Fix bug in dumping prior releases due to MV REFRESH dependency checking.

Reports and suggested patches from Fujii Masao and Andrew Dunstan.

Andrew Dunstan

src/bin/pg_dump/pg_dump.c

@@ -1769,7 +1769,7 @@ makeTableDataInfo(TableInfo *tbinfo, bool oids)
 static void
 buildMatViewRefreshDependencies(Archive *fout)
 {
-	PQExpBuffer query = createPQExpBuffer();
+	PQExpBuffer query;
 	PGresult   *res;
 	int			ntups,
 				i;
@@ -1777,11 +1777,15 @@ buildMatViewRefreshDependencies(Archive *fout)
 				i_objid,
 				i_refobjid;
 
+	/* No Mat Views before 9.3. */
+	if (fout->remoteVersion < 90300)
+		return;
+
 	/* Make sure we are in proper schema */
 	selectSourceSchema(fout, "pg_catalog");
 
-	if (fout->remoteVersion >= 90300)
-	{
+	query = createPQExpBuffer();
+
 	appendPQExpBuffer(query, "with recursive w as "
 					  "( "
 					  "select d1.objid, d2.refobjid, c2.relkind as refrelkind "
@@ -1808,7 +1812,6 @@ buildMatViewRefreshDependencies(Archive *fout)
 					  "select 'pg_class'::regclass::oid as classid, objid, refobjid "
 					  "from w "
 					  "where refrelkind = 'm'");
-	}
 
 	res = ExecuteSqlQuery(fout, query->data, PGRES_TUPLES_OK);