[jboss-user] [Performance Tuning] - Transaction taking long time to execute

[Mayur B]

Mayur B [http://community.jboss.org/people/bingojava] created the discussion

"Transaction taking long time to execute"

To view the discussion, visit: http://community.jboss.org/message/569947#569947

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Hi, I am using Jboss 5.1.0 GA, EJB 3.0 , MySQL 5.x  
My application is running on a Linux server. 
In my  java program(client), multiple threads are trying to access the entity bean "LiveSubscriber" using following funtion:

//=====================================Stateless Session Bean==============================
package com.teshwa.bingogame.clubbeans;
 
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Date;
import java.util.Enumeration;
import java.util.List;
import java.util.Random;
import java.util.Vector;
 
import javax.ejb.Stateless;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.NoResultException;
import javax.persistence.Persistence;
import javax.persistence.PersistenceContext;
import javax.persistence.Query;
import javax.persistence.RollbackException;
 
import com.teshwa.bingo.clubs.ClubBLO;
import com.teshwa.bingo.clubs.ClubDAO;
import com.teshwa.bingo.clubs.ClubManager;
import com.teshwa.bingo.game.Game;
import com.teshwa.bingo.game.ticket.Ticket;
import com.teshwa.bingogame.GameRule;
import com.teshwa.bingogame.LiveClub;
import com.teshwa.bingogame.LiveGame;
import com.teshwa.bingogame.LiveSubscriber;
import com.teshwa.bingogame.jpo.Bingo75_ticket;
import com.teshwa.bingogame.jpo.Bingo90_ticket;
import com.teshwa.bingogame.jpo.Bingo_game;
import com.teshwa.bingogame.jpo.Bingo_game_pattern;
import com.teshwa.bingogame.jpo.Bingo_game_type;
import com.teshwa.bingogame.jpo.Bingo_game_type_rule;
import com.teshwa.bingogame.jpo.Bingo_game_type_rulePK;
import com.teshwa.bingogame.jpo.Bingo_game_winner;
import com.teshwa.bingogame.jpo.Club;
import com.teshwa.bingogame.jpo.Club_schedule_date;
import com.teshwa.bingogame.jpo.Game_jackpot;
import com.teshwa.bingogame.jpo.Game_jackpot_transaction;
import com.teshwa.bingogame.jpo.Game_timetable_detail;
import com.teshwa.bingogame.jpo.Subscriber;
import com.teshwa.bingogame.jpo.Subscriber_purchased_ticket;
@Stateless
public class GameManagerBean implements GameManagerRemote {
@PersistenceContext (unitName=ContextMapper.MAPPINGNAME) private EntityManager manager;
 
public GameManagerBean(){
 
}
@Override
package com.clubbeans;

import statements....

@Stateless
public class GameManagerBean implements GameManagerRemote {
 @PersistenceContext (unitName="gamesproject") private EntityManager manager;
 
 public GameManagerBean(){ 
 }
 @Override
       public List<LiveSubscriber> getAllSubscribers() {
                System.out.println("Inside Method");
                  try{

      return (List<LiveSubscriber>)manager.createQuery("SELECT lb FROM LiveSubscriber lb").getResultList();

               }catch(NoResultException nr){
                      System.out.println("getting out"); 
      return null;
               }
 }// Method ENDS
}// Class ENDS
//=========================================================================================

My Problem:  SOMETIMES (5 out of 100 tries, mostly when number of threads acccessing, increases) the control from this method  doesnt return immediately ... it prints the statement "inside method"...but doesnt print the log statement at client side , immediately after this method call. It was printed after 4 to 5 minutes.

My guess is that since lots of threads accessing the LiveSubscriber (live_subscribers table in DB) , sometimes this thread gets locked for longer time and doesnt comeout immediately . If this happens for 1 or 2 minutes , its ok for my application , but it should come out atleast after 2 minutes , otherwise next scheduling gets screwd up. 

here is information from my persistence.xml ---->
persistence-unit name="gamesproject" transaction-type="JTA"
jta-data-source---->jdbc/ser
class--->com.LiveSubscriber
property name="hibernate.dialect" value="org.hibernate.dialect.MySQL5Dialect"
property name="hibernate.hbm2ddl.auto" value="create"

I am not using any deployment descripter for session beans.  

Do I need to change default isolation level for Datasource (How?)  or this one perticular method should be bean managed using EntityManger.lock?
Basically can anybody tell how to prevent this transaction taking so much time?
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