SQL-Fehler: 0, SQLState: 08S01 Kommunikationsverbindungsfehler

Ich erhalte diesen Fehler (nicht so häufig):

2013-05-08 16:44:35,786  WARN (JDBCExceptionReporter.Java:100) [org.hibernate.util.JDBCExceptionReporter, logExceptions] - SQL Error: 0, SQLState: 08S01
2013-05-08 16:44:35,786 ERROR (JDBCExceptionReporter.Java:101) [org.hibernate.util.JDBCExceptionReporter, logExceptions] - Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
2013-05-08 16:44:35,833 ERROR (AdminDaoImpl.Java:297) [com.myapp.admin.db.AdminDaoImpl, createFilePackage] - data-upload: Exception while adding new file package
org.hibernate.exception.JDBCConnectionException: Cannot open connection
    at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.Java:97) [hibernate-core-3.3.2.GA.jar:3.3.2.GA]
    at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.Java:66) [hibernate-core-3.3.2.GA.jar:3.3.2.GA]
    at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.Java:52) [hibernate-core-3.3.2.GA.jar:3.3.2.GA]
    at org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.Java:449) [hibernate-core-3.3.2.GA.jar:3.3.2.GA]
    at org.hibernate.jdbc.ConnectionManager.getConnection(ConnectionManager.Java:167) [hibernate-core-3.3.2.GA.jar:3.3.2.GA]
    at org.hibernate.jdbc.JDBCContext.connection(JDBCContext.Java:142) [hibernate-core-3.3.2.GA.jar:3.3.2.GA]
    at org.hibernate.transaction.JDBCTransaction.begin(JDBCTransaction.Java:85) [hibernate-core-3.3.2.GA.jar:3.3.2.GA]
    at org.hibernate.impl.SessionImpl.beginTransaction(SessionImpl.Java:1354) [hibernate-core-3.3.2.GA.jar:3.3.2.GA]
    at com.myapp.admin.db.AdminDaoImpl. createFilePackage(AdminDaoImpl.Java:182) [AdminDaoImpl.class:na]
    at com.myapp.admin.ctrl.UploadController.processUploadZip(UploadController.Java:217) [UploadController.class:na]
    at Sun.reflect.GeneratedMethodAccessor106.invoke(Unknown Source) [na:na]
    at Sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.Java:25) [na:1.6.0_35]
    at Java.lang.reflect.Method.invoke(Method.Java:597) [na:1.6.0_35]
    at org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.Java:212) [spring-web-3.1.0.RELEASE.jar:3.1.0.RELEASE]
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.Java:126) [spring-web-3.1.0.RELEASE.jar:3.1.0.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.Java:96) [spring-webmvc-3.1.0.RELEASE.jar:3.1.0.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.Java:617) [spring-webmvc-3.1.0.RELEASE.jar:3.1.0.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.Java:578) [spring-webmvc-3.1.0.RELEASE.jar:3.1.0.RELEASE]
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.Java:80) [spring-webmvc-3.1.0.RELEASE.jar:3.1.0.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.Java:900) [spring-webmvc-3.1.0.RELEASE.jar:3.1.0.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.Java:827) [spring-webmvc-3.1.0.RELEASE.jar:3.1.0.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.Java:882) [spring-webmvc-3.1.0.RELEASE.jar:3.1.0.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.Java:789) [spring-webmvc-3.1.0.RELEASE.jar:3.1.0.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.Java:647) [servlet-api.jar:na]
    at javax.servlet.http.HttpServlet.service(HttpServlet.Java:728) [servlet-api.jar:na]
    at org.Apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.Java:305) [catalina.jar:7.0.35]
    at org.Apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.Java:210) [catalina.jar:7.0.35]
    at org.Apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.Java:222) [catalina.jar:7.0.35]
    at org.Apache.catalina.core.StandardContextValve.invoke(StandardContextValve.Java:123) [catalina.jar:7.0.35]
    at org.Apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.Java:472) [catalina.jar:7.0.35]
    at org.Apache.catalina.core.StandardHostValve.invoke(StandardHostValve.Java:171) [catalina.jar:7.0.35]
    at org.Apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.Java:99) [catalina.jar:7.0.35]
    at org.Apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.Java:118) [catalina.jar:7.0.35]
    at org.Apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.Java:407) [catalina.jar:7.0.35]
    at org.Apache.coyote.ajp.AjpProcessor.process(AjpProcessor.Java:200) [Tomcat-coyote.jar:7.0.35]
    at org.Apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.Java:589) [Tomcat-coyote.jar:7.0.35]
    at org.Apache.Tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.Java:310) [Tomcat-coyote.jar:7.0.35]
    at Java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.Java:886) [na:1.6.0_35]
    at Java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.Java:908) [na:1.6.0_35]
    at Java.lang.Thread.run(Thread.Java:662) [na:1.6.0_35]
Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

