Kryo serialization documentation needs to be updated

[nicknezis]

It is not clear how to leverage Kryo serialization. There is no documentation for how to enable it or how to register serializers. I only found a single page on the website which says that Heron needs to be recompiled to add a custom serializer. This seems wrong.

Could someone more knowledgeable in the topic update this page? (Maybe @huijunw or @nwangtw ?)

Perhaps we should update an example topology in both Topology and Streamlet API examples?

[nwangtw]

An example could be good. "Heron needs to be recompiled" does seem a bit strange. Not 100% sure if it is needed though.

[huijunwu]

If your topology is having "Class is not registered" error with Kryo, you could solve it by adding the following line into your topology source code:

Config config = new Config();
config.registerSerialization(MyClass.class);
Submitter.submitTopology(... config, ...)

If this registration through config, it would need re-compiling the job. (this does not need re-compiling Heron)

@nlu90 thoughts?

[huijunwu]

Checked the code. https://github.com/apache/incubator-heron/blob/master/storm-compatibility/v0.10.2/src/java/org/apache/storm/Config.java#L456 and
https://github.com/apache/incubator-heron/blob/master/storm-compatibility/v0.10.2/src/java/org/apache/storm/Config.java#L76
It looks like, it will generate some code .. this requires re-compiling