diff --git a/WebContent/index.html b/WebContent/index.html
index b85195022..5a75e455e 100644
--- a/WebContent/index.html
+++ b/WebContent/index.html
@@ -200,14 +200,13 @@
 			</select>
 			<input type="text" class="input-medium" placeholder="StartTime"> ~ 
 			<input type="text" class="input-medium" placeholder="EndTime">
-			<button type="button" class="btn btn-primary" onclick="drawChart()">Trace !</button>
+			<button type="button" class="btn btn-primary" onclick="drawChart('flow')">Trace RPC !</button>
+			<button type="button" class="btn btn-primary" onclick="drawChart('flowserver')">Trace Server !</button>
 		</form>
 		
 		<p id="chart"></p>
 	</div>
 	<!-- END OF MENU -->
-
-
 	
 
 	<script type="text/javascript">
@@ -231,90 +230,88 @@
 
 		var path = sankey.link();
 
-//		d3.json("/flow.hippo?host=TEST_AGENT_ID&from=1348565386677&to=1348565386677", function(energy) {
-		d3.json("/flow.hippo?host=TEST_AGENT_ID&from=1348647506695&to=1348647536693", function(energy) {
-			sankey.nodes(energy.nodes).links(energy.links).layout(32);
-
-			/*
-			LINKS			
-			*/
-			var link = svg.append("g").selectAll(".link").data(energy.links)
-					.enter().append("path")
-					.attr("class", "link")
-					.attr("d", path).style("stroke-width", function(d) {
-						return Math.max(1, d.dy);
-					}).sort(function(a, b) {
-						return b.dy - a.dy;
-					}).on("click", function(a, b) {
-						console.log("[LINK CLICK] Get request details here.");
-						console.log(a);
-						console.log(b);
-					});
-
-			link.append("title").text(
-					function(d) {
-						return d.source.name + " → " + d.target.name + "\n"
-								+ format(d.value);
-					});
-
-			/*
-			NODES
-			*/
-			var node = svg.append("g").selectAll(".node").data(energy.nodes)
-					.enter().append("g").attr("class", "node").attr(
-							"transform", function(d) {
-								return "translate(" + d.x + "," + d.y + ")";
-							}).call(d3.behavior.drag().origin(function(d) {
-						return d;
-					}).on("dragstart", function() {
-						this.parentNode.appendChild(this);
-					}).on("drag", dragmove));
-
-			node.on("mouseover", function(d) {
-				//console.log(d.name);
-				
-				//console.log(d3.selectAll(".link"));
-				
-				//console.log(d3.selectAll(".link")[0][0]);
-				
-				console.log(d3.selectAll("#chart .link").select().attr("class", ""));
-				
-				console.log("mouse over");
-			}).on("mouseout", function(d) {
-
+		function drawChart(chartType) {
+//			d3.json("/" + chartType + ".hippo?host=TEST_AGENT_ID&from=1349342029106&to=1349342029572", function(energy) {
+			d3.json("/" + chartType + ".hippo?host=TEST_AGENT_ID&from=1349424219830&to=1349424219998", function(energy) {
+				sankey.nodes(energy.nodes).links(energy.links).layout(32);
+	
+				/*
+				LINKS			
+				*/
+				var link = svg.append("g").selectAll(".link").data(energy.links)
+						.enter().append("path")
+						.attr("class", "link")
+						.attr("d", path).style("stroke-width", function(d) {
+							return Math.max(1, d.dy);
+						}).sort(function(a, b) {
+							return b.dy - a.dy;
+						}).on("click", function(a, b) {
+							console.log("[LINK CLICK] Get request details here.");
+							console.log(a);
+							console.log(b);
+						});
+	
+				link.append("title").text(
+						function(d) {
+							return d.source.name + " → " + d.target.name + "\n"
+									+ format(d.value);
+						});
+	
+				/*
+				NODES
+				*/
+				var node = svg.append("g").selectAll(".node").data(energy.nodes)
+						.enter().append("g").attr("class", "node").attr(
+								"transform", function(d) {
+									return "translate(" + d.x + "," + d.y + ")";
+								}).call(d3.behavior.drag().origin(function(d) {
+							return d;
+						}).on("dragstart", function() {
+							this.parentNode.appendChild(this);
+						}).on("drag", dragmove));
+	
+				node.on("mouseover", function(d) {
+					//console.log(d.name);
+					//console.log(d3.selectAll(".link"));
+					//console.log(d3.selectAll(".link")[0][0]);
+					console.log(d3.selectAll("#chart .link").select().attr("class", ""));
+					console.log("mouse over");
+				}).on("mouseout", function(d) {
+	
+				});
+	
+				node.append("rect").attr("height", function(d) {
+					return d.dy;
+				}).attr("width", sankey.nodeWidth()).style("fill", function(d) {
+					return d.color = color(d.name.replace(/ .*/, ""));
+				}).style("stroke", function(d) {
+					return d3.rgb(d.color).darker(2);
+				}).append("title").text(function(d) {
+					return d.name + "\n" + format(d.value);
+				});
+	
+				node.append("text").attr("x", -6).attr("y", function(d) {
+					return d.dy / 2;
+				}).attr("dy", ".35em").attr("text-anchor", "end").attr("transform",
+						null).text(function(d) {
+					return d.name;
+				}).filter(function(d) {
+					return d.x < width / 2;
+				}).attr("x", 6 + sankey.nodeWidth()).attr("text-anchor", "start");
+	
+				function dragmove(d) {
+					d3.select(this).attr(
+							"transform",
+							"translate("
+									+ d.x
+									+ ","
+									+ (d.y = Math.max(0, Math.min(height - d.dy,
+											d3.event.y))) + ")");
+					sankey.relayout();
+					link.attr("d", path);
+				}
 			});
-
-			node.append("rect").attr("height", function(d) {
-				return d.dy;
-			}).attr("width", sankey.nodeWidth()).style("fill", function(d) {
-				return d.color = color(d.name.replace(/ .*/, ""));
-			}).style("stroke", function(d) {
-				return d3.rgb(d.color).darker(2);
-			}).append("title").text(function(d) {
-				return d.name + "\n" + format(d.value);
-			});
-
-			node.append("text").attr("x", -6).attr("y", function(d) {
-				return d.dy / 2;
-			}).attr("dy", ".35em").attr("text-anchor", "end").attr("transform",
-					null).text(function(d) {
-				return d.name;
-			}).filter(function(d) {
-				return d.x < width / 2;
-			}).attr("x", 6 + sankey.nodeWidth()).attr("text-anchor", "start");
-
-			function dragmove(d) {
-				d3.select(this).attr(
-						"transform",
-						"translate("
-								+ d.x
-								+ ","
-								+ (d.y = Math.max(0, Math.min(height - d.dy,
-										d3.event.y))) + ")");
-				sankey.relayout();
-				link.attr("d", path);
-			}
-		});
+		}
 	</script>
 
