Now I will add the another parameter target_server_type to choose the primary, standby or prefer-standby
as discussed in the upthreads with a new GUC variable.
So just to further confuse things here is a use case for "preferPrimary"
This is from the pgjdbc list.
"if the master instance fails, we would like the driver to communicate with the secondary instance for read-only operations before the failover process is commenced. The second use-case is when the master instance is deliberately shut down for maintenance reasons and we do not want to fail over to the secondary instance, but instead allow it to process user queries throughout the maintenance."
