使用postgresql的非常简单的jsf应用程序中“已经有太多客户端”

Question

I'm getting the "FATAL: sorry, too many clients already" after only a few clicks around on my web application. The app is written using JSF 2. I haven't the slightest idea why this this is happening. I know for a fact I am the only person connected. It happens regardless of whether or not I am also connected using pgadminIII. My app is ridiculously simple.

Here are some relevant bits which may help:

Here's a singleton class I use for the connection:

public class ConnectionSingleton{

private static Connection con;

public static Connection getConnection() throws SQLException
{
    if (con == null || con.isClosed())
    {

        try
        {
            Class.forName("org.postgresql.Driver");

            con = DriverManager.getConnection(
                    "jdbc:postgresql://127.0.0.1:5432/sc_data", "postgres",
                    "password");
        } catch (SQLException e)
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (ClassNotFoundException e)
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    return con;
}
}

Here's an example of typical usage:

    try
    {
        Connection con = ConnectionSingleton.getConnection();

        PreparedStatement stat = con.prepareStatement("select * from song_song where id = ?");
        stat.setInt(1, id);
        ResultSet res = stat.executeQuery();

        if (res.next())
        {               
            id = res.getInt("id");
            name = res.getString("s_name");
            link = res.getString("s_link");
            owner = res.getInt("s_owner");
            critNumber = res.getInt("s_crit_number");

            retval="found";

        }
        else
        {
            retval = "no song";
        }

        res.close();
        con.close();
        stat.close();


    } catch (SQLException e)
    {
        retval = "no song";
        e.printStackTrace();
    }

I can't think of anything else to include here. that's pretty much it. Any ideas?

Answer 1

通常，当您看到此消息时，您的应用程序/ Web服务器配置的子级要多于postgresql配置的允许后端连接的子级。