Delta Replica Recovery Workflow for Failed Database Replicas

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Solution Overview

Problem

Current cloud-based database systems with multiple replicas face inefficiencies due to secondary replicas consuming equal resources as primary replicas, leading to underutilization and increased computing and storage demands, while delta replicas cannot be used for recovery due to lacking full data backups.

Innovation Solution

A recovery workflow utilizing local data from delta replicas and backed-up transaction log data to create a new secondary replica, allowing delta replicas to facilitate database recovery in the event of primary and secondary failures, reducing resource requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple secondary replicas are maintained to ensure database availability and enable recovery, then system reliability is improved, but computing resources and storage demands increase significantly

Engineering Contradiction:

Improvedatabase availabilityVSAvoidcomputing resources

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent segments replica functionality into two distinct types: secondary replicas that maintain full data copies for read operations and recovery, and delta replicas that maintain only transaction log information for quorum support. This segmentation allows the system to achieve reliability through multiple replicas while reducing the resource burden by not requiring all replicas to be full copies.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different replica types are assigned different local qualities or characteristics: secondary replicas have complete data copies with full functionality, while delta replicas have minimal data storage (only transaction logs) with limited functionality. This local quality differentiation optimizes resource usage while maintaining overall system reliability.

Inventive Principle:

Principle #3Local quality

2Reliability

If multiple full secondary replicas are maintained to enable recovery from primary replica failure, then system reliability is improved, but storage demands increase significantly

Engineering Contradiction:

Improverecovery capabilityVSAvoidstorage demands

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent extracts the essential recovery function from the full secondary replica concept and implements it through delta replicas that hold only transaction log information. This extraction allows the system to maintain recovery capability without requiring multiple full data copies, thereby significantly reducing storage demands.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of copying full database data to multiple secondary replicas, the system creates delta replicas that copy only the transaction log information. This selective copying maintains the ability to recover and reconstruct data while dramatically reducing the storage requirements compared to full replicas.

Inventive Principle:

Principle #26Copying

3Use of energy by moving object

If delta replicas with only transaction log information are used, then resource requirements are reduced, but the ability to handle read operations and write operations is lost

Engineering Contradiction:

Improveresource requirementsVSAvoidoperation handling capability

Core Design Contradiction:

Use of energy by moving objectVSAdaptability or versatility

Solution Approach 1:

The patent implements a multi-functional replica architecture where secondary replicas handle read operations and serve as full recovery sources, while delta replicas provide quorum support and enable recovery initiation. Together, these different replica types collectively provide comprehensive functionality that no single replica type could provide alone.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system dynamically assigns different roles and capabilities to different replica types based on their resource characteristics. Secondary replicas are dynamically positioned as read-service and full recovery units, while delta replicas are dynamically positioned as quorum and recovery-initiation units, allowing the system to adapt functionality to resource constraints.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS12585672B2Workflow for database system recovery using local and backed up resources

Publication Date: 2026.03.24 MICROSOFT TECHNOLOGY LICENSING LLC

AI summary

A data processing system implements techniques for operating and recovering databases that includes a plurality of replicas. The plurality of replicas includes a primary replica, a secondary replica, and a delta replica. The primary replica handles read and write operations, the secondary replica is a backup of the primary replica capable of read-only operations. The delta replica comprising a copy of the transactional log information of the primary replica but not the data. The system detects a failure of the primary and secondary replicas. The system instantiates a recovery workflow using the delta replica that includes initializing a second secondary replica; causing the second secondary replica to download backup data that represents a state of the primary replica prior to failure of the primary replica; updating the secondary replica using the backup data; and promoting the secondary replica to the primary replica.