/*
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* CDDL HEADER START
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*
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* The contents of this file are subject to the terms of the
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* Common Development and Distribution License, Version 1.0 only
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* (the "License"). You may not use this file except in compliance
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* with the License.
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*
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* You can obtain a copy of the license at
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* trunk/opends/resource/legal-notices/OpenDS.LICENSE
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* or https://OpenDS.dev.java.net/OpenDS.LICENSE.
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* See the License for the specific language governing permissions
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* and limitations under the License.
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*
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* When distributing Covered Code, include this CDDL HEADER in each
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* file and include the License file at
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* trunk/opends/resource/legal-notices/OpenDS.LICENSE. If applicable,
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* add the following below this CDDL HEADER, with the fields enclosed
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* by brackets "[]" replaced with your own identifying information:
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* Portions Copyright [yyyy] [name of copyright owner]
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*
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* CDDL HEADER END
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*
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*
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* Copyright 2006-2010 Sun Microsystems, Inc.
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* Portions copyright 2011-2013 ForgeRock AS
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*/
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package org.opends.server.replication.server.changelog.je;
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import java.util.ArrayList;
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import java.util.Date;
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import java.util.LinkedList;
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import java.util.List;
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import org.opends.messages.MessageBuilder;
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import org.opends.server.admin.std.server.MonitorProviderCfg;
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import org.opends.server.api.DirectoryThread;
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import org.opends.server.api.MonitorProvider;
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import org.opends.server.config.ConfigException;
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import org.opends.server.core.DirectoryServer;
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import org.opends.server.replication.common.CSN;
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import org.opends.server.replication.protocol.UpdateMsg;
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import org.opends.server.replication.server.ReplicationServer;
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import org.opends.server.replication.server.ReplicationServerDomain;
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import org.opends.server.replication.server.changelog.api.ChangelogException;
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import org.opends.server.replication.server.changelog.api.ReplicaDBCursor;
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import org.opends.server.replication.server.changelog.je.ReplicationDB.*;
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import org.opends.server.types.Attribute;
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import org.opends.server.types.Attributes;
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import org.opends.server.types.DN;
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import org.opends.server.types.InitializationException;
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import org.opends.server.util.TimeThread;
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import static org.opends.messages.ReplicationMessages.*;
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import static org.opends.server.loggers.ErrorLogger.*;
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import static org.opends.server.util.StaticUtils.*;
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/**
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* This class is used for managing the replicationServer database for each
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* server in the topology.
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* It is responsible for efficiently saving the updates that is received from
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* each master server into stable storage.
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* This class is also able to generate a {@link ReplicaDBCursor} that can be
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* used to read all changes from a given {@link CSN}.
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*
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* This class publish some monitoring information below cn=monitor.
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*/
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public class DbHandler implements Runnable
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{
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/**
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* The msgQueue holds all the updates not yet saved to stable storage.
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* <p>
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* This list is only used as a temporary placeholder so that the write in the
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* stable storage can be grouped for efficiency reason. Adding an update
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* synchronously add the update to this list. A dedicated thread loops on
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* flush() and trim().
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* <dl>
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* <dt>flush()</dt>
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* <dd>get a number of changes from the in memory list by block and write them
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* to the db.</dd>
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* <dt>trim()</dt>
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* <dd>deletes from the DB a number of changes that are older than a certain
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* date.</dd>
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* </dl>
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* <p>
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* Changes are not read back by replicationServer threads that are responsible
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* for pushing the changes to other replication server or to LDAP server
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*/
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private final LinkedList<UpdateMsg> msgQueue =
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new LinkedList<UpdateMsg>();
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/**
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* The High and low water mark for the max size of the msgQueue. The threads
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* calling add() method will be blocked if the size of msgQueue becomes larger
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* than the queueHimark and will resume only when the size of the msgQueue
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* goes below queueLowmark.
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*/
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private int queueMaxSize = 5000;
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private int queueLowmark = 1000;
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private int queueHimark = 4000;
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/**
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* The queue himark and lowmark in bytes, this is set to 100 times the himark
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* and lowmark in number of updates.
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*/
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private int queueMaxBytes = 100 * queueMaxSize;
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private int queueLowmarkBytes = 100 * queueLowmark;
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private int queueHimarkBytes = 100 * queueHimark;
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/** The number of bytes currently in the queue. */
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private int queueByteSize = 0;
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private ReplicationDB db;
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private CSN firstChange;
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private CSN lastChange;
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private int serverId;
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private DN baseDN;
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private DbMonitorProvider dbMonitor = new DbMonitorProvider();
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private DirectoryThread thread;
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private final Object flushLock = new Object();
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private ReplicationServer replicationServer;
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private long latestTrimDate = 0;
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/**
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* The trim age in milliseconds. Changes record in the change DB that
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* are older than this age are removed.
