diff --git a/src/include/datatype/timestamp.h b/src/include/datatype/timestamp.h
index f5b6026ef5..5714b842dc 100644
--- a/src/include/datatype/timestamp.h
+++ b/src/include/datatype/timestamp.h
@@ -15,6 +15,8 @@
 #ifndef DATATYPE_TIMESTAMP_H
 #define DATATYPE_TIMESTAMP_H
 
+#include "pgtime.h"
+
 /*
  * Timestamp represents absolute time.
  *