What is causing a Hibernate SQL query exception?

Hi all and sorry in advance for this post but I've spent way too much time going around in circles so I'm hoping someone could shed a light on it here for me. I updated a webapp on Tomcat and I'm getting the following error which didn't exist on the previous version. Though I am quite confident that the part of code I modifed isn't to blame as I have tested the app on two different dev servers.

The production server is configured thus: CentOS 5.4 virtual server with tomcat 5.5.23 running mysql 5.0.77.
The two dev servers are: Windows XP SP2 running tomcat 5.5.23 with mysql 5.1.49
                         Mac OSX 10.6.6 Running tomcat 6 with mysql 5.1.51

The application was developed using struts (1.1 as far as I can gather) with hibernate 3 as the peristence layer. It only fails on the production server for some reason I can't fathom. I'd like to draw your attention to the java.sql.SQLException near the bottom. After some long searching I found this but because it was posted years ago (about 1 year before development started on this app I'm sure Hibernate has evolved from that version. as I can't find a way of implementing his solution. I use Eclipse Helios as an IDE. Thanks in advance for taking your time to read this, to all who manage to reply.

javax.servlet.ServletException: org.hibernate.exception.SQLGrammarException: could not execute query
 at fr.company.action.login.LoginAction.execute(LoginAction.java:219)
 at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:484)
 at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:274)
 at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1482)
 at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:525)
 at javax.servlet.http.HttpServlet.service(HttpServlet.java:710)
 at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
 at fr.company.util.EncodingFilter.doFilter(EncodingFilter.java:37)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:215)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
 at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:210)
 at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:172)
 at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:525)
 at org.apache开发者_开发技巧.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
 at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
 at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)
 at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:151)
 at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:875)
 at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)
 at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)
 at org.apache.tomcat.util.net.MasterSlaveWorkerThread.run(MasterSlaveWorkerThread.java:113)
 at java.lang.Thread.run(Thread.java:636)


javax.servlet.ServletException: org.hibernate.exception.SQLGrammarException: could not execute query
 at fr.company.action.login.LoginAction.execute(LoginAction.java:219)
 at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:484)
 at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:274)
 at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1482)
 at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:525)
 at javax.servlet.http.HttpServlet.service(HttpServlet.java:710)
 at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
 at fr.company.util.EncodingFilter.doFilter(EncodingFilter.java:37)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:215)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
 at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:210)
 at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:172)
 at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:525)
 at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
 at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
 at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)
 at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:151)
 at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:875)
 at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)
 at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)
 at org.apache.tomcat.util.net.MasterSlaveWorkerThread.run(MasterSlaveWorkerThread.java:113)
 at java.lang.Thread.run(Thread.java:636)
java.lang.Exception: org.hibernate.exception.SQLGrammarException: could not execute query
 at fr.company.dao.GenericDAO.findOne(GenericDAO.java:204)
 at fr.company.dao.UserDAO.findOneUser(UserDAO.java:146)
 at fr.company.service.UserPeer.logUser(UserPeer.java:72)
 at fr.company.action.login.LoginAction.execute(LoginAction.java:127)
 at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:484)
 at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:274)
 at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1482)
 at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:525)
 at javax.servlet.http.HttpServlet.service(HttpServlet.java:710)
 at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
 at fr.company.util.EncodingFilter.doFilter(EncodingFilter.java:37)
 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:215)
 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
 at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:210)
 at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:172)
 at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:525)
 at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
 at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
 at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)
 at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:151)
 at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:875)
 at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)
 at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)
 at org.apache.tomcat.util.net.MasterSlaveWorkerThread.run(MasterSlaveWorkerThread.java:113)
 at java.lang.Thread.run(Thread.java:636)
Caused by: org.hibernate.exception.SQLGrammarException: could not execute query
 at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:65)
 at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
 at org.hibernate.loader.Loader.doList(Loader.java:2153)
 at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2029)
 at org.hibernate.loader.Loader.list(Loader.java:2024)
 at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:369)
 at org.hibernate.hql.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:300)
 at org.hibernate.engine.query.HQLQueryPlan.performList(HQLQueryPlan.java:153)
 at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1128)
 at org.hibernate.impl.QueryImpl.list(QueryImpl.java:79)
 at org.hibernate.impl.AbstractQueryImpl.uniqueResult(AbstractQueryImpl.java:749)
 at fr.company.dao.GenericDAO.findOne(GenericDAO.java:198)
 ... 26 more
Caused by: java.sql.SQLException: Unknown column 'user0_1_.poloSize' in 'field list'
 at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2928)
 at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1571)
 at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1666)
 at com.mysql.jdbc.Connection.execSQL(Connection.java:2994)
 at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:936)
 at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:1030)
 at com.mchange.v2.c3p0.impl.NewProxyPreparedStatement.executeQuery(NewProxyPreparedStatement.java:76)
 at org.hibernate.jdbc.AbstractBatcher.getResultSet(AbstractBatcher.java:139)
 at org.hibernate.loader.Loader.getResultSet(Loader.java:1669)
 at org.hibernate.loader.Loader.doQuery(Loader.java:662)
 at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:224)
 at org.hibernate.loader.Loader.doList(Loader.java:2150)
 ... 35 more

The core error message says:

Unknown column 'user0_1_.poloSize' in 'field list'

As you say

It only fails on the production server

could it be possible that the column indicated above is missing from your production DB (while present in the DB(s) used for dev/integration testing)?

Looks like the cause of your problem is here..:

Caused by: java.sql.SQLException: Unknown column 'user0_1_.poloSize' in 'field list' at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2928)

something is with your HQL. try to add to hibernate.cfg.xml

<property name="show_sql">true</property>

and add SQL dump to post (and HQL)