diff --git a/src/inc/tsdb.h b/src/inc/tsdb.h
index 6112b3f5529c34329f720410ae82d94b55960ea6..347ba49818101e679f86bb5da70d350e5746e6fd 100644
--- a/src/inc/tsdb.h
+++ b/src/inc/tsdb.h
@@ -181,6 +181,10 @@ extern "C" {
 #define TSDB_MAX_AVG_BLOCKS             2048
 #define TSDB_DEFAULT_AVG_BLOCKS         4
 
+/*
+ * There is a bug in function taosAllocateId.
+ * When "create database tables 1" is executed, the wrong sid is assigned, so the minimum value is set to 2.
+ */
 #define TSDB_MIN_TABLES_PER_VNODE       2
 #define TSDB_MAX_TABLES_PER_VNODE       220000