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I believe this is just an example of what are the implications of 1 query per ms, not indication that it actually took 1 ms.

In 2019 it was in C++17. Now it's in C++20.

As a matter of fact, I'm still at university and mine actually showed a fair bit of modern C++ (University of Warsaw here). So I don't feel ensured. As for C#, I don't claim I know stuff. I'd just like to learn something new. If you finish at an assertion like yours, sadly I don't learn anything new.

Hey. ScyllaDB employee here. There are several reasons C++ was used and I don't think span ultimately matters. List from top of my head (ordered randomly):

1) we use intrusive containers, so memory managing container data structures is collocated with actual data. 2) memory allocation is not tied to GC, so we don't get pauses 3) there's almost none synchronization between different threads and there are (almost) no globals. For a story why globals are a killer for performance, read https://www.p99conf.io/2021/09/28/hunting-a-numa-performance... 4) the previous is only possible with existence of a user space scheduler which guarantees that specific threads are pinned to a single CPU. Also, there's no need to call mmap multiple times, as Seastar (concurrency framework written with Scylla in mind) allocates whole system memory and takes advantage of overcommitting in Linux. There's no syscall at memory allocation, just some userspace work and a possible page fault.

I'm not sure whether C# can do away with these problems? Let me know if you know. That being said, modern C++ is really convenient. Not anything you've seen 15 years ago in university.

What do you mean here by memory layout? For instance, the order of fields in a rust struct can (theoretically) change by recompiling. It's not defined by the order of fields in the definition.

λ(n) isn't the totient. As it was told, it's the Carmichael function.

I know you stated that's it's informal explanation, but please don't conflate nondeterministic-polynomial with non-polynomial.

Endianess is not the only problem. You can have issues with different cache coherency model, different alignment requirements, different syscalls (which are partially arch-dependent, at least on Linux). The fact that the switch from x86 to arm was trivial just proves the point that arm has matured really well.

That also means that if you used seccomp to restrict mprotect syscall, the child process may never ever write again, which is an unfortunate design choice.

Scylla is not only about throughput. One of the values of Scylla is its reduced latencies or ease of maintenance. Overview of reasons: https://www.scylladb.com/scylla-vs-cassandra

Disclosure: I'm an engineer at ScyllaDB.

Which is around the minimal wage in places such as Ukraine (which isn't the ultimate low either).

Seastar already uses coroutines, however coroutines without Seastar reactor (and all the utilities for IO) are useless by themselves. You still need a way to schedule what's being done when.

Quoting the interview with ScyllaDB CTO, Avi Kivity ( https://www.scylladb.com/2020/06/30/ask-me-anything-with-avi... )

> Q: Would you implement Scylla in Go, Rust or Javascript if you could?

> Avi: Good question. I wouldn’t implement Scylla in Javascript. It’s not really a high-performance language, but I will note that Node.js and Seastar share many characteristics. Both are using a reactor pattern and designed for high concurrency. Of course the performance is going to be very different between the two, but writing code for Node.js and writing code for Seastar is quite similar.

> Go also has an interesting take on concurrency. I still wouldn’t use it for something like Scylla. It is a garbage-collected language so you lose a lot of predictability, and you lose some performance. The concurrency model is great. The language lacks generics. I like generics a lot and I think they are required for complex software. I also hear that Go is getting generics in the next iteration. Go is actually quite close to being useful for writing a high-performance database. It still has the downside of having a garbage collector, so from that point-of-view I wouldn’t pick it.

> If you are familiar with how Scylla uses the direct I/O and asynchronous I/O, this is not something that Go is great at right now. I imagine that it will evolve. So I wouldn’t pick Javascript or Go.

> However, the other language you mentioned, Rust, does have all of the correct characteristics that Scylla requires. Precise control over what happens. It doesn’t have a garbage collector so it means that you have predictability over how much time your things take, like allocation. You don’t have pause times. And it is a well-designed language. I think it is better than C++ which we are currently using. So if we were starting at this point in time, I would take a hard look at Rust, and I imagine that we would pick it instead of C++. Of course, when we started Rust didn’t have the maturity that it has now, but it has progressed a long time since then and I’m following it with great interest. I think it’s a well-done language.

We don't use md5 for private/public keys because md5 is a hashing algorithm, unrelated completely to encryption. Also, what are your reasons to believe that md5 has been used there?

Didn't she possibly have previous partners?

I'm native polish speaker and after 3 years of learning mandarin, and I need to somehow confirm, and somehow rebute. Pinyin ch is almost exactly like polish cz. Pinyin q is quite close to ć, but to make that sound you need to touch your lower teeth with your tongue. In polish the tongue stays mostly flat. There is similar difference in x vs ś and j vs dź.

I'm sorry, this indeed isn't correct. I cannot modify my comment for some reason now.

Brendan Gregg is the author of eBPF, and he writes on his blog. It is fair to assume a basic knowledge of his works when reading his website.

This isn't true, this form of conditionals can be compiled into cmov type of instructions, which is faster than regular jump if condition.

Huh? On telegram you had to explicitly opt in, and there were warnings when you tried to enable this.

I think what they mean is that the manpage you link is just synopsis of command line options and not anything that help understand what happens with QEMU and how to fix it when something goes wrong.

Especially not, since China suffers from disparity with much greater number of boys than girls.

The real popup in Chrome and Firefox exceeds the website frame, so you can easily distinguish it.

Good luck with that if it's a CSRF token.

In Polish everyone says "clickbait" (in English), because there is no direct and terse translation.

Just a nitpick here, it is "Rutkowska" and not "Rutkovska" (although that is how you would pronounce the surname).

The variables used in the expressions might not be in scope (in fact they usually aren't). Also, I'm rather sure that's how it works in C++ (which by accident copies arguments instead of leaving a reference, but the single time default argument evaluation holds).

Source of this info? In Poland people use mostly Messenger. None of my friends use whatsapp. Telegram or Discord are both more popular.

Most probably yes. And if it's Aleksander (male name), he'd be called Olek.

I think this was just an approximation. Nonetheless the order of magnitude is right.