HSQLDB Development

Recent History

2005-2012: After the release of version 1.8.0, we aimed to develop a highly standard-compliant database engine to support advanced data types and SQL syntax. This required a complete rewrite of most core and interface components of the engine. This was done in stages over four years. We avoided early releases in order to provide a complete and well-balanced feature set that is well tested by ourselves before going into public trials.

Version 2.0.0 was finally released in June 2010, after several alpha, beta and RC releases and extensive public tests over a year. We completed all the features listed in the new features page. Since the release of 2.0.0, we have added enhancements, new features and fixing reported bugs, resulting in the latest 2.2.9 in August 2012.

The latest version 2.x is now fully stable in all modes of operation.

Supported Versions

Version 1.8.x will continue to be maintained and supported in the foreseeable future, but no new functionality will be added. New releases of 1.8.x may appear from time to time.

Version 2.2.9 is the current main version.

Current Developments

In addition to regular enhancements to all areas of the engine, we will be enhancing and completing the additional features listed below, which are in an advanced stage of development (or nearly complete). (See the SupportWare page on how you can support the effort financially):

• J2EE features such as XA transactions, connection pooling, JMX, etc.
• Better integration with Open Source projects that enhance or use HSQLDB

In addition, a version of HSQLDB for the .NET platform (based on HSQLDB 1.8.1.X) is in SVN. This version is in its late stages of development.

An ODBC driver for HSQLDB 2.x is also under development. The current code works fine with SQL data statements but does not support database metadata. 

Development code is in SVN. An alpha version for Win32 is in the file download section.

Developers are currently needed to write tests and improve the J2EE and ODBC support for public release.

The Development Team

The development effort and all public releases are coordinated by the full-time Maintainer to ensure continuity and consistency.

We are always looking for new developers to join our team. Anyone who would like to contribute code, tests, documentation or translation is welcome to join. Please send an email to the Maintainer, Fred Toussi, fredt (at) users.sourceforge.net with your proposed enhancement. Before you can contribute code, you are expected to contribute tests that validates your code.

Co-ordination with Users

HSQLDB is used in (or is supported by) a large number of open source projects. We welcome direct, priority contact with developers from those projects to ensure a smooth transition to new versions.

We also value contributions from all other developers who use HSQLDB in their projects. We have been able to fulfil many requests for additional features or bug fixes and will continue to give priority to what users ask for. Users who want to contribute enhancements can post the code to the Patch Tracker or alternatively discuss it directly with the Maintainer.

Some Details

New developments and ongoing maintenance development of 2.x is reflected in the SVN repository. The directories are listed below:

/base version 2.x
/base-one versions up to 1.8.x
/dotnet the .NET implementation of 1.8.x
/odbc the ODBC driver

Some Ancient History

Before HSQLDB: Hypersonic SQL was a small open-source all-Java database engine, first released with source in 1998. By the year 2000 and version 1.43 it had developed into a simple and basic SQL engine. The Hypersonic SQL project stopped development in late 2000 and was closed in 2001.

2001: In March 2001, a number of developers who were using the software for their work got together through the Internet and formed the HSQLDB Development Group to continue the development. The Group released the first version of HSQLDB (1.60) in April 2001, featuring support for SQL triggers and other enhancements and bug fixes. The next version (1.61) followed in July that year.

2002: Growing interest in HSQLDB resulted in more and more enhancements and new features submitted to the project. Development continued for the next 12 months and the next version, 1.7.0, was released with major new functionality, especially Text tables. Version 1.7.1 followed in October with further enhancements. Many old bugs inherited from Hypersonic SQL were fixed in these versions.

2003-2004: Work on version 1.7.2 continued until July 2004 when 1.7.2 was finally released after extensive testing. Features such as compiled prepared statements, cascading deletes and updates where introduced. We continued to fix reported bugs against 1.7.2 and released 10 revisions of the engine. Thomas Mueller, the author of Hypersonic SQL, made a welcome reappearance in 2004 for a short period and submitted enhancements to NULL handling. We released this works in version 1.7.3.

2004-2005: Simultaneous development on the next version, now designated as 1.8.0, was carried out in the second half of 2004. We introduced changes made by Ocke Janssen for OpenOffice.org integration. We also rewrote the whole area of code that controls persistence and handles memory caching of disk based rows. This has made HSQLDB yet more resilient and capable of handling huge tables. Several important new features were also developed, including database schemata, roles and new SQL features. The first release of 1.8.0 came out in July 2005. In the process leading to 1.8.0 the code was modularized, all internal functionality was reviewed or rewritten and regression test coverage of various features were greatly improved. Version 1.8 has undergone regular bug fixes and improvements since its release. The latest version of 1.8.x was released in 2010.

Historic change Logs and Lists

1.6.0 to 1.7.1 releases 2001-02
1.7.2 release 2004
1.7.2 point releases 2004
1.7.3 point releases 2004-5
1.8.0 release 2005
1.8.0 point releases 2005-7