code: public void deleteTenantDB(Tenant tenant) {
          synchronized (m_tenantDBMap) {
              DBService dbservice = m_tenantDBMap.remove(tenant.getName());
              if (dbservice != null) {
                  m_logger.info("Stopping DBService for deleted tenant: {}", tenant.getName());
                  dbservice.stop();
              }
          }
      }
docs: Close the DBService for the given tenant, if is has been cached. This is called
  when a tenant is deleted.
  
  @param tenant    {@link Tenant} being deleted.