From 5c3795e7d2971d91de270284c74c97b961966206 Mon Sep 17 00:00:00 2001
From: Mikhail Nikalayeu <mihailnikalayeu@gmail.com>
Date: Sat, 13 Dec 2025 18:13:37 +0100
Subject: [PATCH 1/3] stress test for repack concurrently

---
 contrib/amcheck/meson.build       |   1 +
 contrib/amcheck/t/007_repack_1.pl | 121 ++++++++++++++++++++++++++++++
 doc/src/sgml/regress.sgml         |  16 ++++
 3 files changed, 138 insertions(+)
 create mode 100644 contrib/amcheck/t/007_repack_1.pl

diff --git a/contrib/amcheck/meson.build b/contrib/amcheck/meson.build
index d5137ef691d..cb4bc32e98a 100644
--- a/contrib/amcheck/meson.build
+++ b/contrib/amcheck/meson.build
@@ -50,6 +50,7 @@ tests += {
       't/004_verify_nbtree_unique.pl',
       't/005_pitr.pl',
       't/006_verify_gin.pl',
+      't/007_repack_1.pl',
     ],
   },
 }
diff --git a/contrib/amcheck/t/007_repack_1.pl b/contrib/amcheck/t/007_repack_1.pl
new file mode 100644
index 00000000000..17f3caa3a38
--- /dev/null
+++ b/contrib/amcheck/t/007_repack_1.pl
@@ -0,0 +1,121 @@
+# Copyright (c) 2021-2026, PostgreSQL Global Development Group
+
+# Test REPACK CONCURRENTLY with concurrent modifications
+use strict;
+use warnings FATAL => 'all';
+
+use PostgreSQL::Test::Cluster;
+use PostgreSQL::Test::Utils;
+
+use Test::More;
+
+# PG_TEST_EXTRA carries a numerical stress value; 0 disables the test,
+# 1 means the test takes about 6 seconds, and the increase should be
+# roughly linear.
+my $matched = ($ENV{PG_TEST_EXTRA} // '') =~ /\bstress_concurrently(?:=(?<stressval>[0-9]*))?\b/;
+my $stressval = $+{stressval} // 1;
+if (!$matched or $stressval == 0)
+{
+	plan skip_all => 'skipping disabled REPACK CONCURRENTLY stress test';
+}
+
+note "stressval is $stressval";
+
+my $node;
+
+# Test set-up
+$node = PostgreSQL::Test::Cluster->new('CIC_test');
+$node->init;
+$node->append_conf('postgresql.conf',
+	'lock_timeout = ' . (1000 * $PostgreSQL::Test::Utils::timeout_default));
+$node->append_conf(
+	'postgresql.conf', qq(
+wal_level = logical
+));
+
+my $nrows = 10_000 * $stressval;
+my $duration = 6 * $stressval;
+my $no_hot = int(rand(2));
+
+$node->start;
+$node->safe_psql('postgres', q(CREATE TABLE tbl(id int PRIMARY KEY, val int)));
+
+if ($no_hot)
+{
+	$node->safe_psql('postgres', q(CREATE INDEX test_idx ON tbl(val);));
+}
+else
+{
+	$node->safe_psql('postgres', q(CREATE INDEX test_idx ON tbl(id);));
+}
+
+
+# Load amcheck
+$node->safe_psql('postgres', q(CREATE EXTENSION amcheck));
+
+# Insert $nrows rows into tbl
+$node->safe_psql('postgres', qq(
+	INSERT INTO tbl SELECT g, g FROM generate_series(1, $nrows) g
+));
+
+my $sum = $node->safe_psql('postgres', q(
+	SELECT SUM(val) AS sum FROM tbl
+));
+
+
+$node->pgbench(
+"--no-vacuum --client=30 --jobs=4 --exit-on-abort -T $duration",
+0,
+[qr{actually processed}],
+[qr{^$}],
+'concurrent operations with REINDEX/CREATE INDEX CONCURRENTLY',
+{
+	'concurrent_ops' => qq(
+		SELECT pg_try_advisory_lock(42)::integer AS gotlock \\gset
+		\\if :gotlock
+			REPACK (CONCURRENTLY) tbl USING INDEX tbl_pkey;
+			SELECT bt_index_parent_check('tbl_pkey', heapallindexed => true);
+			SELECT bt_index_parent_check('test_idx', heapallindexed => true);
+			\\sleep 10 ms
+
+			REPACK (CONCURRENTLY) tbl USING INDEX test_idx;
+			SELECT bt_index_parent_check('tbl_pkey', heapallindexed => true);
+			SELECT bt_index_parent_check('test_idx', heapallindexed => true);
+			\\sleep 10 ms
+
+			REPACK (CONCURRENTLY) tbl;
+			SELECT bt_index_parent_check('tbl_pkey', heapallindexed => true);
+			SELECT bt_index_parent_check('test_idx', heapallindexed => true);
+			\\sleep 10 ms
+
+			SELECT pg_advisory_unlock(42);
+		\\else
+			\\set num_a random(1, $nrows)
+			\\set num_b random(1, $nrows)
+			\\set diff random(1, 10000)
+			BEGIN;
+			UPDATE tbl SET val = val + :diff WHERE id = :num_a;
+			\\sleep 1 ms
+			UPDATE tbl SET val = val - :diff WHERE id = :num_b;
+			\\sleep 1 ms
+			COMMIT;
+
+			BEGIN
+			--TRANSACTION ISOLATION LEVEL REPEATABLE READ
+			;
+			SELECT 1;
+			\\sleep 1 ms
+			SELECT COALESCE(SUM(val), 0) AS sum FROM tbl \\gset p_
+			\\if :p_sum != $sum
+				COMMIT;
+				SELECT (:p_sum) / 0;
+			\\endif
+
+			COMMIT;
+		\\endif
+	)
+});
+
+$node->stop;
+
+done_testing();
diff --git a/doc/src/sgml/regress.sgml b/doc/src/sgml/regress.sgml
index c74941bfbf2..c5b1b79a60c 100644
--- a/doc/src/sgml/regress.sgml
+++ b/doc/src/sgml/regress.sgml
@@ -386,6 +386,22 @@ make check-world PG_TEST_EXTRA='kerberos ldap ssl load_balance libpq_encryption'
      </listitem>
     </varlistentry>
 
+    <varlistentry>
+     <term><literal>stress_concurrently</literal><optional>=VALUE</optional></term>
+     <listitem>
+      <para>
+       Run some additional, moderately expensive tests for commands with a
+       <literal>CONCURRENTLY</literal> option.  Optionally, an integer can be
+       given after an equal sign, which affects how long each such test
+       runs for.
+       Each test is calibrated so that, when given a value of 10,
+       it runs for approximately 60 seconds.
+       If no value is given, 1 is assumed.
+       Explicitly giving a value of 0 causes the test to be skipped.
+      </para>
+     </listitem>
+    </varlistentry>
+
     <varlistentry>
      <term><literal>wal_consistency_checking</literal></term>
      <listitem>
-- 
2.47.3