What is the difference between Scylla read path and Cassandra read path? When I stress Cassandra and Scylla then Scylla read performance poor by 5 times than Cassandra using
As a summary I would say Scylladb and cassandra have the same read / write path memtable, commitlog, sstable.
However implementation is very different: - cassandra rely on OS for low level IO and network (most DBMS does) - scylladb rely on its own lib (seastar) to handle IO and network at a low level independently from OS page cache etc. This is why they can provide feature such as workload scheduling within the same cluster that would be very hard to implement in cassandra.