[201265] Handling large collections by loading CDOIDs in chunks

https://bugs.eclipse.org/bugs/show_bug.cgi?id=201265

12 files changed, 502 insertions, 4 deletions

diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/IDBStoreAccessor.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/IDBStoreAccessor.java
index 7483b8c594..c849826fa3 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/IDBStoreAccessor.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/IDBStoreAccessor.java
@@ -22,6 +22,8 @@ import java.sql.Statement;
  */
 public interface IDBStoreAccessor extends IStoreReader, IStoreWriter
 {
+  public IDBStore getStore();
+
   public Connection getConnection();
 
   public Statement getStatement();
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/IDBStoreChunkReader.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/IDBStoreChunkReader.java
new file mode 100644
index 0000000000..873c8be620
--- /dev/null
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/IDBStoreChunkReader.java
@@ -0,0 +1,21 @@
+/***************************************************************************
+ * Copyright (c) 2004 - 2007 Eike Stepper, Germany.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ * 
+ * Contributors:
+ *    Eike Stepper - initial API and implementation
+ **************************************************************************/
+package org.eclipse.emf.cdo.server.db;
+
+import org.eclipse.emf.cdo.server.IStoreChunkReader;
+
+/**
+ * @author Eike Stepper
+ */
+public interface IDBStoreChunkReader extends IStoreChunkReader
+{
+  public IDBStoreAccessor getStoreAccessor();
+}
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/IReferenceMapping.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/IReferenceMapping.java
index 9cd08b610a..2d3d95b366 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/IReferenceMapping.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/db/IReferenceMapping.java
@@ -12,9 +12,12 @@ package org.eclipse.emf.cdo.server.db;
 
 import org.eclipse.emf.cdo.internal.protocol.revision.CDORevisionImpl;
 import org.eclipse.emf.cdo.protocol.model.CDOFeature;
+import org.eclipse.emf.cdo.server.IStoreChunkReader.Chunk;
 
 import org.eclipse.net4j.db.IDBTable;
 
+import java.util.List;
+
 /**
  * @author Eike Stepper
  */
@@ -27,4 +30,6 @@ public interface IReferenceMapping
   public void writeReference(IDBStoreAccessor storeAccessor, CDORevisionImpl revision);
 
   public void readReference(IDBStoreAccessor storeAccessor, CDORevisionImpl revision);
+
+  public void readChunks(IDBStoreChunkReader chunkReader, List<Chunk> chunks, String string);
 }
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/DBStoreAccessor.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/DBStoreAccessor.java
index 3186e8e717..c8ed97b07d 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/DBStoreAccessor.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/DBStoreAccessor.java
@@ -21,6 +21,7 @@ import org.eclipse.emf.cdo.internal.protocol.revision.CDORevisionImpl;
 import org.eclipse.emf.cdo.protocol.CDOID;
 import org.eclipse.emf.cdo.protocol.CDOIDRange;
 import org.eclipse.emf.cdo.protocol.model.CDOClassRef;
+import org.eclipse.emf.cdo.protocol.model.CDOFeature;
 import org.eclipse.emf.cdo.protocol.model.CDOPackageInfo;
 import org.eclipse.emf.cdo.protocol.model.CDOType;
 import org.eclipse.emf.cdo.protocol.revision.CDORevision;
@@ -28,6 +29,7 @@ import org.eclipse.emf.cdo.server.IPackageManager;
 import org.eclipse.emf.cdo.server.IRepository;
 import org.eclipse.emf.cdo.server.IRevisionManager;
 import org.eclipse.emf.cdo.server.ISession;
+import org.eclipse.emf.cdo.server.IStoreChunkReader;
 import org.eclipse.emf.cdo.server.IView;
 import org.eclipse.emf.cdo.server.db.IDBStoreAccessor;
 import org.eclipse.emf.cdo.server.db.IMapping;
@@ -165,6 +167,11 @@ public class DBStoreAccessor implements IDBStoreAccessor
     return statement;
   }
 
