Comment by Neywiny
16 days ago
I think they're trying to not shame other services, but yes the comparison is vs networked whether that's local on loopback or not. For a small query, which is what they're talking about, it's not inconceivable that formatting into a network packet, passing through the userspace networking functions, into and through kernel, all back out the other side, then again for the response, is indeed meaningfully slower than a simple function call within the program.
Yes, I explicitly said localhost is slower. But the article doesn't say what it's comparing to nor provide any measurements.