Database Resynchronization via Change Tracking Log
