I'm not that great at Java at the moment, but it appears that the single
threaded nature of the elasticsearch sink has trouble keeping up with ~5k
events/second at 2k batch size. It looks like the HDFS sink has the ability
to run multiple threads that write to the HDFS. I can get some performance
increase by adding multiple ElasticSearch sinks to simulate parallelism,
but it would be great for the sink itself to support multiple threads.
Is there a sink example that should be used as a guide towards getting the
same features in the elasticsearch sink?