From 13f31d030c3b205931b63c29b0d6bc1d4eefd163 Mon Sep 17 00:00:00 2001
From: Nicolas Capponi <nicolas.capponi@forgerock.com>
Date: Thu, 21 Aug 2014 13:07:07 +0000
Subject: [PATCH] Checkpoint commit for OPENDJ-1206 : Create a new ReplicationBackend/ChangelogBackend   to support cn=changelog CR-4083

---
 opendj-sdk/opends/src/server/org/opends/server/replication/server/changelog/je/JEChangelogDB.java             |   13 
 opendj-sdk/opends/tests/unit-tests-testng/src/server/org/opends/server/backends/ChangelogBackendTestCase.java |  968 ++++++++++++++++++++++++
 opendj-sdk/opends/src/server/org/opends/server/replication/server/ReplicationServer.java                      |  152 +++
 opendj-sdk/opends/src/server/org/opends/server/replication/server/changelog/je/ECLEnabledDomainPredicate.java |    2 
 opendj-sdk/opends/src/messages/messages/replication.properties                                                |    4 
 opendj-sdk/opends/src/server/org/opends/server/replication/server/changelog/api/ReplicationDomainDB.java      |   28 
 opendj-sdk/opends/tests/unit-tests-testng/src/server/org/opends/server/replication/server/MonitorTest.java    |   12 
 opendj-sdk/opends/src/server/org/opends/server/replication/server/changelog/je/ECLMultiDomainDBCursor.java    |    2 
 opendj-sdk/opends/src/server/org/opends/server/backends/ChangelogBackend.java                                 | 1159 ++++++++++++++++++++++++++--
 opendj-sdk/opends/src/server/org/opends/server/replication/server/changelog/file/FileChangelogDB.java         |   15 
 10 files changed, 2,254 insertions(+), 101 deletions(-)

diff --git a/opendj-sdk/opends/src/messages/messages/replication.properties b/opendj-sdk/opends/src/messages/messages/replication.properties
index e8a0ac6..11702ec 100644
--- a/opendj-sdk/opends/src/messages/messages/replication.properties
+++ b/opendj-sdk/opends/src/messages/messages/replication.properties
@@ -616,3 +616,7 @@
  recovered by removing a partially written record
 NOTICE_SEARCH_CHANGELOG_INSUFFICIENT_PRIVILEGES_285=You do not have sufficient privileges to \
  perform a search request on cn=changelog
+SEVERE_ERR_CHANGELOG_BACKEND_SEARCH_286 =An error occurred when \
+ searching base DN '%s' with filter '%s' in changelog backend : %s
+SEVERE_ERR_CHANGELOG_BACKEND_NUM_SUBORDINATES_287 =An error occurred when \
+ retrieving number of subordinates for entry DN '%s' in changelog backend : %s
\ No newline at end of file
diff --git a/opendj-sdk/opends/src/server/org/opends/server/backends/ChangelogBackend.java b/opendj-sdk/opends/src/server/org/opends/server/backends/ChangelogBackend.java
index f281c8c..1a1ec5c 100644
--- a/opendj-sdk/opends/src/server/org/opends/server/backends/ChangelogBackend.java
+++ b/opendj-sdk/opends/src/server/org/opends/server/backends/ChangelogBackend.java
@@ -25,51 +25,115 @@
  */
 package org.opends.server.backends;
 
-import java.util.Collections;
-import java.util.Set;
-
-import org.opends.server.admin.Configuration;
-import org.opends.server.api.Backend;
-import org.opends.server.config.ConfigEntry;
-import org.opends.server.config.ConfigException;
-import org.opends.server.core.AddOperation;
-import org.opends.server.core.DeleteOperation;
-import org.opends.server.core.DirectoryServer;
-import org.opends.server.core.ModifyDNOperation;
-import org.opends.server.core.ModifyOperation;
-import org.opends.server.core.SearchOperation;
-import org.opends.server.loggers.debug.DebugTracer;
-import org.opends.server.types.AttributeType;
-import org.opends.server.types.BackupConfig;
-import org.opends.server.types.BackupDirectory;
-import org.opends.server.types.CanceledOperationException;
-import org.opends.server.types.ConditionResult;
-import org.opends.server.types.DebugLogLevel;
-import org.opends.server.types.DN;
-import org.opends.server.types.DirectoryException;
-import org.opends.server.types.Entry;
-import org.opends.server.types.IndexType;
-import org.opends.server.types.InitializationException;
-import org.opends.server.types.LDIFExportConfig;
-import org.opends.server.types.LDIFImportConfig;
-import org.opends.server.types.LDIFImportResult;
-import org.opends.server.types.RestoreConfig;
-import org.opends.server.types.ResultCode;
-import org.opends.server.util.Validator;
-
 import static org.opends.messages.BackendMessages.*;
-import static org.opends.server.loggers.debug.DebugLogger.*;
+import static org.opends.messages.ReplicationMessages.*;
+import static org.opends.server.config.ConfigConstants.*;
+import static org.opends.server.loggers.ErrorLogger.*;
+import static org.opends.server.loggers.debug.DebugLogger.debugEnabled;
+import static org.opends.server.loggers.debug.DebugLogger.getTracer;
+import static org.opends.server.replication.protocol.StartECLSessionMsg.ECLRequestType.*;
+import static org.opends.server.replication.server.changelog.api.DBCursor.PositionStrategy.*;
+import static org.opends.server.util.LDIFWriter.*;
 import static org.opends.server.util.ServerConstants.*;
 import static org.opends.server.util.StaticUtils.*;
 
+import java.text.SimpleDateFormat;
+import java.util.*;
+
+import org.opends.messages.Category;
+import org.opends.messages.Message;
+import org.opends.messages.Severity;
+import org.opends.server.admin.Configuration;
+import org.opends.server.api.Backend;
+import org.opends.server.config.ConfigConstants;
+import org.opends.server.config.ConfigException;
+import org.opends.server.controls.EntryChangelogNotificationControl;
+import org.opends.server.controls.ExternalChangelogRequestControl;
+import org.opends.server.core.*;
+import org.opends.server.loggers.debug.DebugTracer;
+import org.opends.server.replication.common.CSN;
+import org.opends.server.replication.common.MultiDomainServerState;
+import org.opends.server.replication.plugin.MultimasterReplication;
+import org.opends.server.replication.protocol.AddMsg;
+import org.opends.server.replication.protocol.DeleteMsg;
+import org.opends.server.replication.protocol.LDAPUpdateMsg;
+import org.opends.server.replication.protocol.ModifyCommonMsg;
+import org.opends.server.replication.protocol.ModifyDNMsg;
+import org.opends.server.replication.protocol.StartECLSessionMsg.ECLRequestType;
+import org.opends.server.replication.protocol.UpdateMsg;
+import org.opends.server.replication.server.ReplicationServer;
+import org.opends.server.replication.server.changelog.api.ChangeNumberIndexDB;
+import org.opends.server.replication.server.changelog.api.ChangeNumberIndexRecord;
+import org.opends.server.replication.server.changelog.api.ChangelogDB;
+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.ReplicationDomainDB;
+import org.opends.server.replication.server.changelog.je.ECLEnabledDomainPredicate;
+import org.opends.server.replication.server.changelog.je.ECLMultiDomainDBCursor;
+import org.opends.server.replication.server.changelog.je.MultiDomainDBCursor;
+import org.opends.server.types.*;
+import org.opends.server.util.StaticUtils;
+
 /**
- * A backend that provides access to the changelog, ie the "cn=changelog" suffix.
- * It is a read-only backend.
+ * A backend that provides access to the changelog, ie the "cn=changelog"
+ * suffix. It is a read-only backend that is created by a
+ * {@code ReplicationServer} and is not configurable.
+ * <p>
+ * There are two modes to search the changelog:
+ * <ul>
+ * <li>Cookie mode: when a "ECL Cookie Exchange Control" is provided with the
+ * request. The cookie provided in the control is used to retrieve entries from
+ * the ReplicaDBs. The <code>changeNumber</code> attribute is not returned with
+ * the entries.</li>
+ * <li>Draft compat mode: when no "ECL Cookie Exchange Control" is provided with
+ * the request. The entries are retrieved using the ChangeNumberIndexDB (or
+ * DraftDB, hence the name) and their attributes are set with the information
+ * from the ReplicasDBs. The <code>changeNumber</code> attribute value is set
+ * from the content of ChangeNumberIndexDB.</li>
+ * </ul>
+ *
+ * @see ReplicationServer
  */
-public class ChangelogBackend extends Backend
+public class ChangelogBackend extends Backend<Configuration>
 {
   private static final DebugTracer TRACER = getTracer();
 
+  /** The id of this backend. */
+  public static final String BACKEND_ID = "changelog";
+
+  private static final long CHANGE_NUMBER_FOR_EMPTY_CURSOR = 0L;
+
+  private static final String CHANGE_NUMBER_ATTR = "changeNumber";
+  private static final String CHANGE_NUMBER_ATTR_LC = CHANGE_NUMBER_ATTR.toLowerCase();
+
+  /** The set of objectclasses that will be used in root entry. */
+  private static final Map<ObjectClass, String>
+    CHANGELOG_ROOT_OBJECT_CLASSES = new LinkedHashMap<ObjectClass, String>(2);
+
+  static
+  {
+    CHANGELOG_ROOT_OBJECT_CLASSES.put(DirectoryServer.getObjectClass(OC_TOP, true), OC_TOP);
+    CHANGELOG_ROOT_OBJECT_CLASSES.put(DirectoryServer.getObjectClass("container", true), "container");
+  }
+
+  /** The set of objectclasses that will be used in ECL entries. */
+  private static final Map<ObjectClass, String>
+    CHANGELOG_ENTRY_OBJECT_CLASSES = new LinkedHashMap<ObjectClass, String>(2);
+
+  static
+  {
+    CHANGELOG_ENTRY_OBJECT_CLASSES.put(DirectoryServer.getObjectClass(OC_TOP, true), OC_TOP);
+    CHANGELOG_ENTRY_OBJECT_CLASSES.put(DirectoryServer.getObjectClass(OC_CHANGELOG_ENTRY, true), OC_CHANGELOG_ENTRY);
+  }
+
+  /** The attribute type for the "creatorsName" attribute. */
+  private static final AttributeType CREATORS_NAME_TYPE =
+      DirectoryConfig.getAttributeType(OP_ATTR_CREATORS_NAME_LC, true);
+
+  /** The attribute type for the "modifiersName" attribute. */
+  private static final AttributeType MODIFIERS_NAME_TYPE =
+      DirectoryConfig.getAttributeType(OP_ATTR_MODIFIERS_NAME_LC, true);
+
   /** The DN for the base changelog entry. */
   private DN baseChangelogDN;
 
@@ -77,52 +141,61 @@
   private DN[] baseDNs;
 
   /** The set of supported controls for this backend. */
-  private final Set<String> supportedControls =
-      Collections.singleton(OID_ECL_COOKIE_EXCHANGE_CONTROL);
+  private final Set<String> supportedControls = Collections.singleton(OID_ECL_COOKIE_EXCHANGE_CONTROL);
+
+  /** The replication server on which the changelog is read. */
+  private final ReplicationServer replicationServer;
+
+  private final ECLEnabledDomainPredicate domainPredicate;
+
+  /**
+   * Creates a new backend with the provided repication server.
+   *
+   * @param replicationServer
+   *          The replication server on which the changes are read.
+   * @param domainPredicate
+   *          Returns whether a domain is enabled for the external changelog.
+   */
+  public ChangelogBackend(final ReplicationServer replicationServer, final ECLEnabledDomainPredicate domainPredicate)
+  {
+    this.replicationServer = replicationServer;
+    this.domainPredicate = domainPredicate;
+    setBackendID(BACKEND_ID);
+    setWritabilityMode(WritabilityMode.DISABLED);
+    setPrivateBackend(true);
+  }
 
   /** {@inheritDoc} */
   @Override
-  public void configureBackend(final Configuration cfg) throws ConfigException
+  public void configureBackend(final Configuration config) throws ConfigException
   {
-    Validator.ensureNotNull(cfg);
+    throw new UnsupportedOperationException("The changelog backend is not configurable");
+  }
 
-    final ConfigEntry configEntry = DirectoryServer.getConfigEntry(cfg.dn());
-
-    // Make sure that a configuration entry was provided. If not, then we will
-    // not be able to complete initialization.
-    if (configEntry == null)
-    {
-      throw new ConfigException(ERR_BACKEND_CONFIG_ENTRY_NULL.get(getBackendID()));
-    }
-
-    // Create the set of base DNs that we will handle. In this case, it's just
-    // the DN of the base changelog entry.
+  /** {@inheritDoc} */
+  @Override
+  public void initializeBackend() throws InitializationException
+  {
     try
     {
       baseChangelogDN = DN.decode(DN_EXTERNAL_CHANGELOG_ROOT);
+      baseDNs = new DN[] { baseChangelogDN };
     }
-    catch (final Exception e)
+    catch (final DirectoryException e)
     {
       if (debugEnabled())
       {
         TRACER.debugCaught(DebugLogLevel.ERROR, e);
       }
-      throw new ConfigException(
+      throw new InitializationException(
           ERR_BACKEND_CANNOT_DECODE_BACKEND_ROOT_DN.get(getBackendID(), getExceptionMessage(e)), e);
     }
 
-    this.baseDNs = new DN[] { baseChangelogDN };
-  }
-
-  /** {@inheritDoc} */
-  @Override
-  public void initializeBackend() throws ConfigException, InitializationException
-  {
     try
     {
       DirectoryServer.registerBaseDN(baseChangelogDN, this, true);
     }
-    catch (final Exception e)
+    catch (final DirectoryException e)
     {
       throw new InitializationException(
           ERR_BACKEND_CANNOT_REGISTER_BASEDN.get(baseChangelogDN.toString(), getExceptionMessage(e)), e);
@@ -137,7 +210,7 @@
     {
       DirectoryServer.deregisterBaseDN(baseChangelogDN);
     }
-    catch (final Exception e)
+    catch (final DirectoryException e)
     {
       if (debugEnabled())
       {
@@ -157,26 +230,26 @@
   @Override
   public void preloadEntryCache() throws UnsupportedOperationException
   {
-    throw new RuntimeException("Not implemented");
+    throw new UnsupportedOperationException("Operation not supported.");
   }
 
