new file mode 100644
--- /dev/null
+++ b/memcached_keepalive_stale.t
@@ -0,0 +1,118 @@
+#!/usr/bin/perl
+
+# (C) Maxim Dounin
+
+# Test for stale events handling in upstream keepalive.
+
+###############################################################################
+
+use warnings;
+use strict;
+
+use Test::More;
+
+BEGIN { use FindBin; chdir($FindBin::Bin); }
+
+use lib 'lib';
+use Test::Nginx;
+
+###############################################################################
+
+select STDERR; $| = 1;
+select STDOUT; $| = 1;
+
+eval { require Cache::Memcached; };
+plan(skip_all => 'Cache::Memcached not installed') if $@;
+
+my $t = Test::Nginx->new()->has('rewrite')->has_daemon('memcached')->plan(2)
+	->write_file_expand('nginx.conf', <<'EOF');
+
+%%TEST_GLOBALS%%
+
+daemon off;
+
+worker_processes 2;
+
+events {
+}
+
+http {
+    %%TEST_GLOBALS_HTTP%%
+
+    upstream memd {
+        server 127.0.0.1:8081;
+        keepalive 1;
+    }
+
+    server {
+        listen       127.0.0.1:8080 sndbuf=32k;
+        server_name  localhost;
+
+        location / {
+            set $memcached_key $uri;
+            memcached_pass memd;
+        }
+    }
+}
+
+EOF
+
+my $memhelp = `memcached -h`;
+my @memopts1 = ();
+
+if ($memhelp =~ /repcached/) {
+	# repcached patches adds additional listen socket memcached
+	# that should be different too
+
+	push @memopts1, '-X', '8091';
+}
+if ($memhelp =~ /-U/) {
+	# UDP ports no longer off by default in memcached 1.2.7+
+
+	push @memopts1, '-U', '0';
+}
+
+$t->run_daemon('memcached', '-l', '127.0.0.1', '-p', '8081', @memopts1);
+
+$t->run();
+
+$t->waitforsocket('127.0.0.1:8081')
+	or die "Unable to start memcached";
+
+###############################################################################
+
+my $memd1 = Cache::Memcached->new(servers => [ '127.0.0.1:8081' ]);
+
+# It's possible that stale events occur, i.e. read event handler called
+# for just saved upstream connection without any data available for
+# read.  We shouldn't close upstream connection in such situation.
+#
+# This happens due to reading from upstream connection on downstream write
+# events.  More likely to happen with multiple workers due to use of posted
+# events.
+#
+# Stale event may only happen if reading response from upstream requires
+# entering event loop, i.e. response should be big enough.  On the other
+# hand, it is less likely to occur with full client's connection output
+# buffer.
+#
+# We use here 2 workers, 20k response and set output buffer on clients
+# connection to 32k.  This allows more or less reliably reproduce stale
+# events at least on FreeBSD testbed here.
+
+$memd1->set('/big', 'X' x 20480);
+
+my $total = $memd1->stats()->{total}->{total_connections};
+
+for (1 .. 100) {
+	http_get('/big');
+}
+
+cmp_ok($memd1->stats()->{total}->{total_connections}, '<=', $total + 2,
+	'only one connection per worker used');
+
+$t->stop();
+
+like(`grep -F '[alert]' ${\($t->testdir())}/error.log`, qr/^$/s, 'no alerts');
+
+###############################################################################