Re: pg_receivewal documentation

On Wed, 2019-07-17 at 10:38 +0900, Michael Paquier wrote:
> +       <para>
> +        Note that while WAL will be flushed with this setting,
> +        <application>pg_receivewal</application> never applies it, so
> +        <xref linkend="guc-synchronous-commit"/> must not be set to
> +        <literal>remote_apply</literal> if <application>pg_receivewal</application>
> +        is the only synchronous standby. Similarly, if
> +        <application>pg_receivewal</application> is part of a quorum-based
> +        set of synchronous standbys, it won't count towards the quorum if
> +        <xref linkend="guc-synchronous-commit"/> is set to
> +        <literal>remote_apply</literal>.
> +       </para>
> 
> I think we should really document the caveat with priority-based sets
> of standbys as much as quorum-based sets.  For example if a user sets
> synchronous_commit = remote_apply in postgresql.conf, and then sets
> s_s_names to '2(pg_receivewal, my_connected_standby)' to get a
> priority-based set, then you have the same problem, and pg_receivewal
> is not the only synchronous standby in this configuration.  The patch
> does not cover that case properly.

I understand the concern, I'm just worried that too much accuracy may
render the sentence hard to read.

How about adding "or priority-based" after "quorum-based"?

Yours,
Laurenz Albe