Re: Adding Rendezvous support to postmaster - Mailing list pgsql-patches

Here is a patch that adds a Rendezvous GUC variable to set the
Rendezvous name.  Chris, would you please test this and let me know how
it works.

I know we are past cutoff, but I want to get Rendezvous completely
functional.  I didn't bother with conditionally including it in
postgresql.conf because we don't do that with other options that aren't
enabled by default, like SSL and Kerberos.

---------------------------------------------------------------------------

Chris Campbell wrote:
> On Wednesday, Jun 11, 2003, at 10:43 US/Eastern, Bruce Momjian wrote:
>
> > Bruce Momjian wrote:
> >> Tom Lane wrote:
> >>> Bruce Momjian <pgman@candle.pha.pa.us> writes:
> >>>> I also _didn't_ add the Rendezvous GUC variable, so we default to
> >>>> the
> >>>> host name.  If there is need, we can add it later.
> >>>
> >>> How do you figure there is not need for it?  What about running more
> >>> than one postmaster at a time?
> >>
> >> No one brought up that idea, and Chris agreed we could try it without
> >> it.  Chris, is that an issue?  I see the port number in the Rendezvous
> >> function call:
>
> Rendezvous advertises the port number of the service, yes, but the
> service name itself (which is usually related to the host name) MUST be
> unique. So if there are two postmasters running on the same machine,
> the first one will be advertised, and when the second one tries to
> register to be advertised, it will silently fail to register. It will
> still work just fine as a postmaster process, but it won't be
> advertised.
>
> This is identical to the situation where there are two machines on the
> same network with identical Rendezvous names -- the second one to
> attempt to register a service with that name will silently fail.
>
> Just to reassure you: nothing will break if the second postmaster fails
> to register its service name -- it just won't be advertised. That's the
> only consequence. There are no additional runtime costs, no strange log
> messages, nothing like that.
>
> I'd love to have that GUC variable so that the service name could be
> configured...but I think that 99% of the people that will want to use
> the Rendezvous support in PostgreSQL will only be running a single
> instance of postmaster on a machine. Like you said, if people need the
> ability to configure the service name, the GUC variable can be added
> later. The way we're doing it now, Rendezvous will be enabled and the
> postmaster will be advertised by default on systems that support it. I
> like that. :) If we add the variable, then it won't be configured and
> advertised by default (I'm assuming).
>
> > Two more issues --- first, I changed 'pgsql' to 'postgresql' as the
> > service name, to match our registered TCP service name.  Second, if we
> > do add a GUC variable, it has to conditionally be included in
> > postgresql.conf.sample if Rendezvous is enabled.
>
> For the first issue, "_postgresql._tcp" sounds great. For the second
> one...is conditional inclusion in postgresql.conf.sample hard? Would it
> suffice to put a "This option can only be configured on systems with
> support for Rendezvous (ex: Darwin, Mac OS X)" comment above the
> (commented out) line that configures the variable?
>
> Thanks!
>
> - Chris
>
>
> ---------------------------(end of broadcast)---------------------------
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>

--
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 359-1001
  +  If your life is a hard drive,     |  13 Roberts Road
  +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073
Index: doc/src/sgml/runtime.sgml
===================================================================
RCS file: /cvsroot/pgsql-server/doc/src/sgml/runtime.sgml,v
retrieving revision 1.193
diff -c -c -r1.193 runtime.sgml
*** doc/src/sgml/runtime.sgml    14 Jul 2003 20:00:22 -0000    1.193
--- doc/src/sgml/runtime.sgml    18 Jul 2003 20:43:38 -0000
***************
*** 732,737 ****
--- 732,747 ----
        </listitem>
       </varlistentry>

+      <varlistentry>
+       <term><varname>RENDEZVOUS_NAME</varname> (<type>string</type>)</term>
+       <listitem>
+        <para>
+         Specifies the Rendezvous broadcast name.  By default, the
+         local hostname is used.
+        </para>
+       </listitem>
+      </varlistentry>
+
       </variablelist>
       </sect3>
       <sect3 id="runtime-config-connection-security">
Index: src/backend/postmaster/postmaster.c
===================================================================
RCS file: /cvsroot/pgsql-server/src/backend/postmaster/postmaster.c,v
retrieving revision 1.333
diff -c -c -r1.333 postmaster.c
*** src/backend/postmaster/postmaster.c    12 Jun 2003 07:36:51 -0000    1.333
--- src/backend/postmaster/postmaster.c    18 Jul 2003 20:43:42 -0000
***************
*** 210,215 ****
--- 210,217 ----
  bool        Log_connections = false;
  bool        Db_user_namespace = false;

