diff --git a/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/data/SpanDataConsumer.java b/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/data/SpanDataConsumer.java
index c5034e2dd..57a555e6e 100644
--- a/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/data/SpanDataConsumer.java
+++ b/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/data/SpanDataConsumer.java
@@ -2,10 +2,7 @@ package com.a.eye.skywalking.storage.data;
 
 import com.a.eye.datacarrier.consumer.IConsumer;
 import com.a.eye.skywalking.storage.data.file.DataFileWriter;
-import com.a.eye.skywalking.storage.data.index.IndexDBConnector;
-import com.a.eye.skywalking.storage.data.index.IndexMetaGroup;
-import com.a.eye.skywalking.storage.data.index.IndexOperator;
-import com.a.eye.skywalking.storage.data.index.IndexDBConnectorCache;
+import com.a.eye.skywalking.storage.data.index.*;
 
 import java.util.Iterator;
 import java.util.List;
@@ -15,7 +12,7 @@ public class SpanDataConsumer implements IConsumer<SpanData> {
     private IndexDBConnectorCache cache;
     private DataFileWriter        fileWriter;
 
-    public SpanDataConsumer(){
+    public SpanDataConsumer() {
         cache = new IndexDBConnectorCache();
         fileWriter = new DataFileWriter();
     }
@@ -23,18 +20,24 @@ public class SpanDataConsumer implements IConsumer<SpanData> {
     @Override
     public void consume(List<SpanData> data) {
 
-        Iterator<IndexMetaGroup> iterator = fileWriter.write(data).group();
+        Iterator<IndexMetaGroup<Long>> iterator =
+                IndexMetaCollections.group(fileWriter.write(data), new GroupKeyBuilder<Long>() {
+                    @Override
+                    public Long buildKey(IndexMetaInfo metaInfo) {
+                        return metaInfo.getStartTime();
+                    }
+                }).iterator();
 
         while (iterator.hasNext()) {
-            IndexMetaGroup metaGroup = iterator.next();
+            IndexMetaGroup<Long> metaGroup = iterator.next();
             IndexOperator indexOperator = IndexOperator.newOperator(getDBConnector(metaGroup));
             indexOperator.batchUpdate(metaGroup);
         }
 
     }
 
-    private IndexDBConnector getDBConnector(IndexMetaGroup metaGroup){
-        return cache.get(metaGroup.getTimestamp());
+    private IndexDBConnector getDBConnector(IndexMetaGroup<Long> metaGroup) {
+        return cache.get(metaGroup.getKey());
     }
 
     @Override
diff --git a/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/data/SpanDataFinder.java b/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/data/SpanDataFinder.java
new file mode 100644
index 000000000..9dfd66d3d
--- /dev/null
+++ b/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/data/SpanDataFinder.java
@@ -0,0 +1,42 @@
+package com.a.eye.skywalking.storage.data;
+
+import com.a.eye.skywalking.storage.block.index.BlockIndexEngine;
+import com.a.eye.skywalking.storage.data.file.DataFileReader;
+import com.a.eye.skywalking.storage.data.file.DataFileWriter;
+import com.a.eye.skywalking.storage.data.index.*;
+
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+
+/**
+ * Created by xin on 2016/11/6.
+ */
+public class SpanDataFinder {
+
+    public static List<byte[]> find(String traceId) {
+        long blockIndex = BlockIndexEngine.newFinder().find(fetchStartTimeFromTraceId(traceId));
+        IndexDBConnector indexDBConnector = new IndexDBConnector(blockIndex);
+        IndexMetaCollection indexMetaCollection = indexDBConnector.queryByTraceId(traceId);
+
+        Iterator<IndexMetaGroup<String>> iterator =
+                IndexMetaCollections.group(indexMetaCollection, new GroupKeyBuilder<String>() {
+                    @Override
+                    public String buildKey(IndexMetaInfo metaInfo) {
+                        return metaInfo.getFileName();
+                    }
+                }).iterator();
+
+        List<byte[]> result = new ArrayList<byte[]>();
+        while (iterator.hasNext()) {
+            IndexMetaGroup<String> group = iterator.next();
+            result.addAll(new DataFileReader(group.getKey()).read(group.getMetaInfo()));
+        }
+
+        return result;
+    }
+
+    private static long fetchStartTimeFromTraceId(String traceId) {
+        return -1;
+    }
+}
diff --git a/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/data/exception/SpanDataReadFailedException.java b/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/data/exception/SpanDataReadFailedException.java
new file mode 100644
index 000000000..6de32e2f3
--- /dev/null
+++ b/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/data/exception/SpanDataReadFailedException.java
@@ -0,0 +1,10 @@
+package com.a.eye.skywalking.storage.data.exception;
+
+/**
+ * Created by xin on 2016/11/6.
+ */
+public class SpanDataReadFailedException extends RuntimeException {
+    public SpanDataReadFailedException(String message, Exception e) {
+        super(message, e);
+    }
+}
diff --git a/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/data/file/DataFile.java b/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/data/file/DataFile.java
index 1ce3f94c1..d057edadc 100644
--- a/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/data/file/DataFile.java
+++ b/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/data/file/DataFile.java
@@ -4,6 +4,7 @@ import com.a.eye.skywalking.storage.config.Config;
 import com.a.eye.skywalking.storage.data.SpanData;
 import com.a.eye.skywalking.storage.data.exception.DataFileOperatorCreateFailedException;
 import com.a.eye.skywalking.storage.data.exception.SpanDataPersistenceFailedException;
+import com.a.eye.skywalking.storage.data.exception.SpanDataReadFailedException;
 import com.a.eye.skywalking.storage.data.index.IndexMetaInfo;
 
