From: Dave Cramer [mailto:pg@fastcrypt.com] > The original desire should have been the ability to connect to a > primary or a standby. So, I think we should go back to the original thinking > (and not complicate the feature), and create a read only GUC_REPORT variable, > say, server_role, that identifies whether the server is a primary or a > standby. > > > > I'm confused as to how this would work. Who or what determines if the server > is a primary or standby?
Overall, the server determines the server role (primary or standby) using the same mechanism as pg_is_in_recovery(), and set the server_role GUC parameter. As the parameter is GUC_REPORT, the change is reported to the clients using the ParameterStatus ('S') message. The clients also get the value at connection.