   /** {@inheritDoc} */
   @Override
   public boolean isLocal()
   {
-    throw new RuntimeException("Not implemented");
+    return true;
   }
 
   /** {@inheritDoc} */
   @Override
-  public boolean isIndexed(AttributeType attributeType, IndexType indexType)
+  public boolean isIndexed(final AttributeType attributeType, final IndexType indexType)
   {
-    throw new RuntimeException("Not implemented");
+    return true;
   }
 
   /** {@inheritDoc} */
   @Override
-  public Entry getEntry(DN entryDN) throws DirectoryException
+  public Entry getEntry(final DN entryDN) throws DirectoryException
   {
     if (entryDN == null)
     {
@@ -188,17 +261,90 @@
 
   /** {@inheritDoc} */
   @Override
-  public ConditionResult hasSubordinates(DN entryDN) throws DirectoryException
+  public ConditionResult hasSubordinates(final DN entryDN)
+      throws DirectoryException
   {
-    throw new RuntimeException("Not implemented");
+    final long num = numSubordinates(entryDN, false);
+    if (num < 0)
+    {
+      return ConditionResult.UNDEFINED;
+    }
+    else if (num == 0)
+    {
+      return ConditionResult.FALSE;
+    }
+    else
+    {
+      return ConditionResult.TRUE;
+    }
+  }
+
+  /** Specific search operation to count number of entries. */
+  private final class NumSubordinatesSearchOperation extends SearchOperationWrapper
+  {
+    private long numSubordinates = -1;
+
+    private NumSubordinatesSearchOperation()
+    {
+      super(null);
+    }
+
+    @Override
+    public boolean returnEntry(Entry entry, List<Control> controls)
+    {
+      numSubordinates++;
+      return true;
+    }
+
+    @Override
+    public DN getBaseDN()
+    {
+      return baseChangelogDN;
+    }
+
+    @Override
+    public SearchFilter getFilter()
+    {
+      return LDAPURL.DEFAULT_SEARCH_FILTER;
+    }
+
+    @Override
+    public SearchScope getScope()
+    {
+      return SearchScope.WHOLE_SUBTREE;
+    }
   }
 
   /** {@inheritDoc} */
   @Override
-  public long numSubordinates(DN entryDN, boolean subtree)
-      throws DirectoryException
+  public long numSubordinates(final DN entryDN, final boolean subtree) throws DirectoryException
   {
-    throw new RuntimeException("Not implemented");
+    // Compute the num subordinates only for the base DN
+    if (entryDN == null || !baseChangelogDN.equals(entryDN))
+    {
+      return -1;
+    }
+    if (!subtree)
+    {
+      return 1;
+    }
+    // Search with cookie mode to count all update messages
+    final Set<String> excludedDomains = MultimasterReplication.getECLDisabledDomains();
+    excludedDomains.add(DN_EXTERNAL_CHANGELOG_ROOT);
+    SearchParams params = new SearchParams("0", excludedDomains);
+    params.requestType = REQUEST_TYPE_FROM_COOKIE;
+    params.multiDomainServerState = new MultiDomainServerState();
+    NumSubordinatesSearchOperation searchOp = new NumSubordinatesSearchOperation();
+    try
+    {
+      search0(params, searchOp);
+    }
+    catch (ChangelogException e)
+    {
+      throw new DirectoryException(ResultCode.UNWILLING_TO_PERFORM, ERR_CHANGELOG_BACKEND_NUM_SUBORDINATES.get(
+          baseChangelogDN.toString(), stackTraceToSingleLineString(e)));
+    }
+    return searchOp.numSubordinates;
   }
 
   /** {@inheritDoc} */
@@ -241,10 +387,35 @@
 
   /** {@inheritDoc} */
   @Override
-  public void search(SearchOperation searchOperation)
-      throws DirectoryException, CanceledOperationException
+  public void search(final SearchOperation searchOperation) throws DirectoryException
   {
-    throw new RuntimeException("Not implemented");
+    final Set<String> excludedDomains = MultimasterReplication.getECLDisabledDomains();
+    excludedDomains.add(DN_EXTERNAL_CHANGELOG_ROOT);
+    SearchParams params = new SearchParams(searchOperation.toString(), excludedDomains);
+    final ExternalChangelogRequestControl eclRequestControl =
+        searchOperation.getRequestControl(ExternalChangelogRequestControl.DECODER);
+    if (eclRequestControl == null)
+    {
+      params.requestType = REQUEST_TYPE_FROM_CHANGE_NUMBER;
+    }
+    else
+    {
+      params.requestType = REQUEST_TYPE_FROM_COOKIE;
+      params.multiDomainServerState = eclRequestControl.getCookie();
+    }
+
+    optimizeSearchParameters(params, searchOperation.getBaseDN(), searchOperation.getFilter());
+    try
+    {
+      search0(params, searchOperation);
+    }
+    catch (ChangelogException e)
+    {
+      throw new DirectoryException(ResultCode.UNWILLING_TO_PERFORM, ERR_CHANGELOG_BACKEND_SEARCH.get(
+          searchOperation.getBaseDN().toString(),
+          searchOperation.getFilter().toString(),
+          stackTraceToSingleLineString(e)));
+    }
   }
 
   /** {@inheritDoc} */
@@ -270,7 +441,7 @@
 
   /** {@inheritDoc} */
   @Override
-  public void exportLDIF(LDIFExportConfig exportConfig)
+  public void exportLDIF(final LDIFExportConfig exportConfig)
       throws DirectoryException
   {
     throw new DirectoryException(ResultCode.UNWILLING_TO_PERFORM,
@@ -297,15 +468,14 @@
   @Override
   public boolean supportsBackup()
   {
-    throw new RuntimeException("Not implemented");
+    return false;
   }
 
   /** {@inheritDoc} */
   @Override
-  public boolean supportsBackup(BackupConfig backupConfig,
-      StringBuilder unsupportedReason)
+  public boolean supportsBackup(BackupConfig backupConfig, StringBuilder unsupportedReason)
   {
-    throw new RuntimeException("Not implemented");
+    return false;
   }
 
   /** {@inheritDoc} */
@@ -318,34 +488,843 @@
 
   /** {@inheritDoc} */
   @Override
-  public void removeBackup(BackupDirectory backupDirectory, String backupID)
-      throws DirectoryException
+  public void removeBackup(BackupDirectory backupDirectory, String backupID) throws DirectoryException
   {
-    throw new DirectoryException(ResultCode.UNWILLING_TO_PERFORM,
-        ERR_BACKEND_BACKUP_AND_RESTORE_NOT_SUPPORTED.get(getBackendID()));
+      throw new DirectoryException(ResultCode.UNWILLING_TO_PERFORM,
+          ERR_BACKEND_BACKUP_AND_RESTORE_NOT_SUPPORTED.get(getBackendID()));
   }
 
   /** {@inheritDoc} */
   @Override
   public boolean supportsRestore()
   {
-    throw new RuntimeException("Not implemented");
+    return false;
   }
 
   /** {@inheritDoc} */
   @Override
-  public void restoreBackup(RestoreConfig restoreConfig)
-      throws DirectoryException
+  public void restoreBackup(RestoreConfig restoreConfig) throws DirectoryException
   {
-    throw new DirectoryException(ResultCode.UNWILLING_TO_PERFORM,
-        ERR_BACKEND_BACKUP_AND_RESTORE_NOT_SUPPORTED.get(getBackendID()));
+      throw new DirectoryException(ResultCode.UNWILLING_TO_PERFORM,
+          ERR_BACKEND_BACKUP_AND_RESTORE_NOT_SUPPORTED.get(getBackendID()));
   }
 
