[Exist-open] Fwd: Fatal Error and various NullPointerException when schedule multiple instances of a xQuery

[Thomas W. <tho...@gm...>]

Dear all,

I have a XQuery that runs fine when it is executed on its own. When I
schedule multiple instances of this XQuery, after couple of executions
I receive on the eXist command window number of java errors (strangely
enough they are not recorded in exist.log).

I have attached  a zip file with the code that will reproduce the errors.
1. Please unzip the files with the directory  structure in    .../webapp/hpSpy
2.  Set the correct password in  xmldb:login( "/db", "admin", "pass" )
in fetch-section.xql, fetch-category.xql, select-category.xql and
batch.xql
2. Execute fetch-section.xql first. It will create all initial data structures.
3. Start the code with  batch.xql?mode=start
4. Observe eXist command window for errors
5. Stop the code with  batch.xql?mode=stop
Increasing  the value of $max-job-per-section at line 120 in batch.xql
will manifest the problems quicker.

This is a short explanation what batch.xql does:
For each section created by fetch-section.xql (at the moment they are
5), it creates $max-job-per-section instances
of a dynamically created XQuery  that executes select-category.xql
with the section id passed as a parameter.  These XQueries are saved
in the database and scheduled to be executed shortly.
When select-category.xql  picks up the first category for update from
the passed section and executes fetch-category.
When a scheduled XQuery is called it logs the call in
/db/hpSpy/log/amazon/batch/{section-id}-{instance}.xml

select-category.xql   and select-category.xql can be  run without
parameters  manually.

I wrote my first  QXuery just 6 weeks ago (and I love it!) and the
world of JAVA is very new to me.
Some of these errors may be trivial оr may be are caused by my lack of
understanding how eXist works.
For me at this moment  they are real show stopper. I will really
appreciate any help and advice.

The top ten lines of the error messages follow bellow.

Regards,
Thomas

-------------------------------------------

[Fatal Error] :836:45: Open quote is expected for attribute "href"
associated with an  element type  "a".

java.lang.NullPointerException
      at org.exist.stax.EmbeddedXMLStreamReader.readNodeId(EmbeddedXMLStreamReader.java:194)
      at org.exist.stax.EmbeddedXMLStreamReader.initNode(EmbeddedXMLStreamReader.java:165)
      at org.exist.stax.EmbeddedXMLStreamReader.next(EmbeddedXMLStreamReader.java:221)
      at org.exist.storage.dom.DOMFile.findValue(DOMFile.java:1348)
      at org.exist.storage.dom.RawNodeIterator.seek(RawNodeIterator.java:135)
      at org.exist.stax.EmbeddedXMLStreamReader.reposition(EmbeddedXMLStreamReader.java:134)
      at org.exist.storage.NativeBroker.getXMLStreamReader(NativeBroker.java:529)
...
java.lang.NullPointerException
      at org.exist.stax.EmbeddedXMLStreamReader.getAttributeCount(EmbeddedXMLStreamReader.java:286)
      at org.exist.dom.NodeProxy.directSelectAttribute(NodeProxy.java:1301)
      at org.exist.dom.NodeSetHelper.directSelectAttributes(NodeSetHelper.java:548)
      at org.exist.dom.AbstractNodeSet.directSelectAttribute(AbstractNodeSet.java:301)
      at org.exist.xquery.LocationStep.getAttributes(LocationStep.java:475)
      at org.exist.xquery.LocationStep.eval(LocationStep.java:317)
      at org.exist.xquery.AbstractExpression.eval(AbstractExpression.java:59)
      at org.exist.xquery.PathExpr.eval(PathExpr.java:238)
      at org.exist.xquery.LetExpr.eval(LetExpr.java:150)
      at org.exist.xquery.LetExpr.eval(LetExpr.java:201)
...
java.lang.ClassCastException: org.exist.memtree.ElementImpl
      at org.exist.xquery.value.ValueSequence.toNodeSet(ValueSequence.java:207)
      at org.exist.xquery.LocationStep.eval(LocationStep.java:296)
      at org.exist.xquery.AbstractExpression.eval(AbstractExpression.java:59)
      at org.exist.xquery.PathExpr.eval(PathExpr.java:238)
      at org.exist.xquery.ConditionalExpression.eval(ConditionalExpression.java:96)
      at org.exist.xquery.AbstractExpression.eval(AbstractExpression.java:59)
      at org.exist.xquery.PathExpr.eval(PathExpr.java:238)
      at org.exist.xquery.LetExpr.eval(LetExpr.java:150)
      at org.exist.xquery.LetExpr.eval(LetExpr.java:201)
      at org.exist.xquery.LetExpr.eval(LetExpr.java:201)
      at org.exist.xquery.LetExpr.eval(LetExpr.java:201)
...
java.lang.NullPointerException
      at org.exist.xquery.functions.transform.Transform$CachedStylesheet.getTemplates(Transform.java:401)
      at org.exist.xquery.functions.transform.Transform$CachedStylesheet.<init>(Transform.java:386)
      at org.exist.xquery.functions.transform.Transform.getSource(Transform.java:346)
      at org.exist.xquery.functions.transform.Transform.createHandler(Transform.java:291)
      at org.exist.xquery.functions.transform.Transform.eval(Transform.java:187)
      at org.exist.xquery.BasicFunction.eval(BasicFunction.java:68)
      at org.exist.xquery.InternalFunctionCall.eval(InternalFunctionCall.java:49)
      at org.exist.xquery.AbstractExpression.eval(AbstractExpression.java:59)
      at org.exist.xquery.PathExpr.eval(PathExpr.java:238)
      at org.exist.xquery.LetExpr.eval(LetExpr.java:150)
      at org.exist.xquery.LetExpr.eval(LetExpr.java:201)
...
java.util.NoSuchElementException
      at org.exist.stax.EmbeddedXMLStreamReader.next(EmbeddedXMLStreamReader.java:219)
      at org.exist.dom.NodeProxy.directSelectAttribute(NodeProxy.java:1298)
      at org.exist.dom.NodeSetHelper.directSelectAttributes(NodeSetHelper.java:548)
      at org.exist.dom.AbstractNodeSet.directSelectAttribute(AbstractNodeSet.java:301)
      at org.exist.xquery.LocationStep.getAttributes(LocationStep.java:475)
      at org.exist.xquery.LocationStep.eval(LocationStep.java:317)
      at org.exist.xquery.AbstractExpression.eval(AbstractExpression.java:59)
      at org.exist.xquery.PathExpr.eval(PathExpr.java:238)
...
java.lang.NullPointerException
      at org.exist.dom.NodeProxy.getNode(NodeProxy.java:347)
      at org.exist.dom.ExtArrayNodeSet.item(ExtArrayNodeSet.java:397)
      at org.exist.xquery.update.Modification.selectAndLock(Modification.java:150)
      at org.exist.xquery.update.Delete.eval(Delete.java:123)
      at org.exist.xquery.AbstractExpression.eval(AbstractExpression.java:59)
..



--
Thomas White

51 Glebewood
Bracknell
Berks RG12 9SD
Mobile:+44 7711 922 966
Skype: thomaswhite
gTalk: thomas.0007
jaxtr: http://www.jaxtr.com/t.white
Linked-In:http://www.linkedin.com/in/thomaswhite0007



-- 
Thomas White

51 Glebewood
Bracknell
Berks RG12 9SD
Mobile:+44 7711 922 966
Skype: thomaswhite
gTalk: thomas.0007
jaxtr: http://www.jaxtr.com/t.white
Linked-In:http://www.linkedin.com/in/thomaswhite0007