Hello,

finally decided (in fact forced because of jar incompatibilities) to upgrade my webapp from hibernate 3.2.5.ga to 4.3.4-final.

this went rather smooth, only needed to change namespaces in config and mapping files (yes, still doing old-school mapping).

as part of my regression tests, i was creating a 'long' report in my webapp. with 3.2.5.ga this took ~15 seconds, with 4.3.4-final this takes ~45 seconds.

what did i check:
+ i enabled the sql statement logging:
- the same number of statements was used in both cases
- 1 type of statement changed (in 3.2.5 a 'left outer join' was used, in 4.3.4 a 'inner join' was used), i assume this is a hibernate optimization
+ i checked the cpu usage with top: with 3.2.5 mysqld uses up to 15%, while with 4.3.4 mysqld only uses up to 5%. tomcat is using in both cases close to 100% of 1 cpu => so bottleneck seems to be in java
+ i tried to replace the c3p0 jar that was packaged with hibernate (c3p0-0.9.2.1.jar) with a more recent one (c3p0-0.9.5-pre6.jar), but this has no effect

does this ring a bell or any suggestion on how to further investigate this?

below is my config file

<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">

<hibernate-configuration>

<session-factory>
<!-- properties -->
<property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="hibernate.connection.url">jdbc:mysql://localhost:5555/bla-app?zeroDateTimeBehavior=convertToNull</property>
<property name="hibernate.connection.username">foo</property>
<property name="hibernate.connection.password">bar</property>

<property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
<property name="hibernate.show_sql">false</property>
<property name="hibernate.transaction.factory_class">org.hibernate.transaction.JDBCTransactionFactory</property>

<!-- to be able to use true, false in HQL -->
<property name="hibernate.query.substitutions"> true 1, false 0 </property>

<property name="hibernate.connection.provider_class">org.hibernate.connection.C3P0ConnectionProvider</property>
<property name="hibernate.c3p0.max_size">50</property>
<property name="hibernate.c3p0.min_size">10</property>
<property name="hibernate.c3p0.timeout">200</property>
<property name="hibernate.c3p0.max_statements">0</property>
<property name="hibernate.c3p0.acquire_increment">3</property>

<!-- mapping files -->
...

</session-factory>

</hibernate-configuration>

Hi, no this doesn't ring a bell. If any it's very surprising, as we did a lot of healthy performance optimisations lately which are inlcluded in 4.3.4.Final so I would expect opposite results.
Is there any way you could profile it and identify the issue? I guess something must be going wrong, and if you can isolate the cause you should win a much better performance.

ok, resolved.

the new version was hitting the configured permgen limit. after increasing this limit, the report creation took the same time in 3.2.5 and 4.3.4.