Wednesday, March 25, 2009

[Tech] HSQLDB Version 1.9 alpha is out

Finally hsqldb 1.9 (alpha, though) is released. This release was announced for, I believe, nearly one year. It seemed to me already that hsqldb is a rather dead projects. I am glad they made the next round, because in a way I still like that system a lot. Sure, Apache Derby is most likely the superior system, and H2 looks very promising too (but is still, as I understand it, a "one man show" without community) however hsqldb has some tiny details that make it very nice: First, it always had a really tiny footprint and was extremly easy to understand and use.

And I particularly liked the feature to fine-tune the memory management, i.e., should the data be stored on disk, purely on memory... and this on a per-table basis. Plus, with one simple command it is possible to write the whole database as SQL statements into a file from which it is also loaded again from that file. A feature that is e.g. missing in Derby. This often turned out handy during development-phase.

Now for version 1.9 they seem to have rewritten significant parts of the software and added an impressive list of new features. What I have to figure out is, if they have finally implemented proper transaction isolation. In my opinion this was (beside the single-threaded kernel) the biggest issue in the previous versions, where dirty read could not be avoided. I am a little bit confused with the announcement(s) now, because they wrote that they have rewritten the core, however, in a forum posting the developers announced, that transaction isolation is not handled in the new release 1.9 but is planned for 2.0. The news announcements on the sourceforge are a little bit confusing for me. Does anyone have a better idea about this issue?

However, good luck for the stabilisation-phase of the new release!

Monday, March 23, 2009

[Misc] Hello World

"Hello World" programs are well known since at least 1978 and often a starting point to get to understand the most basic issues of a new computer language.

Wolfram Roesler collected "Hello World" programs in 421 different computer languages!

Particularly interesting for me was "Hello World" in Chef :-)