已经连接太多了

Question

I am connecting to a remote postgres(version 9.0) database using hibernate. i get following error

2011-03-08 06:48:25,695 ERROR [org.hibernate.util.JDBCExceptionReporter] (http-69.89.2.245-8080-9) FATAL: sorry, too many clients already
2011-03-08 06:48:25,695 ERROR [org.apache.catalina.core.ContainerBase.[jboss.web].[localhost].[/JBOSSINI].[com.java.misc.feedback]] (http-69.89.2.245-8080-9) Servlet.service() for servlet com.java.misc.feedback threw exception: java.lang.NullPointerException
    at com.java.model.HiberEx.InsertsimpleReport(HiberEx.java:95) [:]
    at com.java.misc.feedback.doGet(feedback.java:87) [:]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:734) [:1.0.0.Final]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:847) [:1.0.0.Final]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:324) [:6.0.0.Final]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:242) [:6.0.0.Final]
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:275) [:6.0.0.Final]
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191) [:6.0.0.Final]
    at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:181) [:6.0.0.Final]
    at org.jboss.modcluster.catalina.CatalinaContext$RequestListenerValve.event(CatalinaContext.java:285) [:1.1.0.Final]
    at org.jboss.modcluster.catalina.CatalinaContext$RequestListenerValve.invoke(CatalinaContext.java:261) [:1.1.0.Final]
    at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:88) [:6.0.0.Final]
    at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.invoke(SecurityContextEstablishmentValve.java:100) [:6.0.0.Final]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127) [:6.0.0.Final]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) [:6.0.0.Final]
    at org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:158) [:6.0.0.Final]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) [:6.0.0.Final]
    at org.jboss.web.tomcat.service.request.ActiveRequestResponseCacheValve.invoke(ActiveRequestResponseCacheValve.java:53) [:6.0.0.Final]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:362) [:6.0.0.Final]
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:877) [:6.0.0.Final]
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:654) [:6.0.0.Final]
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:951) [:6.0.0.Final]
    at java.lang.Thread.run(Thread.java:619) [:1.6.0_21]

this my code

public void InsertfailReport(String destination, 
                String source,
                String status,
                String timedate, String smsc,
                String failreason,
                String smsid,
                String message){
                SessionFactory sessionFactory = new Configuration().configure("com/java/hibernate.cfg.xml").buildSessionFactory();
                Session session = sessionFactory.openSession();
                Transaction transaction = null;

                try {
                    transaction = session.beginTransaction();
                    Failreport sobj=new Failreport();
                    sobj.setDestination(destination);
                    sobj.setFailreason(failreason);
                    sobj.setMessage(message);
                    sobj.setSmsc(smsc);
                    sobj.setSmsid(smsid);
                    sobj.setSource(source);
                    sobj.setStatus(status);
                    sobj.setTimedate(timedate);
                    session.save(sobj);
                    transaction.commit();
                } catch (HibernateException e) {
                    transaction.rollback();
                    e.printStackTrace();
                } finally {
                    session.close();
                }
        }

Hibernate.cfg.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
        "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
        "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
    <session-factory name="MyFactory">
        <property name="hibernate.connection.driver_class">org.postgresql.Driver</property>
        <property name="hibernate.connection.password">xxxx</property>
        <property name="hibernate.connection.url">jdbc:postgresql://xx.xx.xx.xx:5432/smslog</property>
        <property name="hibernate.connection.username">xxxxx</property>
        <property name="hibernate.dialect">org.hibernate.dialect.PostgreSQLDialect</property>
        <property name="hibernate.validator.apply_to_ddl">false</property>
        <property name="hibernate.validator.autoregister_listeners">false</property>
        <property name="hibernate.show_sql">true</property>
        <property name="hibernate.jdbc.batch_size">0</property>
          <mapping resource="com/java/model/Kannel.hbm.xml"/>
          <mapping resource="com/java/model/Smsc.hbm.xml"/>
          <mapping resource="com/java/model/Dlr.hbm.xml"/>
          <mapping resource="com/java/model/Routesmsc.hbm.xml"/>
          <mapping resource="com/java/model/Simplereport.hbm.xml"/>
          <mapping resource="com/java/model/Failreport.hbm.xml"/>
    </session-factory>
</hibernate-configuration>

Answer 1

You are exceeding the number of maximum connections configured for your PostgreSQL server.

So you either have your server configured incorrectly to allow not enough connections or you are not closing your connections properly.

If you are absolutely sure you are closing your connections, I would strongly suggest you use a connection pool to limit the maximum number of concurrent sessions.

Alternatively you can change the PostgreSQL configuration and increase the number of allowed connections. See the manual for details:

http://www.postgresql.org/docs/current/static/runtime-config-connection.html#RUNTIME-CONFIG-CONNECTION-SETTINGS

Answer 2

You're creating a new session factory inside the method call which is almost definitely a bad idea- session factories should be considered global shared resources, just like datasources. Not to mention, creating a session factory takes considerable time.

Since you're not closing the session factory, its internal connection pool won't actually be cleared until the session factory itself is GC'd. Typically you create and close session factories during application startup/shutdown (eg InitializingBean/DisposableBean, ServletContextEventListener, ServiceMBean)

Answer 3

Increase max_connection and shared_buffers

in /var/lib/pgsql/data/postgresql.conf

change

max_connections = 100
shared_buffers = 24MB

to

max_connections = 300
shared_buffers = 80MB

and restart PostgreSQL database.