On: Are You Sure You Want to Use MMAP in Your Database Management System? (2022)

[arter4]

Yes, I knew about sendfile() but I wasnt't aware of any web server using that (though I know Kafka uses it).

Then I found out Apache supports it via the EnableSendfile directive. Nice.

>This directive controls whether httpd may use the sendfile support from the kernel to transmit file contents to the client. By default, when the handling of a request requires no access to the data within a file -- for example, when delivering a static file -- Apache httpd uses sendfile to deliver the file contents without ever reading the file if the OS supports it.

[nh2 → arter4]

Pretty much all modern Linux web servers support sendfile(). Examples:

* nginx: [1] * Haskell webserver module: [2] * caddy: [3]

[1]: https://nginx.org/en/docs/http/ngx_http_core_module.html#sen... [2]: https://hackage.haskell.org/package/warp-3.3.28/docs/Network... [3]: https://github.com/caddyserver/caddy/pull/5022

[kentonv → arter4]

I'd expect most serious web servers support it. I've written one that does (workerd), it's not too hard.

That said, it's tricky to use if the server also does TLS termination... then you need kTLS, which is a much bigger can of worms.