One enhancement to John's excellent answers. John wrote:
> If necessary, you can always get the deserialized, object instance > <http://geode.apache.org/releases/latest/javadoc/org/apache/geode/pdx/PdxInstance.html#getObject--> > [3] > of the data and: > However, you should be careful in that once deserialized, Geode will > retain the deserialized form of the data in the Region. I just wanted to clarify that if you do call "getObject" on a PdxInstance then that will not cause the deserialized form to retained. Only the caller of "getObject" has the deserialized form object reference returned by this method. On Fri, Apr 28, 2017 at 11:13 AM, John Blum <[email protected]> wrote: > Hi Paul- > > Answers/comments inline below... > > > On Fri, Apr 28, 2017 at 10:02 AM, Paul Perez <[email protected]> wrote: > >> Hello all >> We develop a kind of aggregation features for our monitoring system. >> In our geode cache, we use the pdx serialisation for our java objets. >> They will not be used elsewhere. >> So come two questions : >> First we developed event listeners to aggregate the event of our >> products. Once the handler receives the asyncEvent, we have to deserialize >> it. Do we use pdx features here as well? >> > > Is there a specific reason why you have to deserialize it? You can work > with PdxInstance(s) > <http://geode.apache.org/releases/latest/javadoc/index.html> [1] directly > (getting/setting fields > <http://geode.apache.org/releases/latest/javadoc/org/apache/geode/pdx/PdxInstance.html#createWriter--> > [2] > of the object's type without deserializing). If necessary, you can always get > the deserialized, object instance > <http://geode.apache.org/releases/latest/javadoc/org/apache/geode/pdx/PdxInstance.html#getObject--> > [3] > of the data (providing the class type is on the classpath of the server > where AEQ Listener is firing). It is even possible to query (with OQL) PDX > serialized bytes without deserializing (unlike Java serialized bytes). > > However, you should be careful in that once deserialized, Geode will > retain the deserialized form of the data in the Region. This will only > cause overhead when the data needs to be re-serialized, which is anytime > the data is persisted/overflowed to disk, replicated between peers, sent > across a WAN or sent to clients. > > You can learn more here > <http://geode.apache.org/docs/guide/11/developing/data_serialization/gemfire_pdx_serialization.html> > [4]. > > [1] http://geode.apache.org/releases/latest/javadoc/index.html > [2] http://geode.apache.org/releases/latest/javadoc/org/ > apache/geode/pdx/PdxInstance.html#createWriter-- > [3] http://geode.apache.org/releases/latest/javadoc/org/ > apache/geode/pdx/PdxInstance.html#getObject-- > [4] http://geode.apache.org/docs/guide/11/developing/data_ > serialization/gemfire_pdx_serialization.html > > >> Seconds question: one of our application use a client cache for memory >> issues. As far as we understood, pdx serialization cannot be defined in >> the cache.xml. >> So, if the client cache doesn't support pdx so are we forced to use the >> classical java serialization to send the ojects to the servers? >> > > Why do you think that? See here > <http://geode.apache.org/docs/guide/11/reference/topics/client-cache.html#cc-pdx> > [5]. > > Unfortunately, the example is WRONG, as it is using the "peer" cache > element tag (<cache> instead of <client-cache>), but this reference ([5]) > is from client-cache section and it is possible to configure PDX on the > client. You must configure PDX serialization on the client to serialize > bytes to the server from the client using PDX. Server-side PDX > configuration maybe optional if you have nothing running in the servers > directly (e.g. a Function or CacheLoader) since the server will retain > the data in the form that it receives, unless, as I mention, above, > something were to cause the data to be deserialized. Then, you need to > specify your serialization strategy, e.g. either by your application > domain objects implementing PdxSerializable > <http://geode.apache.org/docs/guide/11/developing/data_serialization/use_pdx_serializable.html> > [6](invasive, > and not recommended) or by implementing a PdxSerializer > <http://geode.apache.org/docs/guide/11/developing/data_serialization/use_pdx_serializer.html> > [7] > (or perhaps using a OOTB impl... ReflectionBasedAutoSerializer > <http://geode.apache.org/docs/guide/11/developing/data_serialization/auto_serialization.html> > [8], though personally, I think implementing your own PdxSerializer > implementations for your application domain objects is better... you can > even get creative using the *Composite Software Design Pattern* to create > per domain type serializers but treat it as 1 since Geode only allows you > to register 1). > > Anyway, it is possible to use PDX serialization on the client. > > Hope this helps! > > Cheers, > John > > > [5] http://geode.apache.org/docs/guide/11/reference/ > topics/client-cache.html#cc-pdx > [6] http://geode.apache.org/docs/guide/11/developing/data_ > serialization/use_pdx_serializable.html > [7] http://geode.apache.org/docs/guide/11/developing/data_ > serialization/use_pdx_serializable.html > [8] http://geode.apache.org/docs/guide/11/developing/data_ > serialization/auto_serialization.html > > >> >> Thank you for your response >> >> Paul >> >> > > > -- > -John > john.blum10101 (skype) >
