Statistics

Measuring Drupal Core code complexity

Wed, 07 Jan 2026 17:22:23 -0500

I built a dashboard that tracks Drupal Core's code quality over time, across major releases from Drupal 7 through Drupal 11. It measures lines of code, cyclomatic complexity, maintainability index, anti-patterns, and API surface area. Think of it as a health report for Drupal's codebase.

The dashboard updates automatically and is available at https://dbuytaert.github.io/drupal-core-metrics/.

The charts tell a clear story of steady, hard-won progress. A story to be proud of and worth sharing. Code quality is dramatically better than it was in Drupal 7: lower complexity, easier to maintain, fewer anti-patterns, and dramatically better test coverage. Drupal now has nearly twice as much test code as production code!

Drupal Core's API surface has modernized too. As Drupal shifted from procedural to object-oriented patterns, global procedural functions gave way to classes implementing interface methods, services, plugins, and events.

By tracking these metrics publicly, I hope to inform decisions about both code quality and developer experience. When we refactor complex code, we can measure the impact. We can set goals and track progress.

All charts use static code analysis. Static analysis can't measure the experience of learning Drupal, but it can hint at it. As a next step, I'd love to measure developer experience more directly. Dynamic analysis could help, for example by tracking call stack depth or how many files and APIs you need to touch to make a simple change.

The dashboard is open source, and contributions are welcome at https://github.com/dbuytaert/drupal-core-metrics.

Special thanks to catch for multiple rounds of feedback. As the most active Core Committer over the past 12 months, his input was invaluable.

Drupal contributor statistics

Mon, 06 Jun 2011 06:32:02 -0400

I recently extracted some data from the Drupal project's CVS and Git logs to see how the number of code contributors and total contributions have changed over time. If there was any doubt of our continual growth, the resulting charts demolish it.

Aggregated results from core and contributed modules.

As can be seen from the graphs, there is a pretty big spike in commit activity post-Git migration.

Drupal 7 commit history

Mon, 31 Jan 2011 22:16:46 -0500

We opened the Drupal 7 development branch in February 2008, and released Drupal 7.0 in January 2011. This graph shows the stacked commit history from beginning to end. I appointed Angie as my Drupal 7 co-maintainer in August 2008 after having been the sole committer for 7 months. The peak around August 2009 (the highest peak) was the first attempted Drupal 7 code freeze. The momentum steadily built up towards the initial code freeze date. Interestingly, we remained most productive during the extended code freeze period ... more code freezes are better than one code freeze? ;-)

I averaged at 3.6 commits per day, whereas Angie's average is 2.6 commits per day (including weekends and holidays).

Acquia Hosting: an update after 8 months of Drupal hosting

Fri, 14 May 2010 08:52:46 -0400

Roughly 8 months ago at DrupalCon Paris, we launched Acquia Hosting. In this blog post, I wanted to give a quick update on where we are after 8 months.

Current status

For those who don't know, Acquia Hosting is a highly-available cloud-based hosting platform tuned for Drupal performance and scalability. From a technology point of view, we've built tools to automatically launch multi-server hosting environments optimized for Drupal. It is built on Amazon Web Services (i.e. Amazon EC2, Amazon S3, etc) using Open Source components such as Varnish, Puppet, GlusterFS, NginX and more. If you are interested in the technical details, I highly recommend watching Barry Jaspan's DrupalCon San Francisco presentation on the challenges of hosting Drupal on AWS – I'm biased, but it is the best technical presentation that I've seen on hosting websites on Amazon Web Service (AWS). Highly recommended. The presentation is the result of 2.5 years of experience building products exclusively on Amazon Web Services and having to maintain close to 200 EC2 instances.

At Acquia, we're all very proud of what we've built. For example, we were recently able to have a new, enterprise-scale Acquia Hosting customer online only a few days after they first contacted us. It takes most hosting companies weeks or months to roll out, configure and tweak all the servers required to host a high-traffic traffic sites like this one. In just a few days, we scaled past the limits of their previous hosting provider and flawlessly served 3 million page views per hour (i.e. 830+ page views per second or 5000+ HTTP requests per second – yes, Drupal scales). I hope the customer will allow us to write-up a detailed case study at some point. It is a real success story for Drupal, Acquia Hosting, Amazon Web Services and cloud computing in general: incredible time to market, great performance and scalability. We've come a long way since we started working on a Drupal hosting product about a year ago.

The way we started work on Acquia Hosting is the way we have continued: with a very strong focus on engineering. Our first area of focus was on reliability. The results of this were: providing multiple, redundant web nodes; real-time database replication; backups; monitoring infrastructure (we track 25+ system parameters); customer isolation, and so on. Next, we focused our efforts on improving Acquia Hosting's performance by adding tools like Varnish for page caching; customer isolation; reorganizing parts of our underlying architecture; lots of tweaking to Apache, PHP and MySQL; and repeated rounds of realistic load testing. Along the way, we developed deployment tools to make it easy to roll-out and automatically configure our customers' EC2 instances – it takes just a matter of minutes to upgrade a site's capacity.

Roadmap

Considering our costs and other metrics eight months into the hosting business adventure, the real value of our hosting offering comes not from the technology alone, but rather from our support team's work while getting customers' sites online and helping them day in, day out. Once servers are provisioned for a new site, getting customers up-and-running involves detailed site audits (making sure they don't have core hacks, analyzing their site architecture, etc.), teaching them how the Acquia Hosting environment works, helping them learn to best leverage clusters of servers, doing load testing, and helping them get over performance bottlenecks (slow or excessive SQL queries, expensive uncached Views or blocks, etc.). At the end of the day, our team's deep knowledge of Drupal and our technology stack are the essence and ultimate value-proposition of our Drupal hosting offering.

