diff --git a/iotdb/src/test/java/cn/edu/tsinghua/iotdb/queryV2/component/SegmentInputStreamWithMMapTest.java b/iotdb/src/test/java/cn/edu/tsinghua/iotdb/queryV2/component/SegmentInputStreamWithMMapTest.java
index 280c87b7c2c..cbf0325d24e 100644
--- a/iotdb/src/test/java/cn/edu/tsinghua/iotdb/queryV2/component/SegmentInputStreamWithMMapTest.java
+++ b/iotdb/src/test/java/cn/edu/tsinghua/iotdb/queryV2/component/SegmentInputStreamWithMMapTest.java
@@ -3,6 +3,8 @@ package cn.edu.tsinghua.iotdb.queryV2.component;
 import cn.edu.tsinghua.iotdb.queryV2.SimpleFileWriter;
 import cn.edu.tsinghua.iotdb.queryV2.engine.reader.component.SegmentInputStream;
 import cn.edu.tsinghua.iotdb.queryV2.engine.reader.component.SegmentInputStreamWithMMap;
+import sun.nio.ch.DirectBuffer;
+
 import org.junit.After;
 import org.junit.Assert;
 import org.junit.Before;
@@ -47,6 +49,7 @@ public class SegmentInputStreamWithMMapTest {
         testOneSegmentWithMMap(buffer1, 20, 1000);
         testOneSegmentWithMMap(buffer1, 30, 1000);
         testOneSegmentWithMMap(buffer1, 1000, 1000);
+        ((DirectBuffer) buffer1).cleaner().clean();
         randomAccessFile.close();
     }
 
diff --git a/pom.xml b/pom.xml
index 7962538fa6d..2cfbf1e473e 100644
--- a/pom.xml
+++ b/pom.xml
@@ -232,6 +232,7 @@
 				<executions>
 					<execution>
 						<id>check</id>
+						<!-- skip when executing 'mvn clean test' -->
 						<!-- <phase>test</phase> -->
 						<goals>
 							<goal>cobertura</goal>