[jbpm-commits] JBoss JBPM SVN: r1967 - jbpm3/branches/jpdl-3.2.3.CP/bpel/userguide/en/modules.
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Thu Aug 21 19:16:05 EDT 2008
Author: alex.guizar at jboss.com
Date: 2008-08-21 19:16:05 -0400 (Thu, 21 Aug 2008)
New Revision: 1967
Modified:
jbpm3/branches/jpdl-3.2.3.CP/bpel/userguide/en/modules/gettingStarted.xml
Log:
document jboss deployment order: BPEL-291
document transaction manager behavior: BPEL-298
document proxy warn logs: BPEL-299
Modified: jbpm3/branches/jpdl-3.2.3.CP/bpel/userguide/en/modules/gettingStarted.xml
===================================================================
--- jbpm3/branches/jpdl-3.2.3.CP/bpel/userguide/en/modules/gettingStarted.xml 2008-08-21 23:01:15 UTC (rev 1966)
+++ jbpm3/branches/jpdl-3.2.3.CP/bpel/userguide/en/modules/gettingStarted.xml 2008-08-21 23:16:05 UTC (rev 1967)
@@ -60,7 +60,7 @@
<row>
<entry>Host</entry>
- <entry>anoncvs.forge.jboss.com</entry>
+ <entry>anoncvs.jboss.org</entry>
</row>
<row>
@@ -158,6 +158,13 @@
<entry/>
</row>
+ <row>
+ <entry>1.5.0</entry>
+ <entry>4.2.3.GA</entry>
+ <entry>default</entry>
+ <entry/>
+ </row>
+
</tbody>
</tgroup>
@@ -264,9 +271,11 @@
<para>Among the properties in <literal>jbpm.hibernate.cfg.xml</literal>, <literal>
hibernate.connection.datasource</literal> is of particular interest. This property
specifies the name of a data source in the JNDI registry. The preset value,
- <literal>java:/DefaultDS</literal>, references a predeployed data source in
- JBoss AS.</para>
-
+ <literal>java:JbpmDS</literal>, references the data source contained in the
+ <literal>jbpm-ds.xml</literal> descriptor, located in the <literal>deploy</literal>
+ directory. The build file there deploys the data source before the jBPM BPEL
+ enterprise app to ensure the <literal>java:JbpmDS</literal> name is bound.</para>
+
</section>
<section id="getstarted.setup.config.jbpm">
@@ -342,7 +351,7 @@
<section id="getstarted.setup.deploy">
- <title>Deployment</title>
+ <title>Application deployment</title>
<para>Before deploying the service, start JBoss in the server configuration of your choice
(see <ulink url="http://tinyurl.com/rjqkb">Server Configurations</ulink>). Afterward,
@@ -383,10 +392,19 @@
</section>
- <section id="getstarted.setup.restart">
+ </section>
- <title>Remarks on server restart</title>
+ <section id="getstarted.server">
+ <title>Application server notes</title>
+
+ <para>The present section documents known features in JBoss which may affect jBPM BPEL
+ deployments.</para>
+
+ <section id="getstarted.server.restart">
+
+ <title>Server restart</title>
+
<para>The predefined deployment order in JBoss AS results in exceptional behavior when
jBPM BPEL application is up and running, one or more process definitions have been
deployed and the server restarts.</para>
@@ -403,15 +421,18 @@
<orderedlist>
- <listitem><para>Locate the <literal>MainDeployer</literal> service under the
- <literal>jboss.system</literal> category in the JMX agent view.</para></listitem>
+ <listitem><para>Locate the <literal>org.jboss.deployment.MainDeployer-xmbean.xml
+ </literal> file under the <literal>conf/xmdesc</literal> directory of your
+ preferred server profile. For the default profile, the location is
+ <literal>jboss-<version>/server/default/conf/xmdesc</literal>.</para>
+ </listitem>
- <listitem><para>Scroll down until you see the <literal>EnhancedSuffixOrder</literal>
- attribute.</para></listitem>
+ <listitem><para>Look for the <literal>EnhancedSuffixOrder</literal> attribute.</para>
+ </listitem>
<listitem>
- <para>In the value text field, insert the <literal>jbpm-bpel.jar</literal> suffix
+ <para>In the value element, insert the <literal>jbpm-bpel.jar</literal> suffix
anywhere you see fit, <emphasis>before</emphasis> the <literal>.war</literal> suffix.
