Tomorrow, you may notice a blip in Launchpad’s availability around 08.30 UTC. Believe it or not, this is good news 🙂
Until tomorrow, we’d been rolling out database changes — schema updates, database server maintenance, etc — once a month, with a 90 minute period where Launchpad was read-only.
Now, we’re doing things a little differently: two or three times a week, we’ll be doing a fast database update at 08.30 UTC (weekdays only). To start with, it won’t quite be “blink and you’ll miss it”. We’re talking around two minutes but we’ve already identified ways to cut this time. During the update, Launchpad will be effectively unavailable. But it’ll be quick and at a predictable time each day that we do it.
So, other than the obvious bonus of not having Launchpad go read-only for a big 90 minute block every month, why’s this good news? As it’s always at the same and for a short time, we think it’ll be easier to work around. The down-time won’t even be long enough to make a decent cup of tea or coffee. Importantly, it also means you’ll get new Launchpad code faster: if a new feature or a bug fix requires a database schema change, we can now roll it out pretty much within 24 hours rather than waiting up to a month for the next big 90 minute read-only time.
There’s a bug we need to fix: right now, during the fast down-time you’ll get an OOPS when Launchpad tries to access the database. Once we’ve fixed the bug you’ll get a somewhat friendlier and more appropriate 503 error.
While we’re all getting used to it, we’ll still announce these fast database updates on the status feed. We’re hopeful, though, that they’ll be quick enough and predictable enough (08.30 UTC weekdays, two or three times a week) that eventually you’ll have to try hard to notice them.