 	<script type="text/javascript">
diff --git a/src/main/java/com/nhn/hippo/web/controller/FlowChartController.java b/src/main/java/com/nhn/hippo/web/controller/FlowChartController.java
index af61d3045..4dc20d9c6 100644
--- a/src/main/java/com/nhn/hippo/web/controller/FlowChartController.java
+++ b/src/main/java/com/nhn/hippo/web/controller/FlowChartController.java
@@ -1,6 +1,7 @@
 package com.nhn.hippo.web.controller;
 
-import java.util.List;
+import java.util.Arrays;
+import java.util.Set;
 
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Controller;
@@ -11,6 +12,7 @@ import org.springframework.web.bind.annotation.RequestParam;
 
 import com.nhn.hippo.web.calltree.RPCCallTree;
 import com.nhn.hippo.web.service.FlowChartService;
+import com.nhn.hippo.web.vo.TraceId;
 
 /**
  * retrieve data for drawing call tree.
@@ -38,13 +40,24 @@ public class FlowChartController {
 	@RequestMapping(value = "/flow", method = RequestMethod.GET)
 	public String arcus(Model model, @RequestParam("host") String[] hosts, @RequestParam("from") long from, @RequestParam("to") long to) {
 		String[] agentIds = flow.selectAgentIds(hosts);
-		List<byte[]> traceIds = flow.selectTraceIdsFromTraceIndex(agentIds, from, to);
+		System.out.println("");
+		System.out.println("--------------------------------------");
+		System.out.println("agentIds=" + Arrays.toString(agentIds));
+		
+		Set<TraceId> traceIds = flow.selectTraceIdsFromTraceIndex(agentIds, from, to);
+		for(TraceId tid : traceIds) {
+			System.out.println("traceIds=" + tid);
+		}
+		System.out.println("--------------------------------------");
+		System.out.println("");
+		
 		RPCCallTree callTree = flow.selectRPCCallTree(traceIds);
 
 		model.addAttribute("nodes", callTree.getNodes());
 		model.addAttribute("links", callTree.getLinks());
-		model.addAttribute("value", "hello world");
 
+		System.out.println("");
+		System.out.println("--------------------------------------");
 		System.out.println(callTree.toString());
 
 		return "flow";
diff --git a/src/main/java/com/nhn/hippo/web/service/FlowChartService.java b/src/main/java/com/nhn/hippo/web/service/FlowChartService.java
index 29faa2013..64d021632 100755
--- a/src/main/java/com/nhn/hippo/web/service/FlowChartService.java
+++ b/src/main/java/com/nhn/hippo/web/service/FlowChartService.java
@@ -2,9 +2,11 @@ package com.nhn.hippo.web.service;
 
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 import com.nhn.hippo.web.calltree.RPCCallTree;
 import com.nhn.hippo.web.calltree.ServerCallTree;
+import com.nhn.hippo.web.vo.TraceId;
 import com.profiler.common.dto.thrift.Span;
 
