[ElectricalUnion]

> Is it worth scaling app servers or is it better to use Postgres well and scale a managed PG offering?

That is a very good question indeed, it probably depends on whatever compute or the DB offering is cheaper to scale for you; from my very anecdotal experience using both, usually DB is much more expensive to scale up.

> What do you mean by “expand”?

Getting more data thru the pipes, getting closer to the limit of the network pipes.

That doesn't sound like a realistic scenario to me - pulling Y articles from X authors.

If you're not pulling directly from articles, and you're pulling from X authors, X>1, you most likely don't actually want the articles, more likely you want instead some stat of each article like article score, subject, tags or comment counts. Then I don't see neither the JOIN expansion or the JSON ser/de being a serious issue at all compared to the DB retrieval costs.