I was helping debug a performance problem (this networking puzzle) in an Erlang program yesterday. I learned that Erlang is complicated, and that we can learn maybe 2 things about it by just looking at what system calls it’s running. (more…)

Not all systems, especially web applications, need to be upgraded without being taken out of service. But at ikura, we need it. We do ‘relups’ all the time: we don’t take our service down whenever updates are pushed live.

The design decisions that make the Erlang VM reliable also give it great concurrent performance... (more…)

While trying to improve the performance of JSON encoding in an Erlang application last year, I came to wonder about the different representations one can use when writing data to disk or sending it over a socket, and how they map to the OS's underlying f... (more…)

This story is about something perfectly documented, but still a bit surprising for newbies and experienced erlangers alike. The question is when will gen_server's Module:terminate/2 be evaluated? (more…)