When a DynamoDB vector index is actually ready

AWS shipped vector search for DynamoDB on 5th August, straight to GA. I spent a couple of days pinning it down against real DynamoDB so I could add it to my conformance suite , which meant reading the docs properly and then checking whether they were true. Mostly they are. But there's one thing they get wrong three different ways, and the three stack up: knowing when a vector index is ready to…