A note to install Redis to new machine that running CentOS 7 Basic settings for Redis
I write this because just a note or cheatsheet for me to copy and paste from here to make my life easier. Every time when migrate website from one server to one server, I need to recreate the user and database before insert back to the new host.
It is not recommended to use ORDER BY RAND() only, it will slow for query large database like over 50,000 rows. The easiest way to optimize existing code, just add RAND()< (SELECT ((1/COUNT(*))*10) FROM Table_name) after the WHERE before the ORDER, this sub query will speed up the select random from the table. Using this …