Documentation RFE: Embedded Derby in 2.3

[Adam Constabaris <ad...@unc.edu>]

I'm not sure this is worth filing on JIRA, since (if I'm right about it) 
it's really a bug in Derby 10.1.2.1, and the most obvious fix is to note 
that the combination of Roller 2.3 and Hibernate (from the Roller 
support project) is incompatible with using Derby /in embedded mode/ 
(network mode works for me).

The suspected culprit is in the vicinity of DERBY-628:

http://issues.apache.org/jira/browse/DERBY-628?page=all

The bug manifests itself in Roller (produced on two systems with 
completely clean installs of Tomcat and Roller 2.3) this way:  creation 
of first user after installing all the components succeeds, but creating 
a new blog results in the following:

WARN  2006-06-15 13:55:09,360 JDBCExceptionReporter:logExceptions - SQL 
Error: 20000, SQLState: 22005
ERROR 2006-06-15 13:55:09,361 JDBCExceptionReporter:logExceptions - An 
attempt was made to get a data value of type 'CLOB' from a data value of 
type 'VARCHAR'.
ERROR 2006-06-15 13:55:09,366 
AbstractFlushingEventListener:performExecutions -
Could not synchronize database state with session
org.hibernate.exception.DataException: could not insert: 
[org.apache.roller.pojos.WebsiteData]

.. ( Hibernate classes here ) ...

  at 
org.apache.roller.business.hibernate.HibernateWeblogManagerImpl.getWeblogCategoryAncestorAssocs(HibernateWeblogManagerImpl.java:751)

(the last line is the first part of the trace involving Roller)

The error does NOT occur under the same configuration with the sole 
change that Derby connects in Network mode.  This *could* indicate a 
problem with Hibernate's Derby dialect, but given the similarity of the 
symptoms to DERBY-628, I'm inclined to say it's a bug there.

It might be possible to code in a workaround or specify more details in 
the Hibernate mapping file so Derby doesn't get confused, but my take is 
that the best option is to note the issue somewhere in documentation or 
on the wiki.

I don't have the problem isolated well enough to (re)file DERBY-628, but 
perhaps s/he who contributed the Derby support does.

cheers,

AC