diff --git a/db.js b/db.js
index 0d85eb3..08d2517 100644
--- a/db.js
+++ b/db.js
@@ -222,6 +222,24 @@ class DB {
     };
   }
 
+  async getMaxIdx(tblName) {
+    const params = [];
+    let sql = 'SELECT max(idx) AS max_idx FROM `' + tblName + '` ';
+
+    const {err, row} = await this.execQueryOne(sql, params);
+    if (err) {
+      return {
+        'err': err,
+        'maxIdx': BigInt(0)
+      };
+    } else {
+      return {
+        'err': err,
+        'maxIdx': row && row['max_idx'] != null ? BigInt(row['max_idx']) : BigInt(0)
+      };
+    }
+  }
+
 }
 
 module.exports = DB;