diff --git a/skywalking-analysis/src/main/java/com/ai/cloud/skywalking/analysis/AnalysisServerDriver.java b/skywalking-analysis/src/main/java/com/ai/cloud/skywalking/analysis/AnalysisServerDriver.java
index c3b022497..37860944b 100644
--- a/skywalking-analysis/src/main/java/com/ai/cloud/skywalking/analysis/AnalysisServerDriver.java
+++ b/skywalking-analysis/src/main/java/com/ai/cloud/skywalking/analysis/AnalysisServerDriver.java
@@ -12,6 +12,7 @@ import com.ai.cloud.skywalking.analysis.config.HBaseTableMetaData;
 
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.conf.Configured;
+import org.apache.hadoop.hbase.HConstants;
 import org.apache.hadoop.hbase.client.Scan;
 import org.apache.hadoop.hbase.mapreduce.TableMapReduceUtil;
 import org.apache.hadoop.io.Text;
@@ -55,6 +56,8 @@ public class AnalysisServerDriver extends Configured implements Tool {
         conf.set("skywalking.analysis.mode", String.valueOf(Config.AnalysisServer.IS_ACCUMULATE_MODE));
         conf.set("hbase.zookeeper.quorum", Config.HBase.ZK_QUORUM);
         conf.set("hbase.zookeeper.property.clientPort", Config.HBase.ZK_CLIENT_PORT);
+        //-XX:+UseParallelGC -XX:ParallelGCThreads=4 -XX:GCTimeRatio=10 -XX:YoungGenerationSizeIncrement=20 -XX:TenuredGenerationSizeIncrement=20 -XX:AdaptiveSizeDecrementScaleFactor=2
+        conf.set("mapred.child.java.opts",Config.MapReduce.java_opts);
         String[] otherArgs = new GenericOptionsParser(conf, args).getRemainingArgs();
         if (otherArgs.length != 2) {
             System.err.println("Usage: AnalysisServer yyyy-MM-dd/HH:mm:ss yyyy-MM-dd/HH:mm:ss");
diff --git a/skywalking-analysis/src/main/java/com/ai/cloud/skywalking/analysis/chainbuild/ChainBuildMapper.java b/skywalking-analysis/src/main/java/com/ai/cloud/skywalking/analysis/chainbuild/ChainBuildMapper.java
index c02a7f3bf..8ac5a17d5 100644
--- a/skywalking-analysis/src/main/java/com/ai/cloud/skywalking/analysis/chainbuild/ChainBuildMapper.java
+++ b/skywalking-analysis/src/main/java/com/ai/cloud/skywalking/analysis/chainbuild/ChainBuildMapper.java
@@ -19,7 +19,6 @@ import org.apache.hadoop.io.Text;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
-
 import java.io.IOException;
 import java.util.*;
 
@@ -56,8 +55,10 @@ public class ChainBuildMapper extends TableMapper<Text, Text> {
             chainInfo = spanToChainInfo(Bytes.toString(key.get()), spanList);
             logger.debug("convert tid[" + Bytes.toString(key.get())
                     + "] to chain with cid[" + chainInfo.getCID() + "].");
-            context.write(
-                    new Text(chainInfo.getCallEntrance()), new Text(new Gson().toJson(chainInfo)));
+            if (chainInfo.getCallEntrance() != null && chainInfo.getCallEntrance().length() > 0) {
+                context.write(
+                        new Text(chainInfo.getCallEntrance()), new Text(new Gson().toJson(chainInfo)));
+            }
         } catch (Exception e) {
             logger.error("Failed to mapper call chain[" + key.toString() + "]",
                     e);
diff --git a/skywalking-analysis/src/main/java/com/ai/cloud/skywalking/analysis/config/Config.java b/skywalking-analysis/src/main/java/com/ai/cloud/skywalking/analysis/config/Config.java
index 240ce84f4..01df2cabe 100644
--- a/skywalking-analysis/src/main/java/com/ai/cloud/skywalking/analysis/config/Config.java
+++ b/skywalking-analysis/src/main/java/com/ai/cloud/skywalking/analysis/config/Config.java
@@ -29,4 +29,8 @@ public class Config {
     public static class AnalysisServer{
         public static boolean IS_ACCUMULATE_MODE = true;
     }
+
+    public static class MapReduce{
+        public static String java_opts = "-Xmx200m";
+    }
 }
diff --git a/skywalking-analysis/src/main/resources/analysis.conf b/skywalking-analysis/src/main/resources/analysis.conf
index e4369b675..2ece0b01e 100644
--- a/skywalking-analysis/src/main/resources/analysis.conf
+++ b/skywalking-analysis/src/main/resources/analysis.conf
@@ -15,4 +15,6 @@ filter.filter_package_name=com.ai.cloud.skywalking.analysis.chainbuild.filter.im
 
 chainnodesummary.interval=1
 
-reducer.reducer_number=4
\ No newline at end of file
+reducer.reducer_number=4
+
+mapreduce.java_opts=-Xmx512m
\ No newline at end of file