How to stream intermediate data that is stored in external storage?

[kant kodali]

Hi All,

I want to do a full outer join on two streaming data sources and store the
state of full outer join in some external storage like rocksdb or something
else. And then want to use this intermediate state as a streaming source
again, do some transformation and write it to some external store. is
that possible with Flink 1.9?

Also what storage systems support push mechanism for the intermediate data?
For example, In the use case above does rocksdb support push/emit events in
a streaming fashion?

Thanks!