 import java.io.File;
@@ -26,9 +27,8 @@ public class DataFile {
         operator = new DataFileOperator();
     }
 
-    public DataFile(String fileName, long offset) {
+    public DataFile(String fileName) {
         this.fileName = fileName;
-        this.currentOffset = offset;
         operator = new DataFileOperator();
     }
 
@@ -62,6 +62,18 @@ public class DataFile {
         }
     }
 
+    public byte[] read(long offset, int length) {
+        byte[] data = new byte[length];
+        try {
+            operator.getReader().getChannel().position(offset);
+            operator.getReader().read(data, 0, length);
+            return data;
+        } catch (IOException e) {
+            throw new SpanDataReadFailedException(
+                    "Failed to read dataFile[" + fileName + "], offset: " + offset + " " + "lenght: " + length, e);
+        }
+    }
+
     class DataFileOperator {
         private FileOutputStream writer;
         private FileInputStream  reader;
diff --git a/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/data/file/DataFileReader.java b/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/data/file/DataFileReader.java
new file mode 100644
index 000000000..c0b4ba40a
--- /dev/null
+++ b/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/data/file/DataFileReader.java
@@ -0,0 +1,28 @@
+package com.a.eye.skywalking.storage.data.file;
+
+import com.a.eye.skywalking.storage.data.index.IndexMetaInfo;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+/**
+ * Created by xin on 2016/11/6.
+ */
+public class DataFileReader {
+    private DataFile dataFile;
+
+    public DataFileReader(String fileName) {
+        dataFile = new DataFile(fileName);
+    }
+
+    public List<byte[]> read(List<IndexMetaInfo> metaInfo) {
+        List<byte[]> metaData = new ArrayList<byte[]>();
+
+        for (IndexMetaInfo indexMetaInfo : metaInfo){
+            metaData.add(dataFile.read(indexMetaInfo.getOffset(), indexMetaInfo.getLength()));
+        }
+
+        return metaData;
+    }
+}
diff --git a/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/data/file/DataFileWriter.java b/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/data/file/DataFileWriter.java
index 4e6c34281..a6878bc83 100644
--- a/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/data/file/DataFileWriter.java
+++ b/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/data/file/DataFileWriter.java
@@ -1,7 +1,7 @@
 package com.a.eye.skywalking.storage.data.file;
 
 import com.a.eye.skywalking.storage.data.SpanData;
-import com.a.eye.skywalking.storage.data.index.IndexMetaCollections;
+import com.a.eye.skywalking.storage.data.index.IndexMetaCollection;
 
 import java.util.List;
 
