Write-Ahead Logging (WAL) is a durability technique in which changes are recorded to a sequential append-only log before they are applied to the main data store. By guaranteeing that the log is flushed to stable storage before the corresponding pages are modified, the system can recover a consistent state after a crash by replaying or undoing logged operations. WAL is foundational to transactional databases, providing atomicity and durability without expensive synchronous writes to scattered data pages.
Overview
- Data Persistence provides the broader context within which Write-Ahead Logging sits.
- Write-Ahead Logging is treated here as a member of the infrastructure domain at mature maturity.
- It is referenced across the knowledge graph by classes that depend on or compose it, making it a central node that warranted an explicit definition.
Key aspects
- It comprises Audit Trail.
- It requires Data Persistence.
- It requires Data Integrity.
Mechanisms
- Write-Ahead Logging operates by combining its constituent parts into a coherent capability that other classes can rely upon.
- Its guarantees and behaviours are realised through the dependencies and standards captured in the relations below.
Applications
- Enables and supports Transaction.
- Enables and supports Fault Tolerance.
- Enables and supports Data Integrity.
- Enables and supports Relational Database.
- Enables and supports Database Management System.
- Enables and supports Reliability.