MySQLNonTransientConnectionException: बहुत सारे कनेक्शन

Question

साइट पर नेविगेट करते समय मेरा स्प्रिंग-एमवीसी एप्लिकेशन कभी-कभी दुर्घटनाग्रस्त हो जाता है, लॉग से प्राप्त त्रुटि संदेश नीचे पाए जाते हैं। मुझे इस बात का कोई अंदाजा नहीं है कि इसका क्या कारण है और मुझे किसी भी सुझाव के लिए बहुत आभारी होंगे जो मुझे सही दिशा में ले जाएगा।

SEVERE: Servlet.service() for servlet HS threw exception 
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(NativeConstructorAccessorImpl.java:57) 
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) 
    at java.lang.reflect.Constructor.newInstance(Constructor.java:532) 
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:407) 
    at com.mysql.jdbc.Util.getInstance(Util.java:382) 
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1013) 
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:987) 
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:982) 
    at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1116) 
    at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2338) 
    at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2371) 
    at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2163) 
    at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:794) 
    at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47) 
    at sun.reflect.GeneratedConstructorAccessor56.newInstance(Unknown Source) 
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) 
    at java.lang.reflect.Constructor.newInstance(Constructor.java:532) 
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:407) 
    at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:378) 
    at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:305) 
    at org.apache.commons.dbcp.DriverConnectionFactory.createConnection(DriverConnectionFactory.java:38) 
    at org.apache.commons.dbcp.PoolableConnectionFactory.makeObject(PoolableConnectionFactory.java:582) 
    at org.apache.commons.dbcp.BasicDataSource.validateConnectionFactory(BasicDataSource.java:1556) 
    at org.apache.commons.dbcp.BasicDataSource.createPoolableConnectionFactory(BasicDataSource.java:1545) 
    at org.apache.commons.dbcp.BasicDataSource.createDataSource(BasicDataSource.java:1388) 
    at org.apache.commons.dbcp.BasicDataSource.getConnection(BasicDataSource.java:1044) 
    at org.springframework.orm.hibernate3.LocalDataSourceConnectionProvider.getConnection(LocalDataSourceConnectionProvider.java:81) 
    at org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.java:446) 
    at org.hibernate.jdbc.ConnectionManager.getConnection(ConnectionManager.java:167) 
    at org.hibernate.jdbc.AbstractBatcher.prepareQueryStatement(AbstractBatcher.java:161) 
    at org.hibernate.loader.Loader.prepareQueryStatement(Loader.java:1577) 
    at org.hibernate.loader.Loader.doQuery(Loader.java:696) 
    at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:259) 
    at org.hibernate.loader.Loader.doList(Loader.java:2232) 
    at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2129) 
    at org.hibernate.loader.Loader.list(Loader.java:2124) 
    at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:401) 
    at org.hibernate.hql.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:363) 
    at org.hibernate.engine.query.HQLQueryPlan.performList(HQLQueryPlan.java:196) 
    at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1149) 
    at org.hibernate.impl.QueryImpl.list(QueryImpl.java:102) 
    at org.springframework.orm.hibernate3.HibernateTemplate$30.doInHibernate(HibernateTemplate.java:921) 
    at org.springframework.orm.hibernate3.HibernateTemplate$30.doInHibernate(HibernateTemplate.java:1) 
    at org.springframework.orm.hibernate3.HibernateTemplate.doExecute(HibernateTemplate.java:406) 
    at org.springframework.orm.hibernate3.HibernateTemplate.executeWithNativeSession(HibernateTemplate.java:374) 
    at org.springframework.orm.hibernate3.HibernateTemplate.find(HibernateTemplate.java:912) 
    at org.springframework.orm.hibernate3.HibernateTemplate.find(HibernateTemplate.java:904) 
    at se.hs.daos.UserDAOImpl.findByName(UserDAOImpl.java:42) 
    at se.hs.controllers.LoginController.checkPassword(LoginController.java:20) 
    at se.hs.pagecontrollers.LoginPageController.submitForm(LoginPageController.java:26) 
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
    at java.lang.reflect.Method.invoke(Method.java:616) 
    at org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:176) 
    at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:426) 
    at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:414) 
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:790) 
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:719) 
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:644) 
    at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:560) 
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:637) 
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717) 
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290) 
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) 
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233) 
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191) 
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127) 
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) 
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) 
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298) 
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:859) 
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588) 
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489) 
    at java.lang.Thread.run(Thread.java:636) 

