Re: JDBC HighLoad

Stéphane RIFF wrote:

> Hi i have a java aplication which connect to postgresql via jdbc.
> This app make a lot of request per second.
> The problem is that i get delayed records between the moment the
> informations arrived via socket to java and
> the moment it's recorded in the database. It seems that jdbc wait
> before inserting/updating the db because
> they are to much requests.
> For testing i made a little app in c using libpq to see if problem
> persist and there no delay.
>
> So i'd like to know a way to speed up jdbc if possible ???
>
>
Here my connection class, is there something wrong ?

import java.io.*;
import java.util.*;
import java.sql.*;
import java.text.*;
import javax.sql.DataSource;
import org.postgresql.jdbc3.Jdbc3PoolingDataSource;

import org.apache.log4j.Logger;
import org.apache.log4j.PropertyConfigurator;

public class SQLoader {

private Jdbc3PoolingDataSource datasource ;
//query object gps
private PreparedStatement pstmt_gps ;
//query object io
private PreparedStatement pstmt_io ;
//query object gps
private PreparedStatement pstmt_ugps ;
//query object io
private PreparedStatement pstmt_uio ;
//query object gps
private PreparedStatement pstmt_hgps ;
//query object io
private PreparedStatement pstmt_hio ;
//singleton class
private final static SQLoader myRef = new SQLoader();
//Log4j logger object
private static Logger logger =
Logger.getLogger(SQLoader.class.getName());
//jdbc driver
private String driver ;
//jdbc connection string
private String jdbcConnectionString ;
//database user
private String dbUser ;
//database password
private String dbPwd ;

/**
* Private constructor
*
* @since 1.0
*/
private SQLoader() {}

/**
* Give access to the unique instance of this class
*
* @return The instance
* @since 1.0
*/
public static SQLoader getRef()
{
return myRef ;
}

public void connect(String driver,String dbc, String dbu, String dbp)
{
Connection m_conn = null;
try {
datasource = setupDataSource(dbc);
}catch(Exception e){
logger.fatal(e.toString());
System.exit(-1);
}
}

private void prepareQuery(Connection c)
{
try
{
//Construct predefined query
String qry = "INSERT INTO gps_frame (" +
"\"sbox_id\"," +
"\"gps_date\"," +
"\"badge_id\"," +
"\"gmt_creation_date\"," +

"\"wgs84_position\","+
"\"speed\"," +
"\"altitude\","+
"\"heading\","+
"\"validity\"," +
"\"geom\")" +
" VALUES( ?,?,?,?,?,?,?,?,?,?)";
pstmt_gps = c.prepareStatement(qry);

String qry1 = "INSERT INTO io_frame ("+
"\"sbox_id\","+
"\"gps_date\","+
"\"io_type\","+
"\"io_rank\","+
"\"io_value\")"+
" VALUES( ?,?,?,?,?)";
pstmt_io = c.prepareStatement(qry1);

String uqry = "UPDATE gps_frame SET "+
"\"gps_date\"=?,"+
"\"badge_id\"=?,"+
"\"gmt_creation_date\"=?,"+
"\"wgs84_position\"=?,"+
"\"speed\"=?,"+
"\"altitude\"=?,"+
"\"heading\"=?,"+
"\"validity\"=?,"+
"\"geom\"=?"+
" WHERE \"sbox_id\"=?";
pstmt_ugps = c.prepareStatement(uqry);

String uqry1 = "UPDATE io_frame SET "+
"\"gps_date\"=?,"+
"\"io_value\"=?"+
" WHERE \"sbox_id\"=? AND \"io_rank\"=? AND
io_type=?";
pstmt_uio = c.prepareStatement(uqry1);

qry = "INSERT INTO gps_frame_history (" +
"\"sbox_id\"," +
"\"gps_date\"," +
"\"badge_id\"," +
"\"gmt_creation_date\"," +

"\"wgs84_position\","+
"\"speed\"," +
"\"altitude\","+
"\"heading\","+
"\"validity\"," +
"\"geom\")" +
" VALUES( ?,?,?,?,?,?,?,?,?,?)";
pstmt_hgps = c.prepareStatement(qry);

qry1 = "INSERT INTO io_frame_history ("+
"\"sbox_id\","+
"\"gps_date\","+
"\"io_type\","+
"\"io_rank\","+
"\"io_value\")"+
" VALUES( ?,?,?,?,?)";
pstmt_hio = c.prepareStatement(qry1);
}catch( java.sql.SQLException e)
{
logger.fatal(e.toString());
System.exit(-1);
}
}

