09 Nov 2011

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Single lock owner: an important step forward

The single lock owner is a highly requested Infinispan improvement. The basic idea behind it is that, when writing to a key, locks are no longer acquired on all the nodes that own that key, but only on a single designated node (named "main owner").

How does it help me?


Short version : if you use transactions that concurrently write to the same keys, this improvement significantly increases your system' throughput.

Long version : If you're using Infinispan with transactions that modify the same key(s) concurrently then you can easily end up in a deadlock. A deadlock can also occur if two transaction modify the same key at the same time - which is both inefficient and counter-intuitive. Such a deadlock means that at one transaction(or both) eventually rollback but also the lock on the key is held for the duration of a lockAquistionTimout config option (defaults to 10 seconds). These deadlocks reduces the throughput significantly as transactions threads are held inactive during deadlock time. On top of that, other transactions that want to operate on that key are also delayed, potentially resulting in a cascade effect.

What's the added performance penalty?


The only encountered performance penalty is during cluster topology changes. At that point the cluster needs to perform some additional computation (no RPC involved) to fail-over the acquired locks from previous to new owners.
Another noticeable aspect is that locks are now being released asynchronously, after the transaction commits. This doesn't add any burden to the transaction duration, but it means that locks are being held slightly longer. That's not something to be concerned about if you're not using transactions that compete for same locks though.
We plan to benchmark this feature using Radargun benchmark tool - we'll report back!

Want to know more?


You can read the single lock owner design wiki or/and follow the JIRA JIRA discussions.

09 Nov 2011 8:57pm GMT

More locking improvements in Infinispan 5.1.0.BETA4

The latest beta in the Infinispan 5.1 "Brahma" series is out. So, what's in Infinispan 5.1.0.BETA4? Here are the highlights:


As always, please keep the feedback coming. You can download the release from here and you get further details on the issues addressed in the changelog .

Cheers,
Galder

09 Nov 2011 5:57pm GMT

RichFaces 4.1.0.M4 Release Announcement

The RichFaces 4.1 Milestone 4 release is now available for download! With this M4 release we focused on stabilizing the features we introduced in the earlier 4.1 release-train milestones (M1, M2, M3). The release following M4 will be our 4.1 release candidate, so we want to make sure we achieve maximum stability with M4. Some of the key areas we touched are listed below.

If your keen and want to get started right away, you can download the distribution directly, or for maven users, increment the RichFaces version in your pom.xml to 4.1.0.20111101-M4. For more information on setting up a RichFaces 4 application, refer to our getting started guide.

Mobile showcase improvements
The CSS 3 overlay was improved to provide better mobile compatibility of the components. We also added an ajax status indicator to the mobile showcase. Since it is entirely an ajax driven application, the status indicator improves the user experience dramatically.

Resource mapping
The resource mapping feature introduced in M3 has been made more usable, adopting a consistent naming convention, with reasonable defaults. Additionally the ability to completely disable the feature was introduced, should you want to handle resources yourself in your applications.

Client Side validation
Improvements to the client-side validation (CSV) involved better aligning the client-side regexp with the Bean Validation specification. The CSV mechanism for discerning component values on the client (using javascript) was enhanced to improve the CSV interop with other JSF component providers.

Individual component fixes
The file upload component has some new attributes, allowing for more fine-grained control over what the user is able to upload to the server. The pickList saw the switchByClick and switchByDblClick functionality from RichFaces 3 ported to RichFaces 4, further improving the RF 3 to RF 4 migration story.

Misc. Fixes
Some additional issues resolved include a jQuery update (to version 1.6.4), and improvements to both the simpleapp and GAE RichFaces archetypes. Many more fixes and improvements were checked, feel free to browse the issues fixed to see what else has been improved.


Forward: CR1 & Further Stabilisation
The CR1 development is currently ongoing, with a focus on providing documentation for all the new 4.1 features, and further stabilisation. So give M4 a spin, and let us know what you think! Drop a note in the forums, or join us for our weekly community/team meetings in IRC.

09 Nov 2011 5:35pm GMT