Anecdotally, it's still too easy to OOM Cassandra even after moving sstable internals off heap.
FWIW, I agree about the 5x reduction in default timeout being likely to catch many people by surprise, that was my immediate reaction when I read about it in NEWS.txt... but I also agree that 10s is arbitrary and probably too large. So +1.
Did you also change the yaml?
Fair enough, but a 5x reduction seems a tad extreme. I don't want to bikeshed a number though, so +1.
I respect that, but I still think it's time we fixed it:
I'm fine with the memtable change, but the write timeout, especially in a minor, seems like it's going to surprise some people who do large batches.
Patch to reduce default memtable size from 1/3 of heap to 1/4. More importantly, reduces write timeout default from 10s to 2s – this affects how many writes will be buffered before load shedding kicks in.