Date: Fri, 12 Aug 2011 03:58:10 -0700 (PDT)
From: jenopob <jenopob@126.com>
To: pgsql-performance@postgresql.org
Message-ID: <1313146690326-4692837.post@n5.nabble.com>
Subject: pgpool master or slave goes down java access error
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hi pgpool Expert

my architecture as follows: 
Master/Slave with Streaming Replication and pgpool-II 
version of pgpool-II is pgpool-II.3.0.4 
version of PostgreSQL is 9.0.2 

I am using pgpool works as master/slave sub mode stream

and pgpool key configuration is:
=====================================================================================================

num_init_children=100
max_pool=4
child_life_time=60
connection_life_time=0
child_max_connections=0
client_idle_limit=0
connection_cache=true

=====================================================================================================

and java jdbc connection test code as fllows:

=====================================================================================================
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class TestPgpool {
    public static void main(String[] args) { 

        for(;;){ 
           Thread th = new Thread(new TestThread()); 

           th.start(); 
           try { 

               Thread.sleep(10); 

           } catch (InterruptedException e) { 
               System.out.println("1--------------");
               e.printStackTrace(); 
               System.out.println("1--------------");
           } 
       } 
   } 

   static class TestThread implements Runnable{ 

       public void run() { 

           Connection con = null; 

           Statement stmt = null; 
           try { 

               Class.forName("org.postgresql.Driver"); 

               con = DriverManager.getConnection( 

                   
"jdbc:postgresql://192.168.1.116:9999/spring250_20100630_705", 

                    "postgres","postgres"); 

               stmt = con.createStatement(); 

               String sql = "SELECT * FROM bb_member limit 1"; 

               ResultSet rs = stmt.executeQuery(sql); 
               System.out.print("OK("); 

               while(rs.next()){ 

                   System.out.print(rs.getInt(1) + "=" 

                             + rs.getString(2) + " "); 
               } 

               System.out.println(")"); 
               stmt.close(); 
               con.close(); 
           } catch (SQLException e) { 
               System.out.println("2--------------");
               e.printStackTrace();
               System.out.println("2--------------");

           } catch (ClassNotFoundException e) { 
               e.printStackTrace(); 
           } 
       } 
   } 
}
=====================================================================================================

question:

	I do some db falt tests 
	1)the test code run always connect pgpool,
	2)test master or slave go down 

	but when mster or slave go down ,java code throws exception :
	
	org.postgresql.util.PSQLException: An I/O error occurred while sending to
the backend
	org.postgresql.util.PSQLException: The connection attempt failed.
	
	the error happened once for little time,then goes normal.

what should I do to solve this problem?and show the reason about the matter.

thanks for any help

jeno

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