Cassandra MemTable Flush

Question

What I understood about Cassandra Memtable flush is whenever 33% of memtable heap+offheap space is consumed, cassandra flush writer starts flushing the largest memtable. In that case there could be situation where few smaller memtables where not much of writes are happening would lie on the memory. What would happen to those memtables? When are those memtables are going to be flushed.

Answer 1

There are three ways AFAIK.

1. memtable_cleanup_threshold as you described.
2. memtable_flush_period_in_ms per table prop which defines the periodic flush period.
3. nodetool flush and nodetool drain. (drain stops listening for new requests)