More on Signals in Bash
February 13, 2020 . computer

You login a shell and launch a long running script, then quit the shell/terminal but not sure if the script (and its child processes) will continue running or not? You try to catch and handle signals in the script but it does work as you expected? Below are some tests to help you understand these things.

February 12, 2020 . computer

中国驻澳洲大使馆官网,护照有效期不足一年就可以申请换护照 。 所有相关信息、链接 都可以在这个网页找到。回国度长假前切记检查护照有效期。必要的话提前换好护照,免得 过完长假要回来时护照有效期不足6个月。

Filtering MongoDB log based on client IP
February 5, 2020 . computer

Have you encountered the situation that, when reviewing a mongod log file, you'd like to focus on what operations a particular client (identified by its IP address) has done but the mongod was so busy that the log file was inundated with lots of messages/operations from other clients?

Prettify mongod backtrace in mongod log files
February 5, 2020 . computer


October 20, 2016 . computer


Tag Aware Sharding
October 20, 2016 . computer

Let's assume our database manages a collection of users. Each belongs to certain region and we have two data centers, located in one of the regions respectively. To avoid high network latency between regions, we shall store user information in the nearest data center. Following demo showcases how tag aware sharding can help in such kind of cases.

Why Floating-Point Numbers are Imprecise
October 14, 2016 . computer
> 0.1 + 0.2
> 0.1 + 1 - 1

October 1, 2016 . life