Q. Is it normal for Tarantool to use only one core with the Memtx engine? (2016)
A. It is normal. Tarantool has a one-threaded transaction processor, plus it has a network thread and a transaction log thread. So, overall, Tarantool doesn't use more than 3 cores. In most cases, the largest CPU consumer is the transaction processor, so in those cases Tarantool uses only one core.