diff --git a/src/inc/tsdb.h b/src/inc/tsdb.h
index ee873d8a1d52bf477186f043aea009315d619c9b..89a7d52b363b35ea7296b407365096258ac5f973 100644
--- a/src/inc/tsdb.h
+++ b/src/inc/tsdb.h
@@ -97,7 +97,7 @@ extern "C" {
 
 #define TSDB_METER_NAME_LEN       64
 #define TSDB_DB_NAME_LEN          32
-#define TSDB_COL_NAME_LEN         128
+#define TSDB_COL_NAME_LEN         64
 #define TSDB_MAX_SAVED_SQL_LEN    TSDB_MAX_COLUMNS * 16
 #define TSDB_MAX_SQL_LEN          TSDB_PAYLOAD_SIZE
 #define TSDB_MAX_ALLOWED_SQL_LEN  (8*1024*1024U)          // sql length should be less than 6mb