The One True Way to
Make Your Web Apps
Quicker!
Vishnu Gopal

Me
• Born and brought up a Keralite. Mallu.
• Worked in the Mobile VAS sector, founded
Torque, torque.co.in
• Uzanto & SlideShare
• www.vish.in

Lots of Ways
Lots of Approaches
• Profiling Code
• Faster App Server
• Using AJAX/COMET
• Output Compression
• Caching
• A Stateful System
• Better Hardware
• A better web language
• Not using Rich Media
• Optimizing images

Low Hanging Fruit
• Club into three categories:
• Improve your code
• Easy at first, then very hard.
• Improve your dependencies
• Most often impossible to do

Low Hanging Fruit
• Improve your hardware
• Only Rich People will build Rich Internet
Applications.
• One thing in the list quite doesn’t fit

Intelligent Caching works wonders
Caching: The Holy Grail

Lots of Ways
Lots of Approaches
• Profiling Code
• Faster App Server
• Using AJAX/COMET
• Output Compression
• Caching
• A Stateful System
• Better Hardware
• A better web language
• Not using Rich Media
• Optimizing images

Interlude One
A bit of a treat

Performance Testing
• http_load, ab, httperf, ...
• httperf --num-conns=x --rate=y --
host=localhost --uri=/
• Measure a page which is a good indicator of
your app (your home page would be nice)

Interlude Two
Testing

How do I?
• Talking framework/language/platform
agnostic
• I’ll focus on Rails, but generalizations are
easy to come by
• Caching fragments
• Memcached

Fragment Caching
• Assemble Portions of a Page
• Reduce Computation
• Lovely Rails idiom
• <% cache params, expiry do %> and <%
end %> around the block.

Page Caching
• Cache the whole page
• Serve as static HTML by a frontend
webserver bypassing all framework code
• Blazingly fast
• Dynamic portions unique to a user are a
problem

Page Caching Reloaded
• Works for dynamic pages
• Reasonable amount of user-specific content
• Axiom:
• The meat of a page is never its navigation:
and content is usually not user-specific.
• Why sacrifice speed for navigation?

Solution
• Load navigation dynamically after page load
• The page loads, the content is displayed and
unobtrusive changes are made for
personalization
• Target areas: high traffic areas of a webapp
where page caching will be uber cool

Implementation
• hInclude
• Lighttpd
• Lua (scripting lang like Ruby, Python, but
FAST)
• Memcached

hInclude
• <hx:include src="/src/to/dynamic-
content"></hx:include>
• Uses Javascript to load dynamic content in
the background and update.
• Seamless for small updates (feels like page
loading)

So Cache Away!
• Convert partials to a dummy action:
• def personal
• render :partial => 'top_bar/show'
• end.
• Call that using hInclude
• Activate Page Caching, and..

Interlude Three
Magic

What did we do?
• Slow to Fast
• Caching is a lower hanging fruit: It’s easy to do
• Surprisingly good results
• hInclude small dynamic portions for really fast pages

Limitations
• Usability: Don’t surprise the user with randomly changing
content.
• An elegant way to clean page caches would be nice.
• Another javascript library!

Finis
Questions?