मेरी UserDaoImpl क्या लगता है:

package se.hs.daos; 

import java.util.List; 

import org.hibernate.SessionFactory; 
import org.springframework.context.ApplicationContext; 
import org.springframework.context.support.ClassPathXmlApplicationContext; 
import org.springframework.orm.hibernate3.HibernateTemplate; 
import org.springframework.orm.hibernate3.support.HibernateDaoSupport; 

import se.hs.models.User; 

public class UserDAOImpl extends HibernateDaoSupport implements UserDAO { 

    private ApplicationContext context = new ClassPathXmlApplicationContext(
      "classpath*:applicationContext.xml"); 
    private SessionFactory sessionFactory = (SessionFactory) context 
      .getBean("mySessionFactory"); 
    private HibernateTemplate hibernateTemplate = new HibernateTemplate(
      sessionFactory, true); 

    public void saveUser(User user) { 
     hibernateTemplate.save(user); 
    } 

    public User getUserById(Integer id) { 

     User userFromDB = hibernateTemplate.get(User.class, id); 
     return userFromDB; 
    } 

    public void removeUser(User user) { 
     hibernateTemplate.delete(user); 
    } 

    public User findByName(String name) { 

     String query = "SELECT u.userId FROM User u WHERE u.userName='" + name 
       + "'"; 

     @SuppressWarnings("unchecked") 
     List<Integer> list = hibernateTemplate.find(query); 

     User userFromDB = null; 

     if (list.size() > 0) { 
      userFromDB = getUserById(list.get(0)); 
     } 

     return userFromDB; 
    } 

} 

अद्यतन:

exception 

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is org.springframework.jdbc.UncategorizedSQLException: Hibernate operation: Cannot release connection; uncategorized SQLException for SQL [???]; SQL state [null]; error code [0]; Already closed.; nested exception is java.sql.SQLException: Already closed. 
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:656) 
    org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:560) 
    javax.servlet.http.HttpServlet.service(HttpServlet.java:637) 
    javax.servlet.http.HttpServlet.service(HttpServlet.java:717) 
root cause 

org.springframework.jdbc.UncategorizedSQLException: Hibernate operation: Cannot release connection; uncategorized SQLException for SQL [???]; SQL state [null]; error code [0]; Already closed.; nested exception is java.sql.SQLException: Already closed. 
    org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:83) 
    org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:80) 
    org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:80) 
    org.springframework.orm.hibernate3.HibernateAccessor.convertJdbcAccessException(HibernateAccessor.java:424) 
    org.springframework.orm.hibernate3.HibernateAccessor.convertHibernateAccessException(HibernateAccessor.java:410) 
    org.springframework.orm.hibernate3.HibernateTemplate.doExecute(HibernateTemplate.java:411) 
    org.springframework.orm.hibernate3.HibernateTemplate.executeWithNativeSession(HibernateTemplate.java:374) 
    org.springframework.orm.hibernate3.HibernateTemplate.save(HibernateTemplate.java:683) 
    se.hsr.daos.InfoTextDAOImpl.saveInfoText(InfoTextDAOImpl.java:26) 
    se.hsr.controllers.InfoTextController.saveInfoText(InfoTextController.java:31) 
    se.hsr.pagecontrollers.InfoTextPageController.submitForm(InfoTextPageController.java:35) 
    sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
    sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) 
    sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
    java.lang.reflect.Method.invoke(Method.java:616) 
    org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:176) 
    org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:426) 
    org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:414) 
    org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:790) 
    org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:719) 
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:644) 
    org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:560) 
    javax.servlet.http.HttpServlet.service(HttpServlet.java:637) 
    javax.servlet.http.HttpServlet.service(HttpServlet.java:717) 
root cause 

