已经有太多连接

Question

我正在使用 hibernate 连接到远程 postgres（版本 9.0）数据库。 收到以下错误

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]

我的代码

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

您超出了为 PostgreSQL 服务器配置的最大连接数。

因此，您的服务器配置不正确，导致连接不足，或者您没有正确关闭连接。

如果您绝对确定要关闭连接，我强烈建议您使用连接池来限制并发会话的最大数量。

或者，您可以更改 PostgreSQL 配置并增加允许的连接数。有关详细信息，请参阅手册：

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

Answer 2

您在方法调用中创建一个新的会话工厂，这几乎肯定是一个坏主意 - 会话工厂应该被视为全局共享资源，就像数据源一样。更不用说，创建会话工厂需要相当长的时间。

由于您没有关闭会话工厂，因此在会话工厂本身被 GC 之前，其内部连接池实际上不会被清除。通常，您在应用程序启动/关闭期间创建和关闭会话工厂（例如InitializingBean/DisposableBean、ServletContextEventListener、ServiceMBean）

Answer 3

增加

/var/lib/pgsql/data/postgresql.conf中的

max_connection和shared_buffers更改

max_connections = 100
shared_buffers = 24MB

为

max_connections = 300
shared_buffers = 80MB

并重新启动PostgreSQL数据库。