+  public IStoreChunkReader createChunkReader(CDORevision revision, CDOFeature feature)
+  {
+    return new DBStoreChunkReader(this, revision, feature);
+  }
+
   public void writePackages(CDOPackageImpl... cdoPackages)
   {
     for (CDOPackageImpl cdoPackage : cdoPackages)
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/DBStoreChunkReader.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/DBStoreChunkReader.java
new file mode 100644
index 0000000000..8629ef3fcd
--- /dev/null
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/DBStoreChunkReader.java
@@ -0,0 +1,86 @@
+/***************************************************************************
+ * Copyright (c) 2004 - 2007 Eike Stepper, Germany.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ * 
+ * Contributors:
+ *    Eike Stepper - initial API and implementation
+ **************************************************************************/
+package org.eclipse.emf.cdo.server.internal.db;
+
+import org.eclipse.emf.cdo.internal.server.StoreChunkReader;
+import org.eclipse.emf.cdo.protocol.model.CDOClass;
+import org.eclipse.emf.cdo.protocol.model.CDOFeature;
+import org.eclipse.emf.cdo.protocol.revision.CDORevision;
+import org.eclipse.emf.cdo.server.db.IDBStoreAccessor;
+import org.eclipse.emf.cdo.server.db.IDBStoreChunkReader;
+import org.eclipse.emf.cdo.server.db.IMapping;
+import org.eclipse.emf.cdo.server.db.IMappingStrategy;
+import org.eclipse.emf.cdo.server.db.IReferenceMapping;
+
+import org.eclipse.net4j.util.ImplementationError;
+
+import java.util.List;
+
+/**
+ * @author Eike Stepper
+ */
+public class DBStoreChunkReader extends StoreChunkReader implements IDBStoreChunkReader
+{
+  private IReferenceMapping referenceMapping;
+
+  private StringBuilder builder = new StringBuilder();
+
+  public DBStoreChunkReader(IDBStoreAccessor storeAccessor, CDORevision revision, CDOFeature feature)
+  {
+    super(storeAccessor, revision, feature);
+    IMappingStrategy mappingStrategy = storeAccessor.getStore().getMappingStrategy();
+    CDOClass cdoClass = revision.getCDOClass();
+    IMapping mapping = mappingStrategy.getMapping(cdoClass);
+    if (mapping instanceof ValueMapping)
+    {
+      referenceMapping = ((ValueMapping)mapping).getReferenceMapping(feature);
+    }
+    else
+    {
+      throw new ImplementationError();
+    }
+  }
+
+  @Override
+  public IDBStoreAccessor getStoreAccessor()
+  {
+    return (IDBStoreAccessor)super.getStoreAccessor();
+  }
+
+  @Override
+  public void addSimpleChunk(int index)
+  {
+    super.addSimpleChunk(index);
+    builder.append(" AND ");
+    builder.append(ReferenceMapping.FIELD_NAME_IDX);
+    builder.append("=");
+    builder.append(index);
+  }
+
+  @Override
+  public void addRangedChunk(int fromIndex, int toIndex)
+  {
+    super.addRangedChunk(fromIndex, toIndex);
+    builder.append(" AND ");
+    builder.append(ReferenceMapping.FIELD_NAME_IDX);
+    builder.append(" BETWEEN ");
+    builder.append(fromIndex);
+    builder.append(" AND ");
+    builder.append(toIndex);
+  }
+
+  public List<Chunk> executeRead()
+  {
+    List<Chunk> chunks = getChunks();
+    referenceMapping.readChunks(this, chunks, builder.toString());
+    return chunks;
+  }
+}
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/MappingStrategy.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/MappingStrategy.java
index fad44e2ef5..778cea789e 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/MappingStrategy.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/MappingStrategy.java
@@ -19,6 +19,7 @@ import org.eclipse.emf.cdo.server.db.IMapping;
 import org.eclipse.emf.cdo.server.db.IMappingStrategy;
 
 import org.eclipse.net4j.db.DBException;
+import org.eclipse.net4j.db.DBUtil;
 import org.eclipse.net4j.db.IDBTable;
 import org.eclipse.net4j.util.io.CloseableIterator;
 
@@ -199,10 +200,11 @@ public abstract class MappingStrategy implements IMappingStrategy
         if (table != null)
         {
           String sql = prefix + table + suffix;
+          ResultSet resultSet = null;
 
           try
           {
-            ResultSet resultSet = storeAccessor.getStatement().executeQuery(sql);
+            resultSet = storeAccessor.getStatement().executeQuery(sql);
             if (resultSet.next())
             {
               int classID = resultSet.getInt(1);
@@ -213,6 +215,10 @@ public abstract class MappingStrategy implements IMappingStrategy
           {
             throw new DBException(ex);
           }
+          finally
+          {
+            DBUtil.close(resultSet);
+          }
         }
       }
     }
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/ReferenceMapping.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/ReferenceMapping.java
index 6a91e2934b..bb6601f4e0 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/ReferenceMapping.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/ReferenceMapping.java
@@ -1,17 +1,25 @@
 package org.eclipse.emf.cdo.server.internal.db;
 
