code: public Integer deleteByTimestamp(String destination, int interval) {
          HashMap params = Maps.newHashMapWithExpectedSize(2);
          long timestamp = System.currentTimeMillis() - interval * 1000;
          params.put("timestamp", timestamp);
          params.put("destination", destination);
          return getSqlMapClientTemplate().delete("meta_snapshot.deleteByTimestamp", params);
      }
docs: 删除interval秒之前的数据