java.sql.SQLException: Already closed. 
    org.apache.commons.dbcp.PoolableConnection.close(PoolableConnection.java:114) 
    org.apache.commons.dbcp.PoolingDataSource$PoolGuardConnectionWrapper.close(PoolingDataSource.java:191) 
    org.springframework.orm.hibernate3.LocalDataSourceConnectionProvider.closeConnection(LocalDataSourceConnectionProvider.java:95) 
    org.hibernate.jdbc.ConnectionManager.closeConnection(ConnectionManager.java:474) 
    org.hibernate.jdbc.ConnectionManager.aggressiveRelease(ConnectionManager.java:429) 
    org.hibernate.jdbc.ConnectionManager.afterStatement(ConnectionManager.java:304) 
    org.hibernate.jdbc.AbstractBatcher.closePreparedStatement(AbstractBatcher.java:572) 
    org.hibernate.jdbc.AbstractBatcher.closeStatement(AbstractBatcher.java:291) 
    org.hibernate.id.insert.AbstractReturningDelegate.releaseStatement(AbstractReturningDelegate.java:82) 
    org.hibernate.id.insert.AbstractReturningDelegate.performInsert(AbstractReturningDelegate.java:60) 
    org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2176) 
    org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2656) 
    org.hibernate.action.EntityIdentityInsertAction.execute(EntityIdentityInsertAction.java:71) 
    org.hibernate.engine.ActionQueue.execute(ActionQueue.java:279) 
    org.hibernate.event.def.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:321) 
    org.hibernate.event.def.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:204) 
    org.hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:130) 
    org.hibernate.event.def.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:210) 
    org.hibernate.event.def.DefaultSaveEventListener.saveWithGeneratedOrRequestedId(DefaultSaveEventListener.java:56) 
    org.hibernate.event.def.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:195) 
    org.hibernate.event.def.DefaultSaveEventListener.performSaveOrUpdate(DefaultSaveEventListener.java:50) 
    org.hibernate.event.def.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:93) 
    org.hibernate.impl.SessionImpl.fireSave(SessionImpl.java:563) 
    org.hibernate.impl.SessionImpl.save(SessionImpl.java:551) 
    org.hibernate.impl.SessionImpl.save(SessionImpl.java:547) 
    org.springframework.orm.hibernate3.HibernateTemplate$12.doInHibernate(HibernateTemplate.java:686) 
    org.springframework.orm.hibernate3.HibernateTemplate$12.doInHibernate(HibernateTemplate.java:1) 
    org.springframework.orm.hibernate3.HibernateTemplate.doExecute(HibernateTemplate.java:406) 
    org.springframework.orm.hibernate3.HibernateTemplate.executeWithNativeSession(HibernateTemplate.java:374) 
    org.springframework.orm.hibernate3.HibernateTemplate.save(HibernateTemplate.java:683) 
    se.hsr.daos.InfoTextDAOImpl.saveInfoText(InfoTextDAOImpl.java:26) 
    se.hsr.controllers.InfoTextController.saveInfoText(InfoTextController.java:31) 
    se.hsr.pagecontrollers.InfoTextPageController.submitForm(InfoTextPageController.java:35) 
    sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
    sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) 
    sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
    java.lang.reflect.Method.invoke(Method.java:616) 
    org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:176) 
    org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:426) 
    org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:414) 
    org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:790) 
    org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:719) 
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:644) 
    org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:560) 
    javax.servlet.http.HttpServlet.service(HttpServlet.java:637) 
    javax.servlet.http.HttpServlet.service(HttpServlet.java:717) 

Answer 1

इसका मतलब है कि डीबी एसक्यूएल सर्वर कनेक्शन से बाहर चल रहा है। सर्वर में एक कॉन्फ़िगरेशन पैरामीटर है जो निर्दिष्ट करता है कि अधिकतम स्वीकार्य कनेक्शन कैसे हैं।

यह आमतौर पर इंगित करता है कि कनेक्शन बंद नहीं किए जा रहे हैं। क्या आप कनेक्शन कोड को अपने कोड में हाइबरनेट से अनुरोध कर रहे हैं?

अल्प अवधि में, आप इस समस्या को ठीक होने तक अधिकतम कनेक्शन बढ़ा सकते हैं।

Answer 2

यदि आप कनेक्शन की संख्या बढ़ाते हैं तो इसे ठीक कर सकते हैं लेकिन भविष्य में यह वही अपवाद होने की संभावना है।

सुनिश्चित करें कि आपने अपने डेटाबेस कॉन्फ़िगरेशन xml फ़ाइल में <property name="maxIdle" value="1" /> परिभाषित किया है। इसके अलावा मुझे यह समस्या भी थी जब मैंने <property name="maxIdle" value="1" /> को परिभाषित किया, यह मेरी समस्या को ठीक करता था।

<bean id="myDataSource" class="org.apache.commons.dbcp.BasicDataSource" 
     destroy-method="close"> 
     <property name="driverClassName" value="com.mysql.jdbc.Driver" /> 
     <property name="url" value="jdbc:mysql://localhost/crm" /> 
     <property name="username" value="root" /> 
     <property name="password" value="root" /> 
     <property name="initialSize" value="10" /> 
     <property name="maxActive" value="15" /> 
     <property name="maxWait" value="5000" /> 
     <property name="maxIdle" value="1" /> 

    </bean> 

Answer 3

ऊपर टैग में इस लाइन के लिए महत्वपूर्ण है

<property name="maxIdle" value="1" /> 

, काम करेंगे के रूप में यह AJAX या डीबी अनुरोध