Spark Streaming - How to save all items in batchs from beginning to a single stream rdd?

[hawkwang]

Hi guys,

Is it possible to generate a single stream rdd which can be updated with 
new batch rdd content?

I know that we can use updateStateByKey to make aggregation,
but here just want to keep tracking all historical original content.

I also noticed that we can save to redis or other storage system,
but can we just use spark streaming mechanism to make it happen?

Thanks for any suggestion.

Regards,
Hawk