We are very pleased to announce the fourth (and hopefully final) alpha-release of Sesame 2. Sesame 2.0-alpha4 is a release that fixes a large number of issues with the previous alpha releases. It features major improvements in the Repository and SAIL APIs and a completely redesigned query engine for SeRQL and SPARQL. Additionally this release finally has a HTTPSail (thanks to Leo Sauermann, Gunnar Grimnes and Sebastian Weber) which enables transparent client-server communication with Sesame repositories over HTTP.
Sesame 2.0-alpha4 can be found in openRDF.org's download section.
A lot things have changed, most importantly:
- Sesame is now available under a BSD-style license, previous releases are still available under LGPL.
- The Repository and Sail APIs have been revised to use JDBC-style connections.
- The SeRQL query engine has been been replaced with an all new generic query engine that is modelled after the relational algebra for RDBMS's.
- Sesame now has partial support for SPARQL. Ask and describe queries are not yet supported, as well as a number of the SPARQL built-in functions.
- Sesame now has an HTTPSail, which allows clients to transparently communicate with a server over HTTP.
- The semantics of SeRQL set operations have changed: the results of the operands are now combined based on the variable bindings they produce. This means that you have to take care that the operands use the same variables names (or use aliases).
- The REST-style HTTP protocol has been improved. The new protocol is NOT backwards compatible with older versions.
- The Sesame code has been completely modularized into logical units, which makes it easier to reuse parts of Sesame in other projects.
- The Ant-based build system has been replaced with a Maven-based build system.
- The source code has been moved from SourceForge's CVS server to Aduna's SVN server: https://src.aduna-software.org/svn/org.openrdf/
Known issues
- This release contains a HUGE amount of changes to the code and, as a result, is expected to contain a considerable number of bugs.
- The new query engine currently lacks a query optimizer. Because of this you may see inferior query evaluation performance compared to earlier releases.
See the ChangeLog for details on the changes and improvements.
