diff --git a/bobo-browse/src/main/java/com/browseengine/bobo/api/BoboSegmentReader.java b/bobo-browse/src/main/java/com/browseengine/bobo/api/BoboSegmentReader.java
index 4127da12..4c5b7dba 100644
--- a/bobo-browse/src/main/java/com/browseengine/bobo/api/BoboSegmentReader.java
+++ b/bobo-browse/src/main/java/com/browseengine/bobo/api/BoboSegmentReader.java
@@ -364,4 +364,8 @@ public AtomicReader getInnerReader() {
     return in;
   }
 
+  @Override
+  public Object getCoreCacheKey() {
+    return in.getCoreCacheKey();
+  }
 }