4 ms·

This makes me wonder why GitHub is effectively using a single database (though replicated with HA considerations and CQRS-ized). From the article, it appears t

• topspin 8y ago
  This comment... I've thought about this a lot. I think asking this question is probably the most meaningful insight into this failure that has appeared. What GitHub has done is create a giant single point of failure in the form of a globe spanning under-tested mysql database to manage a vast number of unrelated git repos, most of which are dormant. At any moment only a minuscule fraction of these repos are actually mutating. One can imagine a system that doesn't conflate every GitHub repo into a monster distributed mysql database. Each repo could be coupled with an independent SQLite database, for instance, that spins up in a few microseconds and synchronizes with its distributed copies only when necessary. Otherwise these lay dormant and available, safe from the vagaries of some under-specified planet scale mysql instance. I imagine testing such a design would be vastly easier as well; one need not replicate the conditions of this mighty distributed mysql construct. Whatever aggregation is ultimately necessary (analysis, billing, etc.) could be performed with asynchronous ETL into some database with minimal coordination and no risk to availability for customers.