In this post I want to introduce you to Tree structures. What they are, how you can use them, and in which situation they can be helpful.
PHP
Laravel Deadlocks: Queue Jobs That Already Ran End Up in failed_jobs
Below MySQL 8.0.1, or on a server Laravel misreads, workers reserve jobs with a plain FOR UPDATE and can deadlock on the DELETE. One tinker line shows which lock yours use. Read more