/*
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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 legal-notices/CDDLv1_0.txt
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* or http://forgerock.org/license/CDDLv1.0.html.
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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 legal-notices/CDDLv1_0.txt.
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* If applicable, add the following below this CDDL HEADER, with the
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* fields enclosed by brackets "[]" replaced with your own identifying
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* 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 2013-2014 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.*;
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import java.util.Map.Entry;
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import java.util.concurrent.ConcurrentMap;
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import java.util.concurrent.ConcurrentSkipListMap;
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import java.util.concurrent.atomic.AtomicBoolean;
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import org.opends.messages.Message;
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import org.opends.server.api.DirectoryThread;
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import org.opends.server.loggers.debug.DebugTracer;
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import org.opends.server.replication.common.CSN;
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import org.opends.server.replication.common.MultiDomainServerState;
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import org.opends.server.replication.common.ServerState;
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import org.opends.server.replication.plugin.MultimasterReplication;
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import org.opends.server.replication.protocol.UpdateMsg;
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import org.opends.server.replication.server.ChangelogState;
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import org.opends.server.replication.server.changelog.api.*;
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import org.opends.server.types.DN;
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import org.opends.server.types.DirectoryException;
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import org.opends.server.util.StaticUtils;
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import com.forgerock.opendj.util.Pair;
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import static org.opends.messages.ReplicationMessages.*;
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import static org.opends.server.loggers.debug.DebugLogger.*;
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import static org.opends.server.util.StaticUtils.*;
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/**
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* Thread responsible for inserting replicated changes into the ChangeNumber
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* Index DB (CNIndexDB for short). Only changes older than the medium
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* consistency point are inserted in the CNIndexDB. As a consequence this class
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* is also responsible for maintaining the medium consistency point.
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*/
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public class ChangeNumberIndexer extends DirectoryThread
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{
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/** The tracer object for the debug logger. */
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private static final DebugTracer TRACER = getTracer();
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/**
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* If this is true, then the {@link #run()} method must clear its state.
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* Otherwise the run method executes normally.
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*/
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private final AtomicBoolean doClear = new AtomicBoolean();
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private final ChangelogDB changelogDB;
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/** Only used for initialization, and then discarded. */
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private ChangelogState changelogState;
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/*
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* mediumConsistencyRUV and lastSeenUpdates must be thread safe, because
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* 1) initialization can happen while the replication server starts receiving
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* updates 2) many updates can happen concurrently.
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*/
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/**
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* Holds the cross domain medium consistency Replication Update Vector for the
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* current replication server, also known as the previous cookie.
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* <p>
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* Stores the value of the cookie before the change currently processed is
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* inserted in the DB. After insert, it is updated with the CSN of the change
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* currently processed (thus becoming the "current" cookie just before the
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* change is returned.
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*
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* @see <a href=
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* "https://wikis.forgerock.org/confluence/display/OPENDJ/OpenDJ+Domain+Names"
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* >OpenDJ Domain Names - medium consistency RUV</a>
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*/
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private final MultiDomainServerState mediumConsistencyRUV =
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new MultiDomainServerState();
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/**
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* Holds the cross domain medium consistency baseDN and CSN for the current
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* replication server.
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*
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* @see <a href=
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* "https://wikis.forgerock.org/confluence/display/OPENDJ/OpenDJ+Domain+Names"
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* >OpenDJ Domain Names - medium consistency CSN</a>
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*/
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private volatile Pair<DN, CSN> mediumConsistency;
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/**
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* Holds the last time each replica was seen alive, whether via updates or
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* heartbeat notifications, or offline notifications. Data is held for each
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* serverId cross domain.
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* <p>
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* Updates are persistent and stored in the replicaDBs, heartbeats are
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* transient and are easily constructed on normal operations.
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*/
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private final MultiDomainServerState lastAliveCSNs =
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new MultiDomainServerState();
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private final MultiDomainServerState replicasOffline =
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new MultiDomainServerState();
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/**
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* Cursor across all the replicaDBs for all the replication domains. It is
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* positioned on the next change that needs to be inserted in the CNIndexDB.
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* <p>
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* Note: it is only accessed from the {@link #run()} method.
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*/
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private CompositeDBCursor<DN> nextChangeForInsertDBCursor;
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/**
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* New cursors for this Map must be created from the {@link #run()} method,
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* i.e. from the same thread that will make use of them. If this rule is not
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* obeyed, then a JE exception will be thrown about
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* "Non-transactional Cursors may not be used in multiple threads;".
