> > Can you give me a bit idea how key_cache and row_cache effects on > performance of cassandra. How these things works in different scenario > depending upon the data size? > > While reading, if row_cached is set, it check for row_cache first then key_cached, memtable & disk.
row_cache store all data on memory, need tuning, generally lowered preferred key_cache store only key and location of row in memory, higher is preferred if row if frequently read it is good to cache it but row size matters large row size can eat too much memory. Also this may help http://www.datastax.com/docs/0.8/operations/cache_tuning#configuring-key-and-row-caches /Samal