For example,</para>
@@ -419,17 +440,130 @@
</listitem>
- <listitem><para>Apply the changes. The actual suffix order will not change till the next
- restart.</para></listitem>
+ <listitem><para>Save the file. The change will not apply till the next restart.</para>
+ </listitem>
</orderedlist>
-
- <note><para>The above attribute can be set directly in this file as well:</para>
- <para><literal>conf/xmdesc/org.jboss.deployment.MainDeployer-xmbean.xml</literal></para>
- </note>
</section>
+ <section id="getstarted.server.transactions">
+
+ <title>Transaction manager</title>
+
+ <para>From JBoss AS 4.2 onwards, a new transaction manager based on technology
+ acquired from Arjuna replaced the traditional transaction manager. jBPM BPEL relies
+ on the transaction manager to ensure consistent changes to the transactional resources
+ it employs, namely the data source, the EJB timer service and the JMS connection
+ factory.</para>
+
+ <para>While jBPM BPEL works transparently with either transaction manager, it is worth
+ noting that the Arjuna based one is less lenient to non-XA resources. Many databases
+ do not provide XA data sources. Transaction managers are able to deal with at most
+ one local transaction resource, by enlisting it as the last resource. Beyond that,
+ consistency cannot be guaranteed.</para>
+
+ <para>In a pristine JBoss AS 4.2 installation, the EJB timer service is backed by an
+ HSQL data source, which is <emphasis>not</emphasis> XA enabled. If jBPM BPEL is
+ also bound to a local transaction data source, the transaction manager will complain
+ about multiple last resources being enlisted, and mark the transaction for roll back.
+ </para>
+
+ <para>There are quite a few ways out of the above embroilment.</para>
+
+ <orderedlist>
+
+ <listitem><para>Bind jBPM BPEL, the EJB timer service, or both, to an XA data source.
+ </para></listitem>
+
+ <listitem><para>Bind jBPM BPEL and the EJB timer service to the same data source.</para>
+ </listitem>
+
+ <listitem><para>Disable EJB timer persistence.</para></listitem>
+
+ <listitem><para>Configure the new transaction manager to allow multiple last resources.
+ </para></listitem>
+
+ <listitem><para>Revert to the old transaction manager, which allows multiple last
+ resources.</para></listitem>
+
+ </orderedlist>
+
+ <para>Indeed, the first proposal is the only real solution; the rest are workarounds.
+ However, using an XA data source during process development and testing may not be
+ convenient or feasible.</para>
+
+ <para>To change the EJB timer service data source, proceed as follows.</para>
+
+ <orderedlist>
+
+ <listitem><para>Locate file <literal>ejb-deployer.xml</literal> in the
+ <literal>deploy</literal> directory of your server profile.</para></listitem>
+
+ <listitem>
+
+ <para>Look for the
+ <literal>jboss.ejb:service=EJBTimerService,persistencePolicy=database</literal>
+ managed bean.</para>
+
+ <programlisting><![CDATA[<mbean code="org.jboss.ejb.txtimer.DatabasePersistencePolicy"
+name="jboss.ejb:service=EJBTimerService,persistencePolicy=database">
+ <!-- DataSourceBinding ObjectName -->
+ <depends optional-attribute-name="DataSource">
+ jboss.jca:service=DataSourceBinding,name=DefaultDS
+ </depends>
+ <!-- The plugin that handles database persistence -->
+ <attribute name="DatabasePersistencePlugin">
+ org.jboss.ejb.txtimer.GeneralPurposeDatabasePersistencePlugin
+ </attribute>
+ <!-- The timers table name -->
+ <attribute name="TimersTable">TIMERS</attribute>
+</mbean>]]></programlisting>
+
+ </listitem>
+
+ <listitem><para>Set the <literal>DataSource</literal> attribute to the data source
+ of your liking.</para></listitem>
+
+ </orderedlist>
+
+ <para>To disable EJB timer persistence, look for the <literal>
+ jboss.ejb:service=EJBTimerService</literal> bean in <literal>ejb-deployer.xml</literal>.
+ Set the <literal>PersistencePolicy</literal> to <literal>
+ jboss.ejb:service=EJBTimerService,persistencePolicy=noop</literal>.</para>
+
+ <para>The solutions that involve changes in the transaction manager
+ are documented in the <ulink url="http://wiki.jboss.org/wiki/DeployJbpm3.2WebAppUnderJBoss4.2.x">
+ wiki knowledge base</ulink>.</para>
+
+ </section>
+
+ <section>
+
+ <title>Logging</title>
+
+ <para>The Hibernate <ulink
+ url="http://www.hibernate.org/hib_docs/v3/reference/en/html/performance.html#performance-fetching-proxies">
+ user guide</ulink> documents some pitfalls that developers must be aware of while
+ developing polymorphic classes. Hibernate even goes the extra mile and emits a warning
+ the moment a second proxy is acquired for a given persistence object. The next console
+ output corresponds to one such warning.</para>
+
+ <screen>WARN [ProxyWarnLog] Narrowing proxy to class org.jbpm.bpel.graph.def.CompositeActivity&nextLine;
+- this operation breaks ==</screen>
+
+ <para>jBPM's extensive use of polymorphism triggers many of these warnings, despite
+ being legitimate and perfectly safe. If the above warning annoys you, it can be turned
+ off in the log4j configuration file <literal>jboss-log4j.xml</literal>, placed in the
+ <literal>conf</literal> directory of your server profile. Just add the category below.</para>
+
+ <programlisting><![CDATA[<!-- Turn off proxy warnings -->
+<category name="org.hibernate.engine.StatefulPersistenceContext.ProxyWarnLog">
+ <priority value="OFF"/>
+</category>]]></programlisting>
+
+ </section>
+
</section>
-</chapter>
\ No newline at end of file
+</chapter>
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