No. Slim3 loads all data eagerly. Yasuo Higa
On Wednesday, June 8, 2011, Jeff Schnitzer <j...@infohazard.org> wrote: > Ok, I have figured out what's going on. To put it gently, the > benchmark is bogus. > > The benchmark code for the Low-Level API just gets the size() of the > collection and doesn't actually examine the data. GAE (apparently) > lazily populates Entity objects, so the benchmark cuts out a > significant chunk of the work. Objectify eagerly examines the Entity > data to create POJOs - but your real-world app is going to fetch the > data from the Entity too. Presumably Slim3 lazily passes through to > the low-level size() method. This is unrealistic; if you wanted a > count, you would use the query's count() method. > > When you iterate the result set and include an Entity.getProperty() > call, Objectify's 100ms overhead fades into the natural (+/- 500ms) > variance. > > Sloppy work. > > Jeff > > On Wed, Jun 8, 2011 at 1:44 AM, Jeff Schnitzer <j...@infohazard.org> wrote: >> Hmmmm. I just whipped up a test app that uses a mock >> AsyncDatastoreService to provide a set of 10,000 Entity objects to >> Objectify, thus purely measuring the overhead of Objectify. It >> consistently transforms 10,000 entities into POJOs (just long id, >> String value) in 100ms on both my laptop and on the production >> servers. >> >> I'm not quite sure what's going on here, but it's not an issue with >> reflection. >> >> Jeff >> >> On Tue, Jun 7, 2011 at 8:51 PM, Yasuo Higa <higaya...@gmail.com> wrote: >>> I added an objectify sample into the performance samples: >>> http://slim3demo.appspot.com/performance/ >>> >>> One result: >>> The number of entities: 10000 >>> low-level API:get: 1276 millis >>> Slim3: 1327 millis >>> Objectify: 3028 millis >>> JDO: 3222 millis >>> >>> I have not profiled yet. >>> But I know java runtime reflections are very very slow on production server, >>> so slim3 creates the mapping logic between a model and an entity >>> as the source code when compiling. >>> >>> Yasuo Higa >>> >>> On Wed, Jun 8, 2011 at 10:18 AM, Ikai Lan (Google) <ika...@google.com> >>> wrote: >>>> I doubt the low-level API is significantly faster than JDO (have not >>>> profiled, so can't tell you for sure). JDO just dispatches to low-level and >>>> does serialization/deserialization. That should really be a very small part >>>> of the entire operation. >>>> Reasons to use the low-level API include: >>>> - it maps best to how the datastore works (schemaless) >>>> - you always get new features the fastest (async datastore API) >>>> That being said, the Slim3 and Objectify projects move pretty quickly and >>>> add features almost as quickly as we do. They're one level removed from the >>>> schemaless nature of the datastore, but this fits better with the 95% use >>>> case. >>>> >>>> Ikai Lan >>>> Developer Programs Engineer, Google App Engine >>>> Blog: http://googleappengine.blogspot.com >>>> Twitter: http://twitter.com/app_engine >>>> Reddit: http://www.reddit.com/r/appengine >>>> >>>> >>>> On Wed, Jun 8, 2011 at 8:07 AM, Dennis Peterson <dennisbpeter...@gmail.com> >>>> wrote: >>>>> >>>>> That makes more sense, thanks. >>>>> I also found this online benchmark of JDO and LL, which has similar >>>>> results: >>>>> http://gaejava.appspot.com/ >>>>> >>>>> On Tue, Jun 7, 2011 at 8:03 PM, Anders <blabl...@gmail.com> wrote: >>>>>> >>>>>> Yeah, that's what I suspected. Lazy loading. With the modification Slim3 >>>>>> is almost as fast as the native API. Strange that JDO is so slow. I >>>>>> thought >>>>>> most of the time was for accessing the datastore, not for running the >>>>>> Java >>>>>> bytecode. >>>>>> >>>>>> -- >>>>>> You received this message because you are subscribed to the Google Groups >>>>>> "Google App Engine" group. >>>>>> To view this discussion on the web visit >>>>>> https://groups.google.com/d/msg/google-appengine/-/dHRvXzBkWVNkUndK. >>>>>> To post to this group, send email to google-appengine@googlegroups.com. >>>>>> To unsubscribe from this group, send email to >>>>>> -- 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.
