It seems the root cause is the following query defined in the file org/jbpm/db/hibernate.queries.hbm.xml (to be found in jbpm-jpdl.jar) : | <query name="Simulation.calculateAverageTimeForDecisions"> | <![CDATA[ | select | nl.node.id, | nl.node.name, | count(nl.leave), | avg(nl.duration), | min(nl.duration), | max(nl.duration), | stddev(nl.duration) | from org.jbpm.graph.log.NodeLog nl | where nl.node.processDefinition = :processDefinition | and nl.node.class = org.jbpm.graph.node.Decision | and time(nl.enter) > time(:fromTime) and time(nl.enter) < time(:tillTime) | group by nl.node | ]]> | </query> | jBPM Job Executor is attemting to execute this query every so often. However, on going through hibernate soure code for org.hibernate.dialect.HSQLDialect, the problem seems to be that this dialect (HSQLDialect) does not invoke registerFunction for the function named 'stddev' :-( In fact, the function 'stddev' is being registered for only DB2, Oracle8i, Oracle9 and PostgresSQL dialects. The issue did not exist in earlier versions of jBPM source code. This is a weird state of affairs - jBPM code is sort of ahead of the Hibernate code it depends on? Any ideas for how to address this will be highly appreciated? View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4103528#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...