Java development example

Display table size in MySQL

Use the following sql to query the space occupied by each table in the database.

Delete large amounts of data in MySQL

Recently I want to delete a large amount of data from mysql. There are about 400 million records. Fortunately, the data to be deleted can be queried according to the index. If I delete one by one, it will be very slow. If the entire deletion will cause the database to freeze. So I Write a script to delete these data in batches. The script probably looks like this.

mac copy current path to clipboard in terminal

In order to copy the current path to the clipboard you can use the following command.

fib

Problem Description

Sum Root to Leaf Numbers

Problem Description

Binary Tree Paths

Problem Description

Nginx htpasswd old password still working

Today I encountered a problem about htpasswd. I use htpasswd to make simple user authentication for my website. I use nginx as the reverse agent of my personal website. Today I tried to modify a password. I added a random number behind my old password. Like this old_pwd -> old_pwd_666. After the password is modified, I found that the old password can still pass the authentication. It's too strange. After reviewing the htpasswd helping documentation, I found the reason for the problem.