 /**
@@ -30,7 +32,7 @@ public interface FlowChartService {
 	 * @param to
 	 * @return
 	 */
-	public List<byte[]> selectTraceIdsFromTraceIndex(String[] agentIds, long from, long to);
+	public Set<TraceId> selectTraceIdsFromTraceIndex(String[] agentIds, long from, long to);
 
 	/**
 	 * select Traces from Trace table
@@ -46,8 +48,8 @@ public interface FlowChartService {
 	 * @param traceIds
 	 * @return
 	 */
-	public RPCCallTree selectRPCCallTree(List<byte[]> traceIds);
-	
+	public RPCCallTree selectRPCCallTree(Set<TraceId> traceIds);
+
 	/**
 	 * select call tree
 	 * 
diff --git a/src/main/java/com/nhn/hippo/web/service/FlowChartServiceImpl.java b/src/main/java/com/nhn/hippo/web/service/FlowChartServiceImpl.java
index fccab43c3..0b8f0c8fe 100755
--- a/src/main/java/com/nhn/hippo/web/service/FlowChartServiceImpl.java
+++ b/src/main/java/com/nhn/hippo/web/service/FlowChartServiceImpl.java
@@ -2,9 +2,11 @@ package com.nhn.hippo.web.service;
 
 import java.util.ArrayList;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 import org.apache.commons.lang.ArrayUtils;
 import org.apache.hadoop.hbase.client.Get;
@@ -17,6 +19,7 @@ import org.springframework.stereotype.Service;
 import com.nhn.hippo.web.calltree.RPCCallTree;
 import com.nhn.hippo.web.calltree.ServerCallTree;
 import com.nhn.hippo.web.service.TracesProcessor.SpanHandler;
+import com.nhn.hippo.web.vo.TraceId;
 import com.profiler.common.dto.thrift.Span;
 import com.profiler.common.hbase.HBaseClient;
 import com.profiler.common.hbase.HBaseQuery;
@@ -55,11 +58,11 @@ public class FlowChartServiceImpl implements FlowChartService {
 	}
 
 	@Override
-	public List<byte[]> selectTraceIdsFromTraceIndex(String[] agentIds, long from, long to) {
+	public Set<TraceId> selectTraceIdsFromTraceIndex(String[] agentIds, long from, long to) {
 		List<HbaseColumn> column = new ArrayList<HBaseQuery.HbaseColumn>();
 		column.add(new HbaseColumn("Trace", "ID"));
 
-		List<byte[]> list = new ArrayList<byte[]>();
+		Set<TraceId> set = new HashSet<TraceId>();
 
 		for (String agentId : agentIds) {
 			byte[] s = ArrayUtils.addAll(Bytes.toBytes(agentId), Bytes.toBytes(from));
@@ -69,11 +72,11 @@ public class FlowChartServiceImpl implements FlowChartService {
 			Iterator<Map<String, byte[]>> result = client.getHBaseData(query);
 
 			while (result.hasNext()) {
-				list.add(result.next().get("ID"));
+				set.add(new TraceId(result.next().get("ID")));
 			}
 		}
 
-		return list;
+		return set;
 	}
 
 	@Override
@@ -105,10 +108,10 @@ public class FlowChartServiceImpl implements FlowChartService {
 	}
 
 	@Override
-	public RPCCallTree selectRPCCallTree(List<byte[]> traceIds) {
+	public RPCCallTree selectRPCCallTree(Set<TraceId> traceIds) {
 		List<Get> gets = new ArrayList<Get>(traceIds.size());
-		for (byte[] traceId : traceIds) {
-			gets.add(new Get(traceId));
+		for (TraceId traceId : traceIds) {
+			gets.add(new Get(traceId.getBytes()));
 		}
 
 		Result[] results = client.get(HBaseTables.TRACES, gets);
diff --git a/src/main/java/com/nhn/hippo/web/vo/TraceId.java b/src/main/java/com/nhn/hippo/web/vo/TraceId.java
new file mode 100644
index 000000000..7cd5d1961
--- /dev/null
+++ b/src/main/java/com/nhn/hippo/web/vo/TraceId.java
@@ -0,0 +1,35 @@
+package com.nhn.hippo.web.vo;
+
+import java.util.Arrays;
+
+public class TraceId {
+
+	private final byte[] id;
+	private final int hashcode;
+
+	public TraceId(byte[] traceId) {
+		this.id = traceId;
+		this.hashcode = new String(id).hashCode();
+	}
+
+	public byte[] getBytes() {
+		return id;
+	}
+
+	@Override
+	public boolean equals(Object traceId) {
+		if (traceId instanceof TraceId) {
+			return Arrays.equals(id, ((TraceId) traceId).id);
+		}
+		return false;
+	}
+
+	@Override
+	public int hashCode() {
+		return hashcode;
+	}
+
+	public String toString() {
+		return Arrays.toString(id);
+	}
+}