JDBC connection hangs at executing rs.next()

Question

I'm trying to read from a mySQL server (in my LAN) a huge resultSet. I implemented it the way I found looking for the setFetchSize method: BalusC's Example. So I did:

        con = DriverManager.getConnection(url, user, password);

        //con.setAutoCommit(false);
        st = con.createStatement(ResultSet.TYPE_FORWARD_ONLY, ResultSet.CONCUR_READ_ONLY);
        st.setFetchSize(Integer.MIN_VALUE);
        rs = st.executeQuery(query);

        int count = 0;
        while (rs.next ()) {                
            // Process entry
            String rsc = rs.getString ("resource");
            String tpc = rs.getString("topic");   
            System.out.println(count + ": " + rsc); 
            ++count;                
        }

Although, it hangs at row 1077 at the line rs.next(). It doesn't throw exception.

EDIT:

After a timeout something new happened. It returned this error message:

JDWP exit error JVMTI_ERROR_NONE(0): getting frame location [../../../src/share/back/stepControl.c:641]

This error seems to be unrelated.

EDIT2: I've coded a PHP script for retrieving results by stream and happens exactly the same. So it has nothing to do with JDBC... I don't know what is going on!!

Answer 1

OKay, the problem was at the query itself.

I've found that streaming is very sensitive on how query is built. If I make a little change (like adding SELECT DISTINCT) it buffers or hangs. Finally, I left a column out of the query and worked...