Write-Ahead Logging

Write-Ahead Logging (WAL) is a technique used in databases to ensure data integrity. Before any changes are made to the actual data, a record of those changes is written to a special log. This way, if a system unexpectedly crashes, the database can refer to the log to redo or undo transactions, ensuring consistency and durability. Essentially, WAL acts as a security trail, capturing all modifications beforehand so the database can recover accurately after failures without data loss or corruption.