+import org.eclipse.emf.cdo.internal.protocol.CDOIDImpl;
 import org.eclipse.emf.cdo.internal.protocol.revision.CDORevisionImpl;
 import org.eclipse.emf.cdo.protocol.CDOID;
 import org.eclipse.emf.cdo.protocol.model.CDOClass;
 import org.eclipse.emf.cdo.protocol.model.CDOFeature;
 import org.eclipse.emf.cdo.protocol.model.CDOPackage;
 import org.eclipse.emf.cdo.server.IRepository;
+import org.eclipse.emf.cdo.server.IStoreChunkReader.Chunk;
 import org.eclipse.emf.cdo.server.db.IDBStoreAccessor;
+import org.eclipse.emf.cdo.server.db.IDBStoreChunkReader;
 import org.eclipse.emf.cdo.server.db.IReferenceMapping;
 
+import org.eclipse.net4j.db.DBException;
 import org.eclipse.net4j.db.DBType;
+import org.eclipse.net4j.db.DBUtil;
 import org.eclipse.net4j.db.IDBTable;
 
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.util.List;
 import java.util.Map;
 
 /**
@@ -89,6 +97,76 @@ public class ReferenceMapping extends FeatureMapping implements IReferenceMappin
     throw new UnsupportedOperationException("Not yet implemented");
   }
 
+  public void readChunks(IDBStoreChunkReader chunkReader, List<Chunk> chunks, String where)
+  {
+    IDBStoreAccessor storeAccessor = chunkReader.getStoreAccessor();
+    CDOID source = chunkReader.getRevision().getID();
+    int version = chunkReader.getRevision().getVersion();
+    CDOFeature feature = chunkReader.getFeature();
+
+    StringBuilder builder = new StringBuilder();
+    builder.append("SELECT ");
+    builder.append(FIELD_NAME_TARGET);
+    builder.append(" FROM ");
+    builder.append(table);
+    builder.append(" WHERE ");
+    if (withFeature)
+    {
+      builder.append(FIELD_NAME_FEATURE);
+      builder.append("=");
+      builder.append(FeatureServerInfo.getDBID(feature));
+    }
+
+    builder.append(" AND ");
+    builder.append(FIELD_NAME_SOURCE);
+    builder.append("=");
+    builder.append(source.getValue());
+    builder.append(" AND ");
+    builder.append(FIELD_NAME_VERSION);
+    builder.append("=");
+    builder.append(version);
+    builder.append(where);
+    builder.append(" ORDER BY ");
+    builder.append(FIELD_NAME_IDX);
+
+    String sql = builder.toString();
+    ResultSet resultSet = null;
+
+    try
+    {
+      Chunk chunk = null;
+      int chunkSize = 0;
+      int chunkIndex = 0;
+      int indexInChunk = 0;
+
+      resultSet = storeAccessor.getStatement().executeQuery(sql);
+      while (resultSet.next())
+      {
+        long target = resultSet.getLong(1);
+        if (chunk == null)
+        {
+          chunk = chunks.get(chunkIndex++);
+          chunkSize = chunk.size();
+        }
+
+        chunk.addID(indexInChunk++, CDOIDImpl.create(target));
+        if (indexInChunk == chunkSize)
+        {
+          chunk = null;
+          indexInChunk = 0;
+        }
+      }
+    }
+    catch (SQLException ex)
+    {
+      throw new DBException(ex);
+    }
+    finally
+    {
+      DBUtil.close(resultSet);
+    }
+  }
+
   protected void mapReference(CDOClass cdoClass, CDOFeature cdoFeature)
   {
     switch (toMany)
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/ValueMapping.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/ValueMapping.java
index fe71a55345..1db9decbd1 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/ValueMapping.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/ValueMapping.java
@@ -55,6 +55,19 @@ public abstract class ValueMapping extends Mapping
     return referenceMappings;
   }
 
