1. CakePHP at a massive
scale, on a budget
Andy Gale

2. Introduction
• I’m a web developer
• I’ve been with websites since ’96
• I’m from Bristol, UK

3. © Ian Wade http://ianwadephotography.co.uk/
Clifton Suspension Bridge

4. Introduction
• I work for Future Publishing Plc
• We are based in Bath, UK and have offices
in London, San Francisco, New York and
Sydney
• We publish over 180 special-interest
publications

5. Publications
To name a few:
• In the UK we publish SFX, Cycling Plus,
TotalFilm, MBUK, Simply Knitting, Official
Playstation Magazine, .Net
• In the US we publish Mac|Life, World of
Warcraft Official Magazine
• In Australia we publish Guitarist, T3, Official
Nintendo, Official Xbox 360

6. Websites
• TechRadar, BikeRadar, MusicRadar,
GamesRadar, PhotoRadar
• CyclingNews, TotalFilm
• Many more...

7. Websites
• Most websites contain: news, features,
reviews, products, forums
• Ad funded
• Popular sites, lots of traffic, often market
leaders

8. Website Platforms
We try to use the most appropriate
website platform for the job
• Wordpress for small builds
http://www.futureplc.com
• Drupal for medium builds
http://www.photoradar.com
• CakePHP for large custom builds
http://www.totalfilm.com
http://www.cyclingnews.com

10. Our first big CakePHP build
• The first CakePHP build had 6 developers,
2 front-end developers and most hadn’t
used CakePHP before
• Design change halfway through site build
• But the site was completely with time to
spare

11. We learnt some lessons
• Most developers thought they knew better
• They didn’t really embrace CakePHP
conventions - myself included
• They didn’t know better

12. We learnt some lessons
• We ended up with at four different ways of
doing everything
• Our future site builds with CakePHP really
should use developers that “get” the
framework

13. Launch day
• Expecting 30k page views
• Got 100k page views
• Site held up nicely
• We all went to the pub

14. The day after launch day
• Marketing and PR departments announced
the new site and started pimping links
• IMDB liked one of the launch stories and
put a link on their homepage
• We got 500k page views
• CakePHP view caching did not hold up
because the server just couldn’t run
enough copies of PHP

15. Oh crap! It broke
• How did we fix it?
• JavaScript used for dynamic aspects such as
user login/out
• Cached full pages in Memcache via a helper
• Served directly from Memcache with Nginx
• More info:
http://andy-gale.com/cakephp-view-memcache.html

16. Quick fix cache solution wasn’t perfect!
• Hub pages - i.e. the homepage, features -
weren’t immediately updated as content
changed
• Simple changes to content meant entire
sections of the site should be rebuilt
• Susceptible to the “thundering herd”
problem

17. Thundering Herd

18. Thundering Herd
A cache issue
• When cached item expires an unlucky user
has to rebuild item in cache
• But we have many requests every second
• That’s a lot of concurrent requests trying
to rebuild the item in cache
• And then we have an unlucky server

19. Thundering Herd
Solutions - Soft expire
• A single unlucky user rebuilds that cache
item
• And creates a lock in the cache so no
other users try to recreate
• Lock must expire quickly in case rebuild
fails

20. Thundering Herd
Solutions - Update the cache!!!
• The best way to prevent the thundering
herd problem is positive cache expiry
• Update the cache when things change!
• Sometimes easier said than done

21. © Roberto Bettini

22. Our next project
• Recently acquired by Future Publishing
• World’s number one cycling site
• Flat HTML website
• Editors used text editor to hand code
HTML and FTP to update the website
• Laborious to edit but fast to serve

23. Our next project
• CMS driven website needed
• De-skill editorial requirements
• More modern design
• Still needs to handle 4 million page views in
a day during the Tour de France
• Massive peak towards the end of a stage

