Berkeley DB, the open source database frequently used in Linux applications, can now be patched while it's still running. This type of nonstop feature has been sought by Berkeley DB users for years and was a priority of Sleepycat Software, former owner of the embedded database system, in its development road map.

The release last week of version 4.5, which includes the nonstop feature, is a sign that Oracle is heeding that road map. Oracle acquired privately held Sleepycat in February for an undisclosed amount.

Skeptics at the time said Oracle would suppress Berkeley DB development in favor of its existing embeddable database systems, which include the Times Ten In-Memory Database; Oracle Lite, a mobile application database; and Oracle 10g itself.

But Oracle's intentions have become clearer as it let both the former Sleepycat development team and a community of open source contributors continue to add features to the core system. The 4.5 release includes improvements in multiversion concurrency, which is the system's ability to respond to multiple users who want information from the database at the same time that it's being updated.

Berkeley DB now also comes with a replication framework that makes it easier to establish a replication system in which a central database keeps satellite versions in sync. It's a self-maintaining system, meant to be built into an application, configured, and then allowed to run without intervention from a database administrator.

Version 4.5 is available for free download. Oracle makes Berkeley DB available under a commercial license or under a free open source license that requires that new applications be given back to the community.