   /** {@inheritDoc} */
   @Override
   public long getEntryCount()
   {
-    throw new RuntimeException("Not implemented");
+    try
+    {
+      return numSubordinates(baseChangelogDN, true) + 1;
+    }
+    catch (DirectoryException e)
+    {
+      if (debugEnabled())
+      {
+        TRACER.debugCaught(DebugLogLevel.ERROR, e);
+      }
+      return -1;
+    }
+  }
+
+  /**
+   * Represent the search parameters specific to the changelog.
+   *
+   * This class should be visible for tests.
+   */
+  static class SearchParams
+  {
+    private ECLRequestType requestType;
+    private final String operationId;
+    private final Set<String> excludedBaseDNs;
+    private long lowestChangeNumber = -1;
+    private long highestChangeNumber = -1;
+    private CSN csn = new CSN(0, 0, 0);
+    private MultiDomainServerState multiDomainServerState;
+
+    /**
+     * Creates search parameters.
+     */
+    SearchParams()
+    {
+      operationId = "";
+      excludedBaseDNs = Collections.emptySet();
+    }
+
+    /**
+     * Creates search parameters with provided id and excluded domain DNs.
+     *
+     * @param operationId
+     *          The id of the operation.
+     * @param excludedBaseDNs
+     *          Set of DNs to exclude from search.
+     */
+    SearchParams(final String operationId, final Set<String> excludedBaseDNs)
+    {
+      this.operationId = operationId;
+      this.excludedBaseDNs = excludedBaseDNs;
+    }
+
+    /**
+     * Indicates if provided change number is compatible with last change
+     * number.
+     *
+     * @param changeNumber
+     *          The change number to test.
+     * @return {@code true} if and only if the provided change number is in the
+     *         range of the last change number.
+     */
+    boolean changeNumberIsInRange(long changeNumber)
+    {
+      return highestChangeNumber == -1 || changeNumber <= highestChangeNumber;
+    }
+
+    /**
+     * Returns the lowest change number to retrieve (inclusive).
+     *
+     * @return the lowest change number
+     */
+    long getLowestChangeNumber()
+    {
+      return lowestChangeNumber;
+    }
+
+    /**
+     * Returns the highest change number to retrieve (inclusive).
+     *
+     * @return the highest change number
+     */
+    long getHighestChangeNumber()
+    {
+      return highestChangeNumber;
+    }
+
+    /**
+     * Returns the CSN to retrieve.
+     *
+     * @return the CSN, which may be the default CSN with zero values.
+     */
+    CSN getCSN()
+    {
+      return csn;
+    }
+
+    /**
+     * Returns the set of DNs to exclude from the search.
+     *
+     * @return the DNs corresponding to domains to exclude from the search.
+     * @throws DirectoryException
+     *           If a DN can't be decoded.
+     */
+    Set<DN> getExcludedBaseDNs() throws DirectoryException
+    {
+      final Set<DN> excludedDNs = new HashSet<DN>();
+      for (String dn : excludedBaseDNs)
+      {
+        excludedDNs.add(DN.decode(dn));
+      }
+      return excludedDNs;
+    }
+
+  }
+
+  /**
+   * Optimize the search parameters by analyzing the DN and filter.
+   * Populate the provided SearchParams with optimizations found.
+   *
+   * @param params the search parameters that are specific to external changelog
+   * @param baseDN the provided search baseDN.
+   * @param userFilter the provided search filter.
+   * @throws DirectoryException when an exception occurs.
+   */
+   void optimizeSearchParameters(final SearchParams params, final DN baseDN, final SearchFilter userFilter)
+       throws DirectoryException
+  {
+    SearchFilter equalityFilter = null;
+    switch (baseDN.getNumComponents())
+    {
+    case 1:
+      // "cn=changelog" : use user-provided search filter.
+      break;
+    case 2:
+      // It is probably "changeNumber=xxx,cn=changelog", use equality filter
+      // But it also could be "<service-id>,cn=changelog" so need to check on attribute
+      equalityFilter = buildSearchFilterFrom(baseDN, CHANGE_NUMBER_ATTR_LC, CHANGE_NUMBER_ATTR);
+      break;
+    default:
+      // "replicationCSN=xxx,<service-id>,cn=changelog" : use equality filter
+      equalityFilter = buildSearchFilterFrom(baseDN, "replicationcsn", "replicationCSN");
+      break;
+    }
+
+    final SearchParams optimized = optimizeSearchUsingFilter(equalityFilter != null ? equalityFilter : userFilter);
+    params.lowestChangeNumber = optimized.lowestChangeNumber;
+    params.highestChangeNumber = optimized.highestChangeNumber;
+    params.csn = optimized.csn;
+  }
+
+  /**
+   * Build a search filter from given DN and attribute.
+   *
+   * @return the search filter or {@code null} if attribute is not present in
+   *         the provided DN
+   */
+  private SearchFilter buildSearchFilterFrom(final DN baseDN, final String lowerCaseAttr, final String upperCaseAttr)
+  {
+    final RDN rdn = baseDN.getRDN();
+    AttributeType attrType = DirectoryServer.getAttributeType(lowerCaseAttr);
+    if (attrType == null)
+    {
+      attrType = DirectoryServer.getDefaultAttributeType(upperCaseAttr);
+    }
+    final AttributeValue attrValue = rdn.getAttributeValue(attrType);
+    if (attrValue != null)
+    {
+      return SearchFilter.createEqualityFilter(attrType, attrValue);
+    }
+    return null;
+  }
+
+  private SearchParams optimizeSearchUsingFilter(final SearchFilter filter) throws DirectoryException
+  {
+    final SearchParams params = new SearchParams();
+    if (filter == null)
+    {
+      return params;
+    }
+
+    if (matches(filter, FilterType.GREATER_OR_EQUAL, CHANGE_NUMBER_ATTR))
+    {
+      params.lowestChangeNumber = decodeChangeNumber(filter.getAssertionValue());
+    }
+    else if (matches(filter, FilterType.LESS_OR_EQUAL, CHANGE_NUMBER_ATTR))
+    {
+      params.highestChangeNumber = decodeChangeNumber(filter.getAssertionValue());
+    }
+    else if (matches(filter, FilterType.EQUALITY, CHANGE_NUMBER_ATTR))
+    {
+      final long number = decodeChangeNumber(filter.getAssertionValue());
+      params.lowestChangeNumber = number;
+      params.highestChangeNumber = number;
+    }
+    else if (matches(filter, FilterType.EQUALITY, "replicationcsn"))
+    {
+      // == exact CSN
+      params.csn = new CSN(filter.getAssertionValue().toString());
+    }
+    else if (filter.getFilterType() == FilterType.AND)
+    {
+      // TODO: it looks like it could be generalized to N components, not only two
+      final Collection<SearchFilter> components = filter.getFilterComponents();
+      final SearchFilter filters[] = components.toArray(new SearchFilter[0]);
+      long last1 = -1;
+      long first1 = -1;
+      long last2 = -1;
+      long first2 = -1;
+      if (filters.length > 0)
+      {
+        SearchParams msg1 = optimizeSearchUsingFilter(filters[0]);
+        last1 = msg1.highestChangeNumber;
+        first1 = msg1.lowestChangeNumber;
+      }
+      if (filters.length > 1)
+      {
+        SearchParams msg2 = optimizeSearchUsingFilter(filters[1]);
+        last2 = msg2.highestChangeNumber;
+        first2 = msg2.lowestChangeNumber;
+      }
+      if (last1 == -1)
+      {
+        params.highestChangeNumber = last2;
+      }
+      else if (last2 == -1)
+      {
+        params.highestChangeNumber = last1;
+      }
+      else
+      {
+        params.highestChangeNumber = Math.min(last1, last2);
+      }
+
+      params.lowestChangeNumber = Math.max(first1, first2);
+    }
+    return params;
+  }
+
+  private static long decodeChangeNumber(final AttributeValue assertionValue)
+      throws DirectoryException
+  {
+    try
+    {
+      return Long.decode(assertionValue.getNormalizedValue().toString());
+    }
+    catch (NumberFormatException e)
+    {
+      throw new DirectoryException(ResultCode.INVALID_ATTRIBUTE_SYNTAX,
+          Message.raw("Could not convert value '%s' to long", assertionValue.getNormalizedValue().toString()));
+    }
+  }
+
+  private boolean matches(SearchFilter filter, FilterType filterType, String primaryName)
+  {
+    return filter.getFilterType() == filterType
+           && filter.getAttributeType() != null
+           && filter.getAttributeType().getPrimaryName().equalsIgnoreCase(primaryName);
+  }
+
+  private void search0(final SearchParams searchParams, final SearchOperation searchOperation)
+      throws DirectoryException, ChangelogException
+  {
+    switch (searchParams.requestType)
+    {
+      case REQUEST_TYPE_FROM_CHANGE_NUMBER:
+        searchFromChangeNumber(searchParams, searchOperation);
+        break;
+      case REQUEST_TYPE_FROM_COOKIE:
+        searchFromCookie(searchParams, searchOperation);
+        break;
+      default:
+        // not handled
+    }
+  }
+
+  /**
+   * Search the changelog when a cookie control is provided.
+   */
+  private void searchFromCookie(final SearchParams searchParams, final SearchOperation searchOperation)
+      throws DirectoryException, ChangelogException
+  {
+    final ReplicationDomainDB replicationDomainDB = replicationServer.getChangelogDB().getReplicationDomainDB();
+    validateProvidedCookie(searchParams);
+
+    boolean hasReturnedBaseEntry = false;
+    ECLMultiDomainDBCursor replicaUpdatesCursor = null;
+    try
+    {
+      final MultiDomainDBCursor cursor = replicationDomainDB.getCursorFrom(
+          searchParams.multiDomainServerState, AFTER_MATCHING_KEY, searchParams.getExcludedBaseDNs());
+      replicaUpdatesCursor = new ECLMultiDomainDBCursor(domainPredicate, cursor);
+
+      MultiDomainServerState cookie = searchParams.multiDomainServerState;
+      boolean continueSearch = true;
+      while (continueSearch && replicaUpdatesCursor.next())
+      {
+        // Handle creation of base changelog entry on first update message found
+        if (!hasReturnedBaseEntry)
+        {
+          if (!returnBaseChangelogEntry(searchOperation, true))
+          {
+            return;
+          }
+          hasReturnedBaseEntry = true;
+        }
+        // Handle the update message
+        final UpdateMsg updateMsg = replicaUpdatesCursor.getRecord();
+        final DN domainBaseDN = replicaUpdatesCursor.getData();
+        cookie.update(domainBaseDN, updateMsg.getCSN());
+        final Entry entry = createEntryFromMsg(domainBaseDN, 0L, cookie.toString(), updateMsg);
+        if (matchBaseAndScopeAndFilter(entry, searchOperation))
+        {
+          Control control = new EntryChangelogNotificationControl(true, cookie.toString());
+          continueSearch = searchOperation.returnEntry(entry, Arrays.asList(control));
+        }
+      }
+      // Handle creation of base changelog entry when no update message is found
+      if (!hasReturnedBaseEntry)
+      {
+        returnBaseChangelogEntry(searchOperation, false);
+      }
+    }
+    finally
+    {
+      StaticUtils.close(replicaUpdatesCursor);
+    }
+  }
+
+  /**
+   * Validates the cookie contained in search parameters by checking its content
+   * with the actual replication server state.
+   *
+   * @throws DirectoryException
+   *           If the state is not valid
+   */
+  private void validateProvidedCookie(final SearchParams searchParams) throws DirectoryException
+  {
+    final MultiDomainServerState state = searchParams.multiDomainServerState;
+    if (state != null && !state.isEmpty())
+    {
+      replicationServer.validateServerState(state, searchParams.getExcludedBaseDNs());
+    }
+  }
+
+  /**
+   * Search the changelog using change number(s).
+   */
+  private void searchFromChangeNumber(final SearchParams params, final SearchOperation searchOperation)
+      throws ChangelogException, DirectoryException
+  {
+    boolean hasReturnedBaseEntry = false;
+    final ChangelogDB changelogDB = replicationServer.getChangelogDB();
+    DBCursor<ChangeNumberIndexRecord> cnIndexDBCursor = null;
+    MultiDomainDBCursor replicaUpdatesCursor = null;
+    try {
+      cnIndexDBCursor = getCNIndexDBCursor(changelogDB, params.lowestChangeNumber);
+      boolean continueSearch = true;
+      while (continueSearch && cnIndexDBCursor.next())
+      {
+        // Handle creation of base changelog entry on cnIndex record found
+        if (!hasReturnedBaseEntry)
+        {
+          if (!returnBaseChangelogEntry(searchOperation, true))
+          {
+            return;
+          }
+          hasReturnedBaseEntry = true;
+        }
+        // Handle the current cnIndex record
+        final ChangeNumberIndexRecord cnIndexRecord = cnIndexDBCursor.getRecord();
+        if (replicaUpdatesCursor == null)
+        {
+          replicaUpdatesCursor = initializeReplicaUpdatesCursor(changelogDB, cnIndexRecord);
+        }
+        continueSearch = params.changeNumberIsInRange(cnIndexRecord.getChangeNumber());
+        if (continueSearch)
+        {
+           UpdateMsg updateMsg = findReplicaUpdateMessage(cnIndexRecord, replicaUpdatesCursor);
+           if (updateMsg != null)
+           {
+             continueSearch = returnEntryForUpdateMessage(searchOperation, cnIndexRecord, updateMsg);
+             replicaUpdatesCursor.next();
+           }
+        }
+      }
+      // Handle creation of base changelog entry when no update message is found
+      if (!hasReturnedBaseEntry)
+      {
+        returnBaseChangelogEntry(searchOperation, false);
+      }
+    }
+    finally {
+      StaticUtils.close(cnIndexDBCursor, replicaUpdatesCursor);
+    }
+  }
+
+  /**
+   * Create and returns the base changelog entry to provided search operation.
+   *
+   * @return {@code true} if search should continue, {@code false} otherwise
+   */
+  private boolean returnBaseChangelogEntry(final SearchOperation searchOperation, boolean hasSubordinates)
+      throws DirectoryException
+  {
+    final DN baseDN = searchOperation.getBaseDN();
+    final SearchFilter filter = searchOperation.getFilter();
+    final SearchScope scope = searchOperation.getScope();
+
+    if (baseChangelogDN.matchesBaseAndScope(baseDN, scope))
+    {
+      final Entry entry = buildBaseChangelogEntry(hasSubordinates);
+      if (filter.matchesEntry(entry) && !searchOperation.returnEntry(entry, null))
+      {
+        // Abandon, size limit reached.
+        return false;
+      }
+    }
+    if (baseDN.equals(baseChangelogDN) && scope.equals(SearchScope.BASE_OBJECT))
+    {
+      // Only the change log root entry was requested
+      return false;
+    }
+    return true;
+  }
+
+  /**
+   * @return {@code true} if search should continue, {@code false} otherwise
+   */
+  private boolean returnEntryForUpdateMessage(
+      final SearchOperation searchOperation,
+      final ChangeNumberIndexRecord cnIndexRecord,
+      final UpdateMsg updateMsg)
+          throws DirectoryException
+  {
+    final MultiDomainServerState cookie = new MultiDomainServerState(cnIndexRecord.getPreviousCookie());
+    final DN changeDN = cnIndexRecord.getBaseDN();
+    cookie.update(changeDN, cnIndexRecord.getCSN());
+    final Entry entry = createEntryFromMsg(changeDN, cnIndexRecord.getChangeNumber(), cookie.toString(), updateMsg);
+    if (matchBaseAndScopeAndFilter(entry, searchOperation))
+    {
+      return searchOperation.returnEntry(entry, null);
+    }
+    return true;
+  }
+
+  private MultiDomainDBCursor initializeReplicaUpdatesCursor(final ChangelogDB changelogDB,
