Re: allow online change primary_conninfo

Hi

>>  I think we have no futher reason to have a copy of conninfo and slot name in WalRcvData, so i propose remove these fields from pg_stat_get_wal_receiver() (and pg_stat_wal_receiver view). This data can be accesible now via regular GUC commands.
>
> Is that wise? It seems possible that wal receivers run for a while with
> the old connection information, and without this information that seems
> hard to debug.
Hmm... I considered SIGHUP processing was in fast loop and therefore shutdown should be fast. But i recheck code and found a possible long loop without processing SIGHUP (in case we receive new data faster than writes to disk). Ok, i will revert back.
How about write to WalRcvData only clobbered conninfo?

> Should probably note something like
>
> "This parameter can only be set in the <filename>postgresql.conf</filename>
> file or on the server command line."
Seems other PGC_SIGHUP settings have such note, fixed, thank you.

> I'd strongly advocate moving this to a separate function.
Done

regards, Sergei