Hey Julian, > That's an interesting idea, for that particular use case. > > If I reformulate the "relation index entities" query as I understand > it: > 1. [datastore]Traverse the index and return entity keys > 2. [app engine]Transform returned keys to retrieve parent entity > 3. [datastore] Batch get of entities > > Your idea: > 1. [datastore]Traverse the index and to get entity keys > 3. [datastore] Batch get of entities > > So you would save step 2, a roundtrip app engine - datastore, not sure > that's substantial though.
Nice reformulation! However, my proposal would be just a single step: 1. [datastore] Traverse the index and return entities The only additional cost should be an additional if/else clause when *writing* entities -- the datastroe would have to look to see if the entity has an __index__ property. Quite a minimal cost given the savings otherwise! Why should it just be a single step? Because of the way that the datastore works (at least according to the presentation that Ryan gave last year): * http://snarfed.org/space/datastore_talk.html According to it (slide 21): * Each row in an index table includes the index data and entity key With my proposal, when an entity is indexed, the key defined in its __index__ property will be used in place of its own key when the indexes are constructed... Of course these special "related entities" would still be accessible by using their key names... Hope that makes sense. -- love, tav plex:espians/tav | t...@espians.com | +44 (0) 7809 569 369 http://tav.espians.com | http://twitter.com/tav | skype:tavespian --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to google-appengine@googlegroups.com To unsubscribe from this group, send email to google-appengine+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en -~----------~----~----~----~------~----~------~--~---
