[jgrahamc]

The very first project I worked on at Cloudflare but in 2012 was a delta compression-based service called Railgun. We installed software both on the customer's web server and on our end and thus were able to automatically manage shared dictionaries (in this case version of pages sent over Railgun were used as dictionaries automatically). You definitely get incredible compression results.

https://blog.cloudflare.com/cacheing-the-uncacheable-cloudfl...

I am glad to see that things have moved on from SDCH. Be interesting to see how this measures up in the real world.

[Scaevolus]

Delta compression is a huge win for many applications, but it takes a careful hand to make it work well, and inevitably it gets deprecated as the engineers move on and bandwidth stops being a focus-- just like Railgun has been deprecated! https://blog.cloudflare.com/deprecating-railgun

Maybe the basic problem is with how hard it is to find engineers passionate about performance AND compression?

[jgrahamc]

I don't think your characterization of why Railgun was deprecated is accurate. From the blog post you link to:

“I use Railgun for performance improvements.”

Cloudflare has invested significantly in performance upgrades in the eight years since the last release of Railgun. This list is not comprehensive, but highlights some areas where performance can be significantly improved by adopting newer services relative to using Railgun.

Cloudflare Tunnel features Cloudflare’s Argo Smart Routing technology, a service that delivers both “middle mile” and last mile optimization, reducing round trip time by up to 40%. Web assets using Argo perform, on average, 30% faster overall.

Cloudflare Network Interconnect (CNI) gives customers the ability to directly connect to our network, either virtually or physically, to improve the reliability and performance of the connection between Cloudflare’s network and your infrastructure. CNI customers have a dedicated on-ramp to Cloudflare for their origins.

[Scaevolus]

Right, but isn't that part of the general trend of bandwidth becoming far cheaper in the last decade along with dynamic HTML becoming a smaller fraction of total transit?

A 95%+ reduction in bandwidth usage for dynamic server-side-rendered HTML is much less important in 2023 than 2013.

[Twirrim]

Unless you're part of the large majority of people in the world on slower mobile networks. We keep designing and building for people with broadband / wifi, and missing out just how big the 3G / lousy latency markets are.

[jgrahamc]

I think it's related to the size of the Cloudflare network and how good its connectivity is (and our own fibre backbone). But on the eyeball side bandwidth isn't the only game in town: latency is the silent killer.

[lynguist]

I might be naive but isn’t that what rsync is doing?

[jgrahamc]

No. What Railgun did is it enabled the two sides of the connection to agree on a shared dictionary (the most recent version of the page being transmitted) and use that to compress the new page. It required both sides to keep a cache of page versions to compare against.