On Sep 5, 10:24 am, "Jason (Google)" <apija...@google.com> wrote: > Batch puts are supported, yes, and as of yesterday's release, calling > makePersistentAll (JDO) and the equivalent JPA call will take advantage of > this support (previously, you had to use the low-level API). > > Two quick notes: > > 1) All of the entities that you're persisting should be in separate entity > groups since two entities in the same entity group can't be written to > consecutively, and you will see datastore timeout exceptions if many > simultaneous write requests come in for the same entity or entity group.
Sorry Jason, I'm a bit confused now. Wouldn't that be the most common use case for batch puts? According to the GAE documentation, this is the main point of entity groups: "App Engine creates related entities in entity groups automatically to support updating related objects together" ...so you can add them together _logically_ but not chronologically? I've got several cases where I'd have 50,000 to 1000,000 records which logically belong to a single parent entity. If I need to add them to the datastore individually it's going to take about somewhere between 2 to 24 hours to write them all (spread across multiple HTTP requests in any case). If I could batch put the data (within the same entity group) I imagine that the time would be reduced significantly. > 2) Batch puts do not operate in a transaction. This means that some writes > may succeed but others may not, so if you need the ability to rollback, > you'll need transactions. Do you mean that if necessary, the call to makePersistentAll() should be wrapped in a transaction, or that makePersistentAll() _can_not_ be wrapped in a transaction? --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Google App Engine for Java" group. To post to this group, send email to google-appengine-java@googlegroups.com To unsubscribe from this group, send email to google-appengine-java+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/google-appengine-java?hl=en -~----------~----~----~----~------~----~------~--~---
