Mercurial > hg > ngx_http_upstream_keepalive
view t/stale.t @ 45:489c5d4318ff draft
Keepalive: "single" parameter deprecated.
The original idea was to optimize edge cases in case of interchangeable
backends, i.e. don't establish a new connection if we have any one
cached. This causes more harm than good though, as it screws up
underlying balancer's idea about backends used and may result in
various unexpected problems.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Mon, 25 Jun 2012 22:55:53 +0400 |
parents | 2ee28064a04a |
children |
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#!/usr/bin/perl # (C) Maxim Dounin # Test for stale events handling in upstream keepalive. ############################################################################### use warnings; use strict; use Test::More; 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'); ###############################################################################