Predicting the Future with Multi-Page Predictive Prefetching

1
PREDICTING THE FUTURE WITH MULTI-PAGE PREDICTIVE
PREFETCHING
2

• Predicting the future is hard to do, especially
  when it comes to technology. People erroneously
  predicted the demise of the Internet and Apple,
  both of which are alive and well. Even so,
  predictions are everywhere around us on the web.
  Google predicts what we want to search for,
  predictive text helps us quickly compose text
  messages on our mobile phones, and Amazon makes
  predictions about items you might wish to
  purchase based on your previous purchases.
• Technology has emerged which allows web
  applications to predict what content a user is
  likely to request next which can be used to speed
  up the delivery of pages. HTTP/2 offers push
  capabilities to send resources to the browser
  prior to a request being issued. There are also
  resource hints available to speed up delivery of
  web pages
• DNS-prefetch resolves the domains of anticipated
  third-party objects to be loaded.
• Prefetch and preload retrieve objects prior to
  the browser requesting them.
• Prerender fully renders a page in the background
  before a request has been issued.
• The cost of predicting incorrectly can be huge
  with these technologies, but the benefits if the
  predictions are right can also be even greater.
  In a Velocity talk, Yoav Weiss summarized the
  cost/benefit of these various technologies as
  follows

Resource hint Cost if wrong Benefit if right
DNS-prefetch Very low Low
Preload High High
Prefetch Mid to high High for next navigation
Prerender Huge Huge for next navigation
3
Finding ways to make more accurate predictions
will enable users to have a near-instantaneous
response when loading pages. While a user is
viewing a page the browser is idle. This is prime
opportunity to start fetching resources needed on
subsequent pages. Latency is an ongoing
struggle, especially on mobile networks. With
HTTP/2, the browser reduces the negative effects
of latency by multiplexing requests. Even so,
once the page is loaded the browser sits idle. If
the browser can predict what resources will be
needed next, then it can mask latency by
initiating the request prior to the users
actually making it. Prefetch and preload are
newer standards and, as a result, not all
browsers support these technologies. Preload
applies to resources in the current navigation,
while prefetch can be used for resources in
subsequent navigations.
4
Aside from browser support, the larger issue with
prefetching or preloading content is that it
requires the developer to identify which
resources should be retrieved prior to a request
being issued. Humans are bad at making
predictions and remember, prefetching unneeded
content is expensive. From any given web page
there are a number of paths a user can take. For
example, while viewing a product on an eCommerce
site, they might choose to click on a link to
read product reviews they might add the product
to the shopping cart or they might choose to
view one of 4 similar suggested products. Each of
these pages has different resources on them, so
loading content for all six pages is not
efficient. At this point, analytics become your
friend. They can help you identify which action
the majority of users take and prefetch those
resources. But what if the analytics show that
only 20 of users perform that action and the
remaining 80 choose a different path or leave
the site? You have sent data that isnt needed to
80 of your users. This isnt efficient
either. Multi-page Predictive Prefetching from
Instart Logic Enter Instart Logics Multi-page
Predictive Prefetching. Because of our unique
client-side component, the Nanovisor, we can
collect and analyze information from real user
interactions. Multi-page Predictive prefetching
is a three step process. First, user actions are
observed by the Nanovisor and sent back in the
cloud to the Instart Logic application delivery
platform. Using machine learning algorithms,
resource impact and page transitions are analyzed
to identify common static resources across user
flows. Finally, the Nanovisor prepopulates the
browser cache with the predicted
objects. Multi-page Predictive Prefetching
eliminates the risks involved in having humans
predict what a user is going to do next and which
resources should be prefetched. The costs
associated with prefetching content are greatly
reduced, but the benefits remain the same. The
Nanovisor, being JavaScript, works on all
browsers, enabling websites to prefetch content
for all users, not just a small percentage of
them. To learn more about Multi-page Predictive
Prefetching and to sign up for the beta contact
your account manager or support.
5
Instart Logic is the worlds first endpoint-aware
application delivery solution that makes websites
and applications fast, secure, and easy to
operate.
Interested in learning more? Preview our image
optimization capabilities in the Playground
Contact Sales