Drupal Performance - Case Study
Hernâni Borges de Freitas – Drupal PT Meetup – Porto, 27th November

 Biggest online fan community about Sport
Lisboa e Benfica.
 About 10 years old, online since 01/05/2001
 Done as hobby by:
 Staff (20 people among editors and moderators)
 Members (~31 000 users, 8000 Active Members)
 Articles, blog aggregation, image gallery,
forum, press aggregation, matches and
players’ profiles.

 Average per day (October 2010)
 8000 Visits per Day
 185 000 PageViews
 12 pages per Session (!)
 3500 messages per day.
 50 blogs aggregated.

 According to Alexa.com (Oct 2010)
 150th most visited website in
Portugal.
 On top 50 portuguese websites.
 Most popular portuguese website
made in DRUPAL!

 Technology was slowing us down
 Custom designed cms, with 10 years legacy code
and cache control based in smarty.
 Site must be done by community
 Workflow and revision process was weak and
unsafe
 Developments took to much time
 Hard to implement or change existing features.
 Performance problems on traffic peaks
 Around 1700 users at same time.

 Dedicated Server
 Quad Xeon 2,4 Ghz
 4 Gb Memory
 Lighttpd/Apache as App Server
 Php with eAccelerator.
 Most of pageviews are seen by registered users.
 Most pageviews are generated by forum (based
on Simple Machines Forum).
 Cache control was made using smarty and forum
cache system.

 Development started in August 2010
 Done on spare time by 1 Drupalista.
 We went live in 24th October 2010 (2
months ...)
 Website redone from scratch
 Data migration done used custom scripts
 60k nodes, 30k users, 2,5k terms, 16 content types
 100 modules
 Portuguese/English , Web/Mobile Site

 Optimize using iterative improvements
(Progressive Doping)
 Architecture
 Profiling
 Caching
 Application diet
 WebServer Change
 Drupal Tips and Tricks
 Future Ideas

 Optimize queries and function calls
 Measure non-cached page loading times.
 Optimize heavier pages.
 Reduce http calls.
 Turn on page caching system (AuthCache)
 Replace caching backend
 Test, Optmize , Test, Optmize, Test, Optimize
!!

 Use Pressflow!
 High speed drupal fork
▪ Optimized for PHP5 and Mysql (No
wrapper functions)
▪ Designed for Database replication and
Reverse proxies.
▪ Squid / Varnish
▪ Optimized in session and path handling
▪ Non Anon-Sessions (Lazy session creation)
▪ Fast path alias detection
 Avoid tons of calls to drupal_lookup_path.

 Use Devel
 Use xdebug.profiling.
 Identify heavier pages, functions and queries.
 Start by most visited pages
 Try to identify which functions are taking most
time.
 You’ll find a non pleasant detail
 Bootstrap in a normal site can be slow.
 Great to understand how drupal core works!
 Great to measure cost vs importance

Generic Drupal cache handling

 After activate Drupal caching:
 On Bootstrap until
DRUPAL_BOOTSTRAP_LATE_PAGE_CACHE phase
Drupal verify if user is anonymous
▪ If so check if we have a valid cached page
▪ Delivery it without load all modules, render all regions... FAST!
 Blocks and some content is also cached, and can be
served to authenticated users.
 Cached content is stored in database tables
 Tables are flushed
 Nodes and comments are posted
 Cron runs
 Explicits calls to cache_clear_all

 However most of our traffic is authenticated
 We can’t use drupal base cache
 There’s a module for that ! => authcache
 AuthCache
 Register cookie variables on login like roles, login
name and login profile.
 On page_early_cache bootstrap verify if there’s a
cached version of that page to the roles the user
belongs.
 If there isn’t do full_bootstrap , render the page and
save a rendered version on cache to future usage.

 Include a setting in settings.php:
 Configure roles and pages to cache
 We are not caching anything to
editors/moderators, neither any page in admin
section or content edition.
 Be Careful with ajax stuff..
$conf['cache_inc'] = './sites/all/modules/authcache/authcache.inc';

 Small problem: all page looks the same to
everyone.
 We want to customize the header with a
pleasant message.
 Authcache recommendation is to do page
replacements using ajax calls => More http
calls
 To avoid http traffic I tweaked authcache
module to do a str_replace of a certain zone,
and start to store cached pages not gzipped.

 MySql is not designed to be used as a cache
backend.
 Fortunately Drupal allows pluggable cache
backends.
 We started by using cache router, using
memcached
 One bin for most cache table
 We ended up using memcache module because of
several crashs and white screens.

