My starting position:
I have a multi tenant java application which uses JDBC to connect to a database system. I have not only one database system(I am using H2), but rather lots of them - each in a separate db server. Every database server manages data of a few tenants, separated by an own schema. A tenant will be migrated from one server to another if needed, that process is managed by a ressource controller.
I am looking for a database proxy which forwards transactions to the right database server and that mapping (tenant --> db server) should be dynamically: The ressource controller shall change it online. Do you know any db proxy which support that dynamic feature? H2 and my application support sql queries for DB2, Oracle, SQL Server, MySQL and PostgreSQL. So that does hardly ever restrict the tool selection.