Google Summer Of Code

eXist is participating in the Google Summer of Code again. Student applications can be submitted until March 26! The list of proposals along with the timeline can be found here:

Some of our project proposals may sound a bit ambiguous, but please don't be scared: we are here to help ;-) We chose those projects because they represent more or less separate work packages which can be handled without knowing the entire eXist code base.

The list includes, for example, a "remote debugging interface" for XQuery. We certainly don't expect someone to write a full-blown debugger. What we need is a well-defined debugging interface on the server and a simple command-line prototype, which demonstrates the interface.

Or take "index-support for order-by, distinct-values and aggregate functions": eXist's new indexing architecture makes it possible to implement the required functionality as an index plugin. Not too difficult. The challenge though will be to make it efficient.

eXist 1.2 Released

After another three weeks of documentation work, I'm really happy to announce that eXist version 1.2 (codename: Rennes) is now available for download at

We counted more than 2500 software changes for this release, including many serious stability fixes.

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eXist at XML 2007

I have not been there myself, but as we heard from those who attended XML 2007, there were quite a few talks mentioning eXist:

Erik Bruchez: XForms and the eXist XML database: a perfect couple

Dan McCreary: Using XForms and eXist to Manage Metadata

Kurt Cagle: Lightweight XML

Mark Birbeck: XForms, XHTML, and RDFa for Internet-Facing Applications

Mark Birbeck: XForms on the Desktop using Sidewinder

The slides for the first two talks are available online. We also heard Norm Walsh mentioned an XProc implementation in XQuery based on eXist (I guess this must be Jim Fuller's XProcXQ). XProc is an interesting new standard and I would love to see a simple implementation which can be easily integrated with eXist.

99.4% XQuery Conformance

xqts.png

We just reached another milestone in our struggle to make eXist 100% conformant with the XQuery specs: 99.4%! Details can be found on the official W3C XQuery Test Suite pages.

Recent changes were mostly related to namespace handling, though we also had a number of small fixes to the XQuery parser, including whitespace processing and ordering declarations.

Understanding the New Indexing Features

The upcoming next release of eXist will introduce quite a few changes with respect to index types and index creation. While your old index configuration should still work with the new version, knowing the new features and possibilities can sometimes result in a dramatic performance boost.

To better understand the changes, we have to look at two different areas of development, which both have direct effects on indexing features:

  1. The switch to a modularized indexing architecture
  2. The new query-rewriting optimizer
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