/*
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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 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.*;
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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 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.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.DebugLogLevel;
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import org.opends.server.types.DirectoryException;
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import static org.opends.server.loggers.debug.DebugLogger.*;
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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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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. This solution also avoids
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* using a queue that could fill up before we have consumed all its content.
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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 CSN for the current replication
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* 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 CSN mediumConsistencyCSN;
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/**
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* Holds the most recent changes or heartbeats received for each serverIds
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* cross domain.
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*/
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private final MultiDomainServerState lastSeenUpdates =
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new MultiDomainServerState();
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/**
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* Composite cursor across all the replicaDBs for all the replication domains.
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* It is volatile to ensure it supports concurrent update. Each time it is
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* used more than once in a method, the method must take a local copy to
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* ensure the cursor does not get updated in the middle of the method.
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*/
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private volatile CompositeDBCursor<DN> crossDomainDBCursor;
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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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/** This map can be updated by multiple threads. */
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private ConcurrentMap<CSN, DN> newCursors =
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new ConcurrentSkipListMap<CSN, DN>();
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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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lastSeenUpdates.update(baseDN, heartbeatCSN);
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tryNotify(baseDN);
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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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final CSN csn = updateMsg.getCSN();
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lastSeenUpdates.update(baseDN, csn);
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newCursors.put(csn, baseDN);
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tryNotify(baseDN);
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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(DN baseDN)
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{
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if (canMoveForwardMediumConsistencyPoint(baseDN))
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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(DN baseDN)
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{
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final CSN mcCSN = mediumConsistencyCSN;
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if (mcCSN != null)
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{
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final CSN lastSeenSameServerId =
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lastSeenUpdates.getCSN(baseDN, mcCSN.getServerId());
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return mcCSN.isOlderThan(lastSeenSameServerId);
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}
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return true;
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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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mediumConsistencyRUV.update(
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new MultiDomainServerState(newestRecord.getPreviousCookie()));
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}
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// initialize the cross domain DB cursor
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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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for (Integer serverId : entry.getValue())
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{
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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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lastSeenUpdates.update(baseDN, latestKnownState);
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}
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crossDomainDBCursor = newCompositeDBCursor();
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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 = crossDomainDBCursor.getRecord();
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if (!record.getCSN().equals(newestRecord.getCSN()))
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{
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// TODO JNR i18n safety check, should never happen
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throw new ChangelogException(Message.raw("They do not equal! recordCSN="
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+ record.getCSN() + " newestRecordCSN=" + newestRecord.getCSN()));
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}
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mediumConsistencyRUV.update(newestRecord.getBaseDN(), record.getCSN());
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crossDomainDBCursor.next();
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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 CompositeDBCursor<DN> newCompositeDBCursor() 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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final CompositeDBCursor<DN> result = new CompositeDBCursor<DN>(cursors);
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result.next();
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return result;
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}
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private boolean ensureCursorExists(DN baseDN, Integer serverId, CSN csn)
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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, csn);
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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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/** {@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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}
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catch (DirectoryException e)
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{
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// TODO JNR error message i18n
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if (debugEnabled())
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TRACER.debugCaught(DebugLogLevel.ERROR, e);
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return;
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}
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catch (ChangelogException e)
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{
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// TODO JNR error message i18n
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if (debugEnabled())
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TRACER.debugCaught(DebugLogLevel.ERROR, e);
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return;
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}
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while (!isShutdownInitiated())
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{
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try
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{
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createNewCursors();
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final UpdateMsg msg = crossDomainDBCursor.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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wait();
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}
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// advance cursor, success/failure will be checked later
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crossDomainDBCursor.next();
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// loop to check whether new changes have been added to the 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 = crossDomainDBCursor.getData();
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// FIXME problem: what if the serverId is not part of the ServerState?
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// right now, thread will be blocked
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if (!canMoveForwardMediumConsistencyPoint(baseDN))
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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 (!canMoveForwardMediumConsistencyPoint(baseDN))
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{
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wait();
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// loop to check if changes older than the medium consistency
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// point have been added to the ReplicaDBs
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continue;
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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 cursor, success/failure will be checked later
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crossDomainDBCursor.next();
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}
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catch (ChangelogException e)
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{
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if (debugEnabled())
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TRACER.debugCaught(DebugLogLevel.ERROR, e);
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// TODO JNR error message i18n
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}
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catch (InterruptedException ignored)
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{
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// was shutdown called?
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}
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}
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}
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private void moveForwardMediumConsistencyPoint(final CSN csn, final DN baseDN)
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{
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// update, so it becomes the previous cookie for the next change
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mediumConsistencyRUV.update(baseDN, csn);
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mediumConsistencyCSN = csn;
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}
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private void createNewCursors() throws ChangelogException
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{
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if (!newCursors.isEmpty())
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{
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boolean newCursorAdded = false;
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for (Iterator<Entry<CSN, DN>> iter = newCursors.entrySet().iterator();
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iter.hasNext();)
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{
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final Entry<CSN, DN> entry = iter.next();
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final CSN csn = entry.getKey();
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if (!ensureCursorExists(entry.getValue(), csn.getServerId(), null))
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{
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newCursorAdded = true;
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}
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iter.remove();
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}
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if (newCursorAdded)
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{
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crossDomainDBCursor = newCompositeDBCursor();
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}
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}
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}
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}
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