我在eXist-db 2.2上使用Orbeon XForms 4.7。我们总是遇到会话问题，其中会话将在给定时间点之后在eXist-db中到期，但是Orbeon保留会话令牌并且“认为”它仍然登录。这可能是也可能不是我在日志中看到的核心：
2016-11-07 15:06:27,643 INFO ProcessorService - /xforms-server - Received request
2016-11-07 15:06:27,650 INFO ProcessorService - /xforms-server - Timing: 7
2016-11-07 15:06:29,368 INFO ProcessorService - /xforms-server - Received request
2016-11-07 15:06:29,372 ERROR XFormsServer - Unable to retrieve XForms engine state. Please reload the current page. Note that you will lose any unsaved changes. {}
2016-11-07 15:06:29,372 INFO ProcessorService - /xforms-server - Timing: 4
2016-11-07 15:06:29,373 ERROR ProcessorService -
+----------------------------------------------------------------------------------------------------------------------+
|An Error has Occurred |
|----------------------------------------------------------------------------------------------------------------------|
|Unable to retrieve XForms engine state. Please reload the current page. Note that you will lose any unsaved changes. |
|----------------------------------------------------------------------------------------------------------------------|
|Application Call Stack |
|----------------------------------------------------------------------------------------------------------------------|
|oxf:/config/prologue-servlet.xpl |executing processor | 36|
|······················································································································|
|element=<p:processor name="oxf:pipeline">[...]</p:processor> |
|name ={http://www.orbeon.com/oxf/processors}pipeline |
|----------------------------------------------------------------------------------------------------------------------|
|oxf:/ops/xforms/xforms-server.xpl |reading processor output | 43|
|······················································································································|
|element=<p:output name="response" id="xforms-response"/> |
|name =response |
|id =xforms-response |
|----------------------------------------------------------------------------------------------------------------------|
|----------------------------------------------------------------------------------------------------------------------|
|Exception: org.orbeon.oxf.common.OXFException |
|----------------------------------------------------------------------------------------------------------------------|
|org.orbeon.oxf.xforms.state.XFormsStateManager |createDocumentFromStore |XFormsStateManager.java | 489|
|org.orbeon.oxf.xforms.state.XFormsStateManager |findOrRestoreDocument |XFormsStateManager.java | 448|
|org.orbeon.oxf.xforms.state.XFormsStateManager |beforeUpdate |XFormsStateManager.java | 328|
|org.orbeon.oxf.xforms.processor.XFormsServer |doIt |XFormsServer.java | 169|
|org.orbeon.oxf.xforms.processor.XFormsServer |access$000 |XFormsServer.java | 59|
|org.orbeon.oxf.xforms.processor.XFormsServer$1 |readImpl |XFormsServer.java | 85|
|essor.impl.ProcessorOutputImpl$TopLevelOutputFilter|read |ProcessorOutputImpl.java | 257|
|org.orbeon.oxf.processor.impl.ProcessorOutputImpl |read |ProcessorOutputImpl.java | 394|
|----------------------------------------------------------------------------------------------------------------------|
|Exception: org.orbeon.oxf.common.ValidationException |
|----------------------------------------------------------------------------------------------------------------------|
|org.orbeon.oxf.common.OrbeonLocationException$ |wrapException |OrbeonLocationException.scala | 60|
|org.orbeon.oxf.common.OrbeonLocationException |wrapException |OrbeonLocationException.scala | |
每隔几秒就会出现此错误。没有提到XForms触发它的内容，因此无法进行有针对性的搜索。
有谁知道如何解释此错误以及可能如何预防？请注意，用户端根本没有错误，一切似乎都正常。这纯粹是服务器端。