Load testing worker with D1 backend

We are trying to learn if workers with D1 are a solution for our edge compute needs (on-the-fly ID lookup) and how it scales. Therefore we did a test case and wanted to try 1000 parallel https://loadster.app/ clients (not a DOS test in any way – it is about 10% of the expected production load).

It failed with the worker logging outcome=“canceled” after a very short time. I cannot see a service limit that we might have hit, and my only guess is that it’s about some automatic Cloudflare defense mechanism (but I cannot find anything to verify that in the Pro plan dashboard).

How can we verify that a relatively new solution like D1 will scale for the spike load that we know will occur in production (it’s already a worker, and we have historical data to estimate the load)?