(lodged_requests)
         if predicted_requests:
             uow.epc.save_batch(predicted_requests)
+        plan_requests = [
+            PlanSaveRequest(
+                w.plan,
+                property_id=w.property_id,
+                scenario_id=w.scenario_id,
+                portfolio_id=w.portfolio_id,
+                is_default=w.is_default,
+            )
+            for w in writes
+        ]
+        uow.plan.save_batch(plan_requests)
         for w in writes:
             if w.spatial is not None:
                 uow.spatial.save(w.uprn, w.spatial)
@@ -211,13 +223,6 @@ def _flush_writes(engine: Engine, writes: list[_PropertyWrite]) -> None:
                     latitude=w.solar.latitude,
                     insights=w.solar.insights,
                 )
-            uow.plan.save(
-                w.plan,
-                property_id=w.property_id,
-                scenario_id=w.scenario_id,
-                portfolio_id=w.portfolio_id,
-                is_default=w.is_default,
-            )
             uow.property.mark_modelled(
                 w.property_id, has_recommendations=w.has_recommendations
             )

repositories/plan/plan_postgres_repository.py

@@ -41,40 +41,9 @@ class PlanPostgresRepository(PlanRepository):
         portfolio_id: int,
         is_default: bool,
     ) -> int:
-        # Soft-replace (ADR-0012): keep prior Plans as history rather than DELETEing
-        # them — the cascade delete of recommendation rows was the slow part. When
-        # this Plan is the default, demote every prior Plan for the same
-        # (property_id, scenario_id) to is_default=False, so exactly one Plan for
-        # the pair stays default (the one just inserted).
-        if is_default:
-            self._session.exec(  # type: ignore[call-overload]
-                update(PlanModel)
-                .where(
-                    col(PlanModel.property_id) == property_id,
-                    col(PlanModel.scenario_id) == scenario_id,
-                )
-                .values(is_default=False)
-            )
-
-        plan_row = PlanModel.from_domain(
-            plan,
-            property_id=property_id,
-            scenario_id=scenario_id,
-            portfolio_id=portfolio_id,
-            is_default=is_default,
-        )
-        self._session.add(plan_row)
-        self._session.flush()
-        if plan_row.id is None:
-            raise ValueError("plan row did not receive an id")
-
-        for measure in plan.measures:
-            self._session.add(
-                RecommendationModel.from_domain(
-                    measure, property_id=property_id, plan_id=plan_row.id
-                )
-            )
-        return plan_row.id
+        return self.save_batch(
+            [PlanSaveRequest(plan, property_id=property_id, scenario_id=scenario_id, portfolio_id=portfolio_id, is_default=is_default)]
+        )[0]
 
     def save_batch(self, requests: list[PlanSaveRequest]) -> list[int]:
         """Persist all Plans in three statements regardless of batch size.