+  public IReferenceMapping getReferenceMapping(CDOFeature feature)
+  {
+    for (IReferenceMapping referenceMapping : referenceMappings)
+    {
+      if (referenceMapping.getFeature() == feature)
+      {
+        return referenceMapping;
+      }
+    }
+
+    return null;
+  }
+
   public void writeRevision(IDBStoreAccessor storeAccessor, CDORevisionImpl revision)
   {
     if (attributeMappings != null)
diff --git a/plugins/org.eclipse.emf.cdo.server/src/org/eclipse/emf/cdo/internal/server/RevisionManager.java b/plugins/org.eclipse.emf.cdo.server/src/org/eclipse/emf/cdo/internal/server/RevisionManager.java
index a26811ac47..5077568e1f 100644
--- a/plugins/org.eclipse.emf.cdo.server/src/org/eclipse/emf/cdo/internal/server/RevisionManager.java
+++ b/plugins/org.eclipse.emf.cdo.server/src/org/eclipse/emf/cdo/internal/server/RevisionManager.java
@@ -10,15 +10,21 @@
  **************************************************************************/
 package org.eclipse.emf.cdo.internal.server;
 
+import org.eclipse.emf.cdo.internal.protocol.model.CDOClassImpl;
 import org.eclipse.emf.cdo.internal.protocol.model.CDOClassRefImpl;
+import org.eclipse.emf.cdo.internal.protocol.model.CDOFeatureImpl;
 import org.eclipse.emf.cdo.internal.protocol.model.resource.CDOPathFeatureImpl;
 import org.eclipse.emf.cdo.internal.protocol.revision.CDORevisionImpl;
 import org.eclipse.emf.cdo.internal.protocol.revision.CDORevisionResolverImpl;
+import org.eclipse.emf.cdo.internal.protocol.revision.CDORevisionImpl.MoveableList;
 import org.eclipse.emf.cdo.protocol.CDOID;
+import org.eclipse.emf.cdo.protocol.model.CDOFeature;
 import org.eclipse.emf.cdo.protocol.revision.CDOReferenceProxy;
 import org.eclipse.emf.cdo.server.IRevisionManager;
+import org.eclipse.emf.cdo.server.IStoreChunkReader;
 import org.eclipse.emf.cdo.server.IStoreReader;
 import org.eclipse.emf.cdo.server.IStoreWriter;
+import org.eclipse.emf.cdo.server.IStoreChunkReader.Chunk;
 
 import org.eclipse.net4j.util.transaction.ITransaction;
 import org.eclipse.net4j.util.transaction.ITransactionalOperation;
@@ -64,18 +70,120 @@ public class RevisionManager extends CDORevisionResolverImpl implements IRevisio
   }
 
   @Override
-  protected CDORevisionImpl verifyRevision(CDORevisionImpl revision)
+  protected CDORevisionImpl verifyRevision(CDORevisionImpl revision, int referenceChunk)
   {
-    revision = super.verifyRevision(revision);
+    IStoreReader storeReader = null;
+    revision = super.verifyRevision(revision, referenceChunk);
     if (repository.isVerifyingRevisions())
     {
-      IStoreReader storeReader = StoreUtil.getReader();
+      storeReader = StoreUtil.getReader();
       revision = storeReader.verifyRevision(revision);
     }
 
+    ensureChunks(revision, referenceChunk, storeReader);
     return revision;
   }
 
