diff --git a/src/backend/utils/mb/conversion_procs/euc_tw_and_big5/euc_tw_and_big5.c b/src/backend/utils/mb/conversion_procs/euc_tw_and_big5/euc_tw_and_big5.c
index 89ab5d1157..2f11c146ba 100644
--- a/src/backend/utils/mb/conversion_procs/euc_tw_and_big5/euc_tw_and_big5.c
+++ b/src/backend/utils/mb/conversion_procs/euc_tw_and_big5/euc_tw_and_big5.c
@@ -15,8 +15,6 @@
 #include "fmgr.h"
 #include "mb/pg_wchar.h"
 
-#define ENCODING_GROWTH_RATE 4
-
 PG_MODULE_MAGIC;
 
 PG_FUNCTION_INFO_V1(euc_tw_to_big5);