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*/
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private Map<DN, Map<Integer, DBCursor<UpdateMsg>>> allCursors =
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new HashMap<DN, Map<Integer, DBCursor<UpdateMsg>>>();
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/**
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* Holds the newCursors that will have to be created in the next iteration
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* inside the {@link #run()} method.
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* <p>
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* This map can be updated by multiple threads.
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*/
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private ConcurrentMap<Pair<DN, Integer>, CSN> newCursors =
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new ConcurrentSkipListMap<Pair<DN, Integer>, CSN>(
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new Comparator<Pair<DN, Integer>>()
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{
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@Override
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public int compare(Pair<DN, Integer> o1, Pair<DN, Integer> o2)
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{
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final int compareBaseDN = o1.getFirst().compareTo(o2.getFirst());
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if (compareBaseDN == 0)
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{
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return o1.getSecond().compareTo(o2.getSecond());
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}
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return compareBaseDN;
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}
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});
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/**
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* Builds a ChangeNumberIndexer object.
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*
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* @param changelogDB
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* the changelogDB
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* @param changelogState
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* the changelog state used for initialization
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*/
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ChangeNumberIndexer(ChangelogDB changelogDB, ChangelogState changelogState)
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{
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super("Change number indexer");
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this.changelogDB = changelogDB;
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this.changelogState = changelogState;
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}
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/**
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* Ensures the medium consistency point is updated by heartbeats.
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*
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* @param baseDN
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* the baseDN of the domain for which the heartbeat is published
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* @param heartbeatCSN
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* the CSN coming from the heartbeat
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*/
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public void publishHeartbeat(DN baseDN, CSN heartbeatCSN)
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{
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if (!isECLEnabledDomain(baseDN))
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{
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return;
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}
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lastAliveCSNs.update(baseDN, heartbeatCSN);
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tryNotify();
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}
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/**
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* Ensures the medium consistency point is updated by UpdateMsg.
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*
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* @param baseDN
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* the baseDN of the domain for which the heartbeat is published
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* @param updateMsg
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* the updateMsg that will update the medium consistency point
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* @throws ChangelogException
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* If a database problem happened
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*/
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public void publishUpdateMsg(DN baseDN, UpdateMsg updateMsg)
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throws ChangelogException
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{
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if (!isECLEnabledDomain(baseDN))
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{
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return;
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}
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final CSN csn = updateMsg.getCSN();
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// only keep the oldest CSN that will be the new cursor's starting point
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newCursors.putIfAbsent(Pair.of(baseDN, csn.getServerId()), csn);
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lastAliveCSNs.update(baseDN, csn);
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tryNotify();
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}
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/**
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* Returns whether the provided baseDN represents a replication domain enabled
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* for the external changelog.
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* <p>
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* This method is a test seam that break the dependency on a static method.
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*
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* @param baseDN
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* the replication domain to check
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* @return true if the provided baseDN is enabled for the external changelog,
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* false if the provided baseDN is disabled for the external changelog
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* or unknown to multimaster replication.
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* @see MultimasterReplication#isECLEnabledDomain(DN)
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*/
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protected boolean isECLEnabledDomain(DN baseDN)
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{
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return MultimasterReplication.isECLEnabledDomain(baseDN);
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}
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/**
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* Signals a replica went offline.
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*
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* @param baseDN
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* the replica's replication domain
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* @param offlineCSN
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* the serverId and time of the replica that went offline
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*/
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public void replicaOffline(DN baseDN, CSN offlineCSN)
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{
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replicasOffline.update(baseDN, offlineCSN);
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lastAliveCSNs.update(baseDN, offlineCSN);
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tryNotify();
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}
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/**
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* Notifies the Change number indexer thread if it will be able to do some
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* work.
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*/
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private void tryNotify()
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{
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if (canMoveForwardMediumConsistencyPoint())
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{
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synchronized (this)
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{
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notify();
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}
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}
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}
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private boolean canMoveForwardMediumConsistencyPoint()
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{
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final Pair<DN, CSN> mc = mediumConsistency;
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if (mc != null)
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{
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final CSN mcCSN = mc.getSecond();
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final CSN lastTimeSameReplicaSeenAlive =
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lastAliveCSNs.getCSN(mc.getFirst(), mcCSN.getServerId());
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return mcCSN.isOlderThan(lastTimeSameReplicaSeenAlive);
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}
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// ensure that all initial replicas alive information have been updated
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// with CSNs that are acceptable for moving the medium consistency forward
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return allInitialReplicasArePastOldestPossibleCSN();
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}
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private boolean allInitialReplicasArePastOldestPossibleCSN()
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{
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for (DN baseDN : lastAliveCSNs)
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{
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for (CSN csn : lastAliveCSNs.getServerState(baseDN))
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{
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if (csn.getTime() == 0)
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{
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return false;
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}
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}
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}
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return true;
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}
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/**
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* Restores in memory data needed to build the CNIndexDB, including the medium
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* consistency point.
