fix: delete inventory hosts in batches to avoid memory exhaustion

awx/main/tasks/system.py

@@ -1022,6 +1022,33 @@ def update_host_smart_inventory_memberships():
         smart_inventory.update_computed_fields()
 
 
+def _batched_delete_inventory(inventory, batch_size=500):
+    """Delete inventory hosts in batches to avoid high memory usage.
+
+    With ansible facts, loading thousands of hosts at once can use a lot of memory. To avoid
+    this, we delete them in batches (of 500).
+
+    Safe to retry after a crash because inventory.pending_deletion
+    is already set and each batch is its own transaction.
+    """
+    from awx.main.models.inventory import Host
+
+    # first delete all hosts in batches
+    total_deleted = 0
+    while True:
+        pks = list(Host.objects.filter(inventory_id=inventory.id).values_list('pk', flat=True)[:batch_size])
+        if not pks:
+            break
+        with transaction.atomic():
+            deleted_count, _ = Host.objects.filter(pk__in=pks).delete()
+            total_deleted += deleted_count
+        logger.debug('Batch-deleted %d hosts from inventory %d (%d total so far)', len(pks), inventory.id, total_deleted)
+
+    # then delete the inventory itself
+    inventory.delete()
+    logger.info('Batched deletion of inventory %d complete (%d hosts removed)', inventory.id, total_deleted)
+
+
 @task(queue=get_task_queuename, timeout=3600 * 5)
 def delete_inventory(inventory_id, user_id, retries=5):
     # Delete inventory as user
@@ -1034,12 +1061,14 @@ def delete_inventory(inventory_id, user_id, retries=5):
             user = None
     with ignore_inventory_computed_fields(), ignore_inventory_group_removal(), impersonate(user):
         try:
-            Inventory.objects.get(id=inventory_id).delete()
-            emit_channel_notification('inventories-status_changed', {'group_name': 'inventories', 'inventory_id': inventory_id, 'status': 'deleted'})
-            logger.debug('Deleted inventory {} as user {}.'.format(inventory_id, user_id))
+            inv = Inventory.objects.get(id=inventory_id)
         except Inventory.DoesNotExist:
             logger.exception("Delete Inventory failed due to missing inventory: " + str(inventory_id))
             return
+        try:
+            _batched_delete_inventory(inv)
+            emit_channel_notification('inventories-status_changed', {'group_name': 'inventories', 'inventory_id': inventory_id, 'status': 'deleted'})
+            logger.debug('Deleted inventory {} as user {}.'.format(inventory_id, user_id))
         except DatabaseError:
             logger.exception('Database error deleting inventory {}, but will retry.'.format(inventory_id))
             if retries > 0: