There is indeed such a tradeoff. The architecture is designed with an eye towards making this tradeoff tunable (frequency of memtable spills, aggressiveness of compaction) but the work here is not yet finished. We chose to prioritize optimizing bulk-indexing and query performance for GA, since this is already enough for many applications. I'm excited to get to the point where we have brag-worthy benchmark numbers for high-frequency updates as well!