@@ -13,12 +13,12 @@ public class DataFileWriter {
         dataFile = DataFilesManager.createNewDataFile();
     }
 
-    public IndexMetaCollections write(List<SpanData> spanData) {
+    public IndexMetaCollection write(List<SpanData> spanData) {
         if (dataFile.overLimitLength()) {
             dataFile = DataFilesManager.createNewDataFile();
         }
 
-        IndexMetaCollections collections = new IndexMetaCollections();
+        IndexMetaCollection collections = new IndexMetaCollection();
         for (SpanData data : spanData) {
             collections.add(dataFile.write(data));
         }
diff --git a/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/data/index/GroupKeyBuilder.java b/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/data/index/GroupKeyBuilder.java
new file mode 100644
index 000000000..086577e3f
--- /dev/null
+++ b/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/data/index/GroupKeyBuilder.java
@@ -0,0 +1,10 @@
+package com.a.eye.skywalking.storage.data.index;
+
+import com.a.eye.skywalking.storage.data.index.IndexMetaInfo;
+
+/**
+ * Created by xin on 2016/11/6.
+ */
+public interface GroupKeyBuilder<T> {
+    T buildKey(IndexMetaInfo metaInfo);
+}
diff --git a/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/data/index/IndexDBConnector.java b/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/data/index/IndexDBConnector.java
index 89c8e0a9a..c021189ec 100644
--- a/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/data/index/IndexDBConnector.java
+++ b/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/data/index/IndexDBConnector.java
@@ -86,7 +86,7 @@ public class IndexDBConnector {
         return timestamp;
     }
 
-    public void batchUpdate(IndexMetaGroup metaGroup) throws SQLException {
+    public void batchUpdate(IndexMetaGroup<Long> metaGroup) throws SQLException {
         int currentIndex = 0;
         PreparedStatement ps = connection.prepareStatement(INSERT_INDEX);
         for (IndexMetaInfo metaInfo : metaGroup.getMetaInfo()) {
@@ -117,6 +117,10 @@ public class IndexDBConnector {
         return indexSize;
     }
 
+    public IndexMetaCollection queryByTraceId(String traceId) {
+        return null;
+    }
+
     class ConnectURLGenerator {
 
         private String basePath;
diff --git a/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/data/index/IndexMetaCollection.java b/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/data/index/IndexMetaCollection.java
new file mode 100644
index 000000000..33778effe
--- /dev/null
+++ b/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/data/index/IndexMetaCollection.java
@@ -0,0 +1,51 @@
+package com.a.eye.skywalking.storage.data.index;
+
+
+import com.a.eye.skywalking.storage.block.index.BlockFinder;
+import com.a.eye.skywalking.storage.block.index.BlockIndexEngine;
+
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+
+public class IndexMetaCollection implements Iterable<IndexMetaInfo> {
+
+    private List<IndexMetaInfo> metaInfo;
+    private BlockFinder         finder;
+
+    public IndexMetaCollection() {
+        metaInfo = new ArrayList<>();
+        finder = BlockIndexEngine.newFinder();
+    }
+
+    public Iterator<IndexMetaGroup> group() {
+        List<IndexMetaGroup> indexMetaGroups = new ArrayList<IndexMetaGroup>();
+        for (IndexMetaInfo info : metaInfo) {
+            long timestamp = finder.find(info.getStartTime());
+
+            int index = indexMetaGroups.indexOf(new IndexMetaGroup(timestamp));
+            IndexMetaGroup metaGroup;
+
+            if (index == -1) {
+                metaGroup = new IndexMetaGroup(timestamp);
+                indexMetaGroups.add(metaGroup);
+            } else {
+                metaGroup = indexMetaGroups.get(index);
+            }
+
+            metaGroup.addIndexMetaInfo(info);
+        }
+
+        return indexMetaGroups.iterator();
+    }
+
+
+    public void add(IndexMetaInfo info) {
+        metaInfo.add(info);
+    }
+
+    @Override
+    public Iterator<IndexMetaInfo> iterator() {
+        return metaInfo.iterator();
+    }
+}
diff --git a/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/data/index/IndexMetaCollections.java b/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/data/index/IndexMetaCollections.java
index 40c92f2dd..ad229ed32 100644
--- a/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/data/index/IndexMetaCollections.java
+++ b/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/data/index/IndexMetaCollections.java
@@ -1,46 +1,33 @@
 package com.a.eye.skywalking.storage.data.index;
 
