Monday, November 29, 2010

Ehcache 2.4 Beta 1 Welcomes Search, Local Transactions and more...

Ehcache 2.4 Beta has been released. We've been spending the last few years working hard to make Ehcache the best possible solution for users with caching needs. 2.4 beta 1 is another big step forward. The beta includes some significant new features and improvements that can be read about here. This blog is a few notes on getting started with those features and a few comments on why they are important.

Ehcache Search

This is one of the most requested features for Ehcache. I can't count how many times that I have had a map or cache and just wanted to quickly and easily search for an entry. Sure, one can write an iterator and use Java's matchers but that's
  • A bit of annoying coding
  • Only practical for unclustered caches
Ehcache 2.4 Beta 1 has a new search interface in core Ehcache that works throughout our scale continuum. We used the "Fluent Interface/DSL" style that we've been moving towards over the last couple of years in both Ehcache and Quartz Scheduler. This style of interface makes an API easy to use and read like english.

To learn more about it check out this self contained sample app and the documenation. Give us feedback early and often on the Ehcache Forums as the API is still under development and can still be improved.

Local Transactions

Back in Ehcache 2.0 we added JTA support. This was helpful but we found that for some use-cases people wanted a few things.
  • Transactions without a JTA transaction manager
  • More speed
We improved the speed across the board of our XA compliant JTA stuff and we also added the concept of local transactions. Local transactions provide optimistic concurrency and atomicity across caches. They are like XA transactions but aren't completely tolerant of external resource crashes outside of Ehcache (i.e. cache + databases don't have all the guarantees of XA in the node failure cases. Does provide the guarantees across Ehcaches), don't require a transaction coordinator (though can be used with them) and tend to be less resource intensive (read faster).

Improved Enterprise Disk Store

In 2.3 we added an Enterprise version of unclustered Ehcache core. The version added support for very large caches through the seamless BigMemory add-on (1 line of config). We also, somewhat more quietly, added the beginnings of a new Enterprise disk store that no longer stored keys in memory and can handle larger restartable caches.

2.4 beta 1 takes this to another level. The disk store is now way more efficient, better leverages SSD drives and can efficiently grow to very large sizes without any additional heap usage or fragmenting. One can exercise the improvements using the Ehcache Pounder.

Other Improvements

While not everything for the final release was done in time for Beta 1 some significant improvements are in.
  • NonStopCache now built in. Rather than have to add a jar and configure a wrapper to get the non-stop characteristics in clustered land this is now built into the product core and be turned on via configuration
  • Search now works clustered - The new search API is backed by the Terracotta tier. This is still early and we have a lot of performance and HA work to do here. That said, it is testable and usable so give it a try.
  • Explicit locking module is now in the core kit
  • Rejoin now works in non-stop (You can disconnect from a cluster and reconnect to that cluster without restarting)

For those interested in scheduling we have also released Quartz Scheduler 2.0 beta 1. More stuff will be coming in a month or so when we do beta 2 for all products.


  1. Hi,

    Any idea where can I download the ehcache.xsd file 2.4-SNAPSHOT?

    I can not see anything at, which has schema file.

    As of now, I think this gets distributed with download.

  2. Hi

    The ehcache.xsd is located at

    Maven does not provide a place to put this sort of thing. And yes it is in the download bundle.

    The website always reflects trunk. When something is not yet released we specify that in the docs. But the ehcache.xsd listed above has the new searchable stuff in.

    Greg Luck