Hello All,
Has anyone ever had any kind of limitation on the number of objects
that can be retrieved from a database? I basically have a chained (it is
a Vector) set of objects that represent a parent-child relationship. I
build the chain of objects and call db.create on the "root" object. Castor has
no problem with this and creates all the data in the DB just fine. I have
created chains as long as 1000 objects and it writes it to the database
flawlessly. When I try to read the root object back however, any chain
that was created longer than 758 objects will throw a StackOverFlowError.
I have tried adjusting the memory size for the JVM but nothing changes.
I have tried all the different caching methods and nothing changes. I have tried
different machines and nothing changes. It seems to be the length of the
chain that is the problem (BTW, I am using Microsoft SQL Server). Here is the
mapping file that I am using:
------------------------------------------------------------------------------
<!DOCTYPE databases PUBLIC "-//EXOLAB/Castor Mapping DTD Version 1.0//EN"
"http://castor.exolab.org/mapping.dtd";>
<mapping>
<!-- Mapping for ConceptImpl -->
<class name="org.mbari.dsg.Concept" identity="conceptID" key-generator="IDENTITY">
<description>Concept</description>
<map-to table="Concept" />
<cache-type type="none"/>
<!-- Map the conceptID field -->
<field name="conceptID" type="integer">
<sql name="ConceptID" type="integer"/>
</field>
<!-- Map the PrimaryName field -->
<field name="conceptName" type="org.mbari.dsg.ConceptName">
<sql name="PrimaryName"/>
</field>
<!-- Map the parent field -->
<field name="parent" type="org.mbari.dsg.Concept" required="true">
<sql name="parent_conceptID" many-table="child_parent"
many-key="child_conceptID" />
</field>
<!-- Map the child concepts field -->
<field name="childConceptSet" type="org.mbari.dsg.Concept" required="true"
collection="vector">
<sql name="child_conceptID" many-table="child_parent"
many-key="parent_conceptID"/>
</field>
<!-- Map the conceptNameSet field -->
<field name="conceptNameSet" type="org.mbari.dsg.ConceptName" required="true"
collection="vector" set-method="setConceptNameSet" get-method="getConceptNameSet">
<sql many-key="ConceptName_ConceptID"/>
</field>
</class>
<!-- Mapping for ConceptName class -->
<class name="org.mbari.dsg.ConceptName" identity="name"
depends="org.mbari.dsg.Concept" >
<map-to table="ConceptName" />
<cache-type type="none"/>
<field name="name" type="string">
<sql name="ConceptName" type="char" />
</field>
<field name="author" type="string">
<sql name="Author" type="char" />
</field>
<field name="type" type="string">
<sql name="NameType" type="char" />
</field>
<field name="concept" type="org.mbari.dsg.Concept">
<sql name="ConceptName_ConceptID" />
</field>
</class>
</mapping>
-------------------------------------------------------------------------------
The Concept class is the one with the parent-child relationship and the ConceptName
class is just a related class (Concept has one or more ConceptNames, but this does
not appear to affect anything). The parent-child chain of class 'Concept' is the
one that I am testing (Just think of the ConceptName class as the name of the
Concept class). The code snippet looks like this:
-------------------------------------------------------------------------------
org.exolab.castor.jdo.OQLQuery newQuery = jdoDB.getOQLQuery("SELECT c FROM
org.mbari.dsg.Concept c WHERE c.conceptName.name = $1");
newQuery.bind(rootNames[i]);
org.exolab.castor.jdo.QueryResults results = newQuery.execute();
if(results.hasMore()) {
conceptToRead = (Concept)results.next();
}
-------------------------------------------------------------------------------
Again, this works fine until I create a chain of objects longer than 758. Then
I get the following error:
java.lang.reflect.InvocationTargetException: java.lang.StackOverflowError
at org.mbari.dsg.ConceptName.setAuthor(ConceptName.java:93)
at java.lang.reflect.Method.invoke(Native Method)
at org.exolab.castor.persist.FieldMolder.setValue(FieldMolder.java:313)
at org.exolab.castor.persist.ClassMolder.load(ClassMolder.java:705)
at org.exolab.castor.persist.LockEngine.load(LockEngine.java:359)
at
org.exolab.castor.persist.TransactionContext.load(TransactionContext.java:575)
at
org.exolab.castor.persist.TransactionContext.load(TransactionContext.java:486)
at org.exolab.castor.persist.ClassMolder.load(ClassMolder.java:749)
at org.exolab.castor.persist.LockEngine.load(LockEngine.java:359)
at
org.exolab.castor.persist.TransactionContext.load(TransactionContext.java:575)
at
org.exolab.castor.persist.TransactionContext.load(TransactionContext.java:486)
at org.exolab.castor.persist.ClassMolder.load(ClassMolder.java:775)
at org.exolab.castor.persist.LockEngine.load(LockEngine.java:359)
at
org.exolab.castor.persist.TransactionContext.load(TransactionContext.java:575)
at
org.exolab.castor.persist.TransactionContext.load(TransactionContext.java:486)
