1) We are querying Cassandra with around 8000 row-keys and for each row there are 5 subcolumns for the requested supercolumn.
2) We have key cache enabled with caching= KEYS_ONLY with 2 MB of key cache.
3) We are having 10 nodes of cassandra running on Cassandra-1.1
For the first time when keys are not cached it is taking around 35 sec to return the result. If the same query is fired again the result is returned in 1.5 - 2.0 sec.
So I was wondering is there any kind of overhead to Cassandra when it is caching keys in key-cache. And is this a reason it is taking too much time to return a result when keys are not cached? or is this a general behavior?