Hi Bela,

thanks so much for the reply! Your two answers should make our life much simpler if we can get them working as expected then!

The strange thing is, we have already tried to configure TreeCache with the JBoss transaction manager. We set the isolation level to be serializable but it didn't seem to work as expected. We would have thought that the transactions would be ordered contiguously across the cluster. Unfortunately we got lots of errors.

Just to clarify, our treecache xml file looks as follows:

<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD//EN" "http://hibernate.sourceforge.net/hibernate-configuration-2.0.dtd">
<hibernate-configuration>
 <session-factory>

 <property name="query.substitutions">true 1, false 0, yes 'Y', no 'N'</property>

 <!--
 <property name="dialect">net.sf.hibernate.dialect.OracleDialect</property>
 <property name="connection.driver_class">com.inet.ora.OraDriver</property>
 <property name="connection.username">revo_ph</property>
 <property name="connection.password">revo_ph</property>
 <property name="connection.url">jdbc:inetora:toronto:1521:toronto?sduSize=32767&amp;streamstolob=true</property>
 -->

 <!--
 <property name="dialect">net.sf.hibernate.dialect.MySQLDialect</property>
 <property name="connection.driver_class">com.mysql.jdbc.Driver</property>
 <property name="connection.username">root</property>
 <property name="connection.password"></property>
 <property name="connection.url">jdbc:mysql://Kilcormac/test</property>
 <property name="connection.provider_class">net.sf.hibernate.connection.DriverManagerConnectionProvider</property>
 -->


 <property name="dialect">net.sf.hibernate.dialect.OracleDialect</property>
 <property name="connection.datasource">java:/jdbc/inetdriver</property>

 <property name="connection.pool_size">10</property>
 <property name="statement_cache.size">100</property>

 <!-- Use JDBC Transaction factory for a local (per-JVM) application
 <property name="transaction.factory_class">net.sf.hibernate.transaction.JDBCTransactionFactory</property>
 -->
 <!-- Use JTA Trancation factory for a distributed (inter-JVM) application -->
 <property name="transaction.factory_class">net.sf.hibernate.transaction.JTATransactionFactory</property>

 <!-- Added the JBoss Transaction Manager Lookup class (PH) for the distributed (inter-JVM) application -->
 <property name="transaction.manager_lookup_class">net.sf.hibernate.transaction.JBossTransactionManagerLookup</property>

 <!-- The EHCache is a per-JVM (local) second-level cache
 <property name="cache.provider_class">net.sf.ehcache.hibernate.Provider</property>
 -->
 <!-- JBoss TreeCache is a distributed (inter-JVM) transactional cache with replication -->
 <property name="cache.provider_class">net.sf.hibernate.cache.TreeCacheProvider</property>

 <property name="cache.use_query_cache">false</property>
 <property name="cache.use_minimal_puts">true</property>

 <!-- Magic number 8 is serializable, 2 is read_committed. NOTE: this doesn't work if JBoss is managing the JDBC datasource -
 in that case you need to set it in the Oracle-ds.xml file, so the below doesn't work. -->
 <property name="connection.isolation">1</property>

 <property name="show_sql">false</property>
 <property name="jdbc.fetch_size">5000</property>
 <property name="max_fetch_depth">8</property>
 <property name="jdbc.use_get_generated_keys">true</property>
 <property name="jdbc.batch_size">1000</property>
 <property name="jdbc.use_scrollable_resultset">true</property>
 <property name="jdbc.use_streams_for_binary">true</property>
 <property name="use_outer_join">true</property>
 <property name="cglib.use_reflection_optimizer">true</property>

 <!-- mapping files -->
 <mapping resource="com/capetechnologies/inetdriver/domain/Archive.hbm.xml"/>
 <mapping resource="com/capetechnologies/inetdriver/domain/DataPoint.hbm.xml"/>
 <mapping resource="com/capetechnologies/inetdriver/domain/MonitoredProperty.hbm.xml"/>
 </session-factory>
</hibernate-configuration>

<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD//EN" "http://hibernate.sourceforge.net/hibernate-configuration-2.0.dtd">
<hibernate-configuration>
 <session-factory>

 <property name="query.substitutions">true 1, false 0, yes 'Y', no 'N'</property>

 <!--
 <property name="dialect">net.sf.hibernate.dialect.OracleDialect</property>
 <property name="connection.driver_class">com.inet.ora.OraDriver</property>
 <property name="connection.username">revo_ph</property>
 <property name="connection.password">revo_ph</property>
 <property name="connection.url">jdbc:inetora:toronto:1521:toronto?sduSize=32767&amp;streamstolob=true</property>
 -->

 <!--
 <property name="dialect">net.sf.hibernate.dialect.MySQLDialect</property>
 <property name="connection.driver_class">com.mysql.jdbc.Driver</property>
 <property name="connection.username">root</property>
 <property name="connection.password"></property>
 <property name="connection.url">jdbc:mysql://Kilcormac/test</property>
 <property name="connection.provider_class">net.sf.hibernate.connection.DriverManagerConnectionProvider</property>
 -->


 <property name="dialect">net.sf.hibernate.dialect.OracleDialect</property>
 <property name="connection.datasource">java:/jdbc/inetdriver</property>

