I’ve been running a lot lately, and so have been listening to lots of podcasts! Which is how I stumbled upon this great episode of the Lullabot podcast recently — embarrassingly one from over a year ago: “Talking Performance with Pantheon’s David Strauss and Josh Koenig”, with David and Josh from Pantheon and Nate Lampton from Lullabot.
(Also, I’ve been meaning to blog more, including simple responses to other blog posts!)
Interesting remarks about BigPipe
Around 49:00, they start talking about BigPipe. David made these observations around 50:22:
I have some mixed views on exactly whether that’s the perfect approach going forward, in the sense that it relies on PHP pumping cached data through its own system which basically requires handling a whole bunch of strings to send them out, as well as that it seems to be optimized around this sort of HTTP 1.1 behavior. Which, to compare against HTTP 2, there’s not really any cost to additional cost to additional connections in HTTP 2. So I think it still remains to be seen how much benefit it provides in the real world with the ongoing evolution of some of these technologies.
David is right; BigPipe is written for a HTTP 1.1 world, because BigPipe is intended to benefit as many end users as possible.
And around 52:00, Josh then made these observations:
It’s really great that BigPipe is in Drupal core because it’s the kind of thing that if you’re building your application from scratch that you might have to do a six month refactor to even make possible. And the cache layer that supports it, can support lots other interesting things that we’ll be able to develop in the future on top of Drupal 8. […] I would also say that I think the number of cases where BigPipe or ESI are actually called for is very very small. I always whenever we talk about these really hot awesome bleeding-edge cache technologies, I kinda want to go back to what Nate said: start with your Page Cache, figure out when and how to use that, and figure out how to do all the fundamentals of performance before even entertaining doing any of these cutting-edge technologies, because they’re much trickier to implement, much more complex and people sometimes go after those things first and get in over their head, and miss out on a lot of the really big wins that are easier to get and will honestly matter a lot more to end users. “Stop thinking about ESI, turn on your block cache.”
Josh is right too, BigPipe is not a silver bullet for all performance problems; definitely ensure your images and JS are optimized first. But equating BigPipe with ESI is a bit much; ESI is indeed extremely tricky to set up. And … Drupal 8 has always cached blocks by default. 🙂
Finally, around 53:30 David cites another reason to stress why more sites are not handling authenticated traffic:
[…] things like commenting often move to tools like Disqus and whether you want to use Facebook or the Google+ ones or any one of those kind of options; none of those require dynamic interaction with Drupal.
Also true, but we’re now seeing the inverse movement, with the increased skepticism of trusting social media giants, not to mention the privacy (GDPR) implications. Which means sites that have great performance for dynamic/personalized/uncacheable responses are becoming more important again.
David and Josh were being constructively critical; I would expect nothing less! 🙂
But in their description and subsequent questioning of BigPipe, I think they forget its two crucial strengths:
BigPipe works on any server, and is therefore available to everybody, and it works for many things out of the box, including f.e. every uncacheable Drupal block!
Bringing this optimization that sits at the intersection of front-end & back-end performance to the masses rather than having it only be available for web giants like Facebook and LinkedIn is a big step forward in making the entire web fast.
Using BigPipe does not require writing a single line of custom code; the module effectively progressively enhances Drupal’s HTML rendering — and turned on by default since Drupal 8.5!
Like Josh and David say: don’t forget about performance fundamentals! BigPipe is no silver bullet. If you serve 100% anon traffic, BigPipe won’t make a difference. But for sites with auth traffic, personalized and uncacheable blocks on your Drupal site are streamed automatically by BigPipe, no code changes necessary:
(That’s with 2 slow blocks that take 3 s to render. Only one is cacheable. Hence the page load takes ~6 s with cold caches, ~3 s with warm caches.)