Drupal 8 Performance Insights

Making Drupal Fly

Presented by   Gokul NK

Gokul N K

  • Graduated from Rashtreeya Vidyalaya (RVCE)
  • From Bangalore
  • Drupal Consultant at Valuebound
  • Drupal Architect at Azri Solutions
  • Formerly a Java Developer @ Mindtree
  • Drupal since 2011
  • Lead Maintainer for Automatr Module
  • Cofounder of Aziteez
  • Bowling Addict


  • Why performance is important
  • Thumb Rules of performance
  • Why performance is important for Drupal
  • Performance in Drupal 7
  • Drupal 8 Performance Enhancements
  • Code Samples

Why Performance Matters

  • 57% of online consumers will abandon a site after waiting 3 seconds for a page to load.

    Source : webperformancetoday.com

Why Performance Matters

  • 39% say speed is more important than functionality for most websites, while only one in five rank greater site functionality as more important.

    Source : www.webperformancetoday.com/

Why Performance Matters

  • A 1-second delay in page load time equals 11% fewer page views, a 16% decrease in customer satisfaction, and 7% loss in conversions

    Source : www.aberdeen.com

Performance Poverty Line

Source : Kissmetrics

Why Drupal Performance matters

  • The fat head is trampling the long tail
  • Fast CMSes suited for various use cases — from simple blogging to complex data modeling — are essential for the success of the long tail.
  • Performance and Security are the two major challenges for Enterprise Adoption.

Source : https://zesty.io/blog/seo/page-load-times-affect-bounce-rate-and-conversion/

Drupal-8 is performant out of the box.

  • Zero JavaScript is served to anonymous users by default.
  • Support for responsive images.
  • Partial page caching, which results in much faster serving of HTML of personalized pages for authenticated users.
  • Sensible cache defaults like CSS/JS aggregation enabled, JS assets being loaded from the bottom

Thumb Rules of Caching

  • Process Once Use Multiple Times.
  • Live with stale data when possible
  • Clear Caches infrequently and keep it very specific.
  • When possible do the changes at the lowest level in the stack. LAMP - DCCc : Linux, Apache, Mysql, PHP, Drupal Core, Contrib and custom module.

Glossary for Cache

  • Cache Hit.
  • Cache Miss.
  • Hit Ratio.
  • Cache Bin.
  • Cache Invalidation.

Cache Me If You Can

Is Caching Working

  • Improve Cache Hit Ratio
  • Nch X Tchs > Overload added by caching mechanism
  • Simultaneous Cache Rebuilds doesn't take down the system.

There are two hard things in computer science:

  • Cache invalidation,
  • Naming things and
  • Off-by-one errors

Cache Invalidation

  • In Drupal7 we used to invalidate way too much, thus reducing the Cache Hit Ratio
  • By default Drupal7 used to clear all entries from Page Cache Table when any node was edited.

Drupal7 Most scary function

			function cache_clear_all($cid = NULL, $bin = NULL, $wildcard = FALSE) {
			  if (!isset($cid) && !isset($bin)) {
			    // Clear the block cache first, so stale data will
			    // not end up in the page cache.
			    if (module_exists('block')) {
			      cache_clear_all(NULL, 'cache_block');
			    cache_clear_all(NULL, 'cache_page');
			  return _cache_get_object($bin)->clear($cid, $wildcard);

Succinct function?

  • 3 parameters for the function
  • 3 * 3 * 2 = 18 combinations in total
  • Users end up invalidating more cache than necessary

Poormans Cache Implementation

			public function call_method($controller, $method, $params = array(), $call_type = '_do_request_drupal_http') {
			    // We should include the parameters also in the cache id as the result changes based on

			    $cache_id = $controller . '_' . $method . '_' . json_encode($params);
			    cache_set($cache_id, $data);

Welcome CacheTags

Example Tags in Drupal 8

			block_plugin:system_menu_block__account block_view config:block.block.bartik_account_menu config:system.menu.account rendered

Using Cache Tags

			$cache = cache($bin);
			$nid = 1;
			$cache->set('cache_id_one', $some_value, CacheBackendInterface::CACHE_PERMANENT, array('node:' . $nid));
			$cache->set('cache_id_two', $some_value, CacheBackendInterface::CACHE_PERMANENT, array('node:' . $nid));

			Cache::invalidateTags(array('node:' . $nid));

			// Or even Better



  • Each entity can implement its own getCacheTags
  • So that other developers can precisely clear caches when dealing with your entity.

Cache Context

  • Cache contexts are analogous to HTTP's Vary header.
  • Cache contexts provide a declarative way to create context-dependent variations of something that needs to be cached.
  • Cache contexts are now hierarchical.

Implementation of Cache Contexts

By User Module

		   * {@inheritdoc}
		  public function getCacheContexts() {
		    $contexts = parent::getCacheContexts();

		    // This filter depends on the current user.
		    $contexts[] = 'cache.context.user';

		    return $contexts;

Server-side dynamic content substitution

  • All or none caching
  • Personalization and random ordering
  • In a way similar to Edge Side Includes.
  • Substitution happens on server side just before sending the HTML.
  • #post_render_cache is part of Render API.

Client-side dynamic content substitution

  • Best Example new marker on comments.
  • Offloading more work from Server to Client.
  • Just in Time substitutions.
  • Not critical, enhancements.

Reference Links

Thank You!

Gokul NK


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