> How often and by what criteria is the commit log compacted/truncated? Commit log segments (whose size are controllable via the commitlog_rotation_threshold_in_mb option) are eligable for removal when they do not contain any data that has yet to be flushed to memtables. In practice, the memtable settings (flushing thresholds) should be the primary driver of commit log retention. If you have memtables which may go for an hour without being flushed, that puts a lower bound on the amount of time the commitlog may need to be retained.
-- / Peter Schuller
