From 805b53cccd5a90e787447495753b4db9ed1ec765 Mon Sep 17 00:00:00 2001 From: Arseniy Mukhin Date: Mon, 20 Oct 2025 15:14:36 +0300 Subject: [PATCH] TAP test with listener pos race --- src/backend/commands/async.c | 5 + src/test/authentication/meson.build | 1 + .../authentication/t/008_listen-pos-race.pl | 91 +++++++++++++++++++ 3 files changed, 97 insertions(+) create mode 100644 src/test/authentication/t/008_listen-pos-race.pl diff --git a/src/backend/commands/async.c b/src/backend/commands/async.c index 4e6556fb8d1..e4e65b02e98 100644 --- a/src/backend/commands/async.c +++ b/src/backend/commands/async.c @@ -167,6 +167,7 @@ #include "utils/ps_status.h" #include "utils/snapmgr.h" #include "utils/timestamp.h" +#include "utils/injection_point.h" /* @@ -1954,6 +1955,8 @@ SignalBackends(void) int count; ListCell *lc; + INJECTION_POINT("listen-notify-signal-backends", NULL); + /* * Attach to the channel hash if needed. We might not have one if this * backend hasn't done LISTEN, but we need it to find listeners. @@ -2321,6 +2324,8 @@ asyncQueueReadAllNotifications(void) head = QUEUE_HEAD; LWLockRelease(NotifyQueueLock); + INJECTION_POINT("listen-notify-local-pos", NULL); + if (QUEUE_POS_EQUAL(pos, head)) { /* Nothing to do, we have read all notifications already. */ diff --git a/src/test/authentication/meson.build b/src/test/authentication/meson.build index 800b3a5ff40..c33f0065b1d 100644 --- a/src/test/authentication/meson.build +++ b/src/test/authentication/meson.build @@ -16,6 +16,7 @@ tests += { 't/005_sspi.pl', 't/006_login_trigger.pl', 't/007_pre_auth.pl', + 't/008_listen-pos-race.pl', ], }, } diff --git a/src/test/authentication/t/008_listen-pos-race.pl b/src/test/authentication/t/008_listen-pos-race.pl new file mode 100644 index 00000000000..09944407e4f --- /dev/null +++ b/src/test/authentication/t/008_listen-pos-race.pl @@ -0,0 +1,91 @@ +# Copyright (c) 2021-2025, PostgreSQL Global Development Group + +use strict; +use warnings FATAL => 'all'; + +use PostgreSQL::Test::Cluster; +use PostgreSQL::Test::Utils; +use Time::HiRes qw(usleep); +use Test::More; + +if ($ENV{enable_injection_points} ne 'yes') { + plan skip_all => 'Injection points not supported by this build'; +} + +my $node = PostgreSQL::Test::Cluster->new("test"); +$node->init; +$node->start; + + +if (!$node->check_extension('injection_points')) { + plan skip_all => 'Extension injection_points not installed'; +} + +$node->safe_psql('postgres', 'CREATE EXTENSION injection_points'); + +my $listener = $node->background_psql('postgres'); +my $listener_with_invalid_pos = $node->background_psql('postgres'); +my $notifying_psql = $node->background_psql('postgres'); + +# setup injection points +$node->safe_psql('postgres', "SELECT injection_points_attach('listen-notify-signal-backends', 'wait');"); + +$listener_with_invalid_pos->query_safe( + qq[ + SELECT injection_points_set_local(); + SELECT injection_points_attach('listen-notify-local-pos', 'wait'); + ]); + +# listener starts listening to channel ch, and starts a transaction, +# while listener is within an active transaction, its pos will be 0, +# and therefore all new listeners will have to start reading from 0 position too because of it. +$listener->query_safe("LISTEN ch;"); +$listener->query_safe("BEGIN;"); + +# create a lot of notifications and start waiting +# on listen-notify-signal-backends (before direct advancement) +$notifying_psql->query_until( + qr/start/, q( + \echo start + BEGIN; + select pg_notify('ch', repeat('a',3000) || x::text) from generate_series(1,100) as x; + COMMIT; + +)); +# Wait until notifying_psql enters the wait injection point. +$node->wait_for_event('client backend', 'listen-notify-signal-backends'); + +# listener_with_invalid_pos executes LISTEN command and starts +# waiting on the injection point with pos = 0 in local variable +$listener_with_invalid_pos->query_until( + qr/start/, q( + \echo start + LISTEN ch2; +)); +# Wait until listener_with_invalid_pos enters the wait injection point. +$node->wait_for_event('client backend', 'listen-notify-local-pos'); + +# wake up notifying backend. direct advancement should be applied now to listener_with_invalid_pos +# listener_with_invalid_pos is still waiting on injection point with local pos = 0 +$node->safe_psql('postgres', "SELECT injection_points_wakeup('listen-notify-signal-backends');"); + +#sleep just to be sure that direct advancement was applied to listener_with_invalid_pos +sleep 1; + +# let listener to advance its position to unblock queue truncating +$listener->query_safe("COMMIT"); + +# truncate the queue +$node->safe_psql('postgres', "select pg_notification_queue_usage();"); + + +# wake up listener_with_invalid_pos with local copy of pos = 0. queue has been truncated already. +# test should fail after it. 008_listen-pos-race_test.log contains error details +$node->safe_psql('postgres',"SELECT injection_points_wakeup('listen-notify-local-pos');"); + + +$listener->quit(); +$listener_with_invalid_pos->quit(); +$notifying_psql->quit(); + +done_testing(); -- 2.43.0