https://mysqlserverteam.com/mysql-8-0-new-lock-free-scalable-wal-design/
The Write Ahead Log (WAL) is one of the most important components of a database. All the changes to data files are logged in the WAL (called the redo log in InnoDB). This allows to postpone the moment when the modified pages are flushed to disk, still protecting from data losses.