+      final ChangeNumberIndexRecord cnIndexRecord) throws ChangelogException
+  {
+    final MultiDomainServerState state = new MultiDomainServerState();
+    state.update(cnIndexRecord.getBaseDN(), cnIndexRecord.getCSN());
+
+    // No need for ECLMultiDomainDBCursor in this case
+    // as updateMsg will be matched with cnIndexRecord
+    final MultiDomainDBCursor replicaUpdatesCursor =
+        changelogDB.getReplicationDomainDB().getCursorFrom(state, ON_MATCHING_KEY);
+    replicaUpdatesCursor.next();
+    return replicaUpdatesCursor;
+  }
+
+  /**
+   * Returns the replica update message corresponding to the provided
+   * cnIndexRecord.
+   *
+   * @return the update message, which may be {@code null} if the update message
+   *         could not be found because it was purged or because corresponding
+   *         baseDN was removed from the changelog
+   * @throws DirectoryException
+   *           If inconsistency is detected between the available update
+   *           messages and the provided cnIndexRecord
+   */
+  private UpdateMsg findReplicaUpdateMessage(
+      final ChangeNumberIndexRecord cnIndexRecord,
+      final MultiDomainDBCursor replicaUpdatesCursor)
+          throws DirectoryException, ChangelogException
+  {
+    while (true)
+    {
+      final UpdateMsg updateMsg = replicaUpdatesCursor.getRecord();
+      final int compareIndexWithUpdateMsg = cnIndexRecord.getCSN().compareTo(updateMsg.getCSN());
+      if (compareIndexWithUpdateMsg < 0) {
+        // Either update message has been purged or baseDN has been removed from changelogDB,
+        // ignore current index record and go to the next one
+        return null;
+      }
+      else if (compareIndexWithUpdateMsg == 0)
+      {
+        // Found the matching update message
+        return updateMsg;
+      }
+      // Case compareIndexWithUpdateMsg > 0 : the update message has not bean reached yet
+      if (!replicaUpdatesCursor.next())
+      {
+        // Should never happen, as it means some messages have disappeared
+        // TODO : put the correct I18N message
+        throw new DirectoryException(ResultCode.OPERATIONS_ERROR,
+            Message.raw("Could not find replica update message matching index record. " +
+                "No more replica update messages with a csn newer than " + updateMsg.getCSN() + " exist."));
+      }
+    }
+  }
+
+  /** Returns a cursor on CNIndexDB for the provided first change number. */
+  private DBCursor<ChangeNumberIndexRecord> getCNIndexDBCursor(final ChangelogDB changelogDB,
+      final long firstChangeNumber) throws ChangelogException
+  {
+    final ChangeNumberIndexDB cnIndexDB = changelogDB.getChangeNumberIndexDB();
+    long changeNumberToUse = firstChangeNumber;
+    if (changeNumberToUse <= 1)
+    {
+      final ChangeNumberIndexRecord oldestRecord = cnIndexDB.getOldestRecord();
+      changeNumberToUse = oldestRecord == null ? CHANGE_NUMBER_FOR_EMPTY_CURSOR : oldestRecord.getChangeNumber();
+    }
+    return cnIndexDB.getCursorFrom(changeNumberToUse);
+  }
+
+  /** Indicates if the provided entry matches the filter, base and scope. */
+  private boolean matchBaseAndScopeAndFilter(Entry entry, SearchOperation searchOp) throws DirectoryException
+  {
+    return entry.matchesBaseAndScope(searchOp.getBaseDN(), searchOp.getScope())
+        && searchOp.getFilter().matchesEntry(entry);
+  }
+
+  /**
+   * Retrieves the base changelog entry.
+   */
+  private Entry buildBaseChangelogEntry(boolean hasSubordinates)
+  {
+    final Map<AttributeType, List<Attribute>> userAttrs = new LinkedHashMap<AttributeType,List<Attribute>>();
+    final Map<AttributeType, List<Attribute>> operationalAttrs = new LinkedHashMap<AttributeType,List<Attribute>>();
+
+    addAttributeByUppercaseName(ATTR_COMMON_NAME, ATTR_COMMON_NAME, BACKEND_ID, userAttrs, operationalAttrs);
+    addAttributeByUppercaseName(ATTR_SUBSCHEMA_SUBENTRY_LC, ATTR_SUBSCHEMA_SUBENTRY,
+        ConfigConstants.DN_DEFAULT_SCHEMA_ROOT, userAttrs, operationalAttrs);
+    addAttributeByUppercaseName("hassubordinates", "hasSubordinates", Boolean.toString(hasSubordinates),
+        userAttrs, operationalAttrs);
+    addAttributeByUppercaseName("entrydn", "entryDN", baseChangelogDN.toString(),
+        userAttrs, operationalAttrs);
+    return new Entry(baseChangelogDN, CHANGELOG_ROOT_OBJECT_CLASSES, userAttrs, operationalAttrs);
+  }
+
+  /**
+   * Creates a changelog entry.
+   */
+  private Entry createEntryFromMsg(final DN baseDN, final long changeNumber, final String cookie, final UpdateMsg msg)
+      throws DirectoryException
+  {
+    if (msg instanceof AddMsg)
+    {
+      return createAddMsg(baseDN, changeNumber, cookie, msg);
+    }
+    else if (msg instanceof ModifyCommonMsg)
+    {
+      return createModifyMsg(baseDN, changeNumber, cookie, msg);
+    }
+    else if (msg instanceof DeleteMsg)
+    {
+      final DeleteMsg delMsg = (DeleteMsg) msg;
+      return createChangelogEntry(baseDN, changeNumber, cookie, delMsg, null, "delete", delMsg.getInitiatorsName());
+    }
+    throw new DirectoryException(ResultCode.OPERATIONS_ERROR,
+        Message.raw("Unexpected message type when trying to create changelog entry for dn %s : %s", baseDN.toString(),
+            msg.getClass().toString()));
+  }
+
+  /**
+   * Creates an entry from an add message.
+   * <p>
+   * Map addMsg to an LDIF string for the 'changes' attribute, and pull out
+   * change initiators name if available which is contained in the creatorsName
+   * attribute.
+   */
+  private Entry createAddMsg(final DN baseDN, final long changeNumber, final String cookie, final UpdateMsg msg)
+      throws DirectoryException
+  {
+    final AddMsg addMsg = (AddMsg) msg;
+    String changeInitiatorsName = null;
+    String ldifChanges = null;
+    try
+    {
+      final StringBuilder builder = new StringBuilder(256);
+      for (Attribute attr : addMsg.getAttributes())
+      {
+        if (attr.getAttributeType().equals(CREATORS_NAME_TYPE) && !attr.isEmpty())
+        {
+          // This attribute is not multi-valued.
+          changeInitiatorsName = attr.iterator().next().toString();
+        }
+        final String attrName = attr.getNameWithOptions();
+        for (AttributeValue value : attr)
+        {
+          builder.append(attrName);
+          appendLDIFSeparatorAndValue(builder, value.getValue());
+          builder.append('\n');
+        }
+      }
+      ldifChanges = builder.toString();
+    }
+    catch (Exception e)
+    {
+      logEncodingMessageError("add", addMsg.getDN(), e);
+    }
+
+    return createChangelogEntry(baseDN, changeNumber, cookie, addMsg, ldifChanges, "add", changeInitiatorsName);
+  }
+
+  /**
+   * Creates an entry from a modify message.
+   * <p>
+   * Map the modifyMsg to an LDIF string for the 'changes' attribute, and pull
+   * out change initiators name if available which is contained in the
+   * modifiersName attribute.
+   */
+  private Entry createModifyMsg(final DN baseDN, final long changeNumber, final String cookie, final UpdateMsg msg)
+      throws DirectoryException
+  {
+    final ModifyCommonMsg modifyMsg = (ModifyCommonMsg) msg;
+    String changeInitiatorsName = null;
+    String ldifChanges = null;
+    try
+    {
+      final StringBuilder builder = new StringBuilder(128);
+      for (Modification mod : modifyMsg.getMods())
+      {
+        final Attribute attr = mod.getAttribute();
+        if (mod.getModificationType() == ModificationType.REPLACE
+            && attr.getAttributeType().equals(MODIFIERS_NAME_TYPE)
+            && !attr.isEmpty())
+        {
+          // This attribute is not multi-valued.
+          changeInitiatorsName = attr.iterator().next().toString();
+        }
+        final String attrName = attr.getNameWithOptions();
+        builder.append(mod.getModificationType().getLDIFName());
+        builder.append(": ");
+        builder.append(attrName);
+        builder.append('\n');
+
+        for (AttributeValue value : attr)
+        {
+          builder.append(attrName);
+          appendLDIFSeparatorAndValue(builder, value.getValue());
+          builder.append('\n');
+        }
+        builder.append("-\n");
+      }
+      ldifChanges = builder.toString();
+    }
+    catch (Exception e)
+    {
+      logEncodingMessageError("modify", modifyMsg.getDN(), e);
+    }
+
+    final boolean isModifyDNMsg = modifyMsg instanceof ModifyDNMsg;
+    final Entry entry = createChangelogEntry(baseDN, changeNumber, cookie, modifyMsg, ldifChanges,
+        isModifyDNMsg ? "modrdn" : "modify", changeInitiatorsName);
+
+    if (isModifyDNMsg)
+    {
+      final ModifyDNMsg modDNMsg = (ModifyDNMsg) modifyMsg;
+      addAttribute(entry, "newrdn", modDNMsg.getNewRDN());
+      if (modDNMsg.getNewSuperior() != null)
+      {
+        addAttribute(entry, "newsuperior", modDNMsg.getNewSuperior());
+      }
+      addAttribute(entry, "deleteoldrdn", String.valueOf(modDNMsg.deleteOldRdn()));
+    }
+    return entry;
+  }
+
+  /**
+   * Log an encoding message error.
+   *
+   * @param messageType
+   *            String identifying type of message. Should be "add" or "modify".
+   * @param entryDN
+   *            DN of original entry
+   */
+  private void logEncodingMessageError(String messageType, DN entryDN,  Exception exception)
+  {
+    TRACER.debugCaught(DebugLogLevel.ERROR, exception);
+    logError(Message.raw(Category.SYNC, Severity.MILD_ERROR,
+        "An exception was encountered while trying to encode a replication " + messageType + " message for entry \""
+        + entryDN + "\" into an External Change Log entry: " + exception.getMessage()));
+  }
+
+  /**
+   * Create a changelog entry from a set of provided information. This is the part of
+   * entry creation common to all types of msgs (ADD, DEL, MOD, MODDN).
+   */
+  private static Entry createChangelogEntry(final DN baseDN, final long changeNumber, final String cookie,
+      final LDAPUpdateMsg msg, final String ldifChanges, final String changeType,
+      final String changeInitiatorsName) throws DirectoryException
+  {
+    final CSN csn = msg.getCSN();
+    String dnString;
+    if (changeNumber == 0)
+    {
+      // Cookie mode
+      dnString = "replicationCSN=" + csn + "," + baseDN.toString() + "," + DN_EXTERNAL_CHANGELOG_ROOT;
+    }
+    else
+    {
+      // Draft compat mode
+      dnString = "changeNumber=" + changeNumber + "," + DN_EXTERNAL_CHANGELOG_ROOT;
+    }
+
+    final Map<AttributeType, List<Attribute>> userAttrs = new LinkedHashMap<AttributeType, List<Attribute>>();
+    final Map<AttributeType, List<Attribute>> opAttrs = new LinkedHashMap<AttributeType, List<Attribute>>();
+
+    // Operational standard attributes
+    addAttributeByType(ATTR_SUBSCHEMA_SUBENTRY_LC, ATTR_SUBSCHEMA_SUBENTRY_LC,
+        ConfigConstants.DN_DEFAULT_SCHEMA_ROOT, userAttrs, opAttrs);
+    addAttributeByType("numsubordinates", "numSubordinates", "0", userAttrs, opAttrs);
+    addAttributeByType("hassubordinates", "hasSubordinates", "false", userAttrs, opAttrs);
+    addAttributeByType("entrydn", "entryDN", dnString, userAttrs, opAttrs);
+
+    // REQUIRED attributes
+    if (changeNumber != 0)
+    {
+      addAttributeByType("changenumber", "changeNumber", String.valueOf(changeNumber), userAttrs, opAttrs);
+    }
+    SimpleDateFormat dateFormat = new SimpleDateFormat(DATE_FORMAT_GMT_TIME);
+    dateFormat.setTimeZone(TimeZone.getTimeZone("UTC")); // ??
+    final String format = dateFormat.format(new Date(csn.getTime()));
+    addAttributeByType("changetime", "changeTime", format, userAttrs, opAttrs);
+    addAttributeByType("changetype", "changeType", changeType, userAttrs, opAttrs);
+    addAttributeByType("targetdn", "targetDN", msg.getDN().toString(), userAttrs, opAttrs);
+
+    // NON REQUESTED attributes
+    addAttributeByType("replicationcsn", "replicationCSN", csn.toString(), userAttrs, opAttrs);
+    addAttributeByType("replicaidentifier", "replicaIdentifier", Integer.toString(csn.getServerId()),
+        userAttrs, opAttrs);
+
+    if (ldifChanges != null)
+    {
+      addAttributeByType("changes", "changes", ldifChanges, userAttrs, opAttrs);
+    }
+    if (changeInitiatorsName != null)
+    {
+      addAttributeByType("changeinitiatorsname", "changeInitiatorsName", changeInitiatorsName, userAttrs, opAttrs);
+    }
+
+    final String targetUUID = msg.getEntryUUID();
+    if (targetUUID != null)
+    {
+      addAttributeByType("targetentryuuid", "targetEntryUUID", targetUUID, userAttrs, opAttrs);
+    }
+    addAttributeByType("changelogcookie", "changeLogCookie", cookie, userAttrs, opAttrs);
+
+    final List<RawAttribute> includedAttributes = msg.getEclIncludes();
+    if (includedAttributes != null && !includedAttributes.isEmpty())
+    {
+      final StringBuilder builder = new StringBuilder(256);
+      for (final RawAttribute includedAttribute : includedAttributes)
+      {
+        final String name = includedAttribute.getAttributeType();
+        for (final ByteString value : includedAttribute.getValues())
+        {
+          builder.append(name);
+          appendLDIFSeparatorAndValue(builder, value);
+          builder.append('\n');
+        }
+      }
+      final String includedAttributesLDIF = builder.toString();
+      addAttributeByType("includedattributes", "includedAttributes", includedAttributesLDIF, userAttrs, opAttrs);
+    }
+
+    return new Entry(DN.decode(dnString), CHANGELOG_ENTRY_OBJECT_CLASSES, userAttrs, opAttrs);
+  }
+
+  private static void addAttribute(final Entry e, final String attrType, final String attrValue)
+  {
+    e.addAttribute(Attributes.create(attrType, attrValue), null);
+  }
+
+  private static void addAttributeByType(String attrNameLowercase,
+      String attrNameUppercase, String attrValue,
+      Map<AttributeType, List<Attribute>> userAttrs,
+      Map<AttributeType, List<Attribute>> operationalAttrs)
+  {
+    addAttribute(attrNameLowercase, attrNameUppercase, attrValue, userAttrs, operationalAttrs, true);
+  }
+
+  private void addAttributeByUppercaseName(String attrNameLowercase,
+      String attrNameUppercase,  String attrValue,
+      Map<AttributeType, List<Attribute>> userAttrs,
+      Map<AttributeType, List<Attribute>> operationalAttrs)
+  {
+    addAttribute(attrNameLowercase, attrNameUppercase, attrValue, userAttrs, operationalAttrs, false);
+  }
+
+  private static void addAttribute(final String attrNameLowercase,
+      final String attrNameUppercase, final String attrValue,
+      final Map<AttributeType, List<Attribute>> userAttrs,
+      final Map<AttributeType, List<Attribute>> operationalAttrs, final boolean addByType)
+  {
+    AttributeType attrType = DirectoryServer.getAttributeType(attrNameLowercase);
+    if (attrType == null)
+    {
+      attrType = DirectoryServer.getDefaultAttributeType(attrNameUppercase);
+    }
+    final Attribute a = addByType ?
+        Attributes.create(attrType, attrValue) : Attributes.create(attrNameUppercase, attrValue);
+    final List<Attribute> attrList = Collections.singletonList(a);
+    if (attrType.isOperational())
+    {
+      operationalAttrs.put(attrType, attrList);
+    }
+    else
+    {
+      userAttrs.put(attrType, attrList);
+    }
   }
 