-
-import com.a.eye.skywalking.storage.block.index.BlockFinder;
-import com.a.eye.skywalking.storage.block.index.BlockIndexEngine;
-
 import java.util.ArrayList;
-import java.util.Iterator;
 import java.util.List;
 
+/**
+ * Created by xin on 2016/11/6.
+ */
 public class IndexMetaCollections {
 
-    private List<IndexMetaInfo> metaInfo;
-    private BlockFinder         finder;
+    public static <T> List<IndexMetaGroup<T>> group(IndexMetaCollection indexMetaCollection,
+            GroupKeyBuilder<T> builder) {
+        List<IndexMetaGroup<T>> indexMetaGroups = new ArrayList<IndexMetaGroup<T>>();
 
-    public IndexMetaCollections() {
-        metaInfo = new ArrayList<>();
-        finder = BlockIndexEngine.newFinder();
-    }
+        for (IndexMetaInfo metaInfo : indexMetaCollection) {
+            T key = builder.buildKey(metaInfo);
 
-    public Iterator<IndexMetaGroup> group() {
-        List<IndexMetaGroup> indexMetaGroups = new ArrayList<IndexMetaGroup>();
-        for (IndexMetaInfo info : metaInfo) {
-            long timestamp = finder.find(info.getStartTime());
-
-            int index = indexMetaGroups.indexOf(new IndexMetaGroup(timestamp));
+            int index = indexMetaGroups.indexOf(new IndexMetaGroup(key));
             IndexMetaGroup metaGroup;
 
             if (index == -1) {
-                metaGroup = new IndexMetaGroup(timestamp);
+                metaGroup = new IndexMetaGroup(key);
                 indexMetaGroups.add(metaGroup);
             } else {
                 metaGroup = indexMetaGroups.get(index);
             }
 
-            metaGroup.addIndexMetaInfo(info);
+            metaGroup.addIndexMetaInfo(metaInfo);
         }
 
-        return indexMetaGroups.iterator();
-    }
-
-
-    public void add(IndexMetaInfo info) {
-        metaInfo.add(info);
+        return indexMetaGroups;
     }
 }
diff --git a/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/data/index/IndexMetaGroup.java b/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/data/index/IndexMetaGroup.java
index 1e4c90b2b..95f4fa384 100644
--- a/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/data/index/IndexMetaGroup.java
+++ b/skywalking-storage-center/skywalking-storage/src/main/java/com/a/eye/skywalking/storage/data/index/IndexMetaGroup.java
@@ -1,24 +1,25 @@
 package com.a.eye.skywalking.storage.data.index;
 
 import java.util.ArrayList;
+import java.util.Iterator;
 import java.util.List;
 
 /**
  * Created by xin on 2016/11/4.
  */
-public class IndexMetaGroup {
+public class IndexMetaGroup<V>{
 
-    private long timestamp;
+    private V key;
 
     private List<IndexMetaInfo> metaInfo;
 
-    public IndexMetaGroup(long timestamp) {
-        this.timestamp = timestamp;
+    public IndexMetaGroup(V key) {
+        this.key = key;
         metaInfo = new ArrayList<IndexMetaInfo>();
     }
 
-    public long getTimestamp() {
-        return timestamp;
+    public V getKey() {
+        return key;
     }
 
     public List<IndexMetaInfo> getMetaInfo() {
@@ -36,18 +37,19 @@ public class IndexMetaGroup {
         if (o == null || getClass() != o.getClass())
             return false;
 
-        IndexMetaGroup that = (IndexMetaGroup) o;
+        IndexMetaGroup<?> that = (IndexMetaGroup<?>) o;
 
-        return timestamp == that.timestamp;
+        return key.equals(that.key);
 
     }
 
     @Override
     public int hashCode() {
-        return (int) (timestamp ^ (timestamp >>> 32));
+        return key.hashCode();
     }
 
     public int size() {
         return metaInfo.size();
     }
+
 }