I had a look at getting XWiki to run on Firebird, and with some minor
changes to the hbm.xml files, an improved Dialect and unfortunately a
change to Jaybird itself I got it running. Most likely the improved
Dialect is not required, although I need to test that a bit more.

In the current Jaybird versions there is a bug in the handling of Clobs
(when the Clob is set using a non-Jaybird Clob (as Hibernate appears to
do), or with a Reader). See http://tracker.firebirdsql.org/browse/JDBC-281

I will see if there is a way to get Hibernate to not use the
get/setClob, but just get/setString instead (as that should be handled
transparently with Jaybird). Otherwise a new release of Jaybird is
required to get things to work.

Mark
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Mark Rotteveel