Fix filtering of unsupported relations in logical replication

In the pgoutput plugin, skip changes for relations that are not
publishable, per is_publishable_class().  This concerns in particular
materialized views and information_schema tables.  While those relations
cannot be part of a publication, per existing checks, they will be
considered by a FOR ALL TABLES publication.  A subscription would not
actually apply changes for those relations, again per existing checks,
but trying to match incoming changes to local tables on the subscriber
would lead to errors if no matching local table exists.  Skipping those
changes on the publisher avoids sending useless changes and eliminates
the error.

Bug: #15044
Reported-by: Chad Trabant <chad@iris.washington.edu>
Reviewed-by: Petr Jelinek <petr.jelinek@2ndquadrant.com>

src/backend/catalog/pg_publication.c

@@ -105,6 +105,15 @@ is_publishable_class(Oid relid, Form_pg_class reltuple)
 		relid >= FirstNormalObjectId;
 }
 
+/*
+ * Another variant of this, taking a Relation.
+ */
+bool
+is_publishable_relation(Relation rel)
+{
+	return is_publishable_class(RelationGetRelid(rel), rel->rd_rel);
+}
+
 
 /*
  * SQL-callable variant of the above

src/backend/replication/pgoutput/pgoutput.c

@@ -264,6 +264,9 @@ pgoutput_change(LogicalDecodingContext *ctx, ReorderBufferTXN *txn,
 	MemoryContext old;
 	RelationSyncEntry *relentry;
 
+	if (!is_publishable_relation(relation))
+		return;
+
 	relentry = get_rel_sync_entry(data, RelationGetRelid(relation));
 
 	/* First check the table filter */

src/include/catalog/pg_publication.h

@@ -93,6 +93,7 @@ extern List *GetPublicationRelations(Oid pubid);
 extern List *GetAllTablesPublications(void);
 extern List *GetAllTablesPublicationRelations(void);
 
+extern bool is_publishable_relation(Relation rel);
 extern ObjectAddress publication_add_relation(Oid pubid, Relation targetrel,
 						 bool if_not_exists);