首先，在发布此问题之前，我已经阅读了与此错误相关的帖子。但是，他们中的大多数都没有使用PostgreSQL，因此可能会以不同的方式处理此错误。这是此错误的堆栈跟踪：
WARN org.hibernate.util.JDBCExceptionReporter - SQL Error: 0, SQLState: 08006
4450102501 [XmlBlaster.socket_ssl.cbWorkerThread] ERROR org.hibernate.util.JDBCExceptionReporter - An I/O error occured while sending to the backend.
java.lang.RuntimeException: org.hibernate.exception.JDBCConnectionException: could not execute query using iterate
at edu.umd.cattlab.vatraffic.listener.output.VaTrafficDbModule.processSingleMessage(VaTrafficDbModule.java:380)
at edu.umd.cattlab.vatraffic.listener.output.VaTrafficDbModule.processMessage(VaTrafficDbModule.java:266)
at edu.umd.cattlab.vatraffic.listener.input.InputModule.sendMessageToOuputModules(InputModule.java:36)
at edu.umd.cattlab.vatraffic.listener.input.XmlBlaster.update(XmlBlaster.java:173)
at org.xmlBlaster.client.XmlBlasterAccess.update(XmlBlasterAccess.java:1043)
at org.xmlBlaster.client.protocol.AbstractCallbackExtended.update(AbstractCallbackExtended.java:111)
at org.xmlBlaster.client.protocol.AbstractCallbackExtended.update(AbstractCallbackExtended.java:199)
at org.xmlBlaster.util.protocol.RequestReplyExecutor.receiveReply(RequestReplyExecutor.java:444)
at org.xmlBlaster.client.protocol.socket.WorkerThread.run(WorkerThread.java:51)
Caused by: org.hibernate.exception.JDBCConnectionException: could not execute query using iterate
at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:74)
at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
at org.hibernate.loader.hql.QueryLoader.iterate(QueryLoader.java:427)
at org.hibernate.hql.ast.QueryTranslatorImpl.iterate(QueryTranslatorImpl.java:380)
at org.hibernate.engine.query.HQLQueryPlan.performIterate(HQLQueryPlan.java:224)
at org.hibernate.impl.SessionImpl.iterate(SessionImpl.java:1192)
at org.hibernate.impl.QueryImpl.iterate(QueryImpl.java:46)
at edu.umd.cattlab.schema.hibernate.cattXML.extensions.VaTraffic.VaTrafficHelper.laneMap(VaTrafficHelper.java:165)
at edu.umd.cattlab.vatraffic.listener.output.VaTrafficDbModule.processIncidentDescription(VaTrafficDbModule.java:396)
at edu.umd.cattlab.vatraffic.listener.output.VaTrafficDbModule.processSingleMessage(VaTrafficDbModule.java:360)
... 8 more
Caused by: org.postgresql.util.PSQLException: An I/O error occured while sending to the backend.
at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:218)
at org.postgresql.jdbc2.AbstractJdbc2Statement.execute(AbstractJdbc2Statement.java:451)
at org.postgresql.jdbc2.AbstractJdbc2Statement.executeWithFlags(AbstractJdbc2Statement.java:350)
at org.postgresql.jdbc2.AbstractJdbc2Statement.executeQuery(AbstractJdbc2Statement.java:254)
at org.hibernate.jdbc.AbstractBatcher.getResultSet(AbstractBatcher.java:186)
at org.hibernate.loader.Loader.getResultSet(Loader.java:1787)
at org.hibernate.loader.hql.QueryLoader.iterate(QueryLoader.java:404)
... 15 more
Caused by: java.net.SocketException: Broken pipe
at java.net.SocketOutputStream.socketWrite0(Native Method)
at java.net.SocketOutputStream.socketWrite(Unknown Source)
at java.net.SocketOutputStream.write(Unknown Source)
at java.io.BufferedOutputStream.flushBuffer(Unknown Source)
at java.io.BufferedOutputStream.write(Unknown Source)
at org.postgresql.core.PGStream.SendChar(PGStream.java:174)
at org.postgresql.core.v3.QueryExecutorImpl.sendBind(QueryExecutorImpl.java:829)
at org.postgresql.core.v3.QueryExecutorImpl.sendOneQuery(QueryExecutorImpl.java:1053)
at org.postgresql.core.v3.QueryExecutorImpl.sendQueryPreamble(QueryExecutorImpl.java:373)
at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:189)
我们的应用程序使用Hibernate，所以这里是Hibernate配置：
<?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>
<!-- Database connection settings -->
<property name="connection.driver_class">org.postgresql.Driver</property>
<property name="connection.url">jdbc:postgresql://cannottell.umd.edu</property>
<property name="connection.username"></property>
<property name="connection.password"></property>
<!-- JDBC connection pool (use the built-in) -->
<property name="connection.pool_size">1</property>
<!-- Enable C3P0 database connection pool -->
