diff --git a/src/common/backend/parser/keywords.cpp b/src/common/backend/parser/keywords.cpp
index 785635e25..c01845142 100644
--- a/src/common/backend/parser/keywords.cpp
+++ b/src/common/backend/parser/keywords.cpp
@@ -21,9 +21,11 @@
 
 #define PG_KEYWORD(a, b, c) {a, b, c},
 
+// A table that stores keywords information.
+// This table will be used in keyword-matching process. 
 const ScanKeyword ScanKeywords[] = {
 #include "parser/kwlist.h"
 };
 
+// The number of table items, which is also the total number of keywords
 const int NumScanKeywords = lengthof(ScanKeywords);
-