Speeding up SmugMug Search
SmugMug users have uploaded millions of awesome photos, and one of the things we work hard on is making it easy and fun for people to discover them. SmugMug Search is an important part of this, since it allows anyone on the web to search among all public photos on SmugMug. It also helps drive traffic to our Pros, many of whom make a living selling prints of their work.
Naturally we want Search to be fast, intuitive, and beautiful. But more importantly, we want to showcase our users’ gorgeous photos. When people search for photos on SmugMug, they want to see photos, not a bunch of pagination links and other user interface clutter. So, a few months ago, we launched a redesigned Search page that does just that.
We put those big gorgeous photos front and center, and we got rid of the ugly pagination links in favor of infinite scrolling—as you scroll down, more results are loaded automatically. This looks great and works well, but keeping the interface fast and responsive presented a lot of challenges, especially on older browsers or slower computers.
Behind the scenes, the search results are loaded into a YUI Model List via XHR and rendered using YUI Views. As the user scrolls down, more results are loaded automatically, appended to the list, and rendered.
Even worse, as the user scrolled further and further down and more results were loaded, memory usage skyrocketed. With potentially thousands of results on the page at once and a Model and View instance for each, users without lots of RAM sometimes saw things grind to a halt as the browser was forced to rely on virtual memory. This clearly wasn’t a good experience.
Here are some of the things we did to speed stuff up:
Instead of creating a View instance for each image tile, we now use a single master View instance for the entire list of results. As new results are added to the page, the master result view is responsible for rendering those new results without re-rendering any of the existing results on the page. Now, even when there are thousands of images on the page, there’s just a single view managing them all.
We wrote a new ScrollInfo plugin for YUI’s Node component, which provides a highly efficient, throttled wrapper around the browser’s native
scrollevent. Since the
scrollevent can fire hundreds of times per second, throttling ensures that our event handlers only run, say, once every 50 or 100 milliseconds rather than on every single event. This puts less of a burden on the browser and ensures that more system resources are available to render content and keep the page feeling responsive as the user scrolls. This plugin isn’t yet available as part of YUI, but we’ve sent a pull request and we hope they’ll accept it.
Our profiling revealed several memory leaks in YUI’s event system, which we were able to work around to improve memory usage even above and beyond our other improvements. The YUI team is aware of these issues. Some have already been fixed in YUI 3.6.0, and others will be addressed in an upcoming release.
Naturally we also took the opportunity to make lots of other minor improvements and fix lots of little bugs, but those weren’t directly related to the performance effort.
Benchmarks & Pretty Graphs
Here are some pretty graphs demonstrating the effect of the performance improvements we made. Results were gathered using Google Chrome’s profiling tools on a Mac Pro (2.8 GHz Quad-Core) running OS X 10.8.
We also created a jsPerf test for LazyModelList to demonstrate how much faster it is than ModelList.
That Ain’t All
It took some work, but now we’ve got a gorgeous search page that performs well even in older browsers and on slower machines. We’re pretty happy with it, and we hope you are too. But that’s not all! We’ve still got plenty more improvements planned, so keep your eyes peeled.
— Ryan Grove and Brian Strong, SmugMug Sorcerers