Are Objectify @Load annotations obeyed in transactions?

Question

I am using a transaction in Objectify 4 to update a bunch of entities, of Kind_A. These have a number of fields I want to modify within the transaction, but also a number of Refs to other entities, e.g.

class Kind_A {
  @Id Long id;

  @Parent
  @Load
  Ref<Kind_P> parent;

  String name;

  @Load
  Ref<Kind_B> b;
}

My entity group here is defined by an instance of Kind_P, which will have its own Refs, e.g.:

class Kind_P {
  @Id Long id;

  @Load
  Ref<Kind_Q> q;
}

In my transaction, I will ofy().load() a number of entities as List using an ancestor query, like this:

ofy().load().type(Kind_A.class).ancestor(p).list();

I will then iterate the List, modify, say, the name field (not the Ref<>s), then ofy().save() the List.

All the entities I load() should have the same @Parent (p) since it's an ancestor query.

So, on the face of it, when I load() and save() my Kind_A entities, I am dealing with a single entity group (p).

However, I am getting an IllegalArgumentException: operating on too many entity groups in a single transaction. I am guessing this is because Objectify is loading the object graph, including all the Kind_Bs and Kind_Qs.

Is this correct? So the scope of the transaction is suddenly spreading well beyond the entity group defined by p.

If so, is there a way to tell Objectify to ignore the @Load annotations inside a transaction?

Is there a way (in, say, the Eclipse debugger) I can find out the entities that are participating in the transaction?

Any insight would be much appreciated!

UPDATE: removing the @Load annotation on the @Parent seems to resolve the issue, but I would like to know if this is expected, or coincidence. — tx802

stickfigure stickfigure · Accepted Answer · 2013-09-03T15:00:13

@Load is oblivious to transactions - the annotation works whether you have a transaction or not. You can control behavior of @Load by using the groupings eg @Load(Sometimes.class) or @Load(unless=Sometimes.class).

If you remove @Load from your @Parent and that solves your problem, it's likely that you have additional @Load annotations in your @Parented class and thus you are transitively pulling in more entities.

Use @Load sparingly and carefully. Note that in Objectify 4.0rc1, you don't even need to use @Load - when you use Ref.get() it will fetch the referenced entity even if it wasn't @Loaded. @Load is just an optimization so that you get efficient fetching into the session cache.

Are Objectify @Load annotations obeyed in transactions?

1 Answers