/**
* Disconnect from DB
*
* @since 1.0
*/
public void disconnect()
{
try {
shutdownDataSource(datasource);
} catch(Exception e){
logger.fatal(e.toString());
System.exit(-1);
}
}


public void saveTrame(String boxID, String badgeID, String gpsDate,
double speed,
String wgs84, double altitude,
double azimuth,
String validity, String geom,
String sysDate, int[] input, int[] output)
{
Connection m_conn = null;
try
{
m_conn = datasource.getConnection();
m_conn.setAutoCommit(false);
prepareQuery(m_conn);
//set query values for update gps_frame
pstmt_ugps.setString(1, gpsDate);
pstmt_ugps.setString(2, badgeID);
pstmt_ugps.setString(3, sysDate);
pstmt_ugps.setString(4, wgs84);
pstmt_ugps.setDouble(5, speed);
pstmt_ugps.setDouble(6, altitude);
pstmt_ugps.setDouble(7, azimuth);
pstmt_ugps.setString(8, validity);
pstmt_ugps.setString(9, geom);
pstmt_ugps.setString(10, boxID);

if(pstmt_ugps.executeUpdate()==0)
{ //if no frame already exists insert it
pstmt_gps.setString(1, boxID);
pstmt_gps.setString(2, gpsDate);
pstmt_gps.setString(3, badgeID);
pstmt_gps.setString(4, sysDate);
pstmt_gps.setString(5, wgs84);
pstmt_gps.setDouble(6, speed);
pstmt_gps.setDouble(7, altitude);
pstmt_gps.setDouble(8, azimuth);
pstmt_gps.setString(9, validity);
pstmt_gps.setString(10, geom);
pstmt_gps.executeUpdate();

for(int i = 0; i < input.length; i++)
{
pstmt_io.setString(1, boxID);
pstmt_io.setString(2, gpsDate);
pstmt_io.setString(3, "i");
pstmt_io.setInt(4, (i+1));
pstmt_io.setInt(5, input[i]);
pstmt_io.executeUpdate();
}
for(int o = 0; o < output.length; o++)
{
pstmt_io.setString(1, boxID);
pstmt_io.setString(2, gpsDate);
pstmt_io.setString(3, "o");
pstmt_io.setInt(4, (o+1));
pstmt_io.setInt(5, output[o]);
pstmt_io.executeUpdate();
}
}else
{ //if frame already exists in gps_frame update his io
for(int i = 0; i < input.length; i++)
{
pstmt_uio.setString(1, gpsDate);
pstmt_uio.setInt(2, input[i]);
pstmt_uio.setString(3, boxID);
pstmt_uio.setInt(4, (i+1));
pstmt_uio.setString(5,"i");
pstmt_uio.executeUpdate();
}
for(int o = 0; o < output.length; o++)
{
pstmt_uio.setString(1, gpsDate);
pstmt_uio.setInt(2, output[o]);
pstmt_uio.setString(3, boxID);
pstmt_uio.setInt(4, (o+1));
pstmt_uio.setString(5,"o");
pstmt_uio.executeUpdate();
}
}
//insert in hisory
pstmt_hgps.setString(1, boxID);
pstmt_hgps.setString(2, gpsDate);
pstmt_hgps.setString(3, badgeID);
pstmt_hgps.setString(4, sysDate);
pstmt_hgps.setString(5, wgs84);
pstmt_hgps.setDouble(6, speed);
pstmt_hgps.setDouble(7, altitude);
pstmt_hgps.setDouble(8, azimuth);
pstmt_hgps.setString(9, validity);
pstmt_hgps.setString(10, geom);
pstmt_hgps.executeUpdate();

for(int i = 0; i < input.length; i++)
{
pstmt_hio.setString(1, boxID);
pstmt_hio.setString(2, gpsDate);
pstmt_hio.setString(3, "i");
pstmt_hio.setInt(4, (i+1));
pstmt_hio.setInt(5, input[i]);
pstmt_hio.executeUpdate();
}
for(int o = 0; o < output.length; o++)
{
pstmt_hio.setString(1, boxID);
pstmt_hio.setString(2, gpsDate);
pstmt_hio.setString(3, "o");
pstmt_hio.setInt(4, (o+1));
pstmt_hio.setInt(5, output[o]);
pstmt_hio.executeUpdate();
}
m_conn.commit();
}
catch(java.sql.SQLException e){
String msg = e ;
logger.warn(msg);
}
finally {
try { m_conn.close(); } catch(Exception e) { }
}
}

public Jdbc3PoolingDataSource setupDataSource(String connectURI) {
Jdbc3PoolingDataSource ds = new Jdbc3PoolingDataSource();
ds.setDataSourceName("Xxx");
ds.setServerName("xxx.xxx.xxx.xxx");
ds.setDatabaseName("xxxxxxxxxxxxx");
ds.setUser("xxxxx");
ds.setPassword("xxxxx");
ds.setMaxConnections(10);
return ds;
}
public static void shutdownDataSource(DataSource ds) throws
SQLException {
}
}

When i highload postgresql with a multi-threaded serverSocket using this
class,
my app freezes very quickly and all my connection are in idle state.
It seems that the connection aren't released.

It don't know what i can do if someone could help ???
Thanks

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