@ihnorton The code you posted worked and I tried to understand what’s the different. I think the major different here is that the cfg["vfs.s3.region"] = "us-west-1"; needs to be set up before config is assigned to the context and you are also using a single context for each function.
is that what it boils down to? Also, the other thing I wanted to confirm that I do have the region set up in both my ~/.aws/config file and also set in my environment variable. It sounds like tile-db AWS API is able to pick up the credentials(access_key, secret) from the environment variable/credentials file. however, for region the only way to do is to set it in the code. Is that a correct understanding?