Last second protection in metadata retrieve query

src/DBManager.cpp

@@ -143,7 +143,9 @@ DBManager::RowsetSP DBManager::retrieveNewTuples(std::string schema,
 
     RowsetSP rows(new soci::rowset<soci::row>(session.prepare << "select * from "
         << schema << "." << table << " where update_time>'"
-        << boost::posix_time::to_iso_string(timestamp) << "' order by update_time asc"));
+        << boost::posix_time::to_iso_string(timestamp)
+        << "' and update_time<=DATE_SUB(now(), INTERVAL 1 SECOND)"
+        << " order by update_time asc"));
 
     return rows;
 }