The point of DatastoreMutationPool is to provide batching of updates to increase throughput. It is fine to use something else.
On Wed, Jul 8, 2015 at 7:34 AM, Antonio Fornié Casarrubios < [email protected]> wrote: > > Hi all. I didn't find any answer or info for this: > > *Context*: Java Google App Engine project, using Datastore. For a certain > kind, Sale, I save the entities in two ways: > > > 1. From a typical SaleDAO#save(saleEntity) > 2. During MapReduce, from my SaleReducer#emit(saleEntity) > > > So I was investigating how to reuse some behavior as part of both cases, > so I made something like: > > class SaleDAO { > DatastoreService datastore > public save(Entity entity) { > // My common behavior that I want to reuse > datastore.put(entity) > // Some more common behavior that I want to reuse > } > } > > > > And then for the MapReduce part, I extended OutputWriter to call my DAO, > instead of the DatastoreMutationPool#put(entity) method provided for that > purpose. > > > public class SaleOutputWriter extends OutputWriter<Entity> { > @Override > public void write(Entity entity) { > //pool.put(entity); - try to invoke the DAO instead > saleDAO.save(sale) > } > } > > > > > 1. My surprise is that it works! Well, the MR jobs seem to go to a > strange state, but the entities are correctly saved. Still I'm 99% sure > that this must be a bad practice or bring some problems. Can somebody tell > me > 2. If that's not the case, why are we given a certain API for > MapReduce and another one for normal persistence? Will be the same to > invoke DatastoreMutationPool.put than DatastoreService.put (any > implementation)? > > > Honestly, this idea sounded crazy in my head and now that it seems to work > I want to know more about it. > > -- > You received this message because you are subscribed to the Google Groups > "Google App Engine" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/google-appengine. > To view this discussion on the web visit > https://groups.google.com/d/msgid/google-appengine/61276548-616e-4f94-9263-00bcfcb5e33d%40googlegroups.com > <https://groups.google.com/d/msgid/google-appengine/61276548-616e-4f94-9263-00bcfcb5e33d%40googlegroups.com?utm_medium=email&utm_source=footer> > . > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/google-appengine. To view this discussion on the web visit https://groups.google.com/d/msgid/google-appengine/CAN4PiZHeGR%3Dt7NeY8PeG9eJmKe06UTbkm0XTRsPG8mBJe%3DNx9g%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
