介绍几个生成字符画工具，非常有趣。

最近接手Data后，kylin突然挂了，查询后发现，竟然是存储空间不足的问题导致的！

如果有涉及海外的业务，很多时候都会遇到海外手机号获取短信验证码的问题。在测试的时候，需要较多的手机号用户测试注册等内容，如果办理很多海外手机号用于测试，很不现实。

Recently, Ruby 2.7-preview3 is released. This release has an interesting method - Enumable#tally. It counts the occurrence of each element.

When we develop with micro service architechure or high concurrency, the distributed lock must be metioned.

在使用Redis的过程中，最基础最常见的一个场景，就是对key值命名。

When we talk about the software architechure, sometimes the Exception Control concept will be metioned.

We often need to find the dulicate values in array.

The order of multiple rescue_from statements might be unexpected.

Create only the data you need

If you have ever worked in a medium size project(but also in small ones), test suites can be heavy to run. To solve this problem, it’s important not to load more data than needed. Also, if you think you need dozens of records, you are probably wrong.