Re: Libpq support to connect to standby server as priority

On Tue, 15 Jan 2019 at 23:21, Tsunakawa, Takayuki <
tsunakawa(dot)takay(at)jp(dot)fujitsu(dot)com> wrote:

> From: Dave Cramer [mailto:pg(at)fastcrypt(dot)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.
>

Thanks, that clarifies it.

Dave Cramer

davec(at)postgresintl(dot)com
www.postgresintl.com

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