+ char        *rendezvous_name = NULL;
+
  /* For FNCTL_NONBLOCK */
  #if defined(WIN32) || defined(__BEOS__)
  long ioctlsocket_ret;
***************
*** 756,772 ****
                      "socket.");
              }
          }
! #ifdef USE_RENDEZVOUS
!                 if (service_name != NULL)
!                 {
!                         DNSServiceRegistrationCreate(NULL,    /* default to hostname */
!                                                      "_postgresql._tcp.",
!                                                      "",
!                                                      htonl(PostPortNumber),
!                                                      "",
!                                                      (DNSServiceRegistrationReply)reg_reply,
!                                                      NULL);
!                 }
  #endif
      }

--- 758,775 ----
                      "socket.");
              }
          }
! #ifdef USE_RENDEZVOUS
!                 if (service_name != NULL)
!                 {
!                         DNSServiceRegistrationCreate((rendezvous_name && strlen(rendezvous_name) > 0)) ?
!                                                       rendezvous_name : NULL, /* default to hostname */
!                                                      "_postgresql._tcp.",
!                                                      "",
!                                                      htonl(PostPortNumber),
!                                                      "",
!                                                      (DNSServiceRegistrationReply)reg_reply,
!                                                      NULL);
!                 }
  #endif
      }

Index: src/backend/utils/misc/guc.c
===================================================================
RCS file: /cvsroot/pgsql-server/src/backend/utils/misc/guc.c,v
retrieving revision 1.137
diff -c -c -r1.137 guc.c
*** src/backend/utils/misc/guc.c    15 Jul 2003 19:19:56 -0000    1.137
--- src/backend/utils/misc/guc.c    18 Jul 2003 20:43:47 -0000
***************
*** 1299,1304 ****
--- 1299,1313 ----
          PG_KRB_SRVTAB, NULL, NULL
      },

+     {
+         {"rendezvous_name", PGC_POSTMASTER, CONN_AUTH_SETTINGS,
+             gettext_noop("The Rendezvous broadcast service name"),
+             NULL
+         },
+         &rendezvous_name,
+         NULL /* defaults to local hostname */, NULL, NULL
+     },
+
      /* See main.c about why defaults for LC_foo are not all alike */

      {
Index: src/backend/utils/misc/postgresql.conf.sample
===================================================================
RCS file: /cvsroot/pgsql-server/src/backend/utils/misc/postgresql.conf.sample,v
retrieving revision 1.85
diff -c -c -r1.85 postgresql.conf.sample
*** src/backend/utils/misc/postgresql.conf.sample    18 Jul 2003 19:16:03 -0000    1.85
--- src/backend/utils/misc/postgresql.conf.sample    18 Jul 2003 20:43:47 -0000
***************
*** 38,43 ****
--- 38,44 ----
  #unix_socket_group = ''
  #unix_socket_permissions = 0777    # octal
  #virtual_host = ''
+ #rendezvous_name = ''        # defaults to local hostname

  # - Security & Authentication -

Index: src/include/tcop/tcopprot.h
===================================================================
RCS file: /cvsroot/pgsql-server/src/include/tcop/tcopprot.h,v
retrieving revision 1.57
diff -c -c -r1.57 tcopprot.h
*** src/include/tcop/tcopprot.h    5 May 2003 00:44:56 -0000    1.57
--- src/include/tcop/tcopprot.h    18 Jul 2003 20:43:48 -0000
***************
*** 32,37 ****
--- 32,38 ----
  extern bool log_hostname;
  extern bool LogSourcePort;
  extern DLLIMPORT const char *debug_query_string;
+ extern char *rendezvous_name;

  #ifndef BOOTSTRAP_INCLUDE