 }
diff --git a/opendj-sdk/opends/src/server/org/opends/server/replication/server/ReplicationServer.java b/opendj-sdk/opends/src/server/org/opends/server/replication/server/ReplicationServer.java
index 652ce4f..93a9f57 100644
--- a/opendj-sdk/opends/src/server/org/opends/server/replication/server/ReplicationServer.java
+++ b/opendj-sdk/opends/src/server/org/opends/server/replication/server/ReplicationServer.java
@@ -42,6 +42,7 @@
 import org.opends.server.admin.std.server.ReplicationServerCfg;
 import org.opends.server.admin.std.server.UserDefinedVirtualAttributeCfg;
 import org.opends.server.api.VirtualAttributeProvider;
+import org.opends.server.backends.ChangelogBackend;
 import org.opends.server.config.ConfigException;
 import org.opends.server.core.DirectoryServer;
 import org.opends.server.core.WorkflowImpl;
@@ -56,6 +57,7 @@
 import org.opends.server.replication.server.changelog.api.ChangelogDB;
 import org.opends.server.replication.server.changelog.api.ChangelogException;
 import org.opends.server.replication.server.changelog.file.FileChangelogDB;
+import org.opends.server.replication.server.changelog.je.ECLEnabledDomainPredicate;
 import org.opends.server.replication.server.changelog.je.JEChangelogDB;
 import org.opends.server.replication.service.DSRSShutdownSync;
 import org.opends.server.types.*;
@@ -63,6 +65,7 @@
 import org.opends.server.util.StaticUtils;
 import org.opends.server.workflowelement.externalchangelog.ECLWorkflowElement;
 
+import static org.opends.messages.ConfigMessages.*;
 import static org.opends.messages.ReplicationMessages.*;
 import static org.opends.server.loggers.ErrorLogger.*;
 import static org.opends.server.loggers.debug.DebugLogger.*;
@@ -95,11 +98,19 @@
   private final Map<DN, ReplicationServerDomain> baseDNs =
       new HashMap<DN, ReplicationServerDomain>();
 
+  /** The database storing the changes. */
   private final ChangelogDB changelogDB;
+
+  /** The backend that allow to search the changes (external changelog). */
+  private ChangelogBackend changelogBackend;
+
   private final AtomicBoolean shutdown = new AtomicBoolean();
   private boolean stopListen = false;
   private final ReplSessionSecurity replSessionSecurity;
 
+  /** To know whether a domain is enabled for the external changelog. */
+  private final ECLEnabledDomainPredicate domainPredicate;
+
   /** The tracer object for the debug logger. */
   private static final DebugTracer TRACER = getTracer();
 
@@ -136,26 +147,41 @@
    */
   public ReplicationServer(ReplicationServerCfg cfg) throws ConfigException
   {
-    this(cfg, new DSRSShutdownSync());
+    this(cfg, new DSRSShutdownSync(), new ECLEnabledDomainPredicate());
   }
 
