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Tomcat JDBC Pool: Too many connections

Tags:

java

mysql

servlets

tomcat

I am using Tomcat JDBC pool for MySQL DB connection pool in my web application. The JDBC pool is declared as resource in context.xml of application (not at global level). I am developing this web application in Eclipse IDE. So, whenever I make changes to code, eclipse makes Tomcat server to reload context.

But the problem is, when context gets reloaded, tomcat creates JDBC pool with new connections without releasing old pool. And after few more changes to code, the tomcat eventually exhausts MySQL server maximum connection limit, and tomcat starts displaying "Too many connections" error on context reloads.

My context.xml file is like:

<?xml version="1.0" encoding="UTF-8"?>
<Context>
    <Resource
        name="jdbc/myDB"
        auth="Container"
        type="javax.sql.DataSource"
        factory="org.apache.tomcat.jdbc.pool.DataSourceFactory"
        username="root"
        password="admin"
        driverClassName="com.mysql.jdbc.Driver"
        url="jdbc:mysql://localhost:3306/myDB?allowMultiQueries=true"
        defaultAutoCommit="false"
        initialSize="20"
        maxActive="50"
        maxIdle="30"
        minIdle="15"
        maxWait="5000"
        testOnBorrow="true"
        testWhileIdle="true"
        validationQuery="SELECT 1"
        timeBetweenEvictionRunsMillis="35000"
        minEvictableIdleTimeMillis="55000"
        removeAbandoned="true"
        removeAbandonedTimeout="3600"
        logAbandoned="true"
        validationInterval="35000"
    />
</Context>

My web.xml is like:

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">
  <display-name>MyApp</display-name>

  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>

  <resource-ref>
      <description>MyApp DB Connection</description>
      <res-ref-name>jdbc/myDB</res-ref-name>
      <res-type>javax.sql.DataSource</res-type>
      <res-auth>Container</res-auth>
  </resource-ref>

  <context-param>
    <param-name>data-source-lookup-name</param-name>
    <param-value>java:comp/env/jdbc/myDB</param-value>
  </context-param>

  <listener>
    <listener-class>com.project.listeners.AppListener</listener-class>
  </listener>
</web-app>

App Listener is like:

package com.project.listeners;

import java.sql.Driver;
import java.sql.DriverManager;
import java.util.Enumeration;

import javax.servlet.ServletContext;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;

import org.apache.log4j.Logger;

import com.mysql.jdbc.AbandonedConnectionCleanupThread;

public class AppListener implements ServletContextListener {
    private static Logger logger = Logger.getLogger(AppListener.class);

    @Override
    public void contextInitialized(ServletContextEvent event) {
        logger.info("Application context initialing");

        ServletContext context = event.getServletContext();

        DBObjectNames.dataSourceLookupName = context.getInitParameter("data-source-lookup-name");
        if(DBObjectNames.dataSourceLookupName == null){
            logger.fatal("data-source-lookup-name init parameter not supplied, using default: java:comp/env/jdbc/myDB");
            DBObjectNames.dataSourceLookupName = "java:comp/env/jdbc/myDB";
        }
        DBObjectNames.dataSourceLookupName = DBObjectNames.dataSourceLookupName.trim();
        logger.info("data-source-lookup-name set to: " + DBObjectNames.dataSourceLookupName);

        logger.info("Application context initialed");
    }

    @Override
    public void contextDestroyed(ServletContextEvent event) {
        logger.info("Application context destroying");

        try {
            logger.info("Shutting down AbandonedConnectionCleanupThread");
            AbandonedConnectionCleanupThread.shutdown();
            logger.info("Shut down AbandonedConnectionCleanupThread");
        } catch (Throwable t) {
            logger.fatal("Error while shutting down AbandonedConnectionCleanupThread", t);
        }

        Enumeration<Driver> drivers = DriverManager.getDrivers();
        while (drivers.hasMoreElements()) {
            Driver driver = drivers.nextElement();
            try {
                logger.info("Deregistering driver: " + driver);
                DriverManager.deregisterDriver(driver);
                logger.info("Deregistered driver: " + driver);
            } catch (Throwable t) {
                logger.fatal("Error while deregistering driver: " + driver, t);
            }
        }

        logger.info("Application context destroyed");
    }
}

And I get exceptions like:

