diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index 76ed2fbea8..582f6f66c6 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -6786,8 +6786,9 @@ SCRAM-SHA-256$<replaceable>&lt;iteration count&gt;</replaceable>:<replaceable>&l
       <entry><structfield>subslotname</structfield></entry>
       <entry><type>name</type></entry>
       <entry></entry>
-      <entry>Name of the replication slot in the upstream database. Also used
-       for local replication origin name.</entry>
+      <entry>Name of the replication slot in the upstream database (also used
+       for the local replication origin name);
+       null represents <literal>NONE</literal></entry>
      </row>
 
      <row>
@@ -6869,7 +6870,9 @@ SCRAM-SHA-256$<replaceable>&lt;iteration count&gt;</replaceable>:<replaceable>&l
       <entry><type>pg_lsn</type></entry>
       <entry></entry>
       <entry>
-       End LSN for <literal>s</literal> and <literal>r</literal> states.
+       Remote LSN of the state change used for synchronization coordination
+       when in <literal>s</literal> or <literal>r</literal> states,
+       otherwise null
       </entry>
      </row>
     </tbody>
diff --git a/src/backend/catalog/pg_subscription.c b/src/backend/catalog/pg_subscription.c
index afee2838cc..a3a8b4e599 100644
--- a/src/backend/catalog/pg_subscription.c
+++ b/src/backend/catalog/pg_subscription.c
@@ -457,13 +457,20 @@ GetSubscriptionRelations(Oid subid)
 	{
 		Form_pg_subscription_rel subrel;
 		SubscriptionRelState *relstate;
+		Datum		d;
+		bool		isnull;
 
 		subrel = (Form_pg_subscription_rel) GETSTRUCT(tup);
 
 		relstate = (SubscriptionRelState *) palloc(sizeof(SubscriptionRelState));
 		relstate->relid = subrel->srrelid;
 		relstate->state = subrel->srsubstate;
-		relstate->lsn = subrel->srsublsn;
+		d = SysCacheGetAttr(SUBSCRIPTIONRELMAP, tup,
+							Anum_pg_subscription_rel_srsublsn, &isnull);
+		if (isnull)
+			relstate->lsn = InvalidXLogRecPtr;
+		else
+			relstate->lsn = DatumGetLSN(d);
 
 		res = lappend(res, relstate);
 	}
@@ -509,13 +516,20 @@ GetSubscriptionNotReadyRelations(Oid subid)
 	{
 		Form_pg_subscription_rel subrel;
 		SubscriptionRelState *relstate;
+		Datum		d;
+		bool		isnull;
 
 		subrel = (Form_pg_subscription_rel) GETSTRUCT(tup);
 
 		relstate = (SubscriptionRelState *) palloc(sizeof(SubscriptionRelState));
 		relstate->relid = subrel->srrelid;
 		relstate->state = subrel->srsubstate;
-		relstate->lsn = subrel->srsublsn;
+		d = SysCacheGetAttr(SUBSCRIPTIONRELMAP, tup,
+							Anum_pg_subscription_rel_srsublsn, &isnull);
+		if (isnull)
+			relstate->lsn = InvalidXLogRecPtr;
+		else
+			relstate->lsn = DatumGetLSN(d);
 
 		res = lappend(res, relstate);
 	}
diff --git a/src/include/catalog/pg_subscription.h b/src/include/catalog/pg_subscription.h
index 3cb13d897e..796c8794ca 100644
--- a/src/include/catalog/pg_subscription.h
+++ b/src/include/catalog/pg_subscription.h
@@ -53,7 +53,7 @@ CATALOG(pg_subscription,6100,SubscriptionRelationId) BKI_SHARED_RELATION BKI_ROW
 	text		subconninfo BKI_FORCE_NOT_NULL;
 
 	/* Slot name on publisher */
-	NameData	subslotname;
+	NameData	subslotname BKI_FORCE_NULL;
 
 	/* Synchronous commit setting for worker */
 	text		subsynccommit BKI_FORCE_NOT_NULL;
diff --git a/src/include/catalog/pg_subscription_rel.h b/src/include/catalog/pg_subscription_rel.h
index f7df814a18..6f5607d604 100644
--- a/src/include/catalog/pg_subscription_rel.h
+++ b/src/include/catalog/pg_subscription_rel.h
@@ -34,8 +34,18 @@ CATALOG(pg_subscription_rel,6102,SubscriptionRelRelationId)
 	Oid			srsubid;		/* Oid of subscription */
 	Oid			srrelid;		/* Oid of relation */
 	char		srsubstate;		/* state of the relation in subscription */
-	XLogRecPtr	srsublsn;		/* remote lsn of the state change used for
-								 * synchronization coordination */
+
+	/*
+	 * Although srsublsn is a fixed-width type, it is allowed to be NULL, so
+	 * we prevent direct C code access to it just as for a varlena field.
+	 */
+#ifdef CATALOG_VARLEN			/* variable-length fields start here */
+
+	XLogRecPtr	srsublsn BKI_FORCE_NULL;	/* remote LSN of the state change
+											 * used for synchronization
+											 * coordination, or NULL if not
+											 * valid */
+#endif
 } FormData_pg_subscription_rel;
 
 typedef FormData_pg_subscription_rel *Form_pg_subscription_rel;