   /**
-   * Creates a new Replication server using the provided configuration entry.
+   * Creates a new Replication server using the provided configuration entry and shutdown
+   * synchronization object.
    *
    * @param cfg The configuration of this replication server.
    * @param dsrsShutdownSync Synchronization object for shutdown of combined DS/RS instances.
    * @throws ConfigException When Configuration is invalid.
    */
-  public ReplicationServer(ReplicationServerCfg cfg,
-      DSRSShutdownSync dsrsShutdownSync) throws ConfigException
+  public ReplicationServer(ReplicationServerCfg cfg, DSRSShutdownSync dsrsShutdownSync) throws ConfigException
+  {
+    this(cfg, dsrsShutdownSync, new ECLEnabledDomainPredicate());
+  }
+
+  /**
+   * Creates a new Replication server using the provided configuration entry, shutdown
+   * synchronization object and domain predicate.
+   *
+   * @param cfg The configuration of this replication server.
+   * @param dsrsShutdownSync Synchronization object for shutdown of combined DS/RS instances.
+   * @param predicate Indicates whether a domain is enabled for the external changelog.
+   * @throws ConfigException When Configuration is invalid.
+   */
+  public ReplicationServer(final ReplicationServerCfg cfg, final DSRSShutdownSync dsrsShutdownSync,
+      final ECLEnabledDomainPredicate predicate) throws ConfigException
   {
     this.config = cfg;
     this.dsrsShutdownSync = dsrsShutdownSync;
+    this.domainPredicate = predicate;
     ReplicationDBImplementation dbImpl = cfg.getReplicationDBImplementation();
     if (DebugLogger.debugEnabled())
     {
-      TRACER.debugMessage(DebugLogLevel.INFO, "Using " + dbImpl
-          + " as DB implementation for changelog DB");
+      TRACER.debugMessage(DebugLogLevel.INFO, "Using " + dbImpl + " as DB implementation for changelog DB");
     }
     this.changelogDB = dbImpl == ReplicationDBImplementation.JE
         ? new JEChangelogDB(this, cfg)
@@ -165,6 +191,9 @@
     initialize();
     cfg.addChangeListener(this);
 
+    // TODO : uncomment to branch changelog backend
+    //enableExternalChangeLog();
+
     localPorts.add(getReplicationPort());
 
     // Keep track of this new instance
@@ -501,6 +530,57 @@
     registerVirtualAttributeRules();
   }
 
+  /**
+   * Enable the external changelog if it is not already enabled.
+   * <p>
+   * The external changelog is provided by the changelog backend.
+   *
+   * @throws ConfigException
+   *            If an error occurs.
+   */
+  private void enableExternalChangeLog() throws ConfigException
+  {
+    if (DirectoryServer.hasBackend(ChangelogBackend.BACKEND_ID))
+    {
+      // Backend has already been created and initialized
+      // This can occurs in tests
+      return;
+    }
+    try
+    {
+      changelogBackend = new ChangelogBackend(this, domainPredicate);
+      changelogBackend.initializeBackend();
+      try
+      {
+        DirectoryServer.registerBackend(changelogBackend);
+      }
+      catch (Exception e)
+      {
+        logError(WARN_CONFIG_BACKEND_CANNOT_REGISTER_BACKEND.get(changelogBackend.getBackendID(),
+            getExceptionMessage(e)));
+      }
+
+      registerVirtualAttributeRules();
+    }
+    catch (Exception e)
+    {
+      // TODO : I18N with correct message + what kind of exception should we really throw ?
+      // (Directory/Initialization/Config Exception)
+      throw new ConfigException(Message.raw("Error when enabling external changelog"), e);
+    }
+  }
+
+  private void shutdownExternalChangelog()
+  {
+    if (changelogBackend != null)
+    {
+      DirectoryServer.deregisterBackend(changelogBackend);
+      changelogBackend.finalizeBackend();
+      changelogBackend = null;
+    }
+    deregisterVirtualAttributeRules();
+  }
+
   private List<VirtualAttributeRule> getVirtualAttributesRules() throws DirectoryException
   {
     final List<VirtualAttributeRule> rules = new ArrayList<VirtualAttributeRule>();
@@ -609,6 +689,64 @@
     return getReplicationServerDomain(baseDN, false);
   }
 
+  /** Returns the replicated domain DNs minus the provided set of excluded DNs. */
+  private Set<DN> getDomainDNs(Set<DN> excludedBaseDNs) throws DirectoryException
+  {
+    Set<DN> domains = null;
+    synchronized (baseDNs)
+    {
+      domains = new HashSet<DN>(baseDNs.keySet());
+    }
+    domains.removeAll(excludedBaseDNs);
+    return domains;
+  }
+
+  /**
+   * Validate that provided state is coherent with this replication server,
+   * when ignoring the provided set of DNs.
+   * <p>
+   * The state is coherent if and only if it exactly has the set of DNs corresponding to
+   * the replication domains.
+   *
+   * @param state
+   *            The multi domain state (cookie) to validate.
+   * @param ignoredBaseDNs
+   *            The set of DNs to ignore when validating
+   * @throws DirectoryException
+   *            If the state is not valid
+   */
+  public void validateServerState(MultiDomainServerState state, Set<DN> ignoredBaseDNs) throws DirectoryException
+  {
+    // TODO : should skip unused domains, where domain.getLatestServerState(); is empty
+    final Set<DN> domains = getDomainDNs(ignoredBaseDNs);
+    final Set<DN> stateDomains = state.getSnapshot().keySet();
+    final Set<DN> domainsCopy = new HashSet<DN>(domains);
+    final Set<DN> stateDomainsCopy = new HashSet<DN>(stateDomains);
+    domainsCopy.removeAll(stateDomains);
+    if (!domainsCopy.isEmpty())
+    {
+      final StringBuilder missingDomains = new StringBuilder();
+      for (DN dn : domainsCopy)
+      {
+        missingDomains.append(dn).append(":;");
+      }
+      throw new DirectoryException(ResultCode.UNWILLING_TO_PERFORM,
+          ERR_RESYNC_REQUIRED_MISSING_DOMAIN_IN_PROVIDED_COOKIE.get(
+              missingDomains, "<" + state.toString() + missingDomains + ">"));
+    }
+    stateDomainsCopy.removeAll(domains);
+    if (!stateDomainsCopy.isEmpty())
+    {
+      final StringBuilder startState = new StringBuilder();
+      for (DN dn : domains) {
+        startState.append(dn).append(":").append(state.getServerState(dn).toString()).append(";");
+      }
+      throw new DirectoryException(ResultCode.UNWILLING_TO_PERFORM,
+          ERR_RESYNC_REQUIRED_UNKNOWN_DOMAIN_IN_PROVIDED_COOKIE.get(
+              stateDomainsCopy.toString(), startState));
+    }
+  }
+
   /**
    * Get the ReplicationServerDomain associated to the base DN given in
    * parameter.
@@ -706,7 +844,9 @@
       domain.shutdown();
     }
 
+    // TODO : switch to second method when changelog backend is branched
     shutdownECL();
+    //shutdownExternalChangelog();
 
     try
     {
diff --git a/opendj-sdk/opends/src/server/org/opends/server/replication/server/changelog/api/ReplicationDomainDB.java b/opendj-sdk/opends/src/server/org/opends/server/replication/server/changelog/api/ReplicationDomainDB.java
index e275020..8970417 100644
--- a/opendj-sdk/opends/src/server/org/opends/server/replication/server/changelog/api/ReplicationDomainDB.java
+++ b/opendj-sdk/opends/src/server/org/opends/server/replication/server/changelog/api/ReplicationDomainDB.java
@@ -25,6 +25,8 @@
  */
 package org.opends.server.replication.server.changelog.api;
 
+import java.util.Set;
+
 import org.opends.server.replication.common.CSN;
 import org.opends.server.replication.common.MultiDomainServerState;
 import org.opends.server.replication.common.ServerState;
@@ -115,6 +117,32 @@
   public MultiDomainDBCursor getCursorFrom(MultiDomainServerState startState, PositionStrategy positionStrategy)
       throws ChangelogException;
 
+  /**
+   * Generates a {@link DBCursor} across all the domains starting at or after
+   * the provided {@link MultiDomainServerState} for each domain, excluding a
+   * provided set of domain DNs.
+   * <p>
+   * When the cursor is not used anymore, client code MUST call the
+   * {@link DBCursor#close()} method to free the resources and locks used by the
+   * cursor.
+   *
+   * @param startState
+   *          Starting point for each domain cursor. If any {@link ServerState}
+   *          for a domain is null, then start from the oldest CSN for each
+   *          replicaDBs
+   * @param positionStrategy
+   *          Cursor position strategy, which allow to indicates at which exact
+   *          position the cursor must start
+   * @param excludedDomainDns
+   *          Every domain appearing in this set is excluded from the cursor
+   * @return a non null {@link DBCursor}
+   * @throws ChangelogException
+   *           If a database problem happened
+   * @see #getCursorFrom(DN, ServerState, PositionStrategy)
+   */
+  public MultiDomainDBCursor getCursorFrom(MultiDomainServerState startState, PositionStrategy positionStrategy,
+      Set<DN> excludedDomainDns) throws ChangelogException;
+
   // serverId methods
 
   /**
diff --git a/opendj-sdk/opends/src/server/org/opends/server/replication/server/changelog/file/FileChangelogDB.java b/opendj-sdk/opends/src/server/org/opends/server/replication/server/changelog/file/FileChangelogDB.java
index af4cbb8..4db2e85 100644
--- a/opendj-sdk/opends/src/server/org/opends/server/replication/server/changelog/file/FileChangelogDB.java
+++ b/opendj-sdk/opends/src/server/org/opends/server/replication/server/changelog/file/FileChangelogDB.java
@@ -661,11 +661,24 @@
   public MultiDomainDBCursor getCursorFrom(final MultiDomainServerState startState,
       final PositionStrategy positionStrategy) throws ChangelogException
   {
+    final Set<DN> excludedDomainDns = Collections.emptySet();
+    return getCursorFrom(startState, positionStrategy, excludedDomainDns);
+  }
+
+  /** {@inheritDoc} */
+  @Override
+  public MultiDomainDBCursor getCursorFrom(final MultiDomainServerState startState,
+      final PositionStrategy positionStrategy, final Set<DN> excludedDomainDns)
+      throws ChangelogException
+  {
     final MultiDomainDBCursor cursor = new MultiDomainDBCursor(this, positionStrategy);
     registeredMultiDomainCursors.add(cursor);
     for (DN baseDN : domainToReplicaDBs.keySet())
     {
-      cursor.addDomain(baseDN, startState.getServerState(baseDN));
+      if (!excludedDomainDns.contains(baseDN))
+      {
+        cursor.addDomain(baseDN, startState.getServerState(baseDN));
+      }
     }
     return cursor;
   }
diff --git a/opendj-sdk/opends/src/server/org/opends/server/replication/server/changelog/je/ECLEnabledDomainPredicate.java b/opendj-sdk/opends/src/server/org/opends/server/replication/server/changelog/je/ECLEnabledDomainPredicate.java
index d1a4721..9a9972d 100644
--- a/opendj-sdk/opends/src/server/org/opends/server/replication/server/changelog/je/ECLEnabledDomainPredicate.java
+++ b/opendj-sdk/opends/src/server/org/opends/server/replication/server/changelog/je/ECLEnabledDomainPredicate.java
@@ -32,7 +32,7 @@
  *
  * @FunctionalInterface
  */
-class ECLEnabledDomainPredicate
+public class ECLEnabledDomainPredicate
 {
 
   /**
diff --git a/opendj-sdk/opends/src/server/org/opends/server/replication/server/changelog/je/ECLMultiDomainDBCursor.java b/opendj-sdk/opends/src/server/org/opends/server/replication/server/changelog/je/ECLMultiDomainDBCursor.java
index a035657..97a1806 100644
--- a/opendj-sdk/opends/src/server/org/opends/server/replication/server/changelog/je/ECLMultiDomainDBCursor.java
+++ b/opendj-sdk/opends/src/server/org/opends/server/replication/server/changelog/je/ECLMultiDomainDBCursor.java
@@ -33,7 +33,7 @@
  * Multi domain DB cursor that only returns updates for the domains which have
  * been enabled for the external changelog.
  */
-class ECLMultiDomainDBCursor implements DBCursor<UpdateMsg>
+public final class ECLMultiDomainDBCursor implements DBCursor<UpdateMsg>
 {
 