<!----> <!--<property name="c3p0.min_size">2</property>
<property name="c3p0.max_size">5</property>
<property name="c3p0.timeout">600</property>
<property name="c3p0.max_statements">0</property>
<property name="hibernate.c3p0.idle_test_period">300</property>
<property name="hibernate.c3p0.acquire_increment">1</property>-->
<!-- SQL dialect -->
<property name="dialect">org.hibernate.dialect.PostgreSQLDialect</property>
<!-- Oracle doesn't handle prepared statement caching very well. This disables prepared statements. -->
<property name="statement_cache.size">0</property>
<!-- Enable Hibernate's automatic session context management -->
<property name="current_session_context_class">thread</property>
<!-- Disable the second-level cache -->
<property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>
<!-- Echo all executed SQL to stdout -->
<property name="show_sql">false</property>
<!-- Drop and re-create the database schema on startup -->
<property name="hbm2ddl.auto">false</property>
<!-- ritis schema mappings -->
<mapping resource="edu/umd/cattlab/schema/hibernate/cattXML/cattXML.hbm.xml"/>
<mapping resource="edu/umd/cattlab/schema/hibernate/cattXML/cattXMLLookup.hbm.xml"/>
<!-- vatraffic schema mappings -->
<mapping resource="edu/umd/cattlab/schema/hibernate/cattXML/extensions/VaTraffic/vaTraffic.hbm.xml"/>
<mapping resource="edu/umd/cattlab/schema/hibernate/cattXML/extensions/VaTraffic/vaTrafficLookup.hbm.xml"/>
</session-factory>
</hibernate-configuration>
这是我的问题：
如果我问了太多问题，我很抱歉。顺便说一句，如果有必要，我很乐意为这个问题添加更多信息。非常感谢大家的回应。谢谢。
ADDED
这是打开和关闭hibernate会话的代码：
Session sess = HibernateUtil.getSessionFactory().openSession();
Transaction tx = null;
String eventId = null;
try {
sess.getTransaction().setTimeout(new Integer(configuration
.getProperty("messageProcessingTimeout")));
if (!sess.isConnected()) {
attemptReconnect();
} else {
log.debug("Database connection open.");
}
//tx = sess.beginTransaction();
//log.debug("After transaction");
eventId = processIncidentDescription(message, sess);
//tx.commit();
// Sending jmsNotify.
if (Boolean.valueOf(configuration.getProperty("sendJmsNotify"))
&& eventId != null) {
log.debug("Sending jmsNotify message " + "<notify id=\""
+ eventId + "\"/>");
jmsSender.sendMessage("<notify id=\"" + eventId + "\"/>");
}
} catch (Exception e) {
try {
if (tx != null)
tx.rollback();
} catch (TransactionException te) {
log.warn("Unable to roll back transaction.");
}
throw new RuntimeException(e);
} finally {
sess.close();
}
ADDED
以下是可能导致错误的代码：
public static HashMap<String,HashMap<String,Object>> laneMap(Session sess){
HashMap<String,HashMap<String,Object>> table = new HashMap<String,HashMap<String,Object>>();
Query query = sess.createQuery("from Direction");
Iterator<Object> iterate = query.iterate();
while (iterate.hasNext()){
Object obj = iterate.next();
Direction direct = (Direction) obj;
if (table.get("direction") == null){
table.put("direction", new HashMap<String,Object>());
}
String directDesc = direct.getDirectionDescription();
table.get("direction").put(directDesc, direct);
}
Query query2 = sess.createQuery("from LaneStatus");
Iterator<Object> iterate2 = query2.iterate();
while (iterate2.hasNext()){
Object obj = iterate2.next();
LaneStatus laneStatus = (LaneStatus) obj;
if (table.get("lane_status") == null){
table.put("lane_status", new HashMap<String,Object>());
}
String directDesc = laneStatus.getLaneStatusDescription();
table.get("lane_status").put(directDesc, laneStatus);
}
Query query3 = sess.createQuery("from LaneType");
Iterator<Object> iterate3 = query3.iterate();
while (iterate3.hasNext()){
Object obj = iterate3.next();
LaneType laneType = (LaneType) obj;
if (table.get("lane_type") == null){
table.put("lane_type", new HashMap<String,Object>());
}
String directDesc = laneType.getLaneTypeDescription();
table.get("lane_type").put(directDesc, laneType);
}
return table;
}
答案 0 :(得分：4)
当您的应用程序无法再连接到Postgres数据库时，会发生此问题。我已经将VPN发送到我的办公室，然后关闭了VPN连接，从而切断了数据库连接。然后我的本地服务器将显示上述内容。如果您的服务器环境中出现此问题，则需要查看是否存在网络连接问题。
答案 1 :(得分：1)
您的应用是否会尝试同时打开与PostgreSQL的更多连接，而不是PG PG实例中允许的最大并发连接数？