On Mon, Mar 14, 2011 at 1:19 PM, Peter Schuller <peter.schul...@infidyne.com> wrote: >> How is it possible calculate this value? I think that key size, if we use >> RandomPartitioner will 16 bytes so keycache will took 16*(num of keycache >> elements) bytes ?? > > The easiest way right now is probably empirical testing. The issue is > that the "memory use" must include overhead associated with the data > structures involved, as well as longer-term effects like fragmentation > in old-space in the GC (similarly to malloc/free).
In 0.7 and trunk, there is "nodetool clear[row|key]cache", so your testing could be of the form : a) start cluster b) read enough keys to populate your caches per CF c) measure memory usage d) clear cache e) measure memory usage =Rob
