The ManagedConnectionFactory#createManagedConnection method of jdbc-ra calls the validateAndSetIsolation method after acquiring connections from DataSource.
The validateAndSetIsolation method is a role of connection validation and initializing transaction isolation level. If any errors occur in the validateAndSetIsolation method, it will be returned to connector runtime without closing the acquired connection. This indicates the possibility of connection leak.
Attached patch is to resolve this leak issue by calling the ManagedConnection#destroy method to close a physical connection. If connection close also fail after applying this patch, the following message will be printed in server.log.
;|RAR5083 : Exception while destroying physical connection