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*/
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private void initialize() throws ChangelogException, DirectoryException
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{
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final ChangeNumberIndexRecord newestRecord =
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changelogDB.getChangeNumberIndexDB().getNewestRecord();
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if (newestRecord != null)
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{
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// restore the mediumConsistencyRUV from DB
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mediumConsistencyRUV.update(
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new MultiDomainServerState(newestRecord.getPreviousCookie()));
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// Do not update with the newestRecord CSN
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// as it will be used for a sanity check later in the same method
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}
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// initialize the DB cursor and the last seen updates
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// to ensure the medium consistency CSN can move forward
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final ReplicationDomainDB domainDB = changelogDB.getReplicationDomainDB();
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for (Entry<DN, List<Integer>> entry
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: changelogState.getDomainToServerIds().entrySet())
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{
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final DN baseDN = entry.getKey();
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if (!isECLEnabledDomain(baseDN))
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{
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continue;
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}
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for (Integer serverId : entry.getValue())
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{
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/*
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* initialize with the oldest possible CSN in order for medium
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* consistency to wait for all replicas to be alive before moving
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* forward
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*/
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lastAliveCSNs.update(baseDN, oldestPossibleCSN(serverId));
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// start after the actual CSN when initializing from the previous cookie
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final CSN csn = mediumConsistencyRUV.getCSN(baseDN, serverId);
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ensureCursorExists(baseDN, serverId, csn);
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}
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ServerState latestKnownState = domainDB.getDomainNewestCSNs(baseDN);
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lastAliveCSNs.update(baseDN, latestKnownState);
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}
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resetNextChangeForInsertDBCursor();
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if (newestRecord != null)
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{
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// restore the "previousCookie" state before shutdown
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final UpdateMsg record = nextChangeForInsertDBCursor.getRecord();
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// sanity check: ensure that when initializing the cursors at the previous
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// cookie, the next change we find is the newest record in the CNIndexDB
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if (!record.getCSN().equals(newestRecord.getCSN()))
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{
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throw new ChangelogException(
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ERR_CHANGE_NUMBER_INDEXER_INCONSISTENT_CSN_READ.get(newestRecord
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.getCSN().toStringUI(), record.getCSN().toStringUI()));
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}
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// Now we can update the mediumConsistencyRUV
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mediumConsistencyRUV.update(newestRecord.getBaseDN(), record.getCSN());
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nextChangeForInsertDBCursor.next();
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}
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for (Entry<DN, List<CSN>> entry : changelogState.getOfflineReplicas()
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.entrySet())
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{
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final DN baseDN = entry.getKey();
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final List<CSN> offlineCSNs = entry.getValue();
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for (CSN offlineCSN : offlineCSNs)
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{
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if (isECLEnabledDomain(baseDN))
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{
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replicasOffline.update(baseDN, offlineCSN);
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}
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}
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}
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// this will not be used any more. Discard for garbage collection.
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this.changelogState = null;
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}
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private CSN oldestPossibleCSN(int serverId)
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{
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return new CSN(0, 0, serverId);
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}
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private void resetNextChangeForInsertDBCursor() throws ChangelogException
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{
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final Map<DBCursor<UpdateMsg>, DN> cursors =
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new HashMap<DBCursor<UpdateMsg>, DN>();
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for (Entry<DN, Map<Integer, DBCursor<UpdateMsg>>> entry
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: this.allCursors.entrySet())
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{
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for (Entry<Integer, DBCursor<UpdateMsg>> entry2
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: entry.getValue().entrySet())
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{
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cursors.put(entry2.getValue(), entry.getKey());
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}
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}
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// CNIndexer manages the cursor itself,
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// so do not try to recycle exhausted cursors
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CompositeDBCursor<DN> result = new CompositeDBCursor<DN>(cursors, false);
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result.next();
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nextChangeForInsertDBCursor = result;
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}
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private boolean ensureCursorExists(DN baseDN, Integer serverId,
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CSN startAfterCSN) throws ChangelogException
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{
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Map<Integer, DBCursor<UpdateMsg>> map = allCursors.get(baseDN);
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if (map == null)
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{
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map = new ConcurrentSkipListMap<Integer, DBCursor<UpdateMsg>>();
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allCursors.put(baseDN, map);
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}
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DBCursor<UpdateMsg> cursor = map.get(serverId);
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if (cursor == null)
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{
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final ReplicationDomainDB domainDB = changelogDB.getReplicationDomainDB();
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cursor = domainDB.getCursorFrom(baseDN, serverId, startAfterCSN);
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map.put(serverId, cursor);
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return false;
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}
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return true;
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}
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/**
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* Returns the immediately preceding CSN.