Oct 30, 2014 4:16:54 PM org.apache.catalina.core.StandardContext reload
INFO: Reloading Context with name [/myapp] is completed
Oct 30, 2014 4:17:04 PM org.apache.catalina.core.StandardContext reload
INFO: Reloading Context with name [/myapp] has started
2014-10-30 16:17:04,497 [ContainerBackgroundProcessor[StandardEngine[Catalina]]] INFO  com.project.listeners.AppListener  - Application context destroying
2014-10-30 16:17:04,498 [ContainerBackgroundProcessor[StandardEngine[Catalina]]] INFO  com.project.listeners.AppListener  - Shutting down AbandonedConnectionCleanupThread
2014-10-30 16:17:04,498 [ContainerBackgroundProcessor[StandardEngine[Catalina]]] INFO  com.project.listeners.AppListener  - Shut down AbandonedConnectionCleanupThread
2014-10-30 16:17:04,498 [ContainerBackgroundProcessor[StandardEngine[Catalina]]] INFO  com.project.listeners.AppListener  - Application context destroyed
Oct 30, 2014 4:17:04 PM org.apache.jasper.servlet.TldScanner scanJars
INFO: At least one JAR was scanned for TLDs yet contained no TLDs. Enable debug logging for this logger for a complete list of JARs that were scanned but no TLDs were found in them. Skipping unneeded JARs during scanning can improve startup time and JSP compilation time.
2014-10-30 16:17:04,660 [ContainerBackgroundProcessor[StandardEngine[Catalina]]] INFO  com.project.listeners.AppListener  - Application context initialing
2014-10-30 16:17:04,661 [ContainerBackgroundProcessor[StandardEngine[Catalina]]] INFO  com.project.listeners.AppListener  - data-source-lookup-name set to: java:comp/env/jdbc/myDB
2014-10-30 16:17:04,662 [ContainerBackgroundProcessor[StandardEngine[Catalina]]] INFO  com.project.listeners.AppListener  - Application context initialed
Oct 30, 2014 4:17:04 PM org.apache.catalina.core.StandardContext reload
INFO: Reloading Context with name [/myapp] is completed
Oct 30, 2014 4:17:14 PM org.apache.catalina.core.StandardContext reload
INFO: Reloading Context with name [/myapp] has started
2014-10-30 16:17:14,665 [ContainerBackgroundProcessor[StandardEngine[Catalina]]] INFO  com.project.listeners.AppListener  - Application context destroying
2014-10-30 16:17:14,666 [ContainerBackgroundProcessor[StandardEngine[Catalina]]] INFO  com.project.listeners.AppListener  - Shutting down AbandonedConnectionCleanupThread
2014-10-30 16:17:14,666 [ContainerBackgroundProcessor[StandardEngine[Catalina]]] INFO  com.project.listeners.AppListener  - Shut down AbandonedConnectionCleanupThread
2014-10-30 16:17:14,666 [ContainerBackgroundProcessor[StandardEngine[Catalina]]] INFO  com.project.listeners.AppListener  - Application context destroyed
Oct 30, 2014 4:17:14 PM org.apache.tomcat.jdbc.pool.ConnectionPool init
SEVERE: Unable to create initial connections of pool.
com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Data source rejected establishment of connection,  message from server: "Too many connections"
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
    at java.lang.reflect.Constructor.newInstance(Unknown Source)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:377)
    at com.mysql.jdbc.Util.getInstance(Util.java:360)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:956)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:935)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:924)
    at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1037)
    at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2234)
    at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2265)
    at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2064)
    at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:790)
    at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:44)
    at sun.reflect.GeneratedConstructorAccessor12.newInstance(Unknown Source)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
    at java.lang.reflect.Constructor.newInstance(Unknown Source)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:377)
    at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:395)
    at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:325)
    at org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:307)
    at org.apache.tomcat.jdbc.pool.PooledConnection.connect(PooledConnection.java:200)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.createConnection(ConnectionPool.java:699)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.borrowConnection(ConnectionPool.java:633)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.init(ConnectionPool.java:484)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.<init>(ConnectionPool.java:142)
    at org.apache.tomcat.jdbc.pool.DataSourceProxy.pCreatePool(DataSourceProxy.java:115)
    at org.apache.tomcat.jdbc.pool.DataSourceProxy.createPool(DataSourceProxy.java:102)
    at org.apache.tomcat.jdbc.pool.DataSourceFactory.createDataSource(DataSourceFactory.java:553)
    at org.apache.tomcat.jdbc.pool.DataSourceFactory.getObjectInstance(DataSourceFactory.java:241)
    at org.apache.naming.factory.FactoryBase.getObjectInstance(FactoryBase.java:94)
    at javax.naming.spi.NamingManager.getObjectInstance(Unknown Source)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:841)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:152)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:829)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:166)
    at org.apache.catalina.core.NamingContextListener.addResource(NamingContextListener.java:1084)
    at org.apache.catalina.core.NamingContextListener.createNamingContext(NamingContextListener.java:663)
    at org.apache.catalina.core.NamingContextListener.lifecycleEvent(NamingContextListener.java:256)
    at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117)
    at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5120)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.StandardContext.reload(StandardContext.java:3821)
    at org.apache.catalina.loader.WebappLoader.backgroundProcess(WebappLoader.java:292)
    at org.apache.catalina.core.StandardContext.backgroundProcess(StandardContext.java:5576)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1377)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1381)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1381)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1349)
    at java.lang.Thread.run(Unknown Source)

