/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at legal-notices/CDDLv1_0.txt
* or http://forgerock.org/license/CDDLv1.0.html.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at legal-notices/CDDLv1_0.txt.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
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*
* Copyright 2014-2015 ForgeRock AS
*/
package org.opends.server.replication.server.changelog.file;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.concurrent.atomic.AtomicBoolean;
import org.forgerock.opendj.config.server.ConfigException;
import org.forgerock.opendj.ldap.ByteString;
import org.opends.server.admin.std.server.MonitorProviderCfg;
import org.opends.server.api.MonitorProvider;
import org.opends.server.core.DirectoryServer;
import org.opends.server.replication.common.CSN;
import org.opends.server.replication.protocol.ProtocolVersion;
import org.opends.server.replication.protocol.UpdateMsg;
import org.opends.server.replication.server.ReplicationServer;
import org.opends.server.replication.server.ReplicationServerDomain;
import org.opends.server.replication.server.changelog.api.ChangelogException;
import org.opends.server.replication.server.changelog.api.DBCursor;
import org.opends.server.replication.server.changelog.api.DBCursor.KeyMatchingStrategy;
import org.opends.server.replication.server.changelog.api.DBCursor.PositionStrategy;
import org.opends.server.replication.server.changelog.file.Log.RepositionableCursor;
import org.opends.server.types.Attribute;
import org.opends.server.types.Attributes;
import org.opends.server.types.DN;
import org.opends.server.types.InitializationException;
import static org.opends.messages.ReplicationMessages.*;
/**
* Represents a replication server database for one server in the topology.
* <p>
* It is responsible for efficiently saving the updates that is received from
* each master server into stable storage.
* <p>
* It is also able to generate a {@link DBCursor} that can be used to
* read all changes from a given {@link CSN}.
* <p>
* It publishes some monitoring information below cn=monitor.
*/
class FileReplicaDB
{
/** The parser of records stored in Replica DB. */
static final RecordParser<CSN, UpdateMsg> RECORD_PARSER = new ReplicaDBParser();
/**
* Class that allows atomically setting oldest and newest CSNs without
* synchronization.
*
* @Immutable
*/
private static final class CSNLimits
{
private final CSN oldestCSN;
private final CSN newestCSN;
public CSNLimits(CSN oldestCSN, CSN newestCSN)
{
this.oldestCSN = oldestCSN;
this.newestCSN = newestCSN;
}
}
private final AtomicBoolean shutdown = new AtomicBoolean(false);
/** The log in which records are persisted. */
private final Log<CSN, UpdateMsg> log;
/**
* Holds the oldest and newest CSNs for this replicaDB for fast retrieval.
*
* @NonNull
*/
private volatile CSNLimits csnLimits;
private final int serverId;
private final DN baseDN;
private final DbMonitorProvider dbMonitor = new DbMonitorProvider();
private final ReplicationServer replicationServer;
private final ReplicationEnvironment replicationEnv;
/**
* Creates a new ReplicaDB associated to a given LDAP server.
*
* @param serverId
* Id of this server.
* @param baseDN
* the replication domain baseDN.
* @param replicationServer
* The ReplicationServer that creates this ReplicaDB.
* @param replicationEnv
* the Database Env to use to create the ReplicationServer DB. server
* for this domain.
* @throws ChangelogException
* If a database problem happened
*/
FileReplicaDB(final int serverId, final DN baseDN, final ReplicationServer replicationServer,
final ReplicationEnvironment replicationEnv) throws ChangelogException
{
this.serverId = serverId;
this.baseDN = baseDN;
this.replicationServer = replicationServer;
this.replicationEnv = replicationEnv;
this.log = createLog(replicationEnv);
this.csnLimits = new CSNLimits(readOldestCSN(), readNewestCSN());
DirectoryServer.deregisterMonitorProvider(dbMonitor);
DirectoryServer.registerMonitorProvider(dbMonitor);
}
private CSN readOldestCSN() throws ChangelogException
{
final Record<CSN, UpdateMsg> record = log.getOldestRecord();
return record == null ? null : record.getKey();
}
private CSN readNewestCSN() throws ChangelogException
{
final Record<CSN, UpdateMsg> record = log.getNewestRecord();
return record == null ? null : record.getKey();
}
private Log<CSN, UpdateMsg> createLog(final ReplicationEnvironment replicationEnv) throws ChangelogException
{
final ReplicationServerDomain domain = replicationServer.getReplicationServerDomain(baseDN, true);
return replicationEnv.getOrCreateReplicaDB(baseDN, serverId, domain.getGenerationId());
}
/**
* Adds a new message.
*
* @param updateMsg
* The update message to add.
* @throws ChangelogException
* If an error occurs when trying to add the message.
*/
void add(final UpdateMsg updateMsg) throws ChangelogException
{
if (shutdown.get())
{
throw new ChangelogException(
ERR_COULD_NOT_ADD_CHANGE_TO_SHUTTING_DOWN_REPLICA_DB.get(updateMsg
.toString(), String.valueOf(baseDN), String.valueOf(serverId)));
}
log.append(Record.from(updateMsg.getCSN(), updateMsg));
final CSNLimits limits = csnLimits;
final boolean updateNew = limits.newestCSN == null || limits.newestCSN.isOlderThan(updateMsg.getCSN());
final boolean updateOld = limits.oldestCSN == null;
if (updateOld || updateNew)
{
csnLimits = new CSNLimits(
updateOld ? updateMsg.getCSN() : limits.oldestCSN,
updateNew ? updateMsg.getCSN() : limits.newestCSN);
}
}
/**
* Get the oldest CSN that has not been purged yet.
*
* @return the oldest CSN that has not been purged yet.