24. Page views per hour

25. Our next project
• It’s a news site and needs to update
instantly
• High traffic peaks during the Tour de
France or doping story
• Couldn’t tolerate the caching issues of that
TotalFilm
• Don’t have a Facebook’s hardware budget

26. How would we cache it?
• Instead of caching whole pages, cache
individual elements
• We called them “panels”
• The data in each panel relates to a model
so when that model is saved we can update
the cache of panels related to that model

28. 1000 requests per second
• At peak times (i.e. at the end of a stage)
• Not the CSS, JS and other static elements
they are served via a CDN
• That’s serving just the HTML

29. Can we handle that with CakePHP?
• After the success of TotalFilm we wanted
to use CakePHP again
• But we we’re worried it wouldn’t scale to
1000 requests a second
• So we benchmarked it

30. Can we handle that with CakePHP?
• CakePHP with requestAction was very
slow
• CakePHP with elements cached was
actually pretty quick but too slow

31. So what did we do?
• CakePHP for the CMS
• CakePHP generating the HTML separated
into panels
• CakePHP for publishing HTML panels into
Memcache

32. So what did we do?
• We used a very simple PHP script to
compile the HTML into full pages
• Works out which panels are required from
URL, fetches parts of the page from
Memcache and compiles page

33. Benchmarks (average with all panels cached)
• Using CakePHP with cached elements
0.1521 seconds
• Pagecompiler
0.0488 seconds
• Pagecompiler with optimisation
0.0031 seconds

34. How do we update the panels?
• View panel - an article
• When article changes, panel needs to be
updated

35. Two types of panel
Hub panel
Often a listing
Difficult to update

36. Hub panels - Need to update?
• We stored the find params for each panel
• Check beforeSave and afterSave, compare
the resulting arrays and if they’ve changed
the HTML panel needs to be regenerated

37. Model beforeSave
Model->find() for the each panel
associated with model
Model afterSave
Model->find() for the each panel Ensure find query isn’t
associated with model cached!!!
Update HTML panel in cache

38. Lots of panels
• To avoid making the CMS really slow
generating loads of HTML panels for every
save we decided to use a queue
• And made a CakePHP shell to work
through the panels and publish them

39. Panelworker
• CakePHP shell
• Works through the panels and publishes
them
• Queue system prevents panels being
regenerated over and over again when
altered by multiple users

40. Panelworker
• Parent/child architecture with IPC
• Able to process 20 panels at once
• State engine with socket_select()

41. CMS Panelworker
Place changed Next item from queue
panels in queue
Fetch panel HTML from CMS
Panel queue
/news
Publish panel HTML to
/news/view/lance-is-amazing
Memcache
/races/view/tour-de-france
/features/view/some-new-bike
www1 www2

42. What else?
• We cached generated pages for 60 seconds
in Memcache and served directly from
Nginx to give us even more head room
• www. servers also run Panelworkers to
enable them to get panels they don’t have
• Panels are also cached on disk for when
they fall out of Memcache

43. So the site launched
• 1181 forum posts complaining
• Lance Armstrong tweets saying he hates
the site
• But, it easily handled the traffic and we have
loads of head room

44. Alternatively
• If your site needs more interactivity with
users, replace HTML panels with data
• Use a similar system to update data in the
cache when things change
• A queue system similar to the Panelworker
could still be useful to keep your site
responsive

45. What we’d do differently
• Instead of storing find params use a model
method for fetching content for each panel
• Despite being fast the web site lacks
interactively
• Use Membase instead of both Memcache
and files to store panels

46. But...
• Since we did out benchmarks over a year
ago CakePHP 1.3 seems a lot quicker
• LazyModel by Frank de Graaf (and others)
http://bakery.cakephp.org/articles/view/optimizing-model-loading-with-lazymodel
• Although it still connects to MySQL when
there is no need :(

47. But...
• For the new build we’re implementing the
following caching system...

48. Questions or comments?
Twitter: @andygale
http://www.cyclingnews.com
http://www.totalfilm.com
http://www.andy-gale.com