Transaction Log Based Application Error Recovery and Point In-Time Query

TL;DR

This paper introduces a transaction log-based scheme for efficient recovery from user and application errors, enabling point-in-time queries without full backups by integrating with SQL Server snapshots.

Contribution

The proposed method allows for quick error recovery and on-demand access to past data states using transaction logs, reducing reliance on costly full backups.

Findings

Supports recovery from recent user errors efficiently

Enables point-in-time queries without full backups

Integrates with SQL Server snapshot feature

Abstract

Database backups have traditionally been used as the primary mechanism to recover from hardware and user errors. High availability solutions maintain redundant copies of data that can be used to recover from most failures except user or application errors. Database backups are neither space nor time efficient for recovering from user errors which typically occur in the recent past and affect a small portion of the database. Moreover periodic full backups impact user workload and increase storage costs. In this paper we present a scheme that can be used for both user and application error recovery starting from the current state and rewinding the database back in time using the transaction log. While we provide a consistent view of the entire database as of a point in time in the past, the actual prior versions are produced only for data that is accessed. We make the as of data accessible to arbitrary point in time queries by integrating with the database snapshot feature in Microsoft SQL Server.