Hi.

I want to know what are the min. and max. no. of JDBC connections required by Hibernate session. I want configure it for my application.

Regards,
Rakesh S

For one Hibernate session you need one Connection.

HTH
Ernst

are you talking about pool size? this depends on business requirements ;)

Hi Ernst and Dennis. Thanks for your replies. But this doesnt solve my problem.

I have tried out with foll. settings in my application :

I use JBoss as my application server, Teradata as the database and my datasource file looks like this:

<datasources>
<local-tx-datasource>
<jndi-name>CrmDS</jndi-name>
<connection-url>jdbc:teradata://10.77.198.6/DATABASE=tcrm6_st2plus_nov10,TMODE=TERA,LOB_SUPPORT=OFF</connection-url>
<driver-class>com.ncr.teradata.TeraDriver</driver-class>
<user-name>tcrm6_st2plus_nov10</user-name>
<password>tcrm6</password>
<min-pool-size>1</min-pool-size>
<max-pool-size>5</max-pool-size>
<idle-timeout-minutes>5</idle-timeout-minutes>
</local-tx-datasource>
</datasources>

I get the foll. errors:

2005-11-24 10:42:59,415 ERROR [net.sf.hibernate.util.JDBCExceptionReporter] Cannot open connection
org.jboss.util.NestedSQLException: No ManagedConnections available within configured blocking timeout ( 5000 [ms] ); - nested throwable: (javax.resource.ResourceException: No ManagedConnections available within configured blocking timeout ( 5000 [ms] ))
at org.jboss.resource.adapter.jdbc.WrapperDataSource.getConnection(WrapperDataSource.java:106)
at net.sf.hibernate.connection.DatasourceConnectionProvider.getConnection(DatasourceConnectionProvider.java:59)
at net.sf.hibernate.impl.BatcherImpl.openConnection(BatcherImpl.java:278)
at net.sf.hibernate.impl.SessionImpl.connect(SessionImpl.java:3297)
at net.sf.hibernate.impl.SessionImpl.connection(SessionImpl.java:3277)
at com.teradata.tap.system.persistence.hibernate.MacroSequenceGenerator.genId(MacroSequenceGenerator.java:118)
at com.teradata.tap.system.persistence.hibernate.MacroSequenceGenerator.genIdForEJB(MacroSequenceGenerator.java:99)
at com.teradata.tap.system.persistence.hibernate.ejb.SequenceGeneratorBean.next(SequenceGeneratorBean.java:100)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:324)
at org.jboss.ejb.StatelessSessionContainer$ContainerInterceptor.invoke(StatelessSessionContainer.java:683)
at org.jboss.resource.connectionmanager.CachedConnectionInterceptor.invoke(CachedConnectionInterceptor.java:185)
at org.jboss.ejb.plugins.AbstractTxInterceptor.invokeNext(AbstractTxInterceptor.java:84)
at org.jboss.ejb.plugins.AbstractTxInterceptorBMT.invokeNext(AbstractTxInterceptorBMT.java:144)
at org.jboss.ejb.plugins.TxInterceptorBMT.invoke(TxInterceptorBMT.java:62)
at org.jboss.ejb.plugins.StatelessSessionInstanceInterceptor.invoke(StatelessSessionInstanceInterceptor.java:72)
at org.jboss.ejb.plugins.SecurityInterceptor.invoke(SecurityInterceptor.java:118)
at org.jboss.ejb.plugins.LogInterceptor.invoke(LogInterceptor.java:191)
at org.jboss.ejb.plugins.ProxyFactoryFinderInterceptor.invoke(ProxyFactoryFinderInterceptor.java:122)
at org.jboss.ejb.StatelessSessionContainer.internalInvoke(StatelessSessionContainer.java:331)
at org.jboss.ejb.Container.invoke(Container.java:700)
at org.jboss.ejb.plugins.local.BaseLocalProxyFactory.invoke(BaseLocalProxyFactory.java:375)
at org.jboss.ejb.plugins.local.StatelessSessionProxy.invoke(StatelessSessionProxy.java:83)
at $Proxy227.next(Unknown Source)



However when the min-pool-size is 2 and max-pool-size is 20 my application runs absolutely fine.


Does JBoss or Teradata database has anything to do with this??

Regards,
Rakesh S

It depends on your concurrency level. You have no concurrent operations then you need one connection. Otherwise, you will require more, that figure depends on the usage profile of the application.