thekozmo

That's not true. Scylla does multi-threading. Scylla is a single process, single address space. It does pin the threads to individual hyper threads but there are additional other workers in the background as well.

Many need SVB, we (ScyllaDB) received a great service from them in the past. Later on we just used them as one of our banks, obviously, going forward, we're diversifying our services.

The problem for startups is that debt provider who are also a bank require to move most of the business to that provider. It's not the case other types of debt providers. w.r.t debt - everybody use this mechanism, doesn't matter if you're small or big.

ScyllaDB uses AGPL, a good and valid license

There is no magic behind Scylla, mainly lots of hard work, hundreds of years of engineering, based on the former C* design which is based on Dynamo/Bigtable.

The JVM is part of the problem, not all of it. The main issue is that it hides the hardware and makes tracing harder - instruction level and block level. At Scylla we strive for efficiency, every operation is tagged with a priority class for the CPU and I/O schedulers. Folks are welcome to read the blogs about those topic. Lots of details and hard work

This is indeed what we (ScyllaDB) do, pretty much everywhere. It works great for 95% of our users. Discord wanted to add a level of guarantee since they observed a too high level of local disk failures.

Am ScyllaDB but Marc did completely independent work. The client vcpus don't matter that much, the experiment compares the server side, the client shouldn't suck. When we test ScyllaDB or other DBs, we run benchmarks for hours and days. This is just a stateless, static http daemon, so short timing is reasonable.

The whole intent is to make it a learning experience, if you wish to reproduce, try it yourself. It's aligned with past measurements of ours and also with former Linux optimizations by Marc.

Good point. This is more of a tcp stack comparison between the kernel and userspace. Seastar has a sharded (per core) stack, which is very beneficial when the number of threads is high

What's amazing is that the seastar tcp stack hasn't been changed over the past 7 years, while the kernel received plenty of improvements (in order to close the gap vs kernel bypass mechanisms). Still, for >> 99% of users, there is no need to bypass the kernel.

ScyllaDB uses Seastar as an engine and the DynamoDB compatible API use HTTP parsing, so this use case is real. Of course the DB has much more to do than this benchmark with a static http reply but Scylla also uses many more core in the server, thus it is close to real life. We do use the kernel's tcp stack, due to all of its features and also since we don't have capacity for a deeper analysis.

Some K/V workloads are affected by the networking stack and we recently seen issues if we chose not the ideal interrupt mode (multiqueue vs single queue in small machines)