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*/
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private long trimAge;
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/**
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* Creates a new dbHandler associated to a given LDAP server.
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*
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* @param id Identifier of the DB.
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* @param baseDN the baseDN for which this DB was created.
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* @param replicationServer The ReplicationServer that creates this dbHandler.
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* @param dbenv the Database Env to use to create the ReplicationServer DB.
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* server for this domain.
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* @param queueSize The queueSize to use when creating the dbHandler.
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* @throws ChangelogException If a database problem happened
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*/
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public DbHandler(int id, DN baseDN, ReplicationServer replicationServer,
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ReplicationDbEnv dbenv, int queueSize) throws ChangelogException
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{
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this.replicationServer = replicationServer;
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serverId = id;
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this.baseDN = baseDN;
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trimAge = replicationServer.getTrimAge();
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queueMaxSize = queueSize;
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queueLowmark = queueSize / 5;
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queueHimark = queueSize * 4 / 5;
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queueMaxBytes = 200 * queueMaxSize;
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queueLowmarkBytes = 200 * queueLowmark;
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queueHimarkBytes = 200 * queueLowmark;
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db = new ReplicationDB(id, baseDN, replicationServer, dbenv);
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firstChange = db.readFirstChange();
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lastChange = db.readLastChange();
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thread = new DirectoryThread(this, "Replication server RS("
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+ replicationServer.getServerId()
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+ ") changelog checkpointer for Replica DS(" + id
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+ ") for domain \"" + baseDN + "\"");
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thread.start();
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DirectoryServer.deregisterMonitorProvider(dbMonitor);
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DirectoryServer.registerMonitorProvider(dbMonitor);
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}
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/**
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* Add an update to the list of messages that must be saved to the db
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* managed by this db handler.
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* This method is blocking if the size of the list of message is larger
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* than its maximum.
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*
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* @param update The update that must be saved to the db managed by this db
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* handler.
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*/
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public void add(UpdateMsg update)
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{
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synchronized (msgQueue)
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{
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int size = msgQueue.size();
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if (size > queueHimark || queueByteSize > queueHimarkBytes)
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{
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msgQueue.notify();
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}
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while (size > queueMaxSize || queueByteSize > queueMaxBytes)
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{
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try
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{
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msgQueue.wait(500);
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} catch (InterruptedException e)
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{
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// simply loop to try again.
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}
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size = msgQueue.size();
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}
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queueByteSize += update.size();
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msgQueue.add(update);
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if (lastChange == null || lastChange.older(update.getCSN()))
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{
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lastChange = update.getCSN();
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}
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if (firstChange == null)
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{
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firstChange = update.getCSN();
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}
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}
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}
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/**
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* Get some changes out of the message queue of the LDAP server.
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* (from the beginning of the queue)
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* @param number the maximum number of messages to extract.
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* @return a List containing number changes extracted from the queue.
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*/
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private List<UpdateMsg> getChanges(int number)
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{
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synchronized (msgQueue)
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{
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final int minAvailableNb = Math.min(number, msgQueue.size());
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return new LinkedList<UpdateMsg>(msgQueue.subList(0, minAvailableNb));
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}
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}
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/**
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* Get the firstChange.
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* @return Returns the firstChange.
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*/
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public CSN getFirstChange()
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{
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return firstChange;
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}
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/**
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* Get the lastChange.
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* @return Returns the lastChange.
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*/
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public CSN getLastChange()
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{
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return lastChange;
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}
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/**
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* Get the number of changes.
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*
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* @return Returns the number of changes.
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*/
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public long getChangesCount()
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{
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if (lastChange != null && firstChange != null)
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{
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return lastChange.getSeqnum() - firstChange.getSeqnum() + 1;
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}
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return 0;
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}
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/**
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* Generate a new {@link ReplicaDBCursor} that allows to browse the db managed
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* by this dbHandler and starting at the position defined by a given CSN.
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*
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* @param startAfterCSN
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* The position where the cursor must start.
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* @return a new {@link ReplicaDBCursor} that allows to browse the db managed
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* by this dbHandler and starting at the position defined by a given
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* CSN.
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* @throws ChangelogException
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* if a database problem happened.