   private final ECLEnabledDomainPredicate predicate;
diff --git a/opendj-sdk/opends/src/server/org/opends/server/replication/server/changelog/je/JEChangelogDB.java b/opendj-sdk/opends/src/server/org/opends/server/replication/server/changelog/je/JEChangelogDB.java
index 5b3cca6..2706782 100644
--- a/opendj-sdk/opends/src/server/org/opends/server/replication/server/changelog/je/JEChangelogDB.java
+++ b/opendj-sdk/opends/src/server/org/opends/server/replication/server/changelog/je/JEChangelogDB.java
@@ -712,11 +712,22 @@
   public MultiDomainDBCursor getCursorFrom(final MultiDomainServerState startState,
       final PositionStrategy positionStrategy) throws ChangelogException
   {
+    final Set<DN> excludedDomainDns = Collections.emptySet();
+    return getCursorFrom(startState, positionStrategy, excludedDomainDns);
+  }
+
+  /** {@inheritDoc} */
+  @Override
+  public MultiDomainDBCursor getCursorFrom(final MultiDomainServerState startState,
+      final PositionStrategy positionStrategy, final  Set<DN> excludedDomainDns) throws ChangelogException
+  {
     final MultiDomainDBCursor cursor = new MultiDomainDBCursor(this, positionStrategy);
     registeredMultiDomainCursors.add(cursor);
     for (DN baseDN : domainToReplicaDBs.keySet())
     {
-      cursor.addDomain(baseDN, startState.getServerState(baseDN));
+      if (!excludedDomainDns.contains(baseDN)) {
+        cursor.addDomain(baseDN, startState.getServerState(baseDN));
+      }
     }
     return cursor;
   }
diff --git a/opendj-sdk/opends/tests/unit-tests-testng/src/server/org/opends/server/backends/ChangelogBackendTestCase.java b/opendj-sdk/opends/tests/unit-tests-testng/src/server/org/opends/server/backends/ChangelogBackendTestCase.java
new file mode 100644
index 0000000..6e552a3
--- /dev/null
+++ b/opendj-sdk/opends/tests/unit-tests-testng/src/server/org/opends/server/backends/ChangelogBackendTestCase.java
@@ -0,0 +1,968 @@
+/*
+ * 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
+ * information:
+ *      Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ *
+ *
+ *      Copyright 2014 ForgeRock AS.
+ */
+package org.opends.server.backends;
+
+import static org.assertj.core.api.Assertions.*;
+import static org.opends.messages.ReplicationMessages.*;
+import static org.opends.server.TestCaseUtils.*;
+import static org.opends.server.loggers.debug.DebugLogger.*;
+import static org.opends.server.replication.protocol.OperationContext.*;
+import static org.opends.server.types.ResultCode.*;
+import static org.opends.server.util.ServerConstants.*;
+import static org.testng.Assert.*;
+
+import java.io.ByteArrayOutputStream;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.LinkedHashSet;
+import java.util.List;
+import java.util.Set;
+import java.util.SortedSet;
+
+import org.opends.server.TestCaseUtils;
+import org.opends.server.backends.ChangelogBackend.SearchParams;
+import org.opends.server.controls.ExternalChangelogRequestControl;
+import org.opends.server.core.ModifyDNOperation;
+import org.opends.server.core.ModifyDNOperationBasis;
+import org.opends.server.loggers.debug.DebugTracer;
+import org.opends.server.protocols.internal.InternalClientConnection;
+import org.opends.server.protocols.internal.InternalSearchListener;
+import org.opends.server.protocols.internal.InternalSearchOperation;
+import org.opends.server.replication.ReplicationTestCase;
+import org.opends.server.replication.common.CSN;
+import org.opends.server.replication.common.CSNGenerator;
+import org.opends.server.replication.common.MultiDomainServerState;
+import org.opends.server.replication.plugin.DomainFakeCfg;
+import org.opends.server.replication.plugin.ExternalChangelogDomainFakeCfg;
+import org.opends.server.replication.plugin.LDAPReplicationDomain;
+import org.opends.server.replication.plugin.MultimasterReplication;
+import org.opends.server.replication.protocol.AddMsg;
+import org.opends.server.replication.protocol.DeleteMsg;
+import org.opends.server.replication.protocol.ModifyDNMsg;
+import org.opends.server.replication.protocol.ModifyDnContext;
+import org.opends.server.replication.protocol.ModifyMsg;
+import org.opends.server.replication.protocol.UpdateMsg;
+import org.opends.server.replication.server.ReplServerFakeConfiguration;
+import org.opends.server.replication.server.ReplicationServer;
+import org.opends.server.replication.server.changelog.je.ECLEnabledDomainPredicate;
+import org.opends.server.replication.service.DSRSShutdownSync;
+import org.opends.server.replication.service.ReplicationBroker;
+import org.opends.server.types.Attribute;
+import org.opends.server.types.AttributeValue;
+import org.opends.server.types.Attributes;
+import org.opends.server.types.AuthenticationInfo;
+import org.opends.server.types.Control;
+import org.opends.server.types.DN;
+import org.opends.server.types.DereferencePolicy;
+import org.opends.server.types.DirectoryException;
+import org.opends.server.types.Entry;
+import org.opends.server.types.LDIFExportConfig;
+import org.opends.server.types.Modification;
+import org.opends.server.types.ModificationType;
+import org.opends.server.types.Operation;
+import org.opends.server.types.RDN;
+import org.opends.server.types.ResultCode;
+import org.opends.server.types.SearchFilter;
+import org.opends.server.types.SearchResultEntry;
+import org.opends.server.types.SearchScope;
+import org.opends.server.util.LDIFWriter;
+import org.opends.server.util.TimeThread;
+import org.opends.server.workflowelement.localbackend.LocalBackendModifyDNOperation;
+import org.testng.annotations.AfterClass;
+import org.testng.annotations.AfterMethod;
+import org.testng.annotations.BeforeClass;
+import org.testng.annotations.DataProvider;
+import org.testng.annotations.Test;
+
+import com.forgerock.opendj.util.Pair;
+
+@SuppressWarnings("javadoc")
+public class ChangelogBackendTestCase extends ReplicationTestCase
+{
+  private static final DebugTracer TRACER = getTracer();
+
+  private static final String USER1_ENTRY_UUID = "11111111-1111-1111-1111-111111111111";
+  private static final long CHANGENUMBER_ZERO = 0L;
+  private static final int SERVER_ID_1 = 1201;
+  private static final int SERVER_ID_2 = 1202;
+  private static final String TEST_ROOT_DN_STRING2 = "o=test2";
+  private static DN ROOT_DN_OTEST;
+  private static DN ROOT_DN_OTEST2;
+
+  private final int brokerSessionTimeout = 5000;
+  private final int maxWindow = 100;
+
+  /** The replicationServer that will be used in this test. */
+  private ReplicationServer replicationServer;
+
+  /** The port of the replicationServer. */
+  private int replicationServerPort;
+
+  /**
+   * When used in a search operation, it includes all attributes (user and
+   * operational)
+   */
+  private static final Set<String> ALL_ATTRIBUTES = newSet("*", "+");
+  private static final List<Control> NO_CONTROL = null;
+
+  @BeforeClass
+  @Override
+  public void setUp() throws Exception
+  {
+    super.setUp();
+    ROOT_DN_OTEST = DN.decode(TEST_ROOT_DN_STRING);
+    ROOT_DN_OTEST2 = DN.decode(TEST_ROOT_DN_STRING2);
+
+    // This test suite depends on having the schema available.
+    configureReplicationServer();
+  }
+
+  @Override
+  @AfterClass
+  public void classCleanUp() throws Exception
+  {
+    callParanoiaCheck = false;
+    super.classCleanUp();
+
+    remove(replicationServer);
+    replicationServer = null;
+
+    paranoiaCheck();
+  }
+
+  @AfterMethod
+  public void clearReplicationDb() throws Exception
+  {
+    clearChangelogDB(replicationServer);
+  }
+
+  /** Configure a replicationServer for test. */
+  private void configureReplicationServer() throws Exception
+  {
+    replicationServerPort = TestCaseUtils.findFreePort();
+
+    ReplServerFakeConfiguration config = new ReplServerFakeConfiguration(
+          replicationServerPort,
+          "ChangelogBackendTestDB",
+          replicationDbImplementation,
+          0,         // purge delay
+          71,        // server id
+          0,         // queue size
+          maxWindow, // window size
+          null       // servers
+    );
+    config.setComputeChangeNumber(true);
+    replicationServer = new ReplicationServer(config, new DSRSShutdownSync(), new ECLEnabledDomainPredicate()
+    {
+      @Override
+      public boolean isECLEnabledDomain(DN baseDN)
+      {
+        return baseDN.equals(ROOT_DN_OTEST);
+      }
+    });
+    debugInfo("configure", "ReplicationServer created:" + replicationServer);
+  }
+
+  /** Enable replication on provided domain DN and serverid, using provided port. */
+  private Pair<ReplicationBroker, LDAPReplicationDomain> enableReplication(DN domainDN, int serverId,
+      int replicationPort, int timeout) throws Exception
+  {
+    ReplicationBroker broker = openReplicationSession(domainDN, serverId, 100, replicationPort, timeout);
+    DomainFakeCfg domainConf = newFakeCfg(domainDN, serverId, replicationPort);
+    LDAPReplicationDomain replicationDomain = startNewReplicationDomain(domainConf, null, null);
+    return Pair.of(broker, replicationDomain);
+  }
+
+  /** Start a new replication domain on the directory server side. */
+  private LDAPReplicationDomain startNewReplicationDomain(
+      DomainFakeCfg domainConf,
+      SortedSet<String> eclInclude,
+      SortedSet<String> eclIncludeForDeletes)
+          throws Exception
+  {
+    domainConf.setExternalChangelogDomain(new ExternalChangelogDomainFakeCfg(true, eclInclude, eclIncludeForDeletes));
+    // Set a Changetime heartbeat interval low enough
+    // (less than default value that is 1000 ms)
+    // for the test to be sure to consider all changes as eligible.
+    domainConf.setChangetimeHeartbeatInterval(10);
+    LDAPReplicationDomain newDomain = MultimasterReplication.createNewDomain(domainConf);
+    newDomain.start();
+    return newDomain;
+  }
+
+  private void removeReplicationDomains(LDAPReplicationDomain... domains)
+  {
+    for (LDAPReplicationDomain domain : domains)
+    {
+      if (domain != null)
+      {
+        domain.shutdown();
+        MultimasterReplication.deleteDomain(domain.getBaseDN());
+      }
+    }
+  }
+
+  @Test(enabled=false)
+  public void searchChangesOnOneSuffixUsingEmptyCookie() throws Exception
+  {
+    String testName = "FourChangesCookie";
+    debugInfo(testName, "Starting test\n\n");
+
+    CSN[] csns = generateAndPublishChangesForEachOperationType(testName);
+
+    searchChangesForEachOperationTypeUsingEmptyCookie(csns, testName);
+
+    assertChangelogAttributesInRootDSE(true, 1, 4);
+
+    debugInfo(testName, "Ending search with success");
+  }
+
+  @Test(enabled=false)
+  public void searchChangesOnOneSuffixUsingDraftMode() throws Exception
+  {
+    long firstChangeNumber = 1;
+    String testName = "FourChanges/" + firstChangeNumber;
+    debugInfo(testName, "Starting test\n\n");
+
+    CSN[] csns = generateAndPublishChangesForEachOperationType(testName);
+
+    searchChangesForEachOperationTypeUsingDraftMode(firstChangeNumber, csns, testName);
+
+    assertChangelogAttributesInRootDSE(true, 1, 4);
+
+    debugInfo(testName, "Ending search with success");
+  }
+
+  @Test(enabled=false)
+  public void searchChangesOnOneSuffixMultipleTimesUsingDraftMode() throws Exception
+  {
+    replicationServer.getChangelogDB().setPurgeDelay(0);
+
+    // write 4 changes starting from changenumber 1, and search them
+    String testName = "Multiple/1";
+    CSN[] csns = generateAndPublishChangesForEachOperationType(testName);
+    searchChangesForEachOperationTypeUsingDraftMode(1, csns, testName);
+
+    // write 4 more changes starting from changenumber 5, and search them
+    testName = "Multiple/5";
+    csns = generateAndPublishChangesForEachOperationType(testName);
+    searchChangesForEachOperationTypeUsingDraftMode(5, csns, testName);
+
+    // search from the provided change number: 6 (should be the add msg)
+    CSN csnOfLastAddMsg = csns[1];
+    searchChangelogForOneChangeNumber(6, csnOfLastAddMsg);
+
+    // search from a provided change number interval: 5-7
+    searchChangelogFromToChangeNumber(5,7);
+
+    // check first and last change number
+    assertChangelogAttributesInRootDSE(true, 1, 8);
+
+    // add a new change, then check again first and last change number without previous search
+    CSN csn = new CSN(TimeThread.getTime(), 10, SERVER_ID_1);
+    publishChanges(testName, generateDeleteMsg(TEST_ROOT_DN_STRING, csn, testName, 1));
+
+    assertChangelogAttributesInRootDSE(true, 1, 9);
+  }
+
+  /**
+   * Verifies that is not possible to read the changelog without the changelog-read privilege
+   */
+  // TODO : enable when code is checking the privileges correctly
+  @Test(enabled=false)
+  public void searchingChangelogWithoutPrivilegeShouldFail() throws Exception
+  {
+    AuthenticationInfo nonPrivilegedUser = new AuthenticationInfo();
+
+    InternalClientConnection conn = new InternalClientConnection(nonPrivilegedUser);
+    InternalSearchOperation op = conn.processSearch("cn=changelog", SearchScope.WHOLE_SUBTREE, "(objectclass=*)");
+
+    assertEquals(op.getResultCode(), ResultCode.INSUFFICIENT_ACCESS_RIGHTS);
+    assertEquals(op.getErrorMessage().toMessage(), NOTE_SEARCH_CHANGELOG_INSUFFICIENT_PRIVILEGES.get());
+  }
+
+  /**
+   * With an empty RS, a search should return only root entry.
+   */
+  @Test(enabled=false)
+  public void searchWhenNoChangesShouldReturnRootEntryOnly() throws Exception
+  {
+    String testName = "EmptyRS";
+    debugInfo(testName, "Starting test\n\n");
+
+    searchChangelog("(objectclass=*)", 1, SUCCESS, testName);
+
+    debugInfo(testName, "Ending test successfully");
+  }
+
+  @Test(enabled=false)
+  public void searchWithUnknownChangeNumberShouldReturnNoResult() throws Exception
+  {
+    String testName = "UnknownChangeNumber";
+    debugInfo(testName, "Starting test\n\n");
+
+    searchChangelog("(changenumber=1000)", 0, SUCCESS, testName);
+
+    debugInfo(testName, "Ending test with success");
+  }
+
+  @Test(enabled=false)
+  public void operationalAndVirtualAttributesShouldNotBeVisibleOutsideRootDSE() throws Exception
+  {
+    String testName = "attributesVisibleOutsideRootDSE";
+    debugInfo(testName, "Starting test \n\n");
+
+    Set<String> attributes =
+        newSet("firstchangenumber", "lastchangenumber", "changelog", "lastExternalChangelogCookie");
+
+    InternalSearchOperation searchOp = searchDNWithBaseScope(TEST_ROOT_DN_STRING, attributes);
+    waitForSearchOpResult(searchOp, ResultCode.SUCCESS);
+
+    final List<SearchResultEntry> entries = searchOp.getSearchEntries();
+    assertThat(entries).hasSize(1);
+    debugAndWriteEntries(null, entries, testName);
+    SearchResultEntry entry = entries.get(0);
+    assertNull(getAttributeValue(entry, "firstchangenumber"));
+    assertNull(getAttributeValue(entry, "lastchangenumber"));
+    assertNull(getAttributeValue(entry, "changelog"));
+    assertNull(getAttributeValue(entry, "lastExternalChangelogCookie"));
+
+    debugInfo(testName, "Ending test with success");
+  }
+
+  @DataProvider()
+  public Object[][] getFilters()
+  {
+    return new Object[][] {
+      // base DN, filter, expected first change number, expected last change number
+      { "cn=changelog", "(objectclass=*)", -1, -1 },
+      { "cn=changelog", "(changenumber>=2)", 2, -1 },
+      { "cn=changelog", "(&(changenumber>=2)(changenumber<=5))", 2, 5 },
+      { "cn=changelog", "(&(dc=x)(&(changenumber>=2)(changenumber<=5)))", 2, 5 },
+      { "cn=changelog",
+          "(&(&(changenumber>=3)(changenumber<=4))(&(|(dc=y)(dc=x))(&(changenumber>=2)(changenumber<=5))))", 3, 4 },
+      { "cn=changelog", "(|(objectclass=*)(&(changenumber>=2)(changenumber<=5)))", -1, -1 },
+      { "cn=changelog", "(changenumber=8)", 8, 8 },
+
+      { "changeNumber=8,cn=changelog", "(objectclass=*)", 8, 8 },
+      { "changeNumber=8,cn=changelog", "(changenumber>=2)", 8, 8 },
+      { "changeNumber=8,cn=changelog", "(&(changenumber>=2)(changenumber<=5))", 8, 8 },
+    };
+  }
+
+  @Test(dataProvider="getFilters")
+  public void optimizeFiltersWithChangeNumber(String dn, String filter, long expectedFirstCN, long expectedLastCN)
+      throws Exception
+  {
+    final ChangelogBackend backend = new ChangelogBackend(null, null);
+    final DN baseDN = DN.decode(dn);
+    final SearchParams searchParams = new SearchParams();
+
+    backend.optimizeSearchParameters(searchParams, baseDN, SearchFilter.createFilterFromString(filter));
+
+    assertSearchParameters(searchParams, expectedFirstCN, expectedLastCN, null);
+  }
+
+  @Test
+  public void optimizeFiltersWithReplicationCsn() throws Exception
+  {
+    final ChangelogBackend backend = new ChangelogBackend(null, null);
+    final DN baseDN = DN.decode("cn=changelog");
+    final CSN csn = new CSNGenerator(1, 0).newCSN();
+    final SearchParams searchParams = new SearchParams();
+
+    backend.optimizeSearchParameters(searchParams, baseDN,
+        SearchFilter.createFilterFromString("(replicationcsn=" + csn + ")"));
+
+    assertSearchParameters(searchParams, -1, -1, csn);
+  }
+
+  private List<SearchResultEntry> assertChangelogAttributesInRootDSE(boolean isECLEnabled,
+      int expectedFirstChangeNumber, int expectedLastChangeNumber) throws Exception
+  {
+    AssertionError error = null;
+    for (int count = 0 ; count < 30; count++)
+    {
+      try
+      {
+        final Set<String> attributes = new LinkedHashSet<String>();
+        if (expectedFirstChangeNumber > 0)
+        {
+          attributes.add("firstchangenumber");
+        }
+        attributes.add("lastchangenumber");
+        attributes.add("changelog");
+        attributes.add("lastExternalChangelogCookie");
+
+        final InternalSearchOperation searchOp = searchDNWithBaseScope("", attributes);
+        final List<SearchResultEntry> entries = searchOp.getSearchEntries();
+        assertThat(entries).hasSize(1);
+
+        final SearchResultEntry entry = entries.get(0);
+        if (isECLEnabled)
+        {
+          if (expectedFirstChangeNumber > 0)
+          {
+            assertAttributeValue(entry, "firstchangenumber", String.valueOf(expectedFirstChangeNumber));
+          }
+          assertAttributeValue(entry, "lastchangenumber", String.valueOf(expectedLastChangeNumber));
+          assertAttributeValue(entry, "changelog", String.valueOf("cn=changelog"));
+          assertNotNull(getAttributeValue(entry, "lastExternalChangelogCookie"));
+        }
+        else
+        {
+          if (expectedFirstChangeNumber > 0) {
+            assertNull(getAttributeValue(entry, "firstchangenumber"));
+          }
+          assertNull(getAttributeValue(entry, "lastchangenumber"));
+          assertNull(getAttributeValue(entry, "changelog"));
+          assertNull(getAttributeValue(entry, "lastExternalChangelogCookie"));
+        }
+        return entries;
+      }
+      catch (AssertionError ae)
+      {
+        // try again to see if changes have been persisted
+        error = ae;
+      }
+      Thread.sleep(100);
+    }
+    assertNotNull(error);
+    throw error;
+  }
+
+  private void assertSearchParameters(SearchParams searchParams, long firstChangeNumber,
+      long lastChangeNumber, CSN csn) throws Exception
+  {
+    assertEquals(searchParams.getLowestChangeNumber(), firstChangeNumber);
+    assertEquals(searchParams.getHighestChangeNumber(), lastChangeNumber);
+    assertEquals(searchParams.getCSN(), csn == null ? new CSN(0, 0, 0) : csn);
+  }
+
+  private CSN[] generateAndPublishChangesForEachOperationType(String testName) throws Exception
+  {
+    CSN[] csns = generateCSNs(4, SERVER_ID_1);
+
+    List<UpdateMsg> messages = new ArrayList<UpdateMsg>();
+    messages.add(generateDeleteMsg(TEST_ROOT_DN_STRING, csns[0], testName, 1));
+    messages.add(generateAddMsg(TEST_ROOT_DN_STRING, csns[1], USER1_ENTRY_UUID, testName));
+    messages.add(generateModMsg(TEST_ROOT_DN_STRING, csns[2], testName));
+    messages.add(generateModDNMsg(TEST_ROOT_DN_STRING, csns[3], testName));
+
+    publishChanges(testName, messages.toArray(new UpdateMsg[4]));
+    return csns;
+  }
+
+  /** Publish a list changes to the default replication broker used by tests. */
+  private void publishChanges(String testName, UpdateMsg...messages) throws Exception
+  {
+    Pair<ReplicationBroker, LDAPReplicationDomain> replicationObjects = null;
+    try
+    {
+      replicationObjects = enableReplication(ROOT_DN_OTEST, SERVER_ID_1, replicationServerPort, brokerSessionTimeout);
+      ReplicationBroker broker = replicationObjects.getFirst();
+      for (UpdateMsg msg : messages)
+      {
