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Re: Postgres 8.2 and setFetchSize

From: Frédéric Houbie <fh(at)ionicsoft(dot)com>
To: <pgsql-jdbc(at)postgresql(dot)org>
Subject: Re: Postgres 8.2 and setFetchSize
Date: 2007-09-19 12:12:13
Message-ID: 95484F7A889A61469885286054F675DD51252A@altarf.ionicsoft.com (view raw or flat)
Thread:
Lists: pgsql-jdbc
I have one more information, I tried the same code using my local Postgres database (on my XP, 8.2.4), it is working. What can I check on the server to see what's wrong ?
In my log, I can see it is using a cursor
2007-09-19 14:10:51.993  LOG:  duration: 0.000 ms  parse S_1: BEGIN
2007-09-19 14:10:51.993  LOG:  duration: 0.000 ms  bind S_1: BEGIN
2007-09-19 14:10:51.993  LOG:  duration: 0.000 ms  execute S_1: BEGIN
2007-09-19 14:10:51.993  LOG:  duration: 0.000 ms  parse S_2: SELECT * FROM SValues
2007-09-19 14:10:51.993  LOG:  duration: 0.000 ms  bind S_2/C_3: SELECT * FROM SValues
2007-09-19 14:10:51.993  LOG:  duration: 0.000 ms  execute S_2/C_3: SELECT * FROM SValues
20


Thanks

Frédéric

-----Message d'origine-----
De : pgsql-jdbc-owner(at)postgresql(dot)org [mailto:pgsql-jdbc-owner(at)postgresql(dot)org] De la part de Frédéric Houbie
Envoyé : mercredi 19 septembre 2007 13:54
À : pgsql-jdbc(at)postgresql(dot)org
Objet : [JDBC] Postgres 8.2 and setFetchSize

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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Next:From: Oliver JowettDate: 2007-09-19 13:24:35
Subject: Re: Postgres 8.2 and setFetchSize
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