From 4fba5b1e1b6f61acb3508b90825c668a8c6bf70c Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Tue, 24 Aug 2021 18:24:17 +0200
Subject: [PATCH] Make psql cancel test more timing robust

---
 src/bin/psql/t/020_cancel.pl | 31 +++++++++++++++++++++++--------
 1 file changed, 23 insertions(+), 8 deletions(-)

diff --git a/src/bin/psql/t/020_cancel.pl b/src/bin/psql/t/020_cancel.pl
index 7713fff8e4..0319f6b3f1 100644
--- a/src/bin/psql/t/020_cancel.pl
+++ b/src/bin/psql/t/020_cancel.pl
@@ -7,6 +7,7 @@
 use PostgresNode;
 use TestLib;
 use Test::More tests => 2;
+use Time::HiRes qw(usleep);
 
 my $tempdir = TestLib::tempdir;
 
@@ -28,19 +29,33 @@
 	my ($stdin, $stdout, $stderr);
 
 	# Test whether shell supports $PPID.  It's part of POSIX, but some
-	# pre-/non-POSIX shells don't support it (e.g., NetBSD, Solaris).
+	# pre-/non-POSIX shells don't support it (e.g., NetBSD).
 	$stdin = "\\! echo \$PPID";
 	IPC::Run::run(['psql', '-X', '-v', 'ON_ERROR_STOP=1'], '<', \$stdin, '>', \$stdout, '2>', \$stderr);
 	$stdout =~ /^\d+$/ or skip "shell apparently does not support \$PPID", 2;
 
-	local $SIG{ALRM} = sub {
-		my $psql_pid = TestLib::slurp_file("$tempdir/psql.pid");
-		kill 'INT', $psql_pid;
-	};
-	alarm 1;
+	# Now start the real test
+	my $h = IPC::Run::start(['psql', '-X', '-v', 'ON_ERROR_STOP=1'], \$stdin, \$stdout, \$stderr);
 
-	$stdin = "\\! echo \$PPID >$tempdir/psql.pid\nselect pg_sleep(3);";
-	my $result = IPC::Run::run(['psql', '-X', '-v', 'ON_ERROR_STOP=1'], '<', \$stdin, '>', \$stdout, '2>', \$stderr);
+	# Get the PID
+	$stdout = '';
+	$stderr = '';
+	$stdin = "\\! echo \$PPID >$tempdir/psql.pid\n";
+	pump $h while length $stdin;
+	my $count;
+	usleep(10_000) until -s "$tempdir/psql.pid" or ($count++ > 180 * 100 and die 'pid file did not appear');
+	my $psql_pid = TestLib::slurp_file("$tempdir/psql.pid");
+
+	# Send sleep command and wait until the server has registered it
+	$stdin = "select pg_sleep(180);\n";
+	pump $h while length $stdin;
+	$node->poll_query_until('postgres', q{SELECT (SELECT count(*) FROM pg_stat_activity WHERE query ~ 'pg_sleep') > 0;})
+	  or die "timed out";
+
+	# Send cancel request
+	kill 'INT', $psql_pid;
+
+	my $result = finish $h;
 
 	ok(!$result, 'query failed as expected');
 	like($stderr, qr/canceling statement due to user request/, 'query was canceled');
-- 
2.33.0