Changes:
- When I joined in 2015, it was already forbidden to just log text on the server. Only a small number of SREs even had access to the text logs. Any event that you cared about needed to be logged from the system described in "App-specific metrics", which was pretty easy to use. (That said, on desktop we still used logspam because when you're debugging a desktop client doing the wrong thing, sometimes the only lead you have is tracing which lines of code are being run by looking at which logs are being printed.)
- Re: shards, by the time I joined most of the mysql was replaced by a homegrown KV/graph database on top of mysql that had a fixed number of shards (something like 255).
Things that didn't change (at least by the time I left in 2020):
- Everything was in UTC, including in the UIs for everything (e.g. metrics, exceptions, crashes, etc). I ended making a GPS clock that showed UTC to put on my desk as a fun project, and I know at least one SRE who had set basically all their clocks to UTC time (e.g. phone, laptop, calendar, etc). This is in contrast to Google, where almost every system either shows your local time or "Google Standard Time" (which is just Pacific Time).
- Python was still used for virtually everything.