Going forward, a top priority is to make the process of getting new customers online easier for us and better for them. Among other things, that means developing more "self-service"-style systems, improved customer dashboards and documentation, and streamlined, focused support operations to make sure our customers are getting their questions answered and their problems fixed in the shortest time possible so they can worry about their business and not their websites.

Free Acquia Hosting program

We also announced a free Acquia Hosting program. To help support the Drupal community, we give free Acquia Hosting to sites for non-profit groups that promote Drupal use and adoption. We're now hosting 25 community websites including Drupal Edu, SpreadDrupal, Drupal Dojo, Drupal Catalan, Design 4 Drupal Boston and more. There are about 50 more Drupal community sites in the backlog waiting to get setup with an Acquia Hosting account. Yet another reason to make it easier to get new users and customers up and running!

State of Drupal presentation (April 2010)

Mon, 03 May 2010 16:08:48 -0400

Two weeks ago at DrupalCon San Francisco I gave my traditional state of Drupal presentation. A total of 6000 people watched my keynote live; 3000 were present at DrupalCon, and another 3000 watched the live video stream. Nonetheless, a lot of people asked me for my slides. So in good tradition, you can download a copy of my slides (PDF, 48 MB) or you can watch a video recording of my keynote on archive.org.

Picture taken backstage while waiting to go on stage for my keynote.

Picture taken after my keynote just before packing up my laptop.

Future of Open Source Survey 2010

Tue, 23 Feb 2010 14:24:29 -0500

Like last year, I'll be attending the Open Source Business Conference (OSBC) next month, on March 17-18 in San Francisco. Also like last year, I will participate in a panel discussion led by Michael Skok (Partner at North Bridge, Acquia Board Member and personal friend). This year, I'll be in a panel with Larry Augustin (CEO of SugarCRM, VA Linux, SourceForge), Jim Whitehurst (CEO of RedHat) and Tim Yeaton (CEO of Black Duck Software) to discuss the future of Open Source businesses. The panel discussion will draw on the "2010 Future of Open Source survey" so make sure to weigh in and provide your perspective on a number of important Open Source business questions. As a reference, here are the 2009 and 2008 results.

Speed matters

Fri, 18 Dec 2009 07:12:38 -0500

More proof that speed as perceived by the end user matters. This time from a Google Research paper (PDF). Google's experiments demonstrate that increasing web search latency 100 to 400 ms reduces the daily number of searches per user by 0.2% to 0.6%. Furthermore – and this is where it gets really interesting – users do fewer searches the longer they are exposed. In other words, the cost of slower performance increases over time and persists.

To use Peter Van Dijck's words:

In other words, if your website is a little slower, users will use it less (we knew that), but they'll also use it less and less over time, and when it speeds up again, they'll still use it less than before the slowdown.

Based on their observations, Google suggests site builders to think twice about adding a feature that hurts performance if the benefit of the feature is unproven.

State of Drupal presentation (September 2009)

Mon, 21 Sep 2009 07:46:18 -0400

Two weeks ago at DrupalCon Paris, I gave my traditional state of Drupal presentation. The video of the presentation is available from archive.org, and you can download a copy of my slides (PDF, 8 MB) as well.

I don't want to give away the spoiler, but essentially, the state of Drupal is strong. :) We should be really proud of what we have accomplished with Drupal 6, and what we're about to accomplish with Drupal 7. In the presentation, I also talk about what it means for Drupal to grow up, and what the next phase of our life will most likely look like.

Drupal can help pay for your rent

Tue, 07 Jul 2009 12:58:33 -0400

The demand for Drupal talent continues to exceed the supply! What will we do about it?

Source: Indeed.com.

Drupal 6 growth

Sat, 04 Apr 2009 23:09:06 -0400

The graph above is made based on the project usage statistics collected on drupal.org. As ever with statistics of this sort, they don't tell the whole story. This is because only sites running the update status module report data back to drupal.org. This module is part of Drupal 6 and the installer prompts the user to enable the module when Drupal is first installed. It is not required to enable this module. People upgrading from Drupal 5 aren't even prompted to enable it. Plus, many Drupal sites are hidden behind corporate firewalls. As a result, we don't really know how many Drupal 6 sites there are.

Either way, based on the growth data that we do have available, we can predict that we will near 240,000 Drupal 6 sites by January 2010. See the black trendline on the graph. The R-square represents the variability in the data set that is accounted for by the prediction model. Its value indicates how likely the predicted values are – the closer to 1.0, the better. If Drupal 6 continues to grow like it did the past 9 months, our prediction should be pretty accurate. It would mean that the number of Drupal 6 sites will double over the next 9 months. Not bad.

I always believed that the best way to grow Drupal is to make the software better, and that is why we continue to work hard on Drupal 7. But until Drupal 7 is released, there are a lot of things that we can do to help people get started with Drupal 6 – from offering .zip-files instead of .tar-files, to launching the drupal.org redesign, to sharing more Drupal 6 success stories, and more. There are a lot of barriers that could be removed and that would result in faster growth.

Once in a while, it is good to make lists. You're all invited to share your list of "things you think we should do" in the comments of this post. I recommend that you prioritize your list so the most important item is at the top. If you are actively working on any of the items on your list, let us know too. Bonus points for ideas that have high impact, require minimal effort and benefit the Drupal community at large. Penalty points for people that recommend Drupal 7 features based on self-interest. Ready, steady, go!