Thank you for responding to the post.
I had seen article .Based on , you are saying that for every operation a lookup is done in block cache and memstore.
I had tried to verify the theory and that led to my Question  related to cache miss. If for every read request a merge happens (block cache look up done) , why am I not seeing any change in cache hits?
Also, on the consistency point, if scanner finds new data in memstore as compared to block cache, will hbase update the block cache data that corresponds to latest edit in memstore?