The Fastest Drupal Ever is Here!

Drupal 8

  • Utilises BigPipe to send quick content (text, cached items) first. Slow content last.
  • Page renders faster. Slow content filled in as/when ready.
  • Similar technology, SmallPipe, works without JS.

Make the web fast

  • Great user experience, pages load fast for 1 user
  • Great user experience, pages load fast for [n] concurrent users
  • Time to first byte + Asset loading + Rendering + JS exec time == minimal

Optimization

  • Remove as much work as possible from the critical path
  • ACD = Avoid, Cache, Defer

Cache invalidation

  • Drupal 7 clears whole page cache when an element of the page changes
  • Drupal 8 invalidates instantaneously
    • Everything declares what it varies by
    • Allows caching authenticated user content securely

D8 makes it simple

  • Does all the caching logic internally
  • If you give Drupal information then it can be smarter about is decisions
  • Formalizes things in a “language” to make these things fast
    • Potentially can be backported to D7

Dependencies

  • D7 did not track dependencies
  • e.g. drupal_add_css(), drupal_add_js()
    • Global state: impossible to cache
    • #attached asset libraries solves that
  • e.g. url() output depends on
    • <front> config
    • HTTPS config
    • Clean URL config
    • Current site in multisite
    • …
    • Impossible to cache invalidate
  • To make it easier:
    • Renderer:addCacheableDependency($build, $dependency);

Correct invalidation in D8

  • Cache tags (data dependencies)
  • Cache contexts (context dependencies)
  • Cache max-age (time dependencies)
  • Cacheability bubbled during rendering!

Thought process

  1. I’m rendering something. That means I need to think about cacheability?
  2. Is this smething thats expensive to render, and therefore is worth caching?
  • If yes cache keys
  1. Does the representation of the thing I’m rendering vary per combination of permissions, per URL, per interface…
  • If yes, cache context
  • $build['#cache']['contexts'][] = 'user.permissions';
  • $build['#cache']['contexts'][] = 'url';
  1. What causes the representation of the thing i’m rendering to become outdated
  • If yes, cache tags.
  1. When does the representation of the thing I’m rendering become outdated?
  • If yes, cache max-age
  • $build['#cache']['max-age'][] = Cache::PERMANENT;

Cacheability metadata

  • All relevant objects provide cacheability metadata

Page cacheability

  • Pages are static and dynamic
  • Dynamic content slows the page down
    • Gets slower with more content and more users. More unique data which is uncacheable.
  • D8 solves this with placeholders (in core).
    • Removes all dynamic content from page, placeholders there instead. Static content remains, as it is cacheable.

Lazy builder

$build['complex_thing'] = [
  '#lazy_builder' => ['callback', [
    'arg1',
    'arg2',
  ]],
];
  • Effective successor to hook_pre_render()
  • Builds a render array and returns it
  • Output must solely depend on the input (arguments)
    • Able to render in isolation
    • This is what enables BigPipe

Pitfalls

  • Don’t forget to add cache tags!
  • Uncacheable? Don’t forget to set max-age to zero