JBO-28004: Could not lock row in control table for table null

Question

hello.
we have deployed two application on a server.
both have code like this:
     select = "SELECT * from tab";
vo = e.getDBTransaction().createViewObjectFromQueryStmt(select);
                    vo.executeQuery();
                    RowSet rs = vo.getRowSet();
                    if(rs != null)
                         Row lastRow = vo.getRowSet().last();
the last line throws sometimes an exception (.last()).
JBO-28004: Could not lock row in control table for table null
at oracle.jbo.PCollException.throwException(PCollException.java:34)
at oracle.jbo.pcoll.OraclePersistManager.commit(OraclePersistManager.java:229)
at oracle.jbo.pcoll.OraclePersistManager.dropTable(OraclePersistManager.java:499)
at oracle.jbo.pcoll.OraclePersistManager.createTable(OraclePersistManager.java:692)
at oracle.jbo.pcoll.OraclePersistManager.insert(OraclePersistManager.java:1492)
at oracle.jbo.pcoll.PCollNode.passivateElem(PCollNode.java:542)
at oracle.jbo.pcoll.PCollNode.passivate(PCollNode.java:657)
at oracle.jbo.pcoll.PCollection.passivateLRULeafNode(PCollection.java:351)
at oracle.jbo.pcoll.PCollection.checkActiveLeafLimit(PCollection.java:404)
at oracle.jbo.pcoll.PCollection.nodeRecentlyUsed(PCollection.java:252)
at oracle.jbo.pcoll.PCollNode.<init>(PCollNode.java:73)
at oracle.jbo.pcoll.PCollNode.checkForSplit(PCollNode.java:1553)
at oracle.jbo.pcoll.PCollNode.addObject(PCollNode.java:1622)
at oracle.jbo.pcoll.PCollNode.addObject(PCollNode.java:1610)
at oracle.jbo.pcoll.PCollection.addElement(PCollection.java:753)
at oracle.jbo.server.QueryCollection.fetch(QueryCollection.java:1247)
at oracle.jbo.server.QueryCollection.getRowCount(QueryCollection.java:1065)
at oracle.jbo.server.ViewRowSetImpl.getRowCount(ViewRowSetImpl.java:1444)
at oracle.jbo.server.ViewRowSetIteratorImpl.last(ViewRowSetIteratorImpl.java:1183)
at oracle.jbo.server.ViewRowSetImpl.last(ViewRowSetImpl.java:2246)
at oracle.jbo.server.ViewObjectImpl.last(ViewObjectImpl.java:4352)
at com.omv.emis.extemis.bc.EmsFreigabeImpl.checkFullMonth(EmsFreigabeImpl.java:327)
at com.omv.emis.extemis.bc.EmsFreigabeImpl.doDML(EmsFreigabeImpl.java:293)
at oracle.jbo.server.EntityImpl.postChanges(EntityImpl.java:3410)
at oracle.jbo.server.DBTransactionImpl.doPostTransactionListeners(DBTransactionImpl.java:2274)
at oracle.jbo.server.DBTransactionImpl.postChanges(DBTransactionImpl.java:2216)
at oracle.jbo.server.DBTransactionImpl.commitInternal(DBTransactionImpl.java:1511)
at oracle.jbo.server.DBTransactionImpl.commit(DBTransactionImpl.java:1677)
at EmsFreigabeView1_BrowseEdit._jspService(_EmsFreigabeView1__BrowseEdit.java:134)
at com.orionserver.http.OrionHttpJspPage.service(OrionHttpJspPage.java:56)
at oracle.jsp.runtimev2.JspPageTable.service(JspPageTable.java:317)
at oracle.jsp.runtimev2.JspServlet.internalService(JspServlet.java:465)
at oracle.jsp.runtimev2.JspServlet.service(JspServlet.java:379)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at com.evermind.server.http.ResourceFilterChain.doFilter(ResourceFilterChain.java:64)
at oracle.security.jazn.oc4j.JAZNFilter.doFilter(JAZNFilter.java:283)
at com.evermind.server.http.ServletRequestDispatcher.invoke(ServletRequestDispatcher.java:563)
at com.evermind.server.http.ServletRequestDispatcher.forwardInternal(ServletRequestDispatcher.java:309)
at com.evermind.server.http.HttpRequestHandler.processRequest(HttpRequestHandler.java:767)
at com.evermind.server.http.HttpRequestHandler.run(HttpRequestHandler.java:259)
at com.evermind.server.http.HttpRequestHandler.run(HttpRequestHandler.java:106)
this exception does not occur every time just sometimes.
(no other user/application uses the specific table, so there is no other lock)
maybe someone knows an error source.
thx in advance.

Answer 1

Gina:
Could you run you app with diagnostic turned on?
If you're launching your middle tier from command prompt, you should invoke java as
java -Djbo.debugoutput=console ...
If you're launching your middle tier from w/i JDev..
1. Select the project.
2. Do right mouse click and select "Project Settings..."
3. On the Settings dialog, select Configurations/Runner.
4. In the righthand side pane, you should see a textbox for "Java
Options". Please add the following JVM switch:
-Djbo.debugoutput=console
Then, rerun. The run command should include
-Djbo.debugoutput=console as in
"D:\JDev9i\jdk\bin\javaw.exe" -Djbo.debugoutput=console -classpath ...
Then, you should see a lot of diagnostic messages. It will also give you complete stack trace including that of the detail exception.
When you get the exception diagnostic output, please post that to this thread.
Thanks.
Sung