Marc,
There are unfortunately no examples of Berkeley DB
replication available
in Java or for BDB XML. There are examples
in C in the Berkeley DB tree. See
db-4.3.29/examples_c/ex_repquote
and ex_rep.
There are several users who have done replication in BDB
XML.
Maybe one of them will chime in.
Regards,
George
> I'm in the process of evaluating Berkeley DBXML for an
embedded xml
> data store for the bank i work for (Société Générale in
Paris).
>
> The goal is to accelerate report production from
massive xml source
> (9gigs of XML growing fast).
>
> To make this solution viable, i need to implement
replication of
> dbxml database over the network, and i can't find any
example how
> to implement replication in java. Application run on 2
J2EE servers.
>
> Can you help me getting started? I would really
appreciate.
> I attached a java file of were i'm at actually if it
can help
> getting me started.
>
> Thanks in advance.
>
> Marc Deschamps
> Loan Studio Project Manager
> marc.deschamps sgcib.com
>
> package core;
>
> import com.sgcib.lso.dbxml.MyXMLDBEnv;
> import com.sleepycat.dbxml.XmlContainer;
> import com.sleepycat.dbxml.XmlDocument;
> import com.sleepycat.dbxml.XmlDocumentConfig;
> import com.sleepycat.dbxml.XmlManager;
> import com.sleepycat.dbxml.XmlUpdateContext;
> import java.util.LinkedList;
> import org.jgroups.Address;
> import org.jgroups.Channel;
> import org.jgroups.JChannel;
> import org.jgroups.MembershipListener;
> import org.jgroups.Message;
> import org.jgroups.MessageListener;
> import org.jgroups.View;
> import org.jgroups.blocks.PullPushAdapter;
> import org.jgroups.util.Util;
>
> /**
> *
> * author Marc
> */
> public class Sender implements Runnable
> {
>
> public Sender()
> {
> super();
> }
>
> public static void main(String[] args)
> {
> try
> {
> Sender main = new Sender();
> main.run();
> }
> catch (Exception e)
> {
> System.err.println(e.getMessage());
> e.printStackTrace(System.err);
> }
> }
>
> public void run()
> {
> try
> {
> MyXMLDBEnv env = new
MyXMLDBEnv("c:/www/data");
> XmlManager mgr = env.getManager();
> XmlContainer container = null;
> try
> {
> container =
mgr.openContainer("test.dbxml");
> }
> catch (Exception e)
> {
> container =
mgr.createContainer("test.dbxml");
> }
> XmlDocumentConfig docConfig =
> XmlDocumentConfig.DEFAULT.setGenerateName(true);
> XmlUpdateContext uCtx =
mgr.createUpdateContext();
> for(int i = 0; i < 100000; i++)
> {
> XmlDocument doc = mgr.createDocument();
>
doc.setContent("<test>test" + i +
"</test>");
> container.putDocument(doc, uCtx,
docConfig);
> }
> System.out.println("sended 100000
documents");
> while(true)
> {
> Thread.sleep(1000);
> }
> }
> catch (Exception e)
> {
> System.err.println(e.getMessage());
> e.printStackTrace(System.err);
> }
> return;
> }
> }
> package core;
>
> import com.sgcib.lso.dbxml.MyXMLDBEnv;
> import com.sleepycat.dbxml.XmlContainer;
> import com.sleepycat.dbxml.XmlDocument;
> import com.sleepycat.dbxml.XmlDocumentConfig;
> import com.sleepycat.dbxml.XmlManager;
> import com.sleepycat.dbxml.XmlUpdateContext;
> import java.util.LinkedList;
> import org.jgroups.Address;
> import org.jgroups.Channel;
> import org.jgroups.JChannel;
> import org.jgroups.MembershipListener;
> import org.jgroups.Message;
> import org.jgroups.MessageListener;
> import org.jgroups.View;
> import org.jgroups.blocks.PullPushAdapter;
> import org.jgroups.util.Util;
>
> /**
> *
> * author Marc
> */
> public class Receiver implements Runnable
> {
>
> public Receiver()
> {
> super();
> }
>
> public static void main(String[] args)
> {
> try
> {
> Receiver main = new Receiver();
> main.run();
> }
> catch (Exception e)
> {
> System.err.println(e.getMessage());
> e.printStackTrace(System.err);
> }
> }
>
> public void run()
