This is coming up when implementing tenant routing for SQL clients. As requested/suggested by andyk, it would be good to allow routing tenants using a prefix in the dbname provided by clients, for example postgres://.../mytenant.mydb. This is what the SQL proxy does in serverless too. However, we can only do this reliably if the tenant name is guaranteed to not contain a period.

@jeffswenson suggests:

If we want to support SNI on dedicated clusters, then we also need to prohibit ‘_’, since it is not a valid character in dns names.

Proposal: valid DNS identifier, but . forbidden.

Jira issue: CRDB-21884