It might be worth reading the actual post to see how we're fixing slow joins. In terms of the language: it's not Python's fault at all. Instead, Synapse baked

It might be worth reading the actual post to see how we're fixing slow joins. In terms of the language: it's not Python's fault at all. Instead, Synapse baked in a bunch of naive assumptions (being originally a prototype) which we have been steadily fixing... while also adding features, which pulls in the opposite direction. Given a choice between a featureful server that's resource-heavy (which we can then make go faster later) versus one which lacks the features to compete with centralised alternatives, we chose the former.