Database Log Management via Area Remapping

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Solution Overview

Problem

Conventional shared-nothing type DBMS face challenges in securing temporary resources for log combination and sorting during restoration, leading to prolonged recovery times and increased load on computer resources due to the complexity of log management across multiple storage areas.

Innovation Solution

A database management method where a management server allocates data storage areas to database servers, stores logs separately for each server, and applies area remapping logs to facilitate synchronized restoration without the need for log combination and sorting, allowing for high-speed data recovery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If logs from multiple database servers are combined and sorted in chronological order during restoration, then data consistency is maintained, but temporary storage resources are required and recovery time increases

Engineering Contradiction:

Improvedata consistencyVSAvoidrecovery time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary actions by recording area remapping logs that track data storage area allocations before failures occur. During restoration, these pre-recorded remapping logs enable the system to reconstruct the original data layout without requiring complex combination and sorting operations, thus reducing recovery time while maintaining data consistency

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces area remapping logs as an intermediary mechanism between multiple database server logs. Instead of directly combining and sorting logs from multiple servers, the system uses area remapping logs to mediate the restoration process by providing a reference framework that simplifies log application and eliminates the need for extensive temporary storage and sorting operations

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If area remapping is performed to allocate data storage areas dynamically, then system scalability is improved, but log management complexity increases during restoration

Engineering Contradiction:

Improvesystem scalabilityVSAvoidlog management complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The area remapping log serves as an intermediary that captures and stores the mapping relationships between data storage areas and database servers. This intermediary structure simplifies log management during restoration by providing a clear reference of how data was organized, eliminating the need for complex checking and verification processes even as the system scales

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system creates copies of area remapping information in log storage areas, preserving the historical state of data allocations. These copied remapping records enable restoration without requiring access to the original complex allocation logic, simplifying the restoration process while supporting system scalability

Inventive Principle:

Principle #26Copying

3Adaptability or versatility

If logs are stored separately in each database server's log storage area, then system scalability is maintained, but restoration load increases due to need for combination and checking

Engineering Contradiction:

Improvesystem scalabilityVSAvoidrestoration load

Core Design Contradiction:

Adaptability or versatilityVSPower

Solution Approach 1:

The area remapping log acts as an intermediary that provides a reference framework for restoring data across multiple database servers. By using these remapping logs to guide the restoration process, the system can apply logs from multiple servers in parallel without requiring extensive combination and checking operations, thus reducing restoration load while maintaining separate log storage for scalability

Inventive Principle:

Principle #24Intermediary (Mediator)

4Manufacturing precision

If temporary areas are prepared for log combination and sorting, then restoration accuracy is improved, but available computer resources are reduced

Engineering Contradiction:

Improverestoration accuracyVSAvoidcomputer resources

Core Design Contradiction:

Manufacturing precisionVSQuantity of substance

Solution Approach 1:

The system performs preliminary actions by recording area remapping information before failures occur. This pre-recorded information enables accurate restoration without requiring large temporary storage areas, as the remapping logs provide a reference framework that eliminates the need for extensive log combination and sorting operations that would consume significant computer resources

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS7472125B2Method for managing a database system

Publication Date: 2008.12.30 HITACHI LTD

AI summary

To provide a database which has plural log storage areas, and eliminates the sort in the restoration process by means of the application of logs, thereby carrying out the restoration quickly. A management server allocates DB servers to a corresponding one of plural data storage areas so as to access the corresponding one. The DB servers store data to the allocated data storage areas. When the data is referenced or updated, a log representing a data change history is stored in preset log areas for each data server. When the management server transmits a notification to change the data storage areas, area remapping logs are stored in log areas.