GAE caching objectify queries
google-app-engine, gwt, objectify
Solution
Yes, all queries bypass Objectify's integrated memcache and fetch results directly from the datastore. The datastore provides the (increasingly sophisticated) query engine that understands how to return results; determining cache invalidation for query results is pretty much impossible from the client side.
On the other hand, Objectify4 does offer a hybrid query cache whereby queries are automagically converted to a keys-only query followed by a batch get. The keys-only query still requires the datastore, but any entity instances are pulled from (and populate on miss) memcache. It might save you money.
Problem
i have a simple question in the objectify documentation it says that "Only get(), put(), and delete() interact with the cache. query() is not cached" http://code.google.com/p/objectify-appengine/wiki/IntroductionToObjectify#Global_Cache. what i'm wondering - if you have one root entity (i did not use @Parent due to all the scalability issues that it seems to have) that all the other entities have a Key to, and you do a query such as ``` ofy.query(ChildEntity.class).filter("rootEntity", rootEntity).list() ``` is this completely bypassing the cache? If this is the case, is there an efficient caching way to do a query on conditions - or for that matter can you cache a query with a parent where you would have to make an actual ancestor query like the following ``` Key<Parent> rootKey = ObjectifyService.factory().getKey(root) ofy.query(ChildEntity.class).ancestor(rootKey) ``` Thank you as to one of the comments below i've added an edit sample dao (ignore the validate method - it just does some null & quantity checks): this is a sample find all method inside a delegate called from the DAO that the request factory ServiceLocator is using ``` public List<EquipmentCheckin> findAll(Subject subject, Objectify ofy, Event event) { final Business business = (Business) subject.getSession().getAttribute(BUSINESS_ATTRIBUTE); final List<EquipmentCheckin> checkins = ofy.query(EquipmentCheckin.class).filter(BUSINESS_ATTRIBUTE, business) .filter(EVENT_CONDITION, event).list(); return validate(ofy, checkins); } ``` now, when this is executed i find that the following method is actually being called in my AbstractDAO. ``` /** * * @param id * @return */ public T find(Long id) { System.out.println("finding " + clazz.getSimpleName() + " id = " + id); return ObjectifyService.begin().find(clazz, id); } ```