No, we do not support threads in Cloudflare Workers.

(They wouldn't be a good fit for our platform since we really want heavy compute tasks to be distributed across multiple machines. Having one Worker take multiple cores on a single machine would actually be problematic as it would make load balancing much harder. Also there are Spectre concerns.)

Me being lazy too, but can Workers support full-duplex requests, too? https://github.com/posener/h2conn Comes in handy to pool connections from a client if Workers was backed by a db.

@ignoramous haha this seems a little off topic, maybe file a feature request on workerd? :) (Actually, though, workerd itself supports full duplex even on HTTP/1.1, but the rest of the Cloudflare HTTP proxy stack does not...)

@kentonv thank you very much for your answer. I fully understand your policy for the production environment but how about a beta platform? 😉 I know that there are many capable duckdb persons (like @tobilg) who could help you with a beta implementation.

Workers really has no separate "beta platform" and if it did it would be subject to the same policy. We can explore options for implementing some form of support but the kind of multiple thread and blocking http requests discussed so far is not currently possible. Note that we are working on implementing node:fs APIs in workers using a virtual in memory file system. Would a variation on the node binding here be a possibility?