Newsletter :: September 2006
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K U D O O F T H E M O N T H
"We chose db4o for the offline client because of its object oriented model and ease of use. It significantly reduced our product development time."
--Vivek Mishra, 8/15/06
A R T I C L E S
-- V5.5 NOW AVAILABLE FOR PRODUCTION: PERFORMANCE! --
db4o 5.5 has been promoted to a production release and is a recommended upgrade for all earlier releases. You may download version 5.5.001 for free from the db4o Download Center.
This newest production version boosts performance, stability and optimizes memory consumption, in some cases with up to 270x performance improvements! Results are visualized by the Poleposition benchmark in a performance comparison of db4o v5.4 vs. v5.2, e.g.:
- A commit on a class index with a total of 100,000 entries and one changed entry takes 11 milliseconds instead of 656, which is an improvement of 65x (Monaco circuit)
- With a class index of 1 million object entries the commit performance improves from 5390 milliseconds to 20 milliseconds - a 270x improvement! (Monaco)
- 10,000 objects with ten string fields are stored in 841ms instead of 3178ms, a performance improvement by 4x (Nurburgring)
- 1,000 ArrayLists with 300 entries are stored in 998ms instead of 12652ms, a performance improvement of 12x (Montreal)
Version 5.5 features new B-tree index architecture, a new object marshaller, pre-optimized native queries, and a Diagnostics toolkit for performance optimization purposes. Links to detailed release notes can also be found in the version 5.5 folder in the db4o Download Center.
-- V5.6 RELEASED: EXTERNAL CALLBACKS ALLOW PLUGGABLE LISTENERS INTO CORE --
The db4o team has also released version 5.6 as the current development release, available from the db4o Download Center. A development release is designed to solicit early user feedback, before a version can be used in production.
Version 5.6 comes with an extremely powerful new feature that allows you to write Event Listeners for core db4o events (such as before and after an object is stored, updated, or deleted). This feature is called External Callbacks and it opens the doors to many new use cases for db4o, matching frequent user requests:
- Unique Identifiers: You can now set unique identifiers on a field in an object. This is tremendously helpful in building applications across their enclosing VM or VM session and/or when integrating a db4o database into a wider application stack where foreign identifiers or "keys" are a given.
- Query Statistics: You can implement a listener to gather query stats such as the execution time and the number of objects activated, which helps you to further tune your application against performance bottlenecks
- Selective Cascading Deletes: You can selectively delete objects when a delete command is cascading through the object graph rather than deleting the entire graph
- Selective Activation: You can selectively activate objects on a specific level of an object graph, rather than activating the entire graph down to the requested object level. Since you potentially load many fewer objects into memory, this capability can be extremely useful to tune your application for performance, low memory consumption and reduced network traffic.
External callbacks are very easy to use. Get an EventRegistry for an ObjectContainer and add EventListeners to it - done! Multiple listeners can be added to the same events, too, so you can easily add more functionality.
You can read more about this feature and see full examples on the db4o Product News Blog.
-- BOOST IN CHINA FOR db4o --
After the U.S., China hosts db4o's second largest user community with some 3,000 registered users, followed by Germany and Japan.
db4objects has now signed a comprehensive collaboration agreement with Shenzhen Menglongyitong Information Technology Ltd. to further accelerate the adoption of db4o in this important region. As part of this agreement, Shenzhen Menglongyitong will provide Chinese support, sales, and marketing services to better meet the demand of local users. Shenzhen Menglongyitong owns and operates China's most popular open source Java portal, Matrix, with more than 120,000 registered developers and 500,000 visitors per month.
The passionate Chinese db4o Community already provides a host of community-driven resources, such as the Chinese User Forum and the Chinese News Blog. The community now also started a Chinese Wiki, where additional resources are created and distributed, such as Heaven's translation of Rick Grehan's popular whitepaper "The Database Behind the Brains" or Rosen's translation of the Cook/Rosenberger "Native Queries" whitepaper.
-- COMMUNITY 2.0: INVITATION TO CONTRIBUTE --
At the London db4o User Conference in July, db4objects released a host of infrastructure resources to better facilitate contribution and collaboration with and within the db4o user and developer community, specifically:
- A number of Discussion Forums were added (db4o Product Developer Forum, Jobs, Off Topic, French Forum)
- The db4o Download Center was improved and opened to community contributions (Open Tools and Add-Ons, User Groups)
- The advanced Resources Section was amended (expect much more from our integrated "documentation 2.0 project" later this year)
- New Blogs were created (Product News from the Core Team, Kudos, In the News) and made available for RSS subscription
- The blog roller www.planetdb4o.org provides a window into the world, work and lives of db4o contributors
- The photo blog "photos4objects" was launched
The centerpiece of the community server enhancements consists of the Projects section, a fully integrated and moderated Wiki for projects of all kind.
Recent community projects include:
We invite you to contribute to this fast growing community platform, too: Provide the URL to your GPL project based on db4o - they make great samples for others. Write up your experience with db4o to help new users to get their feet wet. Provide a technical article - some article ideas are collected here. Build tools and add-ons, such as plug-ins or integration stacks. Or start your own language community project in Korean? Italian? Turkish? Any contribution helps, no matter how big or small!
To register your own project or to become a contributor to an existing project, please send a private message to the community manager Eric Falsken.
-- db4o CORE DEVELOPMENT MORE OPEN THAN EVER --
db4objects has implemented a couple of measures to make it even easier for you to participate and contribute to the core product development. These include:
All these measures are targeted to increase the core contributions from db4o's fast growing user community, leveraging the power of open source to make db4o an even stronger product going forward.
L O O K I N G I N T O T H E M I R R O R
Press coverage about db4o since the last newsletter:
"The case for a native object database"
Open Tech Press, August 14, 2006, by Jim Paterson (In Japanese)
"Database db4objects Enters China "
PC World China, August 14, 2006, by Chris Matrix (In Chinese)
"The case for a native object database"
IT Manager's Journal, August 9, 2006, by Jim Paterson
"The open source Java portal 'Matrix' management company is representative of db4objects in China"
LinuxToday Japan, August 9, 2006, by Naoko Yamakata (In Japanese)
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With best regards
The db4objects team.
www.db4o.com
newsletter@db4o.com
Phone +1 (650) 577-2340
1900 S Norfolk Street, Suite 350
San Mateo, CA 94403 (USA)