vacuumdb: Fix --missing-stats-only with virtual generated columns.

Statistics aren't created for virtual generated columns, so
"vacuumdb --missing-stats-only" always chooses to analyze tables
that have them.  To fix, modify vacuumdb's query for retrieving
relations that are missing statistics to exclude those columns.

Oversight in commit edba754f05.

Author: Yugo Nagata <nagata@sraoss.co.jp>
Reviewed-by: Fujii Masao <masao.fujii@gmail.com>
Reviewed-by: Corey Huinker <corey.huinker@gmail.com>
Discussion: https://postgr.es/m/20250820104226.8ba51e43164cd590b863ce41%40sraoss.co.jp
Backpatch-through: 18

src/bin/scripts/t/100_vacuumdb.pl

@@ -237,9 +237,10 @@ $node->command_fails_like(
 	qr/cannot vacuum all databases and a specific one at the same time/,
 	'cannot use option --all and a dbname as argument at the same time');
 
-$node->safe_psql('postgres',
-	'CREATE TABLE regression_vacuumdb_test AS select generate_series(1, 10) a, generate_series(2, 11) b;'
-);
+$node->safe_psql('postgres', q|
+  CREATE TABLE regression_vacuumdb_test AS select generate_series(1, 10) a, generate_series(2, 11) b;
+  ALTER TABLE regression_vacuumdb_test ADD COLUMN c INT GENERATED ALWAYS AS (a + b);
+|);
 $node->issues_sql_like(
 	[
 		'vacuumdb', '--analyze-only',

src/bin/scripts/vacuumdb.c

@@ -14,6 +14,7 @@
 
 #include <limits.h>
 
+#include "catalog/pg_attribute_d.h"
 #include "catalog/pg_class_d.h"
 #include "common.h"
 #include "common/connect.h"
@@ -957,6 +958,8 @@ retrieve_objects(PGconn *conn, vacuumingOptions *vacopts,
 							 " AND a.attnum OPERATOR(pg_catalog.>) 0::pg_catalog.int2\n"
 							 " AND NOT a.attisdropped\n"
 							 " AND a.attstattarget IS DISTINCT FROM 0::pg_catalog.int2\n"
+							 " AND a.attgenerated OPERATOR(pg_catalog.<>) "
+							 CppAsString2(ATTRIBUTE_GENERATED_VIRTUAL) "\n"
 							 " AND NOT EXISTS (SELECT NULL FROM pg_catalog.pg_statistic s\n"
 							 " WHERE s.starelid OPERATOR(pg_catalog.=) a.attrelid\n"
 							 " AND s.staattnum OPERATOR(pg_catalog.=) a.attnum\n"
@@ -994,6 +997,8 @@ retrieve_objects(PGconn *conn, vacuumingOptions *vacopts,
 							 " AND a.attnum OPERATOR(pg_catalog.>) 0::pg_catalog.int2\n"
 							 " AND NOT a.attisdropped\n"
 							 " AND a.attstattarget IS DISTINCT FROM 0::pg_catalog.int2\n"
+							 " AND a.attgenerated OPERATOR(pg_catalog.<>) "
+							 CppAsString2(ATTRIBUTE_GENERATED_VIRTUAL) "\n"
 							 " AND c.relhassubclass\n"
 							 " AND NOT p.inherited\n"
 							 " AND EXISTS (SELECT NULL FROM pg_catalog.pg_inherits h\n"