Transaction Log
A transaction log is a persistent, append-only file or data structure that records all changes made to a database or system in chronological order. It serves as a critical component for ensuring data integrity, enabling recovery from failures, and supporting features like replication and auditing. By logging operations before they are applied, it provides a reliable mechanism to reconstruct system state.
Developers should learn about transaction logs when working with databases, distributed systems, or applications requiring ACID compliance, as they are essential for crash recovery and maintaining consistency. They are used in scenarios like database backups, point-in-time recovery, and implementing write-ahead logging (WAL) in systems like PostgreSQL or Kafka. Understanding transaction logs helps in debugging data issues and designing resilient architectures.