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*/
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public ReplicaDBCursor generateCursorFrom(CSN startAfterCSN)
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throws ChangelogException
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{
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if (startAfterCSN == null)
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{
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flush();
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}
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return new JEReplicaDBCursor(db, startAfterCSN, this);
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}
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/**
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* Removes the provided number of messages from the beginning of the msgQueue.
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*
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* @param number the number of changes to be removed.
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*/
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private void clearQueue(int number)
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{
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synchronized (msgQueue)
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{
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int current = 0;
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while (current < number && !msgQueue.isEmpty())
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{
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UpdateMsg msg = msgQueue.remove(); // remove first
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queueByteSize -= msg.size();
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current++;
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}
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if (msgQueue.size() < queueLowmark
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&& queueByteSize < queueLowmarkBytes)
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{
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msgQueue.notifyAll();
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}
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}
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}
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/**
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* Shutdown this dbHandler.
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*/
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public void shutdown()
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{
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if (thread.isShutdownInitiated())
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{
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return;
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}
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thread.initiateShutdown();
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synchronized (msgQueue)
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{
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msgQueue.notifyAll();
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}
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while (msgQueue.size() != 0)
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{
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flush();
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}
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db.shutdown();
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DirectoryServer.deregisterMonitorProvider(dbMonitor);
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}
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/**
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* Run method for this class.
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* Periodically Flushes the ReplicationServerDomain cache from memory to the
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* stable storage and trims the old updates.
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*/
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@Override
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public void run()
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{
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thread.startWork();
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try
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{
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while (!thread.isShutdownInitiated())
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{
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try
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{
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flush();
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trim();
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synchronized (msgQueue)
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{
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if (msgQueue.size() < queueLowmark
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&& queueByteSize < queueLowmarkBytes)
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{
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try
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{
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msgQueue.wait(1000);
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}
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catch (InterruptedException e)
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{
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Thread.currentThread().interrupt();
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}
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}
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}
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}
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catch (Exception end)
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{
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MessageBuilder mb = new MessageBuilder();
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mb.append(ERR_EXCEPTION_CHANGELOG_TRIM_FLUSH.get());
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mb.append(" ");
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mb.append(stackTraceToSingleLineString(end));
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logError(mb.toMessage());
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thread.initiateShutdown();
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if (replicationServer != null)
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{
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replicationServer.shutdown();
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}
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break;
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}
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}
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// call flush a last time before exiting to make sure that
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// no change was forgotten in the msgQueue
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flush();
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}
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finally
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{
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thread.stopWork();
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}
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synchronized (this)
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{
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notifyAll();
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}
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}
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/**
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* Retrieves the latest trim date.
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* @return the latest trim date.
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*/
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public long getLatestTrimDate()
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{
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return latestTrimDate;
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}
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/**
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* Trim old changes from this replicationServer database.
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* @throws ChangelogException In case of database problem.
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*/
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private void trim() throws ChangelogException
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{
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if (trimAge == 0)
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{
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return;
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}
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latestTrimDate = TimeThread.getTime() - trimAge;
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CSN trimDate = new CSN(latestTrimDate, 0, 0);
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// Find the last CSN before the trimDate, in the Database.
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CSN lastBeforeTrimDate = db.getPreviousCSN(trimDate);
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if (lastBeforeTrimDate != null)
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{
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// If we found it, we want to stop trimming when reaching it.
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trimDate = lastBeforeTrimDate;
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}
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for (int i = 0; i < 100; i++)
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{
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synchronized (flushLock)
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{
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/*
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* the trim is done by group in order to save some CPU and IO bandwidth
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* start the transaction then do a bunch of remove then commit
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*/
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final ReplServerDBCursor cursor = db.openDeleteCursor();
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try
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{
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for (int j = 0; j < 50; j++)
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{
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if (thread.isShutdownInitiated())
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{
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return;
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}
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CSN csn = cursor.nextCSN();
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if (csn == null)
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{
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return;
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}
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if (!csn.equals(lastChange) && csn.older(trimDate))
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{
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cursor.delete();
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}
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else
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{
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firstChange = csn;
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return;
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}
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}
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}
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catch (ChangelogException e)
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{
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// mark shutdown for this db so that we don't try again to
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// stop it from cursor.close() or methods called by cursor.close()
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cursor.abort();
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thread.initiateShutdown();
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throw e;
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}
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finally
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{
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cursor.close();
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}
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}
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}
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}
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/**
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* Flush a number of updates from the memory list to the stable storage.
