Ottimizzazioni di un'altra era nell'app Facebook:
In 2012 we took this wild ride at mobile infra at Facebook when trying to reduce the several-seconds long load time for “Newsfeed”. A few people worked on different approaches. Something we quickly realized was that setting up a connection with TCP and TLS was incredibly slow on mobile networks at the time. The fix was to have just one, keep it alive and multiplex. Shaved a whole second off. But it was still slow. Several people were convince that us sending JSON was the problem, so two different teams started to work on compact binary encoding. After a lot of experimentation what actually worked out best was to send JSON with ordered fields and a compile-time generated parser. Turns out both our iOS and Android app would do something silly like: 1) read all JSON data from server into a buffer, 2) decode that buffer with a generic JSON decoder into lists & dicts, 3) traverse those structures and build the final struct/class tree. Oh and another neat thing we eventually did—when the network connection needed to be setup—was to send an optimistic UDP packet to the server saying “get started fetching data for the following query”; once the real connection was established, TLS handshake completed and user session authenticated, the response was already ready to be sent back.