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*
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* @param csn
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* the CSN to use
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* @return the immediately preceding CSN or null if the provided CSN is null.
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*/
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CSN getPrecedingCSN(CSN csn)
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{
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if (csn == null)
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{
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return null;
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}
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if (csn.getSeqnum() > 0)
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{
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return new CSN(csn.getTime(), csn.getSeqnum() - 1, csn.getServerId());
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}
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return new CSN(csn.getTime() - 1, Integer.MAX_VALUE, csn.getServerId());
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}
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/** {@inheritDoc} */
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@Override
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public void initiateShutdown()
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{
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super.initiateShutdown();
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synchronized (this)
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{
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notify();
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}
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}
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/** {@inheritDoc} */
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@Override
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public void run()
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{
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try
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{
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/*
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* initialize here to allow fast application start up and avoid errors due
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* cursors being created in a different thread to the one where they are
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* used.
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*/
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initialize();
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while (!isShutdownInitiated())
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{
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try
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{
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if (doClear.get())
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{
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removeAllCursors();
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resetNextChangeForInsertDBCursor();
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// No need to use CAS here because it is only for unit tests and at
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// this point all will have been cleaned up anyway.
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doClear.set(false);
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}
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else
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{
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final boolean createdCursors = createNewCursors();
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final boolean recycledCursors = recycleExhaustedCursors();
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if (createdCursors || recycledCursors)
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{
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resetNextChangeForInsertDBCursor();
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}
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}
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final UpdateMsg msg = nextChangeForInsertDBCursor.getRecord();
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if (msg == null)
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{
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synchronized (this)
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{
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if (isShutdownInitiated())
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{
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continue;
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}
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wait();
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}
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// loop to check whether new changes have been added to the
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// ReplicaDBs
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continue;
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}
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final CSN csn = msg.getCSN();
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final DN baseDN = nextChangeForInsertDBCursor.getData();
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// FIXME problem: what if the serverId is not part of the ServerState?
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// right now, change number will be blocked
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if (!canMoveForwardMediumConsistencyPoint())
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{
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// the oldest record to insert is newer than the medium consistency
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// point. Let's wait for a change that can be published.
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synchronized (this)
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{
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// double check to protect against a missed call to notify()
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if (!isShutdownInitiated()
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&& !canMoveForwardMediumConsistencyPoint())
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{
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wait();
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// loop to check if changes older than the medium consistency
|
// point have been added to the ReplicaDBs
|
continue;
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}
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}
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}
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|
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// OK, the oldest change is older than the medium consistency point
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// let's publish it to the CNIndexDB.
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final String previousCookie = mediumConsistencyRUV.toString();
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final ChangeNumberIndexRecord record =
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new ChangeNumberIndexRecord(previousCookie, baseDN, csn);
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changelogDB.getChangeNumberIndexDB().addRecord(record);
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moveForwardMediumConsistencyPoint(csn, baseDN);
|
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// advance the cursor we just read from,
|
// success/failure will be checked later
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nextChangeForInsertDBCursor.next();
|
}
|
catch (InterruptedException ignored)
|
{
|
// was shutdown called? loop to figure it out.
|
Thread.currentThread().interrupt();
|
}
|
}
|
}
|
catch (RuntimeException e)
|
{
|
// Nothing can be done about it.
|
// Rely on the DirectoryThread uncaught exceptions handler
|
// for logging error + alert.
|
// Message logged here gives corrective information to the administrator.
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Message msg = ERR_CHANGE_NUMBER_INDEXER_UNEXPECTED_EXCEPTION.get(
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getClass().getSimpleName(), stackTraceToSingleLineString(e));
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TRACER.debugError(msg.toString());
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throw e;
|
}
|
catch (Exception e)
|
{
|
// Nothing can be done about it.
|
// Rely on the DirectoryThread uncaught exceptions handler
|
// for logging error + alert.
|
// Message logged here gives corrective information to the administrator.
