Housekeeping batches

backend/coreapp/housekeeping.py

@@ -13,11 +13,25 @@ def get_model(model_name: str) -> type[DjangoModel]:
     return apps.get_model("coreapp", model_name.capitalize())
 
 
-def perform_delete(qs: QuerySet[Model], dry_run: bool = False) -> int:
+DEFAULT_DELETE_BATCH_SIZE = 1000
+
+
+def perform_delete(
+    qs: QuerySet[Model],
+    dry_run: bool = False,
+    batch_size: int | None = DEFAULT_DELETE_BATCH_SIZE,
+) -> int:
     count = qs.count()
     if dry_run:
         return count
 
+    if batch_size is not None:
+        deleted = 0
+        while ids := list(qs.values_list("pk", flat=True)[:batch_size]):
+            batch_deleted, _ = qs.filter(pk__in=ids).delete()
+            deleted += batch_deleted
+        return deleted
+
     deleted, _ = qs.delete()
     return deleted
 

backend/coreapp/tests/test_housekeeping.py

@@ -4,6 +4,7 @@
 from django.test import TestCase
 
 from coreapp.housekeeping import (
+    perform_delete,
     remove_anonymous_profiles,
     remove_orphan_asms,
     remove_orphan_assemblies,
@@ -99,6 +100,19 @@ def test_dry_run_counts_ownerless_scratches_without_deleting(self) -> None:
         self.assertEqual(deleted, 1)
         self.assertTrue(Scratch.objects.filter(pk=old_ownerless_scratch.pk).exists())
 
+    def test_perform_delete_can_delete_in_batches(self) -> None:
+        asms = [
+            Asm.objects.create(hash=f"batched-asm-{index}", data="jr $ra\nnop")
+            for index in range(3)
+        ]
+
+        deleted = perform_delete(
+            Asm.objects.filter(pk__in=[asm.pk for asm in asms]), batch_size=1
+        )
+
+        self.assertEqual(deleted, 3)
+        self.assertFalse(Asm.objects.filter(pk__in=[asm.pk for asm in asms]).exists())
+
     def test_removes_scratchless_anonymous_profiles_created_before_cutoff(self) -> None:
         old_scratchless_profile = Profile.objects.create(user=None)
         old_profile_with_scratch = Profile.objects.create(user=None)