Hi
I have 2 Jboss3.2.5 applications servers working in a cluster.
I'm using for primary key generation The pattern "sequence blocks" taken from
the book ejb design patterns.
However when i have something like 5 threads that are trying to create new
entities then i get DuplikateKeyException on the primary key. (with only 1
jboss server not in a cluster everything is fine).
I was wondering if anybody could help me pin out the problem, following is my
code:
I estimated it might be an Isolation level problem, however i have updated the
isolation level to be serializable in that way in mysql ds and the problem
still happend...
<user-name>root</user-name>
| <password></password>
| <TransactionIsolation>TRANSACTION_SERIALIZABLE</TransactionIsolation>
|
Sequence entity bean
| package messaging_as.domain.util;
|
| import javax.ejb.*;
|
| import messaging_as.util.jmx.ConfigContainer;
|
| abstract public class SequenceBean implements EntityBean {
| EntityContext entityContext;
| public java.lang.String ejbCreate(java.lang.String name) throws
CreateException {
| setName(name);
| return null;
| }
| public void ejbPostCreate(java.lang.String name) throws CreateException {
|
setSIndex(ConfigContainer.getJMXPropertiesFacade().getSequenceSessionBeanStartIndex());
| }
|
| public void ejbRemove() throws RemoveException {
| }
|
| public abstract void setName(java.lang.String name);
| public abstract void setSIndex(int sIndex);
| public abstract java.lang.String getName();
| public abstract int getSIndex();
| public void ejbLoad() {
| }
|
| public void ejbStore() {
| }
|
| public void ejbActivate() {
| }
|
| public void ejbPassivate() {
| }
|
| public void unsetEntityContext() {
| this.entityContext = null;
| }
| public void setEntityContext(EntityContext entityContext) {
| this.entityContext = entityContext;
| }
| public int getValueAfterIncrementingBy(int blockSize) {
| this.setSIndex(this.getSIndex()+ blockSize);
| return this.getSIndex();
| }
| }
|
sequence session bean
| package messaging_as.domain.util;
|
| import java.sql.Connection;
| import java.sql.ResultSet;
| import java.sql.SQLException;
| import java.sql.Statement;
|
| import javax.ejb.CreateException;
| import javax.ejb.FinderException;
| import javax.ejb.SessionBean;
| import javax.ejb.SessionContext;
| import javax.naming.Context;
| import javax.naming.NamingException;
|
| import messaging_as.domain.AlbumElementHome;
| import messaging_as.domain.AlbumElementShareHome;
| import messaging_as.domain.UserHome;
| import messaging_as.service.exceptions.InternalException;
| import messaging_as.util.jmx.JMXPropertiesFacade;
| import messaging_as.util.sql.MASConnectionManager;
|
| import org.apache.log4j.Category;
|
| public class SequenceSessionBean implements SessionBean {
| SessionContext sessionContext;
| private Category _log;
| private class Entry {
| Sequence sequence;
| int last;
| };
|
| private java.util.HashMap _entries = new java.util.HashMap();
| private int _blockSize;
| private int _retryCount;
| private SequenceHome _sequenceHome;
|
| public void ejbCreate() throws CreateException {
| _log = Category.getInstance(getClass());
| }
|
| public void ejbRemove() {
|
| }
| public void ejbActivate() {
|
| }
| public void ejbPassivate() {
|
| }
|
| public void setSessionContext(SessionContext sessionContext) {
| this.sessionContext = sessionContext;
| Context namingContext = null;
| try {
| namingContext = new javax.naming.InitialContext();
| _blockSize =
JMXPropertiesFacade.getInstance().getSequenceSessionBeanBlockSize();
| _retryCount =
JMXPropertiesFacade.getInstance().getSequenceSessionBeanRetryCount();
|
| _sequenceHome = (SequenceHome)
namingContext.lookup("SequenceLocalHome");
| }
| catch (NamingException e) {
| _log.error(e.getMessage(), e);
| }
| }
|
| public void synch() throws InternalException {
| Connection connection = null;
| ResultSet resultSet = null;
| Statement statement = null;
| int maxObjectID = 0, maxUID = 0, maxShareID = 0;
| try {
| connection = MASConnectionManager.getInstance().createConnection();
|
| String sql = "select max(" + AlbumElementHome.FIELD_NAME_OBJECT_ID +
