pg_stat_{ssl,gssapi}: Show only processes with connections

It is pointless to show in those views auxiliary processes that don't
open network connections.

A small incompatibility is that anybody joining pg_stat_activity and
pg_stat_ssl/pg_stat_gssapi will have to use a left join if they want to
see such auxiliary processes.

Author: Euler Taveira
Discussion: https://postgr.es/m/20190904151535.GA29108@alvherre.pgsql

src/backend/catalog/system_views.sql

@@ -826,7 +826,8 @@ CREATE VIEW pg_stat_ssl AS
             S.ssl_client_dn AS client_dn,
             S.ssl_client_serial AS client_serial,
             S.ssl_issuer_dn AS issuer_dn
-    FROM pg_stat_get_activity(NULL) AS S;
+    FROM pg_stat_get_activity(NULL) AS S
+    WHERE S.client_port IS NOT NULL;
 
 CREATE VIEW pg_stat_gssapi AS
     SELECT
@@ -834,7 +835,8 @@ CREATE VIEW pg_stat_gssapi AS
             S.gss_auth AS gss_authenticated,
             S.gss_princ AS principal,
             S.gss_enc AS encrypted
-    FROM pg_stat_get_activity(NULL) AS S;
+    FROM pg_stat_get_activity(NULL) AS S
+    WHERE S.client_port IS NOT NULL;
 
 CREATE VIEW pg_replication_slots AS
     SELECT

src/include/catalog/catversion.h

@@ -53,6 +53,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	201910251
+#define CATALOG_VERSION_NO	201911121
 
 #endif

src/test/regress/expected/rules.out

@@ -1845,7 +1845,8 @@ pg_stat_gssapi| SELECT s.pid,
     s.gss_auth AS gss_authenticated,
     s.gss_princ AS principal,
     s.gss_enc AS encrypted
-   FROM pg_stat_get_activity(NULL::integer) s(datid, pid, usesysid, application_name, state, query, wait_event_type, wait_event, xact_start, query_start, backend_start, state_change, client_addr, client_hostname, client_port, backend_xid, backend_xmin, backend_type, ssl, sslversion, sslcipher, sslbits, sslcompression, ssl_client_dn, ssl_client_serial, ssl_issuer_dn, gss_auth, gss_princ, gss_enc);
+   FROM pg_stat_get_activity(NULL::integer) s(datid, pid, usesysid, application_name, state, query, wait_event_type, wait_event, xact_start, query_start, backend_start, state_change, client_addr, client_hostname, client_port, backend_xid, backend_xmin, backend_type, ssl, sslversion, sslcipher, sslbits, sslcompression, ssl_client_dn, ssl_client_serial, ssl_issuer_dn, gss_auth, gss_princ, gss_enc)
+  WHERE (s.client_port IS NOT NULL);
 pg_stat_progress_cluster| SELECT s.pid,
     s.datid,
     d.datname,
@@ -1964,7 +1965,8 @@ pg_stat_ssl| SELECT s.pid,
     s.ssl_client_dn AS client_dn,
     s.ssl_client_serial AS client_serial,
     s.ssl_issuer_dn AS issuer_dn
-   FROM pg_stat_get_activity(NULL::integer) s(datid, pid, usesysid, application_name, state, query, wait_event_type, wait_event, xact_start, query_start, backend_start, state_change, client_addr, client_hostname, client_port, backend_xid, backend_xmin, backend_type, ssl, sslversion, sslcipher, sslbits, sslcompression, ssl_client_dn, ssl_client_serial, ssl_issuer_dn, gss_auth, gss_princ, gss_enc);
+   FROM pg_stat_get_activity(NULL::integer) s(datid, pid, usesysid, application_name, state, query, wait_event_type, wait_event, xact_start, query_start, backend_start, state_change, client_addr, client_hostname, client_port, backend_xid, backend_xmin, backend_type, ssl, sslversion, sslcipher, sslbits, sslcompression, ssl_client_dn, ssl_client_serial, ssl_issuer_dn, gss_auth, gss_princ, gss_enc)
+  WHERE (s.client_port IS NOT NULL);
 pg_stat_subscription| SELECT su.oid AS subid,
     su.subname,
     st.pid,