Re: Enhance pg_stat_wal_receiver view to display connected host

On Mon, Jan 15, 2018 at 05:51:58PM +1100, Haribabu Kommi wrote:
> Instead of effective_conninfo, I changed the column name as
> remote_serve_info and
> display only the host, hostaddr and port details. These are the only values
> that differs
> with each remote connection.

I agree that it is pointless to show duplication between both
strings. The differences would be made harder to catch.

+PQconninfoOption *
+PQeffectiveConninfo(PGconn *conn)
+{
+       PQExpBufferData errorBuf;
+       PQconninfoOption *connOptions;
+
+       if (conn == NULL)
+               return NULL;

Shouldn't this check for CONNECTION_BAD as well and return NULL?

If I use something like "port=5432 host=/tmp" as connection string, then
PQeffectiveConninfo gives me the following with hostaddr being weird:
host=/tmp hostaddr=(null) port=5432
This should show an empty hostaddr value.

+     <entry><structfield>remote_server_info</structfield></entry>
+     <entry><type>text</type></entry>
+     <entry>
+      Effective remote server connection info string used by this WAL receiver.
+     </entry>
"Effective" is not a precise term. What about just telling that this is
the set of parameters used for hte active connection, and that this
value should be the one used when using multiple host, hostaddr, and
ports.

Note that I still find this API confusing, it seems to me that just
sorting out the confusion problems with PQhost and then use it would be
more simple.