About index_interval:
1) you have to rebuild stables ( not an issue if you are evaluating, doing test writes.. Etc, not so much in production )
Are you sure of this? As I understand indexes, it's not required because this parameter defines an interval of in-memory index sample, which is created during C* startup basing on a primary on-disk index file. The fact that Heap usage is reduced immediately after C* restart seem to confirm this, but maybe I miss something?
M.
