Clear Cache Tag to Improve Caching Mechanism in Drupal

By Urvashi Melwani Jan 31, 2020

Regardless of the extra-ordinary design, captivating content, and right product illustration on a company’s website, how bad would it be if it fails to engage users most of the times. A Google report unveils that a new visitor will stay and come back only if the app or page loads content within 3 seconds. Having said that, the online brands only get 3 seconds to hook the new visitor to their site or application. 

Though developers pull out all the stops to optimize the performance and improve the speed of the websites/apps, however, the results do not align with the efforts put into it. 

In such a scenario, web caching comes into existence, where the shared page elements, such as JavaScript, CSS, images, etc. are downloaded and stored closer to the user so that the browser can extract this data instantly from the stored location, instead of querying the web server again.

This blog will run you through a Drupal module, Clear Cache Tag - the only existing Drupal module that helps in clearing the cache of particular tags, and not of the whole site. You can learn about the benefits and installation process.

What is Drupal Clear Cache Tag Module?

Cache tags are essential for a content management system like Drupal, which, otherwise become difficult to determine the places where content is being used as well as cached, that too ahead of time. Taking this into account, a question that pops up is, “how can one invalidate all cache items where the content is in use”?

How can one invalidate all cache items where the content is in use?

To address this given issue, the Clear Cache Tag module ensures that the cached data from different bins is invalidated once it becomes old and defunct, apart from accommodating the latest changes to it. The objective is to accurately target multiple cache bins that contain identical data about the same object, page, etc.

In Drupal 7, there were 3 methods of invalidating cache items but none of them allowed users to invalidate the cache items that contained a modified entity as it was impossible to know about it.

But now, the clear cache tag module can invalidate a particular node (cache item(s)), irrespective of its visibility on three blocks or for say, twelve pages.

Thus, this module helps website developers economize on time and effort, which earlier were devoted to maintaining information. Besides, the other advantage is that the whole site doesn’t need to be cached now over and again, thereby enhancing user-experience extensively.

How Caching is Useful In Improving Customer Experience?

Among multiple components responsible for delivering rich user experience, Caching is one of the most important factors. It offers the following advantages-

  1. Reduced latency

As per this report, 51% of online shoppers in the US prefer to abandon a site or purchase if a site takes longer than usual time to load.

Thus, the speed at which the webpage loads is crucial in ensuring a good digital experience. Caching comes as a handy option for the same as it serves content from a location nearest to the users- either on the users’ hard disk or a nearby server. Thereby, reducing the latency in the roundtrip time & recovering the content much faster.

The time taken to retrieve the resource from the cache will be lower than the time it takes from the origin server and thus speeds up the content delivery process significantly.

2.  Content availability

While users access information online across the globe, content availability becomes a major problem to enhanced user experience. There can be many reasons behind poor website speed such as- frequent interruptions in the network or irregular disturbance on the site. In such cases, caching saves the day by serving end-users with the cached content.

3.  Avoids network congestion

The internet handles huge amounts of data throughout the day and so, has to manage heavy traffic as well; thus congestion in the bandwidth can be an issue on major networks.

However, network congestion can be greatly reduced with caching as the path covered in fetching the content is reduced when it is cached. 

Now that all the user requests won’t be redirected to the origin, it will free up the network and reduce the load on the origin server, thereby serving non-cached content faster.

Challenges With Caching

There are some challenges as well that are associated with caching-

  • Keeping Cache Up-to-date

Cached data may not necessarily be the most accurate, especially that information which is time-critical. Therefore, volatile data should not be cached.

  • Personalization and Caching aren’t Always Compatible

Caching and personalization might not go hand-in-hand. This is because if you’ll try to cache one million users’ personalized responses, it would be quite similar to them just requesting the information from the backend directly anyway- so there is no tangible benefit there.

How To Set Up the Clear Cache Tag Module?

Following steps will help you in easy setup of Clear cache tag module-

Step 1: Enable the Clear cache tag module

Step 2: Go to Admin > Configuration > Development > Clear cache 

tag (/admin/config/development/clear-cache-tag)

Step 3: Enter the tag name you want to invalidate.

Step 4: Click on the submit button to invalidate it.

clear cache tag_scrreenshot

Setting up clear cache tags module

You can also install this module via Drush and the composer. Below are the commands for each respectively-

Drush en clear_cache_tag 
composer require 'drupal/ctc:1.x-dev'

Here is the video for the same showcasing the usage of the module-


HubSpot Video


Summing up

Implementing caching techniques is a vital cog to help your business grow and prosper but it is equally important to understand that tailored solutions are the way to go. Since one-size-does not -fit all, enterprises must formulate optimal caching policies as per your business requirements.

Ultimately, it’s crucial to understand that caching may not be the amulet of luck, but it will ensure that your business stays on foot and well-off with minimal endeavors.

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