+        debugInfo(testName, " publishes " + msg.getCSN());
+        broker.publish(msg);
+      }
+    }
+    finally
+    {
+      if (replicationObjects != null)
+      {
+        removeReplicationDomains(replicationObjects.getSecond());
+        stop(replicationObjects.getFirst());
+      }
+    }
+  }
+
+  private void searchChangesForEachOperationTypeUsingEmptyCookie(CSN[] csns, String testName) throws Exception
+  {
+    int nbEntries = 4;
+    String cookie= "";
+
+    InternalSearchOperation searchOp =
+        searchChangelogUsingCookie("(targetdn=*" + testName + "*,o=test)", cookie, nbEntries, SUCCESS, testName);
+
+    final String[] cookies = new String[nbEntries];
+    for (int j = 0; j < cookies.length; j++)
+    {
+      cookies[j] = "o=test:" + csns[j] + ";";
+    }
+    final List<SearchResultEntry> searchEntries = searchOp.getSearchEntries();
+    assertDelEntry(searchEntries.get(0), testName + 1, testName + "uuid1", CHANGENUMBER_ZERO, csns[0], cookies[0]);
+    assertAddEntry(searchEntries.get(1), testName + 2, USER1_ENTRY_UUID, CHANGENUMBER_ZERO, csns[1], cookies[1]);
+    assertModEntry(searchEntries.get(2), testName + 3, testName + "uuid3", CHANGENUMBER_ZERO, csns[2], cookies[2]);
+    assertModDNEntry(searchEntries.get(3), testName + 4, testName + "new4", testName+"uuid4", CHANGENUMBER_ZERO,
+        csns[3], cookies[3]);
+    assertResultsContainCookieControl(searchOp, cookies);
+  }
+
+  private void searchChangesForEachOperationTypeUsingDraftMode(long firstChangeNumber, CSN[] csns, String testName)
+      throws Exception
+  {
+    // Search the changelog and check 4 entries are returned
+    String filter = "(targetdn=*" + testName + "*,o=test)";
+    InternalSearchOperation searchOp = searchChangelog(filter, 4, SUCCESS, testName);
+
+    assertContainsNoControl(searchOp);
+    assertEntriesForEachOperationType(searchOp.getSearchEntries(), firstChangeNumber, testName, USER1_ENTRY_UUID, csns);
+
+    // Search the changelog with filter on change number and check 4 entries are returned
+    filter =
+        "(&(targetdn=*" + testName + "*,o=test)"
+          + "(&(changenumber>=" + firstChangeNumber + ")"
+            + "(changenumber<=" + (firstChangeNumber + 3) + ")))";
+    searchOp = searchChangelog(filter, 4, SUCCESS, testName);
+
+    assertContainsNoControl(searchOp);
+    assertEntriesForEachOperationType(searchOp.getSearchEntries(), firstChangeNumber, testName, USER1_ENTRY_UUID, csns);
+  }
+
+  /**
+   * Search on the provided change number and check the result.
+   *
+   * @param changeNumber
+   *          Change number to search
+   * @param expectedCsn
+   *          Expected CSN in the entry corresponding to the change number
+   */
+  private void searchChangelogForOneChangeNumber(long changeNumber, CSN expectedCsn) throws Exception
+  {
+    String testName = "searchOneChangeNumber/" + changeNumber;
+    debugInfo(testName, "Starting search\n\n");
+
+    InternalSearchOperation searchOp =
+        searchChangelog("(changenumber=" + changeNumber + ")", 1, SUCCESS, testName);
+
+    SearchResultEntry entry = searchOp.getSearchEntries().get(0);
+    String uncheckedUid = null;
+    assertEntryCommonAttributes(entry, uncheckedUid, USER1_ENTRY_UUID, changeNumber, expectedCsn,
+        "o=test:" + expectedCsn + ";");
+
+    debugInfo(testName, "Ending search with success");
+  }
+
+  private void searchChangelogFromToChangeNumber(int firstChangeNumber, int lastChangeNumber) throws Exception
+  {
+    String testName = "searchFromToChangeNumber/" + firstChangeNumber + "/" + lastChangeNumber;
+    debugInfo(testName, "Starting search\n\n");
+
+    String filter = "(&(changenumber>=" + firstChangeNumber + ")" + "(changenumber<=" + lastChangeNumber + "))";
+    final int expectedNbEntries = lastChangeNumber - firstChangeNumber + 1;
+    searchChangelog(filter, expectedNbEntries, SUCCESS, testName);
+
+    debugInfo(testName, "Ending search with success");
+  }
+
+  private InternalSearchOperation searchChangelogUsingCookie(String filterString,
+      String cookie, int expectedNbEntries, ResultCode expectedResultCode, String testName)
+      throws Exception
+  {
+    debugInfo(testName, "Search with cookie=[" + cookie + "] filter=[" + filterString + "]");
+    return searchChangelog(filterString, ALL_ATTRIBUTES, createCookieControl(cookie),
+        expectedNbEntries, expectedResultCode, testName);
+  }
+
+  private InternalSearchOperation searchChangelog(String filterString, int expectedNbEntries,
+      ResultCode expectedResultCode, String testName) throws Exception
+  {
+    return searchChangelog(filterString, ALL_ATTRIBUTES, NO_CONTROL, expectedNbEntries, expectedResultCode, testName);
+  }
+
+  private InternalSearchOperation searchChangelog(String filterString, Set<String> attributes,
+      List<Control> controls, int expectedNbEntries, ResultCode expectedResultCode, String testName) throws Exception
+  {
+    InternalSearchOperation searchOperation = null;
+    int sizeLimitZero = 0;
+    int timeLimitZero = 0;
+    InternalSearchListener noSearchListener = null;
+    int count = 0;
+    do
+    {
+      Thread.sleep(10);
+      boolean typesOnlyFalse = false;
+      searchOperation = connection.processSearch("cn=changelog", SearchScope.WHOLE_SUBTREE,
+          DereferencePolicy.NEVER_DEREF_ALIASES, sizeLimitZero, timeLimitZero, typesOnlyFalse, filterString,
+          attributes, controls, noSearchListener);
+      count++;
+    }
+    while (count < 300 && searchOperation.getSearchEntries().size() != expectedNbEntries);
+
+    final List<SearchResultEntry> entries = searchOperation.getSearchEntries();
+    assertThat(entries).hasSize(expectedNbEntries);
+    debugAndWriteEntries(getLDIFWriter(), entries, testName);
+    waitForSearchOpResult(searchOperation, expectedResultCode);
+    return searchOperation;
+  }
+
+  private InternalSearchOperation searchDNWithBaseScope(String dn, Set<String> attributes) throws Exception
+  {
+    final InternalSearchOperation searchOp = connection.processSearch(
+        dn,
+        SearchScope.BASE_OBJECT,
+        DereferencePolicy.NEVER_DEREF_ALIASES,
+        0,     // Size limit
+        0,     // Time limit
+        false, // Types only
+        "(objectclass=*)",
+        attributes);
+    waitForSearchOpResult(searchOp, ResultCode.SUCCESS);
+    return searchOp;
+  }
+
+  /** Build a list of controls including the cookie provided. */
+  private List<Control> createCookieControl(String cookie) throws DirectoryException
+  {
+    final MultiDomainServerState state = new MultiDomainServerState(cookie);
+    final Control cookieControl = new ExternalChangelogRequestControl(true, state);
+    return newList(cookieControl);
+  }
+
+  private static LDIFWriter getLDIFWriter() throws Exception
+  {
+    ByteArrayOutputStream stream = new ByteArrayOutputStream();
+    LDIFExportConfig exportConfig = new LDIFExportConfig(stream);
+    return new LDIFWriter(exportConfig);
+  }
+
+  private CSN[] generateCSNs(int numberOfCsns, int serverId)
+  {
+    long startTime = TimeThread.getTime();
+
+    CSN[] csns = new CSN[numberOfCsns];
+    for (int i = 0; i < numberOfCsns; i++)
+    {
+      // seqNum must be greater than 0, so start at 1
+      csns[i] = new CSN(startTime + i, i + 1, serverId);
+    }
+    return csns;
+  }
+
+  private UpdateMsg generateDeleteMsg(String baseDn, CSN csn, String testName, int testIndex)
+      throws Exception
+  {
+    String dn = "uid=" + testName + testIndex + "," + baseDn;
+    return new DeleteMsg(DN.decode(dn), csn, testName + "uuid" + testIndex);
+  }
+
+  private UpdateMsg generateAddMsg(String baseDn, CSN csn, String user1entryUUID, String testName)
+      throws Exception
+  {
+    String baseUUID = "22222222-2222-2222-2222-222222222222";
+    String entryLdif = "dn: uid="+ testName + "2," + baseDn + "\n"
+        + "objectClass: top\n" + "objectClass: domain\n"
+        + "entryUUID: "+ user1entryUUID +"\n";
+    Entry entry = TestCaseUtils.entryFromLdifString(entryLdif);
+    return new AddMsg(
+        csn,
+        DN.decode("uid="+testName+"2," + baseDn),
+        user1entryUUID,
+        baseUUID,
+        entry.getObjectClassAttribute(),
+        entry.getAttributes(),
+        Collections.<Attribute> emptyList());
+  }
+
+  private UpdateMsg generateModMsg(String baseDn, CSN csn, String testName) throws Exception
+  {
+    DN baseDN = DN.decode("uid=" + testName + "3," + baseDn);
+    List<Modification> mods = createAttributeModif("description", "new value");
+    return new ModifyMsg(csn, baseDN, mods, testName + "uuid3");
+  }
+
+  private List<Modification> createAttributeModif(String attributeName, String valueString)
+  {
+    Attribute attr = Attributes.create(attributeName, valueString);
+    return newList(new Modification(ModificationType.REPLACE, attr));
+  }
+
+  private UpdateMsg generateModDNMsg(String baseDn, CSN csn, String testName) throws Exception
+  {
+    final DN newSuperior = ROOT_DN_OTEST2;
+    ModifyDNOperation op = new ModifyDNOperationBasis(connection, 1, 1, null,
+        DN.decode("uid=" + testName + "4," + baseDn), // entryDN
+        RDN.decode("uid=" + testName + "new4"), // new rdn
+        true,  // deleteoldrdn
+        newSuperior);
+    op.setAttachment(SYNCHROCONTEXT, new ModifyDnContext(csn, testName + "uuid4", "newparentId"));
+    LocalBackendModifyDNOperation localOp = new LocalBackendModifyDNOperation(op);
+    return new ModifyDNMsg(localOp);
+  }
+
+  //TODO : share this code with other classes ?
+  private void waitForSearchOpResult(Operation operation, ResultCode expectedResult) throws Exception
+  {
+    int i = 0;
+    while (operation.getResultCode() == ResultCode.UNDEFINED || operation.getResultCode() != expectedResult)
+    {
+      Thread.sleep(50);
+      i++;
+      if (i > 10)
+      {
+        assertEquals(operation.getResultCode(), expectedResult, operation.getErrorMessage().toString());
+      }
+    }
+  }
+
+  /** Verify that no entry contains the ChangeLogCookie control. */
+  private void assertContainsNoControl(InternalSearchOperation searchOp)
+  {
+    for (SearchResultEntry entry : searchOp.getSearchEntries())
+    {
+      assertTrue(entry.getControls().isEmpty(), "result entry " + entry.toString() +
+          " should contain no control(s)");
+    }
+  }
+
+  /** Verify that all entries contains the ChangeLogCookie control with the correct cookie value. */
+  private void assertResultsContainCookieControl(InternalSearchOperation searchOp, String[] cookies) throws Exception
+  {
+    for (SearchResultEntry entry : searchOp.getSearchEntries())
+    {
+      boolean cookieControlFound = false;
+      for (Control control : entry.getControls())
+      {
+        if (control.getOID().equals(OID_ECL_COOKIE_EXCHANGE_CONTROL))
+        {
+          String cookieString =
+              searchOp.getRequestControl(ExternalChangelogRequestControl.DECODER).getCookie().toString();
+          assertThat(cookieString).isIn((Object[]) cookies);
+          cookieControlFound = true;
+        }
+      }
+      assertTrue(cookieControlFound, "result entry " + entry.toString() + " should contain the cookie control");
+    }
+  }
+
+  /** Check the DEL entry has the right content. */
+  private void assertDelEntry(SearchResultEntry entry, String uid, String entryUUID,
+      long changeNumber, CSN csn, String cookie)
+  {
+    assertAttributeValue(entry, "changetype", "delete");
+    assertAttributeValue(entry, "targetuniqueid", entryUUID);
+    assertAttributeValue(entry, "targetentryuuid", entryUUID);
+    assertEntryCommonAttributes(entry, uid, entryUUID, changeNumber, csn, cookie);
+  }
+
+  /** Check the ADD entry has the right content. */
+  private void assertAddEntry(SearchResultEntry entry, String uid, String entryUUID,
+      long changeNumber, CSN csn, String cookie)
+  {
+    assertAttributeValue(entry, "changetype", "add");
+    assertEntryMatchesLDIF(entry, "changes",
+        "objectClass: domain",
+        "objectClass: top",
+        "entryUUID: " + entryUUID);
+    assertEntryCommonAttributes(entry, uid, entryUUID, changeNumber, csn, cookie);
+  }
+
+  private void assertModEntry(SearchResultEntry entry, String uid, String entryUUID,
+      long changeNumber, CSN csn, String cookie)
+  {
+    assertAttributeValue(entry, "changetype", "modify");
+    assertEntryMatchesLDIF(entry, "changes",
+        "replace: description",
+        "description: new value",
+        "-");
+    assertEntryCommonAttributes(entry, uid, entryUUID, changeNumber, csn, cookie);
+  }
+
+  private void assertModDNEntry(SearchResultEntry entry, String uid, String newUid,
+      String entryUUID, long changeNumber, CSN csn, String cookie)
+  {
+    assertAttributeValue(entry, "changetype", "modrdn");
+    assertAttributeValue(entry, "newrdn", "uid=" + newUid);
+    assertAttributeValue(entry, "newsuperior", TEST_ROOT_DN_STRING2);
+    assertAttributeValue(entry, "deleteoldrdn", "true");
+    assertEntryCommonAttributes(entry, uid, entryUUID, changeNumber, csn, cookie);
+
+  }
+
+  private void assertEntryCommonAttributes(SearchResultEntry resultEntry,
+      String uid, String entryUUID, long changeNumber, CSN csn, String cookie)
+  {
+    if (changeNumber == 0)
+    {
+      assertDNWithCSN(resultEntry, csn);
+    }
+    else
+    {
+      assertDNWithChangeNumber(resultEntry, changeNumber);
+      assertAttributeValue(resultEntry, "changenumber", String.valueOf(changeNumber));
+    }
+    assertAttributeValue(resultEntry, "targetentryuuid", entryUUID);
+    assertAttributeValue(resultEntry, "replicaidentifier", String.valueOf(SERVER_ID_1));
+    assertAttributeValue(resultEntry, "replicationcsn", csn.toString());
+    assertAttributeValue(resultEntry, "changelogcookie", cookie);
+    // A null value can be provided for uid if it should not be checked
+    if (uid != null)
+    {
+      final String targetDN = "uid=" + uid + "," + TEST_ROOT_DN_STRING;
+      assertAttributeValue(resultEntry, "targetdn", targetDN);
+    }
+  }
+
+  private void assertEntriesForEachOperationType(List<SearchResultEntry> entries, long firstChangeNumber,
+      String testName, String entryUUID, CSN... csns) throws Exception
+  {
+    debugAndWriteEntries(getLDIFWriter(), entries, testName);
+
+    assertThat(entries).hasSize(4);
+
+    CSN csn = csns[0];
+    assertDelEntry(entries.get(0), testName + "1", testName + "uuid1", firstChangeNumber, csn, "o=test:" + csn + ";");
+
+    csn = csns[1];
+    assertAddEntry(entries.get(1), testName + "2", entryUUID, firstChangeNumber+1, csn, "o=test:" + csn + ";");
+
+    csn = csns[2];
+    assertModEntry(entries.get(2), testName + "3", testName + "uuid3", firstChangeNumber+2, csn,
+        "o=test:" + csn + ";");
+
+    csn = csns[3];
+    assertModDNEntry(entries.get(3), testName + "4", testName + "new4", testName + "uuid4", firstChangeNumber+3, csn,
+        "o=test:" + csn + ";");
+  }
+
+  /**
+   * Asserts the attribute value as LDIF to ignore lines ordering.
+   */
+  private static void assertEntryMatchesLDIF(Entry entry, String attrName, String... expectedLDIFLines)
+  {
+    final String actualVal = getAttributeValue(entry, attrName);
+    final Set<Set<String>> actual = toLDIFEntries(actualVal.split("\n"));
+    final Set<Set<String>> expected = toLDIFEntries(expectedLDIFLines);
+    assertThat(actual)
+        .as("In entry " + entry + " incorrect value for attr '" + attrName + "'")
+        .isEqualTo(expected);
+  }
+
+  private static void assertAttributeValue(Entry entry, String attrName, String expectedValue)
+  {
+    assertFalse(expectedValue.contains("\n"),
+        "You should use assertEntryMatchesLDIF() method for asserting on this value: \"" + expectedValue + "\"");
+    final String actualValue = getAttributeValue(entry, attrName);
+    assertThat(actualValue)
+        .as("In entry " + entry + " incorrect value for attr '" + attrName + "'")
+        .isEqualToIgnoringCase(expectedValue);
+  }
+
+  private void assertDNWithChangeNumber(SearchResultEntry resultEntry, long changeNumber)
+  {
+    String actualDN = resultEntry.getDN().toNormalizedString();
+    String expectedDN = "changenumber=" + changeNumber + ",cn=changelog";
+    assertThat(actualDN).isEqualToIgnoringCase(expectedDN);
+  }
+
+  private void assertDNWithCSN(SearchResultEntry resultEntry, CSN csn)
+  {
+    String actualDN = resultEntry.getDN().toNormalizedString();
+    String expectedDN = "replicationcsn=" + csn + "," + TEST_ROOT_DN_STRING + ",cn=changelog";
+    assertThat(actualDN).isEqualToIgnoringCase(expectedDN);
+  }
+
+  /**
+   * Returns a data structure allowing to compare arbitrary LDIF lines. The
+   * algorithm splits LDIF entries on lines containing only a dash ("-"). It
+   * then returns LDIF entries and lines in an LDIF entry in ordering
+   * insensitive data structures.
+   * <p>
+   * Note: a last line with only a dash ("-") is significant. i.e.:
+   *
+   * <pre>
+   * <code>
+   * boolean b = toLDIFEntries("-").equals(toLDIFEntries()));
+   * System.out.println(b); // prints "false"
+   * </code>
+   * </pre>
+   */
+  private static Set<Set<String>> toLDIFEntries(String... ldifLines)
+  {
+    final Set<Set<String>> results = new HashSet<Set<String>>();
+    Set<String> ldifEntryLines = new HashSet<String>();
+    for (String ldifLine : ldifLines)
+    {
+      if (!"-".equals(ldifLine))
+      {
+        // same entry keep adding
+        ldifEntryLines.add(ldifLine);
+      }
+      else
+      {
+        // this is a new entry
+        results.add(ldifEntryLines);
+        ldifEntryLines = new HashSet<String>();
+      }
+    }
+    results.add(ldifEntryLines);
+    return results;
+  }
+
+  // TODO : share this code with other classes
+  private static String getAttributeValue(Entry entry, String attrName)
+  {
+    List<Attribute> attrs = entry.getAttribute(attrName.toLowerCase());
+    if (attrs == null)
+    {
+      return null;
+    }
+    Attribute a = attrs.iterator().next();
+    AttributeValue av = a.iterator().next();
+    return av.toString();
+  }
+
+  private void debugAndWriteEntries(LDIFWriter ldifWriter,List<SearchResultEntry> entries, String tn) throws Exception
+  {
+    if (entries != null)
+    {
+      for (SearchResultEntry entry : entries)
+      {
+        // Can use entry.toSingleLineString()
+        debugInfo(tn, " RESULT entry returned:" + entry.toLDIFString());
+        if (ldifWriter != null)
+        {
+          ldifWriter.writeEntry(entry);
+        }
+      }
+    }
+  }
+
+  /**
+   * Utility - log debug message - highlight it is from the test and not
+   * from the server code. Makes easier to observe the test steps.
+   */
+  private void debugInfo(String testName, String message)
+  {
+    if (debugEnabled())
+    {
+      TRACER.debugInfo("** TEST " + testName + " ** " + message);
+    }
+  }
+}
+
diff --git a/opendj-sdk/opends/tests/unit-tests-testng/src/server/org/opends/server/replication/server/MonitorTest.java b/opendj-sdk/opends/tests/unit-tests-testng/src/server/org/opends/server/replication/server/MonitorTest.java
index 77c5dff..baf76db 100644
--- a/opendj-sdk/opends/tests/unit-tests-testng/src/server/org/opends/server/replication/server/MonitorTest.java
+++ b/opendj-sdk/opends/tests/unit-tests-testng/src/server/org/opends/server/replication/server/MonitorTest.java
@@ -41,6 +41,8 @@
 import org.opends.server.replication.plugin.LDAPReplicationDomain;
 import org.opends.server.replication.protocol.AddMsg;
 import org.opends.server.replication.protocol.ReplicationMsg;
+import org.opends.server.replication.server.changelog.je.ECLEnabledDomainPredicate;
+import org.opends.server.replication.service.DSRSShutdownSync;
 import org.opends.server.replication.service.ReplicationBroker;
 import org.opends.server.tools.LDAPSearch;
 import org.opends.server.types.Attribute;
@@ -174,7 +176,15 @@
     ReplServerFakeConfiguration conf =
         new ReplServerFakeConfiguration(chPort, chDir, replicationDbImplementation, 0, changelogId, 0,
             100, servers);
-    ReplicationServer replicationServer = new ReplicationServer(conf);
+    final DN testBaseDN = this.baseDN;
+    ReplicationServer replicationServer = new ReplicationServer(conf, new DSRSShutdownSync(), new ECLEnabledDomainPredicate()
+    {
+      @Override
+      public boolean isECLEnabledDomain(DN baseDN)
+      {
+        return testBaseDN.equals(baseDN);
+      }
+    });
     Thread.sleep(1000);
 
     return replicationServer;

--
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