*/
CSN getOldestCSN()
{
return csnLimits.oldestCSN;
}
/**
* Get the newest CSN that has not been purged yet.
*
* @return the newest CSN that has not been purged yet.
*/
CSN getNewestCSN()
{
return csnLimits.newestCSN;
}
/**
* Returns a cursor that allows to retrieve the update messages from this DB.
* The actual starting position is defined by the provided CSN, the key
* matching strategy and the positioning strategy.
*
* @param startCSN
* The position where the cursor must start. If null, start from the
* oldest CSN
* @param matchingStrategy
* Cursor key matching strategy
* @param positionStrategy
* Cursor position strategy
* @return a new {@link DBCursor} to retrieve update messages.
* @throws ChangelogException
* if a database problem happened
*/
DBCursor<UpdateMsg> generateCursorFrom(final CSN startCSN, final KeyMatchingStrategy matchingStrategy,
final PositionStrategy positionStrategy) throws ChangelogException
{
RepositionableCursor<CSN, UpdateMsg> cursor = log.getCursor(startCSN, matchingStrategy, positionStrategy);
CSN actualStartCSN = (startCSN != null && startCSN.getServerId() == serverId) ? startCSN : null;
return new FileReplicaDBCursor(cursor, actualStartCSN, positionStrategy);
}
/** Shutdown this ReplicaDB. */
void shutdown()
{
if (shutdown.compareAndSet(false, true))
{
log.close();
DirectoryServer.deregisterMonitorProvider(dbMonitor);
}
}
/**
* Synchronously purge changes older than purgeCSN from this replicaDB.
*
* @param purgeCSN
* The CSN up to which changes can be purged. No purging happens when
* it is {@code null}.
* @throws ChangelogException
* In case of database problem.
*/
void purgeUpTo(final CSN purgeCSN) throws ChangelogException
{
if (purgeCSN == null)
{
return;
}
final Record<CSN, UpdateMsg> oldestRecord = log.purgeUpTo(purgeCSN);
if (oldestRecord != null)
{
csnLimits = new CSNLimits(oldestRecord.getKey(), csnLimits.newestCSN);
}
}
/**
* Implements monitoring capabilities of the ReplicaDB.
*/
private class DbMonitorProvider extends MonitorProvider<MonitorProviderCfg>
{
/** {@inheritDoc} */
@Override
public List<Attribute> getMonitorData()
{
final List<Attribute> attributes = new ArrayList<>();
create(attributes, "replicationServer-database",String.valueOf(serverId));
create(attributes, "domain-name", baseDN.toString());
final CSNLimits limits = csnLimits;
if (limits.oldestCSN != null)
{
create(attributes, "first-change", encode(limits.oldestCSN));
}
if (limits.newestCSN != null)
{
create(attributes, "last-change", encode(limits.newestCSN));
}
return attributes;
}
private void create(final List<Attribute> attributes, final String name, final String value)
{
attributes.add(Attributes.create(name, value));
}
private String encode(final CSN csn)
{
return csn + " " + new Date(csn.getTime());
}
/** {@inheritDoc} */
@Override
public String getMonitorInstanceName()
{
ReplicationServerDomain domain = replicationServer.getReplicationServerDomain(baseDN);
return "Changelog for DS(" + serverId + "),cn=" + domain.getMonitorInstanceName();
}
/** {@inheritDoc} */
@Override
public void initializeMonitorProvider(MonitorProviderCfg configuration)
throws ConfigException, InitializationException
{
// Nothing to do for now
}
}
/** {@inheritDoc} */
@Override
public String toString()
{
final CSNLimits limits = csnLimits;
return getClass().getSimpleName() + " " + baseDN + " " + serverId + " "
+ limits.oldestCSN + " " + limits.newestCSN;
}
/**
* Clear the changes from this DB, from both memory cache and persistent
* storage.
*
* @throws ChangelogException
* If an error occurs while removing the changes from the DB.
*/
void clear() throws ChangelogException
{
// Remove all persisted data and reset generationId to default value
log.clear();
replicationEnv.resetGenerationId(baseDN);
csnLimits = new CSNLimits(null, null);
}
/**
* Return the number of records of this replicaDB.
* <p>
* For test purpose.
*
* @return The number of records of this replicaDB.
* @throws ChangelogException
* If an error occurs
*/
long getNumberRecords() throws ChangelogException
{
return log.getNumberOfRecords();
}
/**
* Dump this DB as text files, intended for debugging purpose only.
*
* @throws ChangelogException
* If an error occurs during dump
*/
void dumpAsTextFiles() throws ChangelogException {
log.dumpAsTextFile(log.getPath());
}
/** Parser of records persisted in the ReplicaDB log. */
private static class ReplicaDBParser implements RecordParser<CSN, UpdateMsg>
{
@Override
public ByteString encodeRecord(final Record<CSN, UpdateMsg> record)
{
final UpdateMsg message = record.getValue();
return ByteString.wrap(message.getBytes());
}
@Override
public Record<CSN, UpdateMsg> decodeRecord(final ByteString data) throws DecodingException
{
try
{
final UpdateMsg msg =
(UpdateMsg) UpdateMsg.generateMsg(data.toByteArray(), ProtocolVersion.REPLICATION_PROTOCOL_V7);
return Record.from(msg.getCSN(), msg);
}
catch (Exception e)
{
throw new DecodingException(e);
}
}
/** {@inheritDoc} */
@Override
public CSN decodeKeyFromString(String key) throws ChangelogException
{
return new CSN(key);
}
/** {@inheritDoc} */
@Override
public String encodeKeyToString(CSN key)
{
return key.toString();
}
/** {@inheritDoc} */
@Override
public CSN getMaxKey()
{
return CSN.MAX_CSN_VALUE;
}
}
}