Write-Ahead Logging (WAL) Techniques For Databases Explained
Write-Ahead Logging (WAL) ensures data integrity & durability by logging changes before applying them. Each DBMS has its own nuances, but all use redo & undo behaviors for recovery.
Write-Ahead Logging (WAL) is a standard technique in databases to ensure data integrity and durability. The core idea is simple: before any changes are applied to the actual database, the changes are first written to a log. This guarantees that even if a system crash occurs, the database can be recovered by replaying the log. The concept of WAL evolved from early research on transaction processing and recovery mechanisms, particularly in IBM's System R project—one of the first relational database systems developed in the mid-1970s. System R introduced many core ideas behind modern database arc...