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* Flush is done by chunk sized to 500 messages, starting from the
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* beginning of the list.
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*/
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public void flush()
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{
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int size;
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int chunksize = Math.min(queueMaxSize, 500);
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do
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{
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synchronized(flushLock)
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{
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// get N (or less) messages from the queue to save to the DB
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// (from the beginning of the queue)
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List<UpdateMsg> changes = getChanges(chunksize);
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// if no more changes to save exit immediately.
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if (changes == null || (size = changes.size()) == 0)
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{
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return;
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}
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// save the change to the stable storage.
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db.addEntries(changes);
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// remove the changes from the list of changes to be saved
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// (remove from the beginning of the queue)
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clearQueue(changes.size());
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}
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// loop while there are more changes in the queue
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} while (size == chunksize);
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}
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/**
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* This internal class is used to implement the Monitoring capabilities
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* of the dbHandler.
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*/
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private class DbMonitorProvider extends MonitorProvider<MonitorProviderCfg>
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{
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/**
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* {@inheritDoc}
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*/
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@Override
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public List<Attribute> getMonitorData()
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{
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List<Attribute> attributes = new ArrayList<Attribute>();
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attributes.add(Attributes.create("replicationServer-database",
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String.valueOf(serverId)));
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attributes.add(Attributes.create("domain-name",
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baseDN.toNormalizedString()));
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if (firstChange != null)
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{
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attributes.add(Attributes.create("first-change", encode(firstChange)));
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}
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if (lastChange != null)
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{
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attributes.add(Attributes.create("last-change", encode(lastChange)));
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}
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attributes.add(
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Attributes.create("queue-size", String.valueOf(msgQueue.size())));
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attributes.add(
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Attributes.create("queue-size-bytes", String.valueOf(queueByteSize)));
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return attributes;
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}
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private String encode(CSN csn)
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{
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return csn + " " + new Date(csn.getTime());
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}
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/**
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* {@inheritDoc}
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*/
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@Override
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public String getMonitorInstanceName()
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{
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ReplicationServerDomain domain = replicationServer
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.getReplicationServerDomain(baseDN);
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return "Changelog for DS(" + serverId + "),cn="
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+ domain.getMonitorInstanceName();
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}
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/**
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* {@inheritDoc}
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*/
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@Override
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public void initializeMonitorProvider(MonitorProviderCfg configuration)
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throws ConfigException,InitializationException
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{
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// Nothing to do for now
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}
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}
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/**
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* {@inheritDoc}
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*/
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@Override
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public String toString()
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{
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return baseDN + " " + serverId + " " + firstChange + " " + lastChange;
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}
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/**
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* Set the Purge delay for this db Handler.
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* @param delay The purge delay in Milliseconds.
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*/
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public void setPurgeDelay(long delay)
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{
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trimAge = delay;
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}
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/**
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* Clear the changes from this DB (from both memory cache and DB storage).
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* @throws ChangelogException When an exception occurs while removing the
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* changes from the DB.
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*/
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public void clear() throws ChangelogException
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{
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synchronized(flushLock)
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{
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msgQueue.clear();
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queueByteSize = 0;
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db.clear();
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firstChange = db.readFirstChange();
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lastChange = db.readLastChange();
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}
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}
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/**
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* Getter for the serverID of the server for which this database is managed.
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*
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* @return the serverId.
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*/
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public int getServerId()
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{
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return this.serverId;
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}
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/**
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* Return the size of the msgQueue (the memory cache of the DbHandler).
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* For test purpose.
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* @return The memory queue size.
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*/
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public int getQueueSize()
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{
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return this.msgQueue.size();
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}
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/**
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* Set the counter writing window size (public for unit tests only).
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* @param size Size in number of record.
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*/
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public void setCounterWindowSize(int size)
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{
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db.setCounterWindowSize(size);
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}
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/**
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* Return the number of changes between 2 provided CSNs.
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* This a alternative to traverseAndCount, expected to be much more efficient
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* when there is a huge number of changes in the Db.
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* @param from The lower (older) CSN.
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* @param to The upper (newer) CSN.
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* @return The computed number of changes.
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*/
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public long getCount(CSN from, CSN to)
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{
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// Now that we always keep the last CSN in the DB to avoid expiring cookies
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// too quickly, we need to check if the "to" is older than the trim date.
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if (to == null || !to.older(new CSN(latestTrimDate, 0, 0)))
|
{
|
flush();
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return db.count(from, to);
|
}
|
return 0;
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}
|
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}
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