Hi Vincent, I modified all the type from string in xwiki.hbm.xml to CLOB if the size is > 4K, and from binary to BLOB if the size is > 4K. Then put the xml back into the xwiki.jar and delete all the tables in Oracle. Restart Tomcat, and now I get all tables created successfully. But it failed at saving CalendarEvent or reading XWikiPreferences. I am wondering if any developer can cast some light on this part. Maybe it is still a data type mapping issue for retreiving/saving CLOB/BLOB data. Thanks a lot _________________________________________________________________ Hibernate: select xwikidocum0_.XWD_ID as XWD1_0_0_, xwikidocum0_.XWD_ARCHIVE as XWD23_0_0_ from xwikidoc xwikidocum0_ where xwikidocum0_.XWD_ID=? 17:44:21,365 WARN http-80-1 http://localhost/xwiki/bin/view/Main/ WebHome JDBCExceptionReporter:logExceptions:71 - SQL Error: 17041, SQLState: null 17:44:21,365 ERROR http-80-1 http://localhost/xwiki/bin/view/Main/ WebHome JDBCExceptionReporter:logExceptions:72 - Missing IN or OUT parameter at index:: 1 com.xpn.xwiki.XWikiException: Error number 3201 in 3: Exception while saving document XWiki.CalendarEvent Wrapped Exception: Error number 3212 in 3: Exception while loading archive XWiki.CalendarEvent Wrapped Exception: Error number 3212 in 3: Exception while loading archive -237,561,194 Wrapped Exception: could not load an entity: [com.xpn.xwiki.doc.XWikiDocumentArchive#-237561194] at com.xpn.xwiki.store.XWikiHibernateStore.saveXWikiDoc (XWikiHibernateStore.java:310) at com.xpn.xwiki.store.XWikiCacheStore.saveXWikiDoc (XWikiCacheStore.java:96) at com.xpn.xwiki.store.XWikiCacheStore.saveXWikiDoc (XWikiCacheStore.java:90) at com.xpn.xwiki.XWiki.saveDocument(XWiki.java:750) at com.xpn.xwiki.plugin.calendar.CalendarPlugin.getCalendarEventClass (CalendarPlugin.java:83) at com.xpn.xwiki.plugin.calendar.CalendarPlugin.init (CalendarPlugin.java:332)