Question about "Simultaneous Open Connections" limit

[hacktek]

I’m on the unlimited plan.

This page talks about the simultaneous open connection limit being 6: https://developers.cloudflare.com/workers/about/limits/

“While handling a request, each Worker script is allowed to have up to six connections open simultaneously.”

It is unclear to me if this means that each worker can only handle 6 connections at once or if each worker execution can have up to 6 connections using any combination of the APIs stated there (fetch, get, list, etc).

As an example, if I have a worker that calls fetch() for all requests and my application makes say 30 parallel requests to the worker, would the above limit mean that only 6 of those would be serviced at once before servicing others or would there be essentially no limit since each worker execution is calling a single fetch()?

Thanks!

[arunesh90]

A question I have related to this is whether you can do more than 6 requests simultaneously if the origin you’re trying to fetch from supports http/2, or do the workers only support http/1.x for fetching?

[harris]

It is unclear to me if this means that each worker can only handle 6 connections at once or if each worker execution can have up to 6 connections using any combination of the APIs stated there (fetch, get, list, etc).

The connection limit applies to outbound connections established on behalf of a single request. Thus, we don’t count inbound connections against a worker’s limit.

As an example, if I have a worker that calls fetch() for all requests and my application makes say 30 parallel requests to the worker, would the above limit mean that only 6 of those would be serviced at once before servicing others or would there be essentially no limit since each worker execution is calling a single fetch()?

The limit would not apply, since there’s only one outbound connection (the fetch()) per inbound request.

A question I have related to this is whether you can do more than 6 requests simultaneously if the origin you’re trying to fetch from supports http/2, or do the workers only support http/1.x for fetching?

That would be nice! However, the answer is no. Cloudflare only supports HTTP/1.x for fetching from upstream in general (regardless of whether or not there’s a worker on the path).

Harris

[hacktek]

Awesome! Thanks for the clear response.