which Kafka StateStore could I use ?

[杰 杨]

HI：
I use kafka streams for real-time data analysis
and I meet a problem.
now I process a record in kafka and compute it and send to db.
but db concurrency level is not suit for me.
so I want that
1）when there is not data in kakfa ,the statestore is  no results.
2) when there is a lot of data records in kafka the statestore save computed 
result and I need send its once to db.
which StateStoe can I use for do that above
________________________________
funk...@live.com