Question

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Connection Pool Exception: Cannot get a connection, pool error Timeout waiting for idle object

I am getting Cannot get a connection, pool error Timeout waiting for idle object error, When I try to create more than 250 threads in my web application. I am creating web application using JSF 2.0 and Hibernate.

I have tried with modified hibernate.xml,server.xml,context.xml and also mysql properties.

The followings are I am getting.

WARN (JDBCExceptionReporter.java:233) - SQL Error: 0, SQLState: null
ERROR (JDBCExceptionReporter.java:234) - Cannot get a connection, pool error Timeout waiting for idle object
ERROR (BaseServlet.java:301) - ******** java.lang.Thread.getStackTrace(Thread.java:1426)
    Caused by: org.hibernate.exception.GenericJDBCException: Cannot open connection
    org.hibernate.exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:140)
    org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:128)
    org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66)
    org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:52)
    org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.java:449)
    org.hibernate.jdbc.ConnectionManager.getConnection(ConnectionManager.java:167)
    org.hibernate.jdbc.JDBCContext.connection(JDBCContext.java:160)
    org.hibernate.transaction.JDBCTransaction.begin(JDBCTransaction.java:81)
    org.hibernate.impl.SessionImpl.beginTransaction(SessionImpl.java:1473)
    sun.reflect.GeneratedMethodAccessor378.invoke(Unknown Source)
    Caused by: org.apache.tomcat.dbcp.dbcp.SQLNestedException: Cannot get a connection, pool error Timeout waiting for idle object
    org.apache.tomcat.dbcp.dbcp.PoolingDataSource.getConnection(PoolingDataSource.java:114)
    org.apache.tomcat.dbcp.dbcp.BasicDataSource.getConnection(BasicDataSource.java:1044)
    org.hibernate.connection.DatasourceConnectionProvider.getConnection(DatasourceConnectionProvider.java:92)
    org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.java:446)
    org.hibernate.jdbc.ConnectionManager.getConnection(ConnectionManager.java:167)
    org.hibernate.jdbc.JDBCContext.connection(JDBCContext.java:160)
    org.hibernate.transaction.JDBCTransaction.begin(JDBCTransaction.java:81)
    org.hibernate.impl.SessionImpl.beginTransaction(SessionImpl.java:1473)
    sun.reflect.GeneratedMethodAccessor378.invoke(Unknown Source)
    sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    Caused by: java.util.NoSuchElementException: Timeout waiting for idle object
    org.apache.tomcat.dbcp.pool.impl.GenericObjectPool.borrowObject(GenericObjectPool.java:1144)
    org.apache.tomcat.dbcp.dbcp.PoolingDataSource.getConnection(PoolingDataSource.java:106)
    org.apache.tomcat.dbcp.dbcp.BasicDataSource.getConnection(BasicDataSource.java:1044)
    org.hibernate.connection.DatasourceConnectionProvider.getConnection(DatasourceConnectionProvider.java:92)
    org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.java:446)
    org.hibernate.jdbc.ConnectionManager.getConnection(ConnectionManager.java:167)
    org.hibernate.jdbc.JDBCContext.connection(JDBCContext.java:160)
    org.hibernate.transaction.JDBCTransaction.begin(JDBCTransaction.java:81)
    org.hibernate.impl.SessionImpl.beginTransaction(SessionImpl.java:1473)
    sun.reflect.GeneratedMethodAccessor378.invoke(Unknown Source)

Please if have any idea about this help me……

Answer 1

Maybe you have set a timeout for “dead” connections and some queries take longer than that. That means that your pool removed a busy connection as “dead” from the pool and requests another from the DB – until the DB pulls the plug.

To debug this, enable logging for your connection pool, so you can see when it requests new connections.

also check your mysql connection settings. and try to close connection when you are done with your db coz next time(beyond maxConnectionAge limit) that connection state will be dead .