| From: | Frédéric Houbie <fh(at)ionicsoft(dot)com> | 
|---|---|
| To: | <pgsql-jdbc(at)postgresql(dot)org> | 
| Subject: | Postgres 8.2 and setFetchSize | 
| Date: | 2007-09-19 11:53:31 | 
| Message-ID: | 95484F7A889A61469885286054F675DD512526@altarf.ionicsoft.com | 
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| Thread: | |
| Lists: | pgsql-jdbc | 
Hi,
I'm trying to use the setFetchSize method to get back results faster. I'm using PostgreSQL 8.2 under XP. I'm using postgresql-8.2-505.jdbc3.jar driver. I'm connecting to a Postgres on Linux (PostgreSQL 8.2.4 on i686-pc-linux-gnu, compiled by GCC gcc (GCC) 4.1.2 20061115 (prerelease) (Debian 4.1.1-21)). I think that the setFetchSize do not work. I've read a lot about the conditions for that to work (autocommit false) but it's not working.
Here is my sample code:
   public static void main(String[] args) throws Exception{
        Connection con=null;
        try {
                Class.forName("org.postgresql.Driver");
            } catch (ClassNotFoundException e) {
                e.printStackTrace();
            }
            String s_server = "jdbc:postgresql://regulus:5432/ignimport" ;
            try {
                 con = DriverManager.getConnection(s_server, "bs", "");
            } catch(Exception e)
            {
                e.printStackTrace();
            }
        Statement st = con.createStatement();
        con.setAutoCommit(false);
        st.setFetchSize(Integer.parseInt(args[0]));
        System.out.println("FetchSize : " + st.getFetchSize());
	  String q="SELECT a FROM SValues WHERE  Name = 'title'";
        long t1 = System.currentTimeMillis();
        ResultSet resultSet = st.executeQuery(q);
        if (resultSet.next())
        {
            String s = resultSet.getString(1);
        }
        long t2 = System.currentTimeMillis();
        System.out.println("exec time : " + (t2 - t1));
}
It always take the same time (long time) whatever value I pass to this code for the FetchSize. It is really a problem because I can't use the LIMIT keywords as I don't know the exact number of records I need.
Any advice ?
Thanks
 
 
Frédéric Houbie
 
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