Hi

I am new to Hibernate. Can anybody tell me , which is the best connection pool for production use with Hibernate 3.1.3. And how can I configure it? What are the entries required in hibernate.cfg.xml file?

Thanks and Regards
Albin Joseph
http://www.javacertificate.net

This depends on your deployment model. Also is subjective. Anyway;

Application server: The best is to use the application server's connection pool/data resource(s).

Non-application server: I use C3P0. Configuring is easy and samples are in the documentation and on C3P0 web site.

Hibernate supports the following connection pool:
for production - C3PO, Apache DBCP and Proxol
for trivial testing - there is default pooling mechanism
[C3PO, Proxol are recommended]

You must test it out to see which connection pool suits you best.
For example, if you use C3P0, then you can mention it in the hibernate.properties as:

hibernate.c3p0.property=value

There are several properties:for example
hibernate.c3p0.min_size=5

refer Hibernate API doc and C3P0 doc for details

As of Hibernate 3, Hibernate doesn't officially support Apache DBCP anymore.

Ref: http://forum.hibernate.org/viewtopic.php?t=942293&highlight=apache+dbcp

[edit]I thought there was a post from gavin or one of the other team members that was stickied for a while explaining this, but I can't find it for the life of me.

Thanks for that update

I am using Tomcat as my container. But I don't want to use tomcat's connection pooling mechanism.

Thanks to all.

I have configured c3po in my application. But now I am getting an exception. Below is the stack trace of my application.

java.lang.NoClassDefFoundError: com/mchange/v2/c3p0/PoolConfig
at org.hibernate.connection.C3P0ConnectionProvider.configure(C3P0ConnectionProvider.java:84)
at org.hibernate.connection.ConnectionProviderFactory.newConnectionProvider(ConnectionProviderFactory.java:124)
at org.hibernate.connection.ConnectionProviderFactory.newConnectionProvider(ConnectionProviderFactory.java:56)
at org.hibernate.cfg.SettingsFactory.createConnectionProvider(SettingsFactory.java:366)
at org.hibernate.cfg.SettingsFactory.buildSettings(SettingsFactory.java:60)
at org.hibernate.cfg.Configuration.buildSettings(Configuration.java:1881)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1174)
at com.javacertificate.data.table.Exam.findByPrimaryKey(Unknown Source)
at com.ibm._jsp._exam._jspService(_exam.java:74)
at com.ibm.ws.jsp.runtime.HttpJspBase.service(HttpJspBase.java:88)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java:1212)
at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:629)
at com.ibm.wsspi.webcontainer.servlet.GenericServletWrapper.handleRequest(GenericServletWrapper.java:117)
at com.ibm.ws.jsp.webcontainerext.JSPExtensionServletWrapper.handleRequest(JSPExtensionServletWrapper.java:171)
at com.ibm.ws.webcontainer.webapp.WebApp.handleRequest(WebApp.java:2837)
at com.ibm.ws.webcontainer.webapp.WebGroup.handleRequest(WebGroup.java:220)
at com.ibm.ws.webcontainer.VirtualHost.handleRequest(VirtualHost.java:204)
at com.ibm.ws.webcontainer.WebContainer.handleRequest(WebContainer.java:1681)
at com.ibm.ws.webcontainer.channel.WCChannelLink.ready(WCChannelLink.java:77)
at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.handleDiscrimination(HttpInboundLink.java:421)
at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.handleNewInformation(HttpInboundLink.java:367)
at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.ready(HttpInboundLink.java:276)
at com.ibm.ws.tcp.channel.impl.NewConnectionInitialReadCallback.sendToDiscriminaters(NewConnectionInitialReadCallback.java:201)
at com.ibm.ws.tcp.channel.impl.NewConnectionInitialReadCallback.complete(NewConnectionInitialReadCallback.java:103)
at com.ibm.ws.tcp.channel.impl.WorkQueueManager.requestComplete(WorkQueueManager.java:548)
at com.ibm.ws.tcp.channel.impl.WorkQueueManager.attemptIO(WorkQueueManager.java(Compiled Code))
at com.ibm.ws.tcp.channel.impl.WorkQueueManager.workerRun(WorkQueueManager.java:934)
at com.ibm.ws.tcp.channel.impl.WorkQueueManager$Worker.run(WorkQueueManager.java:1021)
at com.ibm.ws.util.ThreadPool$Worker.run(ThreadPool.java:1332)


Below is my c3p0.properties file.

c3p0.acquireIncrement = 2
c3p0.acquireRetryAttempts = 25
c3p0.acquireRetryDelay = 1000
c3p0.autoCommitOnClose = false
c3p0.automaticTestTable
c3p0.breakAfterAcquireFailure
c3p0.checkoutTimeout = 0
c3p0.connectionTesterClassName
c3p0.factoryClassLocation
c3p0.forceIgnoreUnresolvedTransactions
c3p0.idleConnectionTestPeriod
c3p0.initialPoolSize =
c3p0.maxIdleTime
c3p0.maxStatementsPerConnection
c3p0.numHelperThreads
c3p0.preferredTestQuery
c3p0.propertyCycle
c3p0.testConnectionOnCheckin
c3p0.testConnectionOnCheckout
c3p0.usesTraditionalReflectiveProxies



Below is my hibernate.cfg.xml file

<property name="hibernate.connection.provider_class">org.hibernate.connection.C3P0ConnectionProvider</property>
<property name="hibernate.c3p0.acquire_increment">2</property>
<property name="hibernate.c3p0.idle_test_period">100</property>
<property name="hibernate.c3p0.max_size">100</property>
<property name="hibernate.c3p0.max_statements">0</property>
<property name="hibernate.c3p0.min_size">10</property>
<property name="hibernate.c3p0.timeout">100</property>

What is the solution for this problem.

"NoClassDefFoundError" should be a class-path problem.....so whether all necessary jar files are there in the classpath has to be checked if you use IDE(from project properties) or "CLASSPATH" variable, if you use console(windows/unix)

If I am removing the c3po.properties from my classpath, The code is working fine. So all the required jar files are present in the classpath. I guess there is something wrong with the properties file.

I am not sure about the c3p0.properties file....why are you using it when the properties are mentioned in the .cfg file itself....this redunduncy may perhaps is confusing the Hibernate Loader mechanism