Yes -- it's a good talk, but it focuses mostly on tricks you can do (spatial indexing, geometry subdividing) on the PostGIS side to make lookups/calculations faster, but discussion of actually scaling to multiple databases is a bit light. There is mention of Citus (which Microsoft has purchased and rebranded as Hyperscale), but it has a minimum cost that is more than I can afford right now.
I didn't know if there were other architectures to consider for rails -- like having a few read replicas for web traffic, and then a single large writable master for sidekiq/background jobs, for instance.
