DatastoreInputReader using entity kind with ancestor
You cannot specify an ancestor for the DatastoreInputReader -- except for a namespace -- so the pipeline will always go through all your Domain entities in a given namespace.
Is there a way to use the standard DatastoreInputReader from AppEngine's mapreduce with entity kind requiring ancestors ?
Let's say I have an entity kind Domain with ancestor kind SuperDomain (useful for transactions), where do I specify in mapreduce_pipeline.MapreducePipeline how to use a specific SuperDomain entity as ancestor to all queries?