> > Also, I was wondering if the key cache maintains a count of how many local > accesses a key undergoes. Such information might be very useful for > compactions of sstables by splitting data by frequency of use so that those > can be preferentially compacted.
No we don't currently have metrics for that, only overall cache hits/misses. Measuring individual local accesses would probably have a performance and memory impact but there's probably a way to do it efficiently. Has this been exploited... ever? Not that I know of. I've theorised about using it previously with some friends, but never got around to trying it. I imagine if you did you'd probably have to fix some parts of the code to make it work (like potentially discoverComponentsFor). Typically I think any conversation that is relevant to the internals of Cassandra is fine for the dev list, and that's the desired audience. Not every dev watches the user list and only developers will really be able to answer these questions. Lets face it, the dev list is pretty dead so not sure why we care about a few emails landing there.
