cmp performance problem with getmethod

[smilidon]

Hi,

i have a cmp bean "Minfo" and get my results in my client this way:

code:


try {
Collection c = getHome().findByDisk(disk);
Iterator iterator = c.iterator();

Minfo info = null;
while (iterator.hasNext()){
Object obj = iterator.next();
if (obj instanceof Minfo) info = (Minfo)obj;
System.out.println(info.getDisk()+" "+ info.getExtension());
}
} catch (RemoteException e1) {
e1.printStackTrace();



Every time i call a get-function, JBoss make a database query like this:

Executing SQL: SELECT filename, extension, disk, size, id3title, id3artist, id3length, id3bitrate FROM minfo WHERE (id=?)

is it possible to get the information for all get-functions with one sql-call for each bean? is it possible to configure my bean or jboss for this behavior? if the finder has a result, is it possible to load all the bean data? or is there a other way i can improve performance?

i have a performance problem if i call a lot of get-Methods.

Thanks a lot and sorry for my bad english.

P.S.I don't have the Admin and Dev book

[kabirkhan]

You need to execute in the context of a transaction. The Admin and Devel docs are available from the big blue picture on the right that say "Free JBoss Documentation" :-)

[smilidon]

ok, thanks :)

i try it and i have a problem to add this tags to my jbosscmp-jdbc.xml

 <load-groups>
 <load-group>
 <load-group-name>all</load-group-name>
 <field-name>filename</field-name>
 <field-name>extension</field-name>
 <field-name>disk</field-name>
 <field-name>size</field-name>
 <field-name>id3title</field-name>
 <field-name>id3artist</field-name>
 <field-name>id3length</field-name>
 <field-name>id3bitrate</field-name>
 </load-group>
 <eager-load-group>all</eager-load-group>
 </load-groups>

i get the exception:

16:04:55,408 INFO [EjbModule] Deploying Minfo
16:04:55,596 ERROR [XmlFileLoader] XmlFileLoader: File jar:file:/D:/Coding/jboss-3.2.5/server/default/tmp/deploy/tmp44502MediaMod.jar!/META-INF/jbosscmp-jdbc.xml process error. Line: 87. Error message: The content of element type "load-groups" must match "(load-group)+".
16:04:55,596 ERROR [EntityContainer] Starting failed jboss.j2ee:jndiName=MinfoBean,service=EJB
org.jboss.deployment.DeploymentException: Invalid XML: file=jar:file:/D:/Coding/jboss-3.2.5/server/default/tmp/deploy/tmp44502MediaMod.jar!/META-INF/jbosscmp-jdbc.xml
at org.jboss.metadata.XmlFileLoader.getDocument(XmlFileLoader.java:296)
at org.jboss.metadata.XmlFileLoader.getDocument(XmlFileLoader.java:247)
at org.jboss.metadata.XmlFileLoader.getDocumentFromURL(XmlFileLoader.java:219)
at org.jboss.metadata.XmlFileLoader.getDocument(XmlFileLoader.java:203)
at org.jboss.ejb.plugins.cmp.jdbc.metadata.JDBCXmlFileLoader.load(JDBCXmlFileLoader.java:74)
.
.
.

if i delete the line <eager-load-group>all</eager-load-group>, i can deploy, but it doesnt change anything.
i also get an exception if i put these lines except <eager-load-group>all</eager-load-group> to the top or bottom of jbosscmp-jdbc.xml(in tag). it must be placed between the cmp-fields and the querys?!?!

here is more of my jbosscmp-jdbc.xml

<jbosscmp-jdbc>
 <defaults>
 <datasource>java:/MySqlDS</datasource>
 <datasource-mapping>mySQL</datasource-mapping>
 <preferred-relation-mapping>foreign-key</preferred-relation-mapping>
 </defaults>

 <enterprise-beans>

 <!--
 To add beans that you have deployment descriptor info for, add
 a file to your XDoclet merge directory called jbosscmp-jdbc-beans.xml
 that contains the <entity></entity> markup for those beans.
 -->

 <entity>
 <ejb-name>Minfo</ejb-name>

 <read-ahead>
 <strategy>on-load</strategy>
 <page-size>4</page-size>
 <eager-load-group>all</eager-load-group>
 </read-ahead>
 <table-name>minfo</table-name>

 <cmp-field>
 <field-name>filename</field-name>
 <column-name>filename</column-name>

 </cmp-field>
.
.
.
 <load-groups>
 <load-group>
 <load-group-name>all</load-group-name>
 <field-name>filename</field-name>
 <field-name>extension</field-name>
 <field-name>disk</field-name>
 <field-name>size</field-name>
 <field-name>id3title</field-name>
 <field-name>id3artist</field-name>
 <field-name>id3length</field-name>
 <field-name>id3bitrate</field-name>
 </load-group>
 <eager-load-group>all</eager-load-group>
 </load-groups>
 <query>
 <query-method>
 <method-name>findAll</method-name>
 <method-params>
 </method-params>
 </query-method>
 <jboss-ql>[CDATA[SELECT OBJECT(a) FROM minfo as a]]</jboss-ql>

 <read-ahead>
 <strategy>on-load</strategy>
 <page-size>4</page-size>
 <eager-load-group>all</eager-load-group>
 </read-ahead>
 </query>
.
.
.
 <entity-command name="mysql-get-generated-keys">
 </entity-command>
<!-- jboss 3.2 features -->
<!-- optimistic locking does not express the exclusions needed -->
 </entity>

 </enterprise-beans>

</jbosscmp-jdbc>

Thanks again...!

[smilidon]

p.s. i use jboss 3.2.5

[aloubyansky]

Read the Optimized Loading chapter once again and pay attention to DTD and transactions.