How ActionCable broke Puma

Four few known facts that are often ignored: POSIX systems (Linux, BSD, macOS) use “file descriptors” for sockets.These file descriptors are a numerical value that usually translates to a kernel array index linked to the process. 2. the select system call breaks when the file descriptor value is over 1023 (on some systems 2047). On Linux, this is a libc restriction rather than a kernel restriction

[willnet]

selectだと1023までしかファイルディスクリプタ使えないの知らなかったな