From 92a4178c1d1e50ff7a193f9b1caf50de2f18a008 Mon Sep 17 00:00:00 2001
From: Shlok Kyal <shlok.kyal.oss@gmail.com>
Date: Tue, 13 Oct 2026 15:03:34 +0530
Subject: [PATCH v1] BUG #19733

---
 src/test/recovery/t/bug19733_repro.pl | 101 ++++++++++++++++++++++++++
 1 file changed, 101 insertions(+)
 create mode 100644 src/test/recovery/t/bug19733_repro.pl

diff --git a/src/test/recovery/t/bug19733_repro.pl b/src/test/recovery/t/bug19733_repro.pl
new file mode 100644
index 00000000000..926626e62d3
--- /dev/null
+++ b/src/test/recovery/t/bug19733_repro.pl
@@ -0,0 +1,101 @@
+use strict;
+use warnings FATAL => 'all';
+
+use IPC::Run;
+use PostgreSQL::Test::Cluster;
+use PostgreSQL::Test::Utils;
+use Test::More;
+
+plan skip_all => 'Injection points not supported by this build'
+  unless ($ENV{enable_injection_points} // '') eq 'yes';
+
+my $node = PostgreSQL::Test::Cluster->new('bug19733');
+$node->init(allows_streaming => 'logical');
+$node->start;
+
+if (!$node->check_extension('injection_points'))
+{
+	plan skip_all => 'Extension injection_points not installed';
+}
+
+$node->safe_psql('postgres', q(
+	CREATE EXTENSION injection_points;
+	CREATE TABLE bug19733_txn
+	(
+		id integer PRIMARY KEY,
+		version bigint NOT NULL
+	);
+	INSERT INTO bug19733_txn VALUES (1, 0);
+	SELECT pg_create_logical_replication_slot(
+		'bug19733_slot', 'test_decoding');
+));
+
+my $output_file = $node->basedir . '/logical-output.log';
+my ($receiver_stdout, $receiver_stderr);
+my $receiver = IPC::Run::start(
+	[
+		'pg_recvlogical',
+		'--dbname' => $node->connstr('postgres'),
+		'--slot' => 'bug19733_slot',
+		'--start',
+		'--file' => $output_file,
+		'--fsync-interval' => '1',
+	],
+	'>' => \$receiver_stdout,
+	'2>' => \$receiver_stderr);
+
+my $writer = $node->background_psql('postgres');
+my $writer_pid = $writer->query_safe('SELECT pg_backend_pid()');
+
+$writer->query_safe(q(
+	SELECT injection_points_set_local();
+	SELECT injection_points_attach('commit-before-clog-update', 'wait');
+));
+
+$writer->query_until(
+	qr/writer-started/,
+	q(
+		\echo writer-started
+		BEGIN;
+		UPDATE bug19733_txn
+		   SET version = version + 1
+		 WHERE id = 1;
+		SELECT pg_logical_emit_message(
+			true, 'bug19733', '1:1');
+		COMMIT;
+	));
+
+$node->poll_query_until(
+	'postgres',
+	"SELECT wait_event = 'commit-before-clog-update' "
+	  . "FROM pg_stat_activity WHERE pid = $writer_pid")
+  or die 'writer did not reach commit injection point';
+
+wait_for_file(
+	$output_file,
+	qr/message: transactional: 1 prefix: bug19733, .*content:1:1/);
+
+is(
+	$node->safe_psql(
+		'postgres',
+		'SELECT version FROM bug19733_txn WHERE id = 1'),
+	'0',
+	'logical message is received while a new snapshot still sees old row');
+
+$node->safe_psql(
+	'postgres',
+	"SELECT injection_points_wakeup('commit-before-clog-update')");
+$writer->quit;
+
+is(
+	$node->safe_psql(
+		'postgres',
+		'SELECT version FROM bug19733_txn WHERE id = 1'),
+	'1',
+	'row becomes visible after commit leaves the injection point');
+
+$receiver->signal('TERM');
+$receiver->finish();
+$node->stop;
+
+done_testing();
-- 
2.34.1