") maxObjectID from " + AlbumElementHome.TABLE_NAME;
| statement = connection.createStatement();
| _log.debug("SQL : " + sql);
| statement.execute(sql);
| resultSet = statement.getResultSet();
| if (resultSet.next()) {
| maxObjectID = resultSet.getInt("maxObjectID");
| _log.debug(String.valueOf(maxObjectID));
| }
| resultSet.close();
| statement.close();
| ((Sequence)
_sequenceHome.findByPrimaryKey(AlbumElementHome.JNDI_NAME)).setSIndex(maxObjectID
+ 1);
|
| sql = "select max(" + UserHome.FIELD_UID + ") maxUID from " +
UserHome.TABLE_NAME;
| statement = connection.createStatement();
| _log.debug("SQL : " + sql);
| statement.execute(sql);
| resultSet = statement.getResultSet();
| if (resultSet.next()) {
| maxUID = resultSet.getInt("maxUID");
| _log.debug(String.valueOf(maxUID));
| }
| resultSet.close();
| statement.close();
| ((Sequence)
_sequenceHome.findByPrimaryKey(UserHome.JNDI_NAME)).setSIndex(maxUID + 1);
|
| sql = "select max(" + AlbumElementShareHome.FIELD_SHARE_ID + ")
maxShareID from " + AlbumElementShareHome.TABLE_NAME;
| statement = connection.createStatement();
| _log.debug("SQL : " + sql);
| statement.execute(sql);
| resultSet = statement.getResultSet();
| if (resultSet.next()) {
| maxShareID = resultSet.getInt("maxShareID");
| _log.debug(String.valueOf(maxShareID));
| }
| resultSet.close();
| statement.close();
| ((Sequence)
_sequenceHome.findByPrimaryKey(AlbumElementShareHome.JNDI_NAME)).setSIndex(maxShareID
+ 1);
|
| } catch (SQLException e1) {
| _log.error(e1.getMessage(), e1);
| } catch (FinderException e) {
| throw new InternalException(e);
| } finally {
| try {
| if (connection != null && !connection.isClosed())
connection.close();
| } catch (SQLException e) {
| _log.error(e.getMessage(), e);
| }
| }
|
| }
|
| public int getNextSequenceNumber(String name) {
| try
| {
| Entry entry = (Entry) _entries.get(name);
|
| if (entry == null)
| {
| // add an entry to the sequence table
| entry = new Entry();
| try
| {
| entry.sequence = _sequenceHome.findByPrimaryKey(name);
| }
| catch (javax.ejb.FinderException e)
| {
| _log.info("can't find sequence: " + name + " trying to
create it");
| // if we couldn't find it, then create it...
| entry.sequence = _sequenceHome.create(name);
| _log.info("sequence: " + name + " created");
| }
| _entries.put(name, entry);
| }
| if (entry.last % _blockSize == 0)
| {
| for (int retry = 0; true; retry++)
| {
| try
| {
| entry.last =
entry.sequence.getValueAfterIncrementingBy(_blockSize);
| break;
| }
| catch (javax.ejb.TransactionRolledbackLocalException e)
| {
| if (retry < _retryCount)
| {
| // we hit a concurrency exception, so try again...
| _log.info("RETRYING");
| continue;
| }
| else
| {
| // we tried too many times, so fail...
| throw new javax.ejb.EJBException(e);
| }
| }
| }
| }
|
| return entry.last++;
| }
| catch (javax.ejb.CreateException e)
| {
| throw new javax.ejb.EJBException(e);
| }
| }
|
|
| }
|
from ejb-jar.xml
| <container-transaction>
| <method>
| <description />
| <ejb-name>SequenceSession</ejb-name>
| <method-name>getNextSequenceNumber</method-name>
| <method-params>
| <method-param>java.lang.String</method-param>
| </method-params>
| </method>
| <trans-attribute>RequiresNew</trans-attribute>
| </container-transaction>
|
jboss.xml
| <container-configurations>
| <container-configuration>
| <container-name>Standard CMP 2.x EntityBean with cache
invalidation</container-name>
| <commit-option>A</commit-option>
| <cache-invalidation>True</cache-invalidation>
| </container-configuration>
| </container-configurations>
| .
| .
| .
| <entity>
| <ejb-name>Sequence</ejb-name>
| <local-jndi-name>SequenceLocalHome</local-jndi-name>
| <!-- no cache for this entity bean -->
| </entity>
|
anybody can help with what the problem might be?
did i update the isolation level correctly?
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http://www.jboss.org/index.html?module=bb&op=viewtopic&p=3881060#3881060
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http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&p=3881060
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