If you're caching feeds, would you require thousands of requests to the db per second, or just thousands of web requests?
It'd be an interesting test to try setting up a simple stack of psql/nginx/memcache and your go processes behind, and serving up the same data from it, to see what sort of performance you get, but I understand why you wouldn't bother if your app is somewhat tied in to the datastore already and works fine for you as is. Just out of interest, did you start on something else and move over to Google App Engine for performance, or start there?
Started on app engine. I've been using and happy with it for 4 years.
Yes, I could set up a simple psql stack. But I would lose automatic multi data center replication and infinite scaling, so that's not a win. My database hit 500GB in a few months. I don't want to deal with scaling up psql instances when it doubles in size over the next year again. See my first post linked below about when newsblur hit the HN frontpage and was effectively down for 3 days due to load. It's because psql doesn't scale in that direction.
Thanks for elucidating - I work on sites with a different balance of users vs traffic and data (maybe more users but less data and not so spiky), so it's interesting to hear about your experience on that and why you'd go for app engine, which compared to self hosting can seem like an expensive option.
It'd be an interesting test to try setting up a simple stack of psql/nginx/memcache and your go processes behind, and serving up the same data from it, to see what sort of performance you get, but I understand why you wouldn't bother if your app is somewhat tied in to the datastore already and works fine for you as is. Just out of interest, did you start on something else and move over to Google App Engine for performance, or start there?