 <property name="connection.pool_size">10</property>
 <property name="statement_cache.size">100</property>

 <!-- Use JDBC Transaction factory for a local (per-JVM) application
 <property name="transaction.factory_class">net.sf.hibernate.transaction.JDBCTransactionFactory</property>
 -->
 <!-- Use JTA Trancation factory for a distributed (inter-JVM) application -->
 <property name="transaction.factory_class">net.sf.hibernate.transaction.JTATransactionFactory</property>

 <!-- Added the JBoss Transaction Manager Lookup class (PH) for the distributed (inter-JVM) application -->
 <property name="transaction.manager_lookup_class">net.sf.hibernate.transaction.JBossTransactionManagerLookup</property>

 <!-- The EHCache is a per-JVM (local) second-level cache
 <property name="cache.provider_class">net.sf.ehcache.hibernate.Provider</property>
 -->
 <!-- JBoss TreeCache is a distributed (inter-JVM) transactional cache with replication -->
 <property name="cache.provider_class">net.sf.hibernate.cache.TreeCacheProvider</property>

 <property name="cache.use_query_cache">false</property>
 <property name="cache.use_minimal_puts">true</property>

 <!-- Magic number 8 is serializable, 2 is read_committed. NOTE: this doesn't work if JBoss is managing the JDBC datasource -
 in that case you need to set it in the Oracle-ds.xml file, so the below doesn't work. -->
 <property name="connection.isolation">1</property>

 <property name="show_sql">false</property>
 <property name="jdbc.fetch_size">5000</property>
 <property name="max_fetch_depth">8</property>
 <property name="jdbc.use_get_generated_keys">true</property>
 <property name="jdbc.batch_size">1000</property>
 <property name="jdbc.use_scrollable_resultset">true</property>
 <property name="jdbc.use_streams_for_binary">true</property>
 <property name="use_outer_join">true</property>
 <property name="cglib.use_reflection_optimizer">true</property>

 <!-- mapping files -->
 <mapping resource="com/capetechnologies/inetdriver/domain/Archive.hbm.xml"/>
 <mapping resource="com/capetechnologies/inetdriver/domain/DataPoint.hbm.xml"/>
 <mapping resource="com/capetechnologies/inetdriver/domain/MonitoredProperty.hbm.xml"/>
 </session-factory>
</hibernate-configuration>

 <!--
 | The fast in-memory transaction manager.
 -->
 <mbean code="org.jboss.tm.plugins.tyrex.TransactionManagerService"
 name="jboss:service=TransactionManager"
 xmbean-dd="resource:xmdesc/TransactionManagerService-xmbean.xml">
 <attribute name="TransactionTimeout">300</attribute>

 <depends optional-attribute-name="XidFactory">jboss:service=XidFactory</depends>
 </mbean>

<datasources>


 <local-tx-datasource>
 <jndi-name>jdbc/inetdriver</jndi-name>

 <connection-url>jdbc:inetora:ireland:1521:ireland</connection-url>

 <driver-class>com.inet.ora.OraDriver</driver-class>

 <!-- Full effective serialisation (supported by Oracle 9i) -->
 <transaction-isolation>TRANSACTION_SERIALIZABLE</transaction-isolation>

 <!-- Read committed data is only statement level isolation
 <transaction-isolation>TRANSACTION_READ_COMMITTED</transaction-isolation>
-->
 <user-name>user</user-name>
 <password>pass</password>

 <connection-property name="sduSize">32767</connection-property>
 <connection-property name="streamstolob">true</connection-property>

 <check-valid-connection-sql>select sysdate from dual</check-valid-connection-sql>

 <prepared-statement-cache-size>50</prepared-statement-cache-size>

 </local-tx-datasource>

</datasources>

Sorry Bela,

I made one mistake above, we actually DO have the default JBoss transaction manager service deployed (not the tyrex one that I posted above). We have the following in our jboss-service as the mbean.

 <!--
 | The fast in-memory transaction manager.
 -->
 <mbean code="org.jboss.tm.TransactionManagerService"
 name="jboss:service=TransactionManager"
 xmbean-dd="resource:xmdesc/TransactionManagerService-xmbean.xml">
 <attribute name="TransactionTimeout">300</attribute>

 <depends optional-attribute-name="XidFactory">jboss:service=XidFactory</depends>
 </mbean>

Hi Bela,

sorry for not getting back to you sooner on this. We have been busy figuring out what's going on.

Firstly, the application we ran is on a two node JBoss cluster where each node has an Updater task and a Reader task which both "update" or "read" the same 1000 entries in the same database table (in oracle).

We set the transaction isolation level to be Serializable.

We configured the TreeCache to be the second level cache of hibernate.

Firstly the problem that we encountered is as follows:

One updater task managed to update the entries inside a transaction, however the other one periodically failed with an Oracle "cannot serialize transaction exception".

We think the reason for this is as follows:

Given two transactions A and B as below

transactin A
transaction B

start A |-----------------------------------|

start B |-----------------------------------|

When A commits, B may or may not fail (depending on the common data) due to state change. In our case transaction B consistently failed as it was working on the same rows.

So I think we now understand what's happening. Thanks for your help.