Re: Memory Leak

On Feb 26, 2010, at 12:16 AM, Christopher G. Stach II wrote:

>=20
> ----- "William Taylor" <[email protected]> wrote:
>=20
>> On Feb 25, 2010, at 11:44 PM, Christopher G. Stach II wrote:
>>>> Working on some code where I select 4 million rows and store the
>>>> results in a short array.
>>>=20


Here is the test case. This is with the newest connector J 5.1.12

table name is test with a single smallint column.  4 million rows.

first console output shows 0mb used by the problem.
each output after that shows ~255MB of ram used.
regardless of how long you let the program run the GC never reclaims the =
memory.
top says java is using ~289MB ram.
mysqld shows ~7.4mb ram

public class Test
{

    public static void main(String[] args)=20
    {
        new Test();
    }
   =20
    public Test()
    {
        System.out.println((Runtime.getRuntime().totalMemory() - =
Runtime.getRuntime().freeMemory())/(1024*1024)+" MB");
       =20
        try=20
        {
            Class.forName("com.mysql.jdbc.Driver").newInstance();        =
   =20
        }=20
        catch (InstantiationException e)=20
        {
            e.printStackTrace();                       =20
        }=20
        catch (IllegalAccessException e)=20
        {
            e.printStackTrace();           =20
        }=20
        catch (ClassNotFoundException e)=20
        {
            e.printStackTrace();
            System.exit(1);           =20
        }
       =20
        try
        {           =20
            String url =3D =
"jdbc:mysql://localhost/yourDataBase";//?dontTrackOpenResources=3Dtrue";
            String userName =3D "username";
            String password =3D "password";
           =20
            Connection connection =3D DriverManager.getConnection (url, =
userName, password);
            PreparedStatement statement =3D =
connection.prepareStatement("select id from test");
            ResultSet resultSet =3D statement.executeQuery();       =20
           =20
            resultSet.close();           =20
            statement.close();
            connection.close();
        }
        catch (SQLException e)
        {
            e.printStackTrace();
        }   =20
       =20
        while(true)
        {
            try
            {
                Thread.sleep(1000);
            }
            catch (InterruptedException e)
            {
                e.printStackTrace();
            }
           =20
            System.out.println((Runtime.getRuntime().totalMemory() - =
Runtime.getRuntime().freeMemory())/(1024*1024)+" MB");
        }
    }
}=

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