4.10. too many clients already

➢ 问题
执行查询时报错"FATAL","53300","sorry, too many clients already"
➢ 解答
说明连接已满，检查 master 与 segment 看是否超出连接限制；检查应用是否有连接溢出；删除不必要的连接或者使用连接池。