Oct 30, 2014 4:17:14 PM org.apache.tomcat.jdbc.pool.ConnectionPool abandon
WARNING: Connection has been abandoned PooledConnection[com.mysql.jdbc.JDBC4Connection@1090e8d6]:java.lang.Exception
    at org.apache.tomcat.jdbc.pool.ConnectionPool.getThreadDump(ConnectionPool.java:1052)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.createConnection(ConnectionPool.java:704)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.borrowConnection(ConnectionPool.java:633)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.init(ConnectionPool.java:484)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.<init>(ConnectionPool.java:142)
    at org.apache.tomcat.jdbc.pool.DataSourceProxy.pCreatePool(DataSourceProxy.java:115)
    at org.apache.tomcat.jdbc.pool.DataSourceProxy.createPool(DataSourceProxy.java:102)
    at org.apache.tomcat.jdbc.pool.DataSourceFactory.createDataSource(DataSourceFactory.java:553)
    at org.apache.tomcat.jdbc.pool.DataSourceFactory.getObjectInstance(DataSourceFactory.java:241)
    at org.apache.naming.factory.FactoryBase.getObjectInstance(FactoryBase.java:94)
    at javax.naming.spi.NamingManager.getObjectInstance(Unknown Source)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:841)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:152)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:829)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:166)
    at org.apache.catalina.core.NamingContextListener.addResource(NamingContextListener.java:1084)
    at org.apache.catalina.core.NamingContextListener.createNamingContext(NamingContextListener.java:663)
    at org.apache.catalina.core.NamingContextListener.lifecycleEvent(NamingContextListener.java:256)
    at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117)
    at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5120)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.StandardContext.reload(StandardContext.java:3821)
    at org.apache.catalina.loader.WebappLoader.backgroundProcess(WebappLoader.java:292)
    at org.apache.catalina.core.StandardContext.backgroundProcess(StandardContext.java:5576)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1377)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1381)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1381)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1349)
    at java.lang.Thread.run(Unknown Source)

Oct 30, 2014 4:17:14 PM org.apache.tomcat.jdbc.pool.ConnectionPool abandon
WARNING: Connection has been abandoned PooledConnection[com.mysql.jdbc.JDBC4Connection@c572aa4]:java.lang.Exception
    at org.apache.tomcat.jdbc.pool.ConnectionPool.getThreadDump(ConnectionPool.java:1052)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.createConnection(ConnectionPool.java:704)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.borrowConnection(ConnectionPool.java:633)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.init(ConnectionPool.java:484)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.<init>(ConnectionPool.java:142)
    at org.apache.tomcat.jdbc.pool.DataSourceProxy.pCreatePool(DataSourceProxy.java:115)
    at org.apache.tomcat.jdbc.pool.DataSourceProxy.createPool(DataSourceProxy.java:102)
    at org.apache.tomcat.jdbc.pool.DataSourceFactory.createDataSource(DataSourceFactory.java:553)
    at org.apache.tomcat.jdbc.pool.DataSourceFactory.getObjectInstance(DataSourceFactory.java:241)
    at org.apache.naming.factory.FactoryBase.getObjectInstance(FactoryBase.java:94)
    at javax.naming.spi.NamingManager.getObjectInstance(Unknown Source)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:841)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:152)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:829)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:166)
    at org.apache.catalina.core.NamingContextListener.addResource(NamingContextListener.java:1084)
    at org.apache.catalina.core.NamingContextListener.createNamingContext(NamingContextListener.java:663)
    at org.apache.catalina.core.NamingContextListener.lifecycleEvent(NamingContextListener.java:256)
    at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117)
    at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5120)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.StandardContext.reload(StandardContext.java:3821)
    at org.apache.catalina.loader.WebappLoader.backgroundProcess(WebappLoader.java:292)
    at org.apache.catalina.core.StandardContext.backgroundProcess(StandardContext.java:5576)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1377)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1381)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1381)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1349)
    at java.lang.Thread.run(Unknown Source)

