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 DevelUse 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 Extensionconf = 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 loadPressflow 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 !