+  protected void ensureChunks(CDORevisionImpl revision, int referenceChunk, IStoreReader storeReader)
+  {
+    CDOClassImpl cdoClass = revision.getCDOClass();
+    CDOFeatureImpl[] features = cdoClass.getAllFeatures();
+    for (int i = 0; i < features.length; i++)
+    {
+      CDOFeatureImpl feature = features[i];
+      if (feature.isReference() && feature.isMany())
+      {
+        MoveableList list = revision.getList(feature);
+        int chunkEnd = Math.min(referenceChunk, list.size());
+        storeReader = ensureChunk(revision, feature, storeReader, list, 0, chunkEnd);
+      }
+    }
+  }
+
+  protected IStoreReader ensureChunk(CDORevisionImpl revision, CDOFeature feature, IStoreReader storeReader,
+      MoveableList list, int chunkStart, int chunkEnd)
+  {
+    IStoreChunkReader chunkReader = null;
+    int fromIndex = -1;
+    for (int j = chunkStart; j < chunkEnd; j++)
+    {
+      if (list.get(j) == CDORevisionImpl.UNINITIALIZED)
+      {
+        if (fromIndex == -1)
+        {
+          fromIndex = j;
+        }
+      }
+      else
+      {
+        if (fromIndex != -1)
+        {
+          if (chunkReader == null)
+          {
+            if (storeReader == null)
+            {
+              storeReader = StoreUtil.getReader();
+            }
+
+            chunkReader = storeReader.createChunkReader(revision, feature);
+          }
+
+          int toIndex = j - 1;
+          if (fromIndex == toIndex)
+          {
+            chunkReader.addSimpleChunk(fromIndex);
+          }
+          else
+          {
+            chunkReader.addRangedChunk(fromIndex, toIndex);
+          }
+
+          fromIndex = -1;
+        }
+      }
+    }
+
+    // Add last chunk
+    if (fromIndex != -1)
+    {
+      if (chunkReader == null)
+      {
+        if (storeReader == null)
+        {
+          storeReader = StoreUtil.getReader();
+        }
+
+        chunkReader = storeReader.createChunkReader(revision, feature);
+      }
+
+      int toIndex = chunkEnd - 1;
+      if (fromIndex == toIndex)
+      {
+        chunkReader.addSimpleChunk(fromIndex);
+      }
+      else
+      {
+        chunkReader.addRangedChunk(fromIndex, toIndex);
+      }
+    }
+
+    if (chunkReader != null)
+    {
+      List<Chunk> chunks = chunkReader.executeRead();
+      for (Chunk chunk : chunks)
+      {
+        int startIndex = chunk.getStartIndex();
+        for (int indexInChunk = 0; indexInChunk < chunk.size(); indexInChunk++)
+        {
+          CDOID id = chunk.getID(indexInChunk);
+          list.set(startIndex + indexInChunk, id);
+        }
+      }
+    }
+
+    return storeReader;
+  }
+
   @Override
   protected CDORevisionImpl loadRevision(CDOID id, int referenceChunk)
   {
diff --git a/plugins/org.eclipse.emf.cdo.server/src/org/eclipse/emf/cdo/internal/server/StoreChunkReader.java b/plugins/org.eclipse.emf.cdo.server/src/org/eclipse/emf/cdo/internal/server/StoreChunkReader.java
new file mode 100644
index 0000000000..44aed4c3bc
--- /dev/null
+++ b/plugins/org.eclipse.emf.cdo.server/src/org/eclipse/emf/cdo/internal/server/StoreChunkReader.java
@@ -0,0 +1,70 @@
+/***************************************************************************
+ * Copyright (c) 2004 - 2007 Eike Stepper, Germany.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ * 
+ * Contributors:
+ *    Eike Stepper - initial API and implementation
+ **************************************************************************/
+package org.eclipse.emf.cdo.internal.server;
+
+import org.eclipse.emf.cdo.protocol.model.CDOFeature;
+import org.eclipse.emf.cdo.protocol.revision.CDORevision;
+import org.eclipse.emf.cdo.server.IStoreAccessor;
+import org.eclipse.emf.cdo.server.IStoreChunkReader;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * @author Eike Stepper
+ */
+public abstract class StoreChunkReader implements IStoreChunkReader
+{
+  private IStoreAccessor storeAccessor;
+
+  private CDORevision revision;
+
+  private CDOFeature feature;
+
+  private List<Chunk> chunks = new ArrayList<Chunk>(0);
+
+  public StoreChunkReader(IStoreAccessor storeAccessor, CDORevision revision, CDOFeature feature)