> {
> try
> {
> MyXMLDBEnv env = new
MyXMLDBEnv("c:/www/data_replicated");
> XmlManager mgr = env.getManager();
> XmlContainer container = null;
> try
> {
> container =
mgr.openContainer("test.dbxml");
> }
> catch (Exception e)
> {
> container =
mgr.createContainer("test.dbxml");
> }
> while(true)
> {
> Thread.sleep(1000);
> }
> }
> catch (Exception e)
> {
> System.err.println(e.getMessage());
> e.printStackTrace(System.err);
> }
> return;
> }
> }
> package com.sgcib.lso.dbxml;
>
> import com.sleepycat.db.DatabaseEntry;
> import com.sleepycat.db.LogSequenceNumber;
> import com.sleepycat.db.ReplicationTransport;
> import com.sleepycat.db.internal.DbConstants;
> import com.sleepycat.dbxml.XmlManagerConfig;
> import java.io.File;
>
> import com.sleepycat.db.DatabaseException;
> import com.sleepycat.db.Environment;
> import com.sleepycat.db.EnvironmentConfig;
> import com.sleepycat.dbxml.XmlManager;
> import java.io.Serializable;
> import java.util.LinkedList;
> import org.jgroups.Address;
> import org.jgroups.Channel;
> import org.jgroups.JChannel;
> import org.jgroups.MembershipListener;
> import org.jgroups.Message;
> import org.jgroups.MessageListener;
> import org.jgroups.View;
> import org.jgroups.blocks.LockingException;
> import org.jgroups.blocks.PullPushAdapter;
> import org.jgroups.blocks.ReplicationManager;
> import org.jgroups.blocks.ReplicationReceiver;
> import org.jgroups.blocks.UpdateException;
> import org.jgroups.blocks.Xid;
> import org.jgroups.util.Util;
>
> //Class used to open and close a Berkeley DB
environment
> public class MyXMLDBEnv implements
ReplicationTransport,
> MessageListener, MembershipListener
> {
> // database
> private Environment dbEnv = null;
> private XmlManager mgr = null;
> private boolean dbEnvIsOpen = false;
> private File home = null;
> private LinkedList history = new LinkedList();
>
> //Replication
> private Integer id;
> private Integer masterId;
>
> private Channel channel;
> private PullPushAdapter adapter;
> private final String group_name =
"BerkeleyDBXMLGroup";
> private final String props="UDP
>
(mcast_addr=228.10.10.10;mcast_port=45566;bind_addr=127.0.0.
1):"
> + "PING:"
> + "FD:"
> + "STABLE:"
> + "NAKACK:"
> + "UNICAST:"
> + "FRAG:"
> + "FLUSH:"
> + "GMS:"
> + "VIEW_ENFORCER:"
> + "STATE_TRANSFER:"
> + "QUEUE";
>
> public MyXMLDBEnv(String path2DbEnv)
> {
> try
> {
> home = new File(path2DbEnv);
> if (!home.isDirectory())
> {
> throw new Exception(home.getPath() +
" does not
> exist or is not a directory.");
> }
>
> channel=new JChannel(props);
> channel.setOpt(Channel.AUTO_RECONNECT,
Boolean.TRUE);
> channel.setOpt(Channel.AUTO_GETSTATE,
Boolean.TRUE);
> System.out.println("Connecting to
" + group_name);
> channel.connect(group_name);
>
> adapter=new PullPushAdapter(channel, this,
this);
> channel.getState(null, 5000);
> id = new Integer((int)
channel.getView().getVid().getId
> ());
>
> EnvironmentConfig config =
EnvironmentConfig.DEFAULT;
> config.setCacheSize(50 * 1024 * 1024);
> config.setAllowCreate(true);
> config.setInitializeCache(true);
> config.setTransactional(true);
> config.setInitializeLocking(true);
> config.setInitializeLogging(true);
> config.setInitializeCache(true);
> config.setInitializeReplication(true);
> config.setErrorStream(System.err);
> config.setMessageStream(System.out);
>
config.setReplicationTransport(id.intValue(), this);
> dbEnv = new Environment(home, config);
> dbEnv.checkpoint(null);
> dbEnv.removeOldLogFiles();
>
> XmlManagerConfig xmlConfig = new
XmlManagerConfig();
> xmlConfig.setAdoptEnvironment(true);
> xmlConfig.setAllowAutoOpen(true);
> xmlConfig.setAllowExternalAccess(true);
>
> // Boolean used to know whether to close
the environment
> // when the cleanup() method is called.