|
Message msg = ERR_CHANGE_NUMBER_INDEXER_UNEXPECTED_EXCEPTION.get(
|
getClass().getSimpleName(), stackTraceToSingleLineString(e));
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TRACER.debugError(msg.toString());
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throw new RuntimeException(e);
|
}
|
finally
|
{
|
removeAllCursors();
|
}
|
}
|
|
private void moveForwardMediumConsistencyPoint(final CSN mcCSN,
|
final DN mcBaseDN) throws ChangelogException
|
{
|
// update, so it becomes the previous cookie for the next change
|
mediumConsistencyRUV.update(mcBaseDN, mcCSN);
|
mediumConsistency = Pair.of(mcBaseDN, mcCSN);
|
final int mcServerId = mcCSN.getServerId();
|
final CSN offlineCSN = replicasOffline.getCSN(mcBaseDN, mcServerId);
|
final CSN lastAliveCSN = lastAliveCSNs.getCSN(mcBaseDN, mcServerId);
|
if (offlineCSN != null)
|
{
|
if (lastAliveCSN != null && offlineCSN.isOlderThan(lastAliveCSN))
|
{
|
// replica is back online, we can forget the last time it was offline
|
replicasOffline.removeCSN(mcBaseDN, offlineCSN);
|
}
|
else if (offlineCSN.isOlderThan(mcCSN))
|
{
|
/*
|
* replica is not back online and Medium consistency point has gone past
|
* its last offline time: remove everything known about it: cursor,
|
* offlineCSN from lastAliveCSN and remove all knowledge of this replica
|
* from the medium consistency RUV.
|
*/
|
removeCursor(mcBaseDN, mcCSN);
|
lastAliveCSNs.removeCSN(mcBaseDN, offlineCSN);
|
mediumConsistencyRUV.removeCSN(mcBaseDN, offlineCSN);
|
}
|
}
|
}
|
|
private void removeAllCursors()
|
{
|
if (nextChangeForInsertDBCursor != null)
|
{
|
nextChangeForInsertDBCursor.close();
|
nextChangeForInsertDBCursor = null;
|
}
|
for (Map<Integer, DBCursor<UpdateMsg>> map : allCursors.values())
|
{
|
StaticUtils.close(map.values());
|
}
|
allCursors.clear();
|
newCursors.clear();
|
}
|
|
private void removeCursor(final DN baseDN, final CSN csn)
|
throws ChangelogException
|
{
|
for (Entry<DN, Map<Integer, DBCursor<UpdateMsg>>> entry1
|
: allCursors.entrySet())
|
{
|
if (baseDN.equals(entry1.getKey()))
|
{
|
for (Iterator<Entry<Integer, DBCursor<UpdateMsg>>> iter =
|
entry1.getValue().entrySet().iterator(); iter.hasNext();)
|
{
|
final Entry<Integer, DBCursor<UpdateMsg>> entry2 = iter.next();
|
if (csn.getServerId() == entry2.getKey())
|
{
|
iter.remove();
|
StaticUtils.close(entry2.getValue());
|
resetNextChangeForInsertDBCursor();
|
return;
|
}
|
}
|
}
|
}
|
}
|
|
private boolean recycleExhaustedCursors() throws ChangelogException
|
{
|
boolean succesfullyRecycled = false;
|
for (Map<Integer, DBCursor<UpdateMsg>> map : allCursors.values())
|
{
|
for (DBCursor<UpdateMsg> cursor : map.values())
|
{
|
// try to recycle it by calling next()
|
if (cursor.getRecord() == null && cursor.next())
|
{
|
succesfullyRecycled = true;
|
}
|
}
|
}
|
return succesfullyRecycled;
|
}
|
|
private boolean createNewCursors() throws ChangelogException
|
{
|
if (!newCursors.isEmpty())
|
{
|
boolean newCursorAdded = false;
|
for (Iterator<Entry<Pair<DN, Integer>, CSN>> iter =
|
newCursors.entrySet().iterator(); iter.hasNext();)
|
{
|
final Entry<Pair<DN, Integer>, CSN> entry = iter.next();
|
final DN baseDN = entry.getKey().getFirst();
|
final CSN csn = entry.getValue();
|
// start after preceding CSN so the first CSN read will exactly be the
|
// current one
|
final CSN startFromCSN = getPrecedingCSN(csn);
|
if (!ensureCursorExists(baseDN, csn.getServerId(), startFromCSN))
|
{
|
newCursorAdded = true;
|
}
|
iter.remove();
|
}
|
return newCursorAdded;
|
}
|
return false;
|
}
|
|
/**
|
* Asks the current thread to clear its state and blocks until state is
|
* cleared.
|
* <p>
|
* This method is only useful for unit tests.
|
*/
|
public void clear()
|
{
|
doClear.set(true);
|
while (doClear.get() && !State.TERMINATED.equals(getState()))
|
{
|
// wait until clear() has been done by thread, always waking it up
|
synchronized (this)
|
{
|
notify();
|
}
|
// ensures unit tests wait that this thread's state is cleaned up
|
Thread.yield();
|
}
|
}
|
|
}
|