Ich habe zwei Webanwendungen (Spring MVC + Hibernate + MySQL), die auf einem gemeinsam genutzten Server gehostet werden:

1) Haupt-App zum Anzeigen von Dateien zum Herunterladen (die über die Admin-App eingefügt wird)

2) Admin-App mit CRUD-Operationen

Dieser Fehler tritt irgendwann auf, wenn ich die Anwendung "admin" zum Hochladen von Dateien für die "Haupt" -App verwende. Nehmen wir an, nach erfolgreichem Hochladen/Verarbeiten von 100-120 Dateien/Anforderungen und bei jeder Anforderung, die die Datenbank mit 10-20 Einfügung/trifft. Aktualisierungsabfragen.

Hosting-Details:

Private Tomcat hosting
Java 1.6.0_35-b10
Tomcat 7.0.35
heap size 288MB
MySQL Server 5
commons-dbcp 1.2.2
mysql-connector-Java 5.1.9

Database + Hibernate + DBCP-Eigenschaften:

<bean id="dbDataSource" class="org.Apache.commons.dbcp.BasicDataSource">
    <property name="driverClassName" value="com.mysql.jdbc.Driver" />
    <property name="username" value="test" />
    <property name="password" value="test" />
    <property name="url" value="jdbc:mysql://localhost/my_database?useUnicode=yes&characterEncoding=UTF-8" />

    <!-- DBCP Connection Pool Settings -->
    <property name="defaultAutoCommit" value="true" />
    <property name="initialSize" value="10" />
    <property name="maxActive" value="500" />
    <property name="maxIdle" value="8" />
    <property name="minIdle" value="0" />
    <property name="maxWait" value="30000" />
    <property name="validationQuery" value="SELECT 1" />
    <property name="testOnBorrow" value="true" />
    <property name="testOnReturn" value="false" />
    <property name="testWhileIdle" value="false" />
    <property name="timeBetweenEvictionRunsMillis" value="-1" />
    <property name="numTestsPerEvictionRun" value="3" />
    <property name="minEvictableIdleTimeMillis" value="180000" />
    <property name="poolPreparedStatements" value="true" />
    <property name="maxOpenPreparedStatements" value="25" />
    <property name="accessToUnderlyingConnectionAllowed" value="false" />
    <property name="removeAbandoned" value="false" />
    <property name="removeAbandonedTimeout" value="300" />
    <property name="logAbandoned" value="false" />
</bean>

hibernate.dialect=org.hibernate.dialect.MySQLDialect
hibernate.hbm2ddl.auto=none
hibernate.jdbc.batch_size=100
hibernate.show_sql=false
hibernate.format_sql=false
hibernate.cache.use_second_level_cache=true
hibernate.cache.use_query_cache=false
hibernate.cache.provider_class=org.hibernate.cache.NoCacheProvider
hibernate.current_session_context_class=thread

Betroffener Code:

public String createFilePackage(FilePackage package) {
    String message = "";

    Session session = getSessionFactory().openSession();
    Transaction tx = null;
    try {
        tx = session.beginTransaction();

        // handling package, around 10-14 DB insert, 10 SELECT and 5 update queries on same session

        tx.commit();

    } catch(Exception e) {
        logger.error("file-upload: Exception while adding new font package", e);
        if(tx != null) { tx.rollback(); }
    } finally {
        session.close();
    }
    return message;
}

ratschläge, wie Sie dieses Problem lösen können?