> this.dbEnvIsOpen = true;
> this.mgr = new XmlManager(dbEnv,
xmlConfig);
> }
> catch(Exception e)
> {
> e.printStackTrace(System.err);
> throw new
ExceptionInInitializerError(e.getMessage());
> }
> }
>
> // Returns the path to the database environment
> public File getDbEnvPath()
> {
> return home;
> }
>
> // Returns the database environment encapsulated by
this class.
> public Environment getEnvironment()
> {
> return dbEnv;
> }
>
> // Returns the XmlManager encapsulated by this
class.
> public XmlManager getManager()
> {
> return mgr;
> }
>
> // Used to close the environment
> public void cleanup() throws DatabaseException
> {
> if (dbEnvIsOpen)
> {
> dbEnv.close();
> dbEnvIsOpen = false;
> }
> }
>
> public int send(Environment dbenv, DatabaseEntry
control,
> DatabaseEntry rec, LogSequenceNumber lsn, int envid,
boolean
> noBuffer, boolean permanent) throws DatabaseException
> {
> int result = 0;
> try
> {
> MyMsg mymsg = new MyMsg(control, rec,
envid);
> Message msg = new Message(null, null,
> Util.objectToByteBuffer(mymsg));
> channel.send(msg);
> }
> catch (Exception e)
> {
> result = -1;
> }
> return result;
> }
>
> public void receive(Message message)
> {
> try
> {
> Object o=
Util.objectToByteBuffer(message.getObject());
> if(o instanceof MyMsg)
> {
> MyMsg mymsg = (MyMsg) o;
>
dbEnv.processReplicationMessage(mymsg.control,
> mymsg.rec, mymsg.envid);
> }
> System.out.println(o + " [" +
message.getSrc() + "]\n");
> history.add(o);
> }
> catch(Exception e)
> {
> System.err.println("Chat.receive():
" + e);
> }
> return;
> }
>
> public byte[] getState()
> {
> try
> {
> return Util.objectToByteBuffer(history);
> }
> catch(Exception e)
> {
> return null;
> }
> }
>
> public void setState(byte[] state)
> {
> try
> {
>
history=(LinkedList)Util.objectFromByteBuffer(state);
> }
> catch(Exception e)
> {
> e.printStackTrace();
> }
> return;
> }
>
> public void viewAccepted(View new_view)
> {
> System.out.println("Received view "
+ new_view + '\n');
> int members =
channel.getView().getMembers().size();
>
> if(members > 1)
> {
> System.out.println("We're now a
group of " + members +
> " members!");
> try
> {
> Thread t = new Thread()
> {
> public void run()
> {
> try
> {
> int i =
dbEnv.electReplicationMaster
> (channel.getView().getMembers().size(), 2, 1, 1000);
> masterId = new Integer(i);
> }
> catch (Exception e)
> {
> e.printStackTrace();
> }
> }
> };
>
> t.start();
> t.join();
>
> if(id.equals(masterId))
> dbEnv.startReplication(new
DatabaseEntry(), true);
> else if(masterId.intValue() >= 0)
> dbEnv.startReplication(new
DatabaseEntry(),
> false);
> }
> catch (Exception e)
> {
> e.printStackTrace();
> }
> }
> return;
> }
>
>
> public void suspect(Address suspected_mbr)
> {
> }
>
>
> public void block()
> {
> }
>
> class MyMsg implements Serializable
> {
>
> public MyMsg(DatabaseEntry control,
DatabaseEntry rec, int
> envid)
> {
> this.control = control;
> this.rec = rec;
> this.envid = envid;
> }
> int envid;
> DatabaseEntry control;
> DatabaseEntry rec;
> }
>
> class MyElectionThread implements Runnable
> {
> public void run()
> {
> try
> {
> }
> catch (Exception e)
> {
> throw new
RuntimeException(e.getMessage());
> }
> }
> }
> }
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