+  {
+    this.storeAccessor = storeAccessor;
+    this.revision = revision;
+    this.feature = feature;
+  }
+
+  public IStoreAccessor getStoreAccessor()
+  {
+    return storeAccessor;
+  }
+
+  public CDORevision getRevision()
+  {
+    return revision;
+  }
+
+  public CDOFeature getFeature()
+  {
+    return feature;
+  }
+
+  public List<Chunk> getChunks()
+  {
+    return chunks;
+  }
+
+  public void addSimpleChunk(int index)
+  {
+    chunks.add(new Chunk(index));
+  }
+
+  public void addRangedChunk(int fromIndex, int toIndex)
+  {
+    chunks.add(new Chunk(fromIndex, toIndex - fromIndex));
+  }
+}
diff --git a/plugins/org.eclipse.emf.cdo.server/src/org/eclipse/emf/cdo/server/IStoreChunkReader.java b/plugins/org.eclipse.emf.cdo.server/src/org/eclipse/emf/cdo/server/IStoreChunkReader.java
new file mode 100644
index 0000000000..96c7ff8c1d
--- /dev/null
+++ b/plugins/org.eclipse.emf.cdo.server/src/org/eclipse/emf/cdo/server/IStoreChunkReader.java
@@ -0,0 +1,99 @@
+/***************************************************************************
+ * Copyright (c) 2004 - 2007 Eike Stepper, Germany.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ * 
+ * Contributors:
+ *    Eike Stepper - initial API and implementation
+ **************************************************************************/
+package org.eclipse.emf.cdo.server;
+
+import org.eclipse.emf.cdo.protocol.CDOID;
+import org.eclipse.emf.cdo.protocol.model.CDOFeature;
+import org.eclipse.emf.cdo.protocol.revision.CDORevision;
+
+import java.util.List;
+
+/**
+ * @author Eike Stepper
+ */
+public interface IStoreChunkReader
+{
+  public CDORevision getRevision();
+
+  public CDOFeature getFeature();
+
+  public void addSimpleChunk(int index);
+
+  public void addRangedChunk(int fromIndex, int toIndex);
+
+  public List<Chunk> executeRead();
+
+  /**
+   * @author Eike Stepper
+   */
+  public class Chunk
+  {
+    private int startIndex;
+
+    private Object ids;
+
+    public Chunk(int startIndex)
+    {
+      this.startIndex = startIndex;
+    }
+
+    public Chunk(int startIndex, int size)
+    {
+      this(startIndex);
+      ids = new CDOID[size];
+    }
+
+    public int getStartIndex()
+    {
+      return startIndex;
+    }
+
+    public int size()
+    {
+      if (ids instanceof CDOID)
+      {
+        return 1;
+      }
+
+      return ((CDOID[])ids).length;
+    }
+
+    public CDOID getID(int indexInChunk)
+    {
+      if (ids instanceof CDOID)
+      {
+        if (indexInChunk == 0)
+        {
+          return (CDOID)ids;
+        }
+
+        throw new ArrayIndexOutOfBoundsException(indexInChunk);
+      }
+
+      return ((CDOID[])ids)[indexInChunk];
+    }
+
+    public void addID(int indexInChunk, CDOID id)
+    {
+      if (ids instanceof CDOID)
+      {
+        if (indexInChunk == 0)
+        {
+          ids = id;
+        }
+
+        throw new ArrayIndexOutOfBoundsException(indexInChunk);
+      }
+
+      ((CDOID[])ids)[indexInChunk] = id;
+    }
+  }
+}
diff --git a/plugins/org.eclipse.emf.cdo.server/src/org/eclipse/emf/cdo/server/IStoreReader.java b/plugins/org.eclipse.emf.cdo.server/src/org/eclipse/emf/cdo/server/IStoreReader.java
index 392a6a8626..5dea6eb87c 100644
--- a/plugins/org.eclipse.emf.cdo.server/src/org/eclipse/emf/cdo/server/IStoreReader.java
+++ b/plugins/org.eclipse.emf.cdo.server/src/org/eclipse/emf/cdo/server/IStoreReader.java
@@ -15,6 +15,7 @@ import org.eclipse.emf.cdo.internal.protocol.revision.CDORevisionImpl;
 import org.eclipse.emf.cdo.internal.server.StoreUtil;
 import org.eclipse.emf.cdo.protocol.CDOID;
 import org.eclipse.emf.cdo.protocol.model.CDOClassRef;
+import org.eclipse.emf.cdo.protocol.model.CDOFeature;
 import org.eclipse.emf.cdo.protocol.model.CDOPackageInfo;
 import org.eclipse.emf.cdo.protocol.revision.CDORevision;
 
@@ -30,6 +31,8 @@ public interface IStoreReader extends IStoreAccessor
 {
   public ISession getSession();
 
+  public IStoreChunkReader createChunkReader(CDORevision revision, CDOFeature feature);
+
   public Collection<CDOPackageInfo> readPackageInfos();
 
   /**