There has been a significant increase in interest in the Memcached, the open source distributed memory object-caching system, in recent months, as a number of vendors look to exploit its popularity in Web 2.0 and social networking environments.

Like Hadoop, which has become the focus of a number of commercial plays, it would appear that the time is right for commercialization of Memcached. But what is it, here did it come from, and what are the chances for vendors to rake in serious cash? Here are the details.

What is it?
Pronounced mem-cash-dee, Memcached was originally created by Danga Interactive (the developer of LiveJournal, which was acquired by Six Apart in 2005) to speed up the performance of dynamic Web applications by alleviating database load. Memcached has become an industry standard for improving the performance of dynamic websites.

The code is available from the remaining Danga website, as well as from Google Code, and the main server is under the BSD license.

What is is for?
Memcached is designed to speed-up the performance of dynamic web applications by providing a memory cache of frequently accessed objects, reducing the load requirements on the database toer and improving application performance.

What is it not?
Memcached is often associated with improving the scalability of web application infrastructure, but as this post from dormando illustrates, it is not actually designed to enable scale-out architectures.

“What memcached really is, is a giant floating magnifying glass. It takes what you have already built and makes stretch ten times further. I insist on not confusing caching with scaleout as when your little stretch-armstrong of a website hits that tenfold limit, you’re still screwed.”

Other things Memcached is not include a database, a queue system and a proxy.

Who uses it?
Example users include LiveJournal, Slashdot, Wikipedia, SourceForge and Kayak. For an overview of Facebook’s use of Memcached, see here. In fact Facebook claims to have become the largest user of memcached and actively contributes modifications back to the project

Who is supporting Memcached?
Until recently the list of corporate backers was small - in fact Memcached could be considered a true open source community development project. MySQL included support for Memcached in its MySQL Enterprise subscription, while in February Sun provided Memcached support as part of its GlassFish Web Stack.

Then the floodgates opened. In April Gear6 launched its Gear6 Web Cache, a Memcached appliance, as did Virident, and Schooner Information Technology. (Subscribers can see our formal assessments of Gear6, Virident and Schooner).

Additionally, EnterpriseDB is using Memcached as the basis for Infinite Cache, which provides a cache behind the database to improve the performance of read-intensive transactional applications (our formal take is here). Meanwhile NorthScale provides Memcached training, services and support, and has plenty of other plans up its sleeve.

All of these vendors, and more, are either already contributing improvements to the Memcached code, or plan to do so, further increasing its relevance.

Other points of interest
Microsoft’s Velocity project has been described by the company as its attempt to replicate Memcached for Windows environments. Terracotta, the Java caching vendor, reports seeing increased usage of Memcached in competitive environments. It arguably faces the biggest threat from the rise of commercial Memcached support providers.