 Install MemCache, MemCache Pecl Extension
conf = array(
'memcache_servers' => array('localhost:11211' => 'default',
'localhost:11212' => 'cache_block',
'localhost:11213' => 'cache_page',
'localhost:11214' => 'users',
'localhost:11215' => 'session'),
'memcache_bins' => array('cache' => 'default',
'cache_block' => 'cache_block',
'cache_page' => 'cache_page',
'users'=>'users',
'session'=>'session'),
'memcache_key_prefix' => 'sb10prod',
);
$conf['cache_inc'] = './sites/all/modules/authcache/authcache.inc';

 On popular pages use custom cache!
 We are storing in cache_block to allow block
refresh when new content arrives.
if($content=cache_get('artigos:home:cronicas','cache_block')) {
$block->content=$content->data;
}
else {
$view=views_get_view('artigos');
$view->set_display('panel_pane_1');
$block->content=$view->render();
$block->content.='<span style="clear:both;float:right">'.l(t("View all"),'cronicas').'</span>’;
cache_set('artigos:home:cronicas',$block->content,'cache_block');
}

 Sessions Table was heavily used.
 We replace it with memcache session module.

 Serious dropdown on server load
 Pressflow already does not store sessions for
anon users => non_anon module does the
same.
UPDATE sessions SET uid = 1, cache = 0, hostname = '10.1.1.2', session = '', timestamp =
1243567406 WHERE sid = '74db42a7f35d1d54fc6b274ce840736e'
$conf['session_inc'] = './sites/all/modules/memcache/memcache-session.inc';

 In forum pages just call what is needed.
require_once './includes/bootstrap.inc';
drupal_bootstrap(DRUPAL_BOOTSTRAP_PATH);
$arg0=arg(0);
if($arg0=='forum’) {
require_once './includes/common.inc';
drupal_load('module','serbenfiquista');
drupal_load('module','filter');
drupal_load('module','locale');
require_once './includes/theme.inc';
$content=render_forum();
/*
do some load of modules when content not cached, vars will be available at theme
….
*/
require_once ('./sites/default/themes/serbenfiquista/page.tpl.php');
}

 Remember we were redirecting only non-
static content to apache
 What about css/js aggregated files and
imagecache files ? => They were going to
apache also..
$HTTP["url"] !~ ".(js|css|png|gif|jpg|ico|txt|swf)$" {
proxy.server = ( "" => (
(
"host" => ”localhost ", "port" => 81)
)
)
}

07/Nov/2010 –Things went bad

 Apache was handling too much connections.
 We were runnning out of memory, and no
more connections available...
 After that nightmare by night we decide to
switch to nginx.
.

 Using php in php-fpm mode
 Configuration based on perusio’s examples:
 https://github.com/perusio/drupal-with-nginx
 Using eAccelerator 0.9.5.3 as opcode cache to use shared
keys in memory used by SMF.
extension="eaccelerator.so”
eaccelerator.shm_size="300"
eaccelerator.cache_dir="/tmp/eaccelerator"
eaccelerator.enable="1"
eaccelerator.optimizer="1"
eaccelerator.check_mtime=“0” #avoids to check if file has changed
eaccelerator.shm_max=”0

 Don’t forget to use Css and JS aggregation to avoid http
connections
 Index customization (Use EXPLAIN on your queries)
 Run cron twice a day
 Do not use cron to import feeds
 Use Apache Solr to index your content.
0 */12 * * * cd /var/www/html/ && drush core-cron >> /var/log/crondrupal
*/10 * * * * cd /var/www/html/ && drush feeds-refresh blogs >> /var/log/cronblogs
select title,created,nid from node use index(node_status_type) where status=1 and
type='usernews' order by created desc limit 0,4

 We have load peaks when some content is changed: most of
cached content is erased.
 Control in detail what is cached and expire only what is
invalid.
 Pre-Cache most page details.
 Use Cache Actions and Rules to clean specific views/blocks
/panes.
 When page is regenerated its components are already
rendered.
 I wish we could be more elastic by serving content from S3 or
other smaller webservers.

SerBenfiquista.com by:
Alberto Rodrigues, André Garcia, André
Sabino, André Marques, António Alves,
António Costa, Bernardo Azevedo,
Diogo Sarmento, Élvio da Silva,Filipe
Varela, Francisco Castro, Hugo Manita,
Hernâni Freitas, João Pessoa Jorge,
João Cunha, João Mariz, José Barata,
Isabel Cutileiro,, Luis Correia,Miguel
Ferreira, Nelson Vidal, Nuno Silva,
Paulo Paulos, Pedro Lança, Pedro
Neto, Rafael Santos, Rodrigo Marques,
Ricardo Martins, Ricardo Solnado,
Valter Gouveia
and plenty others !