Juan Ignacio Villa <[EMAIL PROTECTED]> writes:
> Hello.
>
> My java application uses memory more and more until it
> crash. It is strange because not use new variables nor
> I do not create them dynamically. I have an for with
> which I make select SQL by means of inserted dynamic
> values. The peculiar thing is that in each return of
> for for, the program uses memory more and more, but I
> do not create new variables, but reusing same
> variables. I proved to garbage it with runtime.gc but
> there was no difference. Dont free it.
>
> I can do it of other way, but I have discovered that
> gc does not work to me in the application. It does not
> release memory until the application finalizes, and
> cannot be in a server application.
> It is necessary to make some extra task to release
> statements, resultsets or connections?
> The used memory comes from another part?
>
> derbydev.pdf tells that the memory to gc is closed
> normally. Also I have seen that driver it maintains a
> list of resultset not closed and does not release the
> memory.
>
> My code is:
>
> Class.forName"org.apache...");
> java.sql.Connection DbConexion =
> DriverManager.getConnection("jdbc:derby:" + addpath
> +"/prueba....");
>
> String sql ="";
> Statement Consulta =null;
> ResultSet Rs = null;
>
> for (int i=1; i<400; i++) {
> sql="SELECT * FROM tipo2 WHERE " + consul[i];
// This creates a new dynamic object
> Consulta =
> DBConexion.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);
// ... as does this
> Rs = Consulta.executeQuery(sql);
// .. and this
> Rs.close();
> Rs = null;
> Consulta.close();
> Consulta = null;
> }
>
> try{
> Rs.close();
> Consulta.close();
> Rs = null;
> Consulta = null;
> }catch(...)
>
Try using prepared statements instead. That is something like (untested):
PreparedStatement Consulta = DBConnexion.prepareStatement("SELECT *
FROM tipo2 WHERE <someColumn> <op> ?");
// Replace <someColumn> and <op> as appropriate
for (int i=1; i<400; i++) {
Consulta.set<Type>(1, consul[i]); // Replace <Type> with the type of
consul[i]
Rs = Consulta.executeQuery();
// Do something with Rs ??
Rs.close();
}
--
dt
However, experience shows that for many people and many applications a
dose of paranoia is reasonable - Bjarne Stroustrup