Oct 30, 2014 4:17:14 PM org.apache.tomcat.jdbc.pool.ConnectionPool abandon
WARNING: Connection has been abandoned PooledConnection[com.mysql.jdbc.JDBC4Connection@72e8fcdd]:java.lang.Exception
    at org.apache.tomcat.jdbc.pool.ConnectionPool.getThreadDump(ConnectionPool.java:1052)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.createConnection(ConnectionPool.java:704)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.borrowConnection(ConnectionPool.java:633)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.init(ConnectionPool.java:484)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.<init>(ConnectionPool.java:142)
    at org.apache.tomcat.jdbc.pool.DataSourceProxy.pCreatePool(DataSourceProxy.java:115)
    at org.apache.tomcat.jdbc.pool.DataSourceProxy.createPool(DataSourceProxy.java:102)
    at org.apache.tomcat.jdbc.pool.DataSourceFactory.createDataSource(DataSourceFactory.java:553)
    at org.apache.tomcat.jdbc.pool.DataSourceFactory.getObjectInstance(DataSourceFactory.java:241)
    at org.apache.naming.factory.FactoryBase.getObjectInstance(FactoryBase.java:94)
    at javax.naming.spi.NamingManager.getObjectInstance(Unknown Source)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:841)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:152)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:829)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:166)
    at org.apache.catalina.core.NamingContextListener.addResource(NamingContextListener.java:1084)
    at org.apache.catalina.core.NamingContextListener.createNamingContext(NamingContextListener.java:663)
    at org.apache.catalina.core.NamingContextListener.lifecycleEvent(NamingContextListener.java:256)
    at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117)
    at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5120)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.StandardContext.reload(StandardContext.java:3821)
    at org.apache.catalina.loader.WebappLoader.backgroundProcess(WebappLoader.java:292)
    at org.apache.catalina.core.StandardContext.backgroundProcess(StandardContext.java:5576)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1377)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1381)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1381)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1349)
    at java.lang.Thread.run(Unknown Source)

Oct 30, 2014 4:17:14 PM org.apache.naming.NamingContext lookup
WARNING: Unexpected exception resolving reference
com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Data source rejected establishment of connection,  message from server: "Too many connections"
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
    at java.lang.reflect.Constructor.newInstance(Unknown Source)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:377)
    at com.mysql.jdbc.Util.getInstance(Util.java:360)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:956)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:935)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:924)
    at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1037)
    at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2234)
    at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2265)
    at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2064)
    at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:790)
    at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:44)
    at sun.reflect.GeneratedConstructorAccessor12.newInstance(Unknown Source)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
    at java.lang.reflect.Constructor.newInstance(Unknown Source)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:377)
    at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:395)
    at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:325)
    at org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:307)
    at org.apache.tomcat.jdbc.pool.PooledConnection.connect(PooledConnection.java:200)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.createConnection(ConnectionPool.java:699)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.borrowConnection(ConnectionPool.java:633)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.init(ConnectionPool.java:484)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.<init>(ConnectionPool.java:142)
    at org.apache.tomcat.jdbc.pool.DataSourceProxy.pCreatePool(DataSourceProxy.java:115)
    at org.apache.tomcat.jdbc.pool.DataSourceProxy.createPool(DataSourceProxy.java:102)
    at org.apache.tomcat.jdbc.pool.DataSourceFactory.createDataSource(DataSourceFactory.java:553)
    at org.apache.tomcat.jdbc.pool.DataSourceFactory.getObjectInstance(DataSourceFactory.java:241)
    at org.apache.naming.factory.FactoryBase.getObjectInstance(FactoryBase.java:94)
    at javax.naming.spi.NamingManager.getObjectInstance(Unknown Source)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:841)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:152)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:829)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:166)
    at org.apache.catalina.core.NamingContextListener.addResource(NamingContextListener.java:1084)
    at org.apache.catalina.core.NamingContextListener.createNamingContext(NamingContextListener.java:663)
    at org.apache.catalina.core.NamingContextListener.lifecycleEvent(NamingContextListener.java:256)
    at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117)
    at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5120)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.StandardContext.reload(StandardContext.java:3821)
    at org.apache.catalina.loader.WebappLoader.backgroundProcess(WebappLoader.java:292)
    at org.apache.catalina.core.StandardContext.backgroundProcess(StandardContext.java:5576)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1377)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1381)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1381)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1349)
    at java.lang.Thread.run(Unknown Source)

Oct 30, 2014 4:17:14 PM org.apache.catalina.core.NamingContextListener addResource
WARNING: Failed to register in JMX: javax.naming.NamingException: Data source rejected establishment of connection,  message from server: "Too many connections"
Oct 30, 2014 4:17:14 PM org.apache.jasper.servlet.TldScanner scanJars
INFO: At least one JAR was scanned for TLDs yet contained no TLDs. Enable debug logging for this logger for a complete list of JARs that were scanned but no TLDs were found in them. Skipping unneeded JARs during scanning can improve startup time and JSP compilation time.
2014-10-30 16:17:14,788 [ContainerBackgroundProcessor[StandardEngine[Catalina]]] INFO  com.project.listeners.AppListener  - Application context initialing
2014-10-30 16:17:14,789 [ContainerBackgroundProcessor[StandardEngine[Catalina]]] INFO  com.project.listeners.AppListener  - data-source-lookup-name set to: java:comp/env/jdbc/myDB
2014-10-30 16:17:14,791 [ContainerBackgroundProcessor[StandardEngine[Catalina]]] INFO  com.project.listeners.AppListener  - Application context initialed
Oct 30, 2014 4:17:14 PM org.apache.catalina.core.StandardContext reload
INFO: Reloading Context with name [/myapp] is completed

More information:

These happens without testing application, that is, I am not executing web application to open connections, still just writing code, so there wont be any matter of opening connection and keeping it alive without closing it.

Using Apache Tomcat: Version 8.0. and Eclipse Luna Release.

Please help me on this.

EDIT

Every time context is getting reloaded, I see more 15 opened connections to DB in MySQL Workbench before hitting maximum connection limit of 151 connections to MySQL server.

like image 419
nullptr Avatar asked Dec 04 '22 05:12

nullptr

2 Answers

I think you have to add closeMethod="close" to your Resource in context.xml. Then Tomcat should close your DB connections when you reload context.

Modified context.xml:

<?xml version="1.0" encoding="UTF-8"?>
 <Context>
    <Resource
        name="jdbc/myDB"
        auth="Container"
        type="javax.sql.DataSource"
        factory="org.apache.tomcat.jdbc.pool.DataSourceFactory"
        username="root"
        password="admin"
        driverClassName="com.mysql.jdbc.Driver"
        url="jdbc:mysql://localhost:3306/myDB?allowMultiQueries=true"
        defaultAutoCommit="false"
        initialSize="20"
        maxActive="50"
        maxIdle="30"
        minIdle="15"
        maxWait="5000"
        testOnBorrow="true"
        testWhileIdle="true"
        validationQuery="SELECT 1"
        timeBetweenEvictionRunsMillis="35000"
        minEvictableIdleTimeMillis="55000"
        removeAbandoned="true"
        removeAbandonedTimeout="3600"
        logAbandoned="true"
        validationInterval="35000"
        closeMethod="close"
    />
</Context>
like image 81
jakub.petr Avatar answered Dec 06 '22 18:12

jakub.petr

Remove factory="org.apache.tomcat.jdbc.pool.DataSourceFactory"

Within the most recent upgrade to apache-tomcat-8.0.28, "factory=..." was added to the DataSource Configuration, then connection sessions to oracle database went crazy. After taking it out, the connection sessions went to the noraml status. I have tried to understand the reason, but I couldn't. This comment might be helpful to someone else.

The following is the datasource config from Apache TomEE http://tomee.apache.org/datasource-config.html. It should be a good reference for anyone who is looking for a solution.

<Resource id="myDataSource" type="javax.sql.DataSource">
    accessToUnderlyingConnectionAllowed = false
    alternateUsernameAllowed = false
    connectionProperties = 
    defaultAutoCommit = true
    defaultReadOnly = 
    definition = 
    ignoreDefaultValues = false
    initialSize = 0
    jdbcDriver = org.hsqldb.jdbcDriver
    jdbcUrl = jdbc:hsqldb:mem:hsqldb
    jtaManaged = true
    maxActive = 20
    maxIdle = 20
    maxOpenPreparedStatements = 0
    maxWaitTime = -1 millisecond
    minEvictableIdleTime = 30 minutes
    minIdle = 0
    numTestsPerEvictionRun = 3
    password = 
    passwordCipher = PlainText
    poolPreparedStatements = false
    serviceId = 
    testOnBorrow = true
    testOnReturn = false
    testWhileIdle = false
    timeBetweenEvictionRuns = -1 millisecond
    userName = sa
    validationQuery = 
</Resource>
like image 44
caot Avatar answered Dec 06 '22 17:12

caot
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