Memroy leak with jdbc

Using this test case with 9000 interations I get this output:

used: 474,296 free: 1,557,320 total: 2,031,616 max: 67,108,864
....................................................................................................
used: 4,646,760 free: 3,643,544 total: 8,290,304 max: 67,108,864
=================
used: 4,607,728 free: 3,682,576 total: 8,290,304 max: 67,108,864

I have no idea why this memory leak is happening. It only happens with this one select
statement, not all select statements.

/**
* PostgresMemTest.java
*
*
* Created: Mon May 5 18:40:29 2003
*
* @author <a href="mailto:jks(at)selectacast(dot)net">Joseph Shraibman</a>
* @version 1.0
*/
import java.sql.*;
public class PostgresMemTest {

transient protected Connection db;

public PostgresMemTest(String url,String usr,String pwd) throws Exception{

// try {
// Load the driver
Class.forName("org.postgresql.Driver");
// } catch (ClassNotFoundException e){
// e.printStackTrace();
//return;
//}
// try{
db = DriverManager.getConnection(url, usr, pwd);
// } catch (SQLException e){
//e.printStackTrace();
//return;
// }
Statement st = null;
st = db.createStatement();
st.executeUpdate("BEGIN;");
st.executeUpdate("create temp table taba(pkey int, puindex int);");
st.executeUpdate("create temp table tabpu(pukey int, ukey int, pu text);");
st.executeUpdate("create temp table tabu(ukey int, akey int);");
st.executeUpdate("insert into taba values(1,2);");
st.executeUpdate("insert into tabu values(3,1);");
st.executeUpdate("insert into tabpu values(2,3,'blah');");

} // PostgresMemTest constructor
void doQuery() throws Exception{
String line = null;
//None of these remmed out lines produce the memory leak
//line = "SELECT 'blah'";
//line = "SELECT (SELECT 'blah');";
//line = "select pu from tabpu where pukey = 2 and ukey = 3";
line = "select (select pu from tabpu where pukey = taba.puindex and ukey =
tabu.ukey) from tabu where ukey = 3 and akey = 1;";
Statement st = null;
st = db.createStatement();
ResultSet rs = st.executeQuery(line);

}
private static String uft(){
Runtime rt = Runtime.getRuntime();
long free = rt.freeMemory(), total = rt.totalMemory(), used = total - free;
long max = rt.maxMemory();
long max2 = max - 67108864;

java.text.NumberFormat nf = java.text.NumberFormat.getInstance() ;
return "used: "+nf.format(used)+" free: "+nf.format(free)+
" total: "+nf.format(total)+" max: "+nf.format(max2);
}
//Usage java PostgresMemTest <iterations> <url> <username> <passwd>
public static void main(String args[])throws Exception{
PostgresMemTest pmt = new PostgresMemTest(args[1],args[2],args[3]);
System.out.println(uft());
int times = Integer.parseInt(args[0]);
final int perc = times/100;
for(int i = 0; i < times; i++){
pmt.doQuery();
if (i % perc == 0){
System.out.print('.');
System.out.flush();
}
}
System.out.println();
System.out.println(uft());
System.gc();
System.gc();
System.gc();
System.out.println("=================");
System.out.println(uft());

}
} // PostgresMemTest

--
Joseph Shraibman
joseph(at)xtenit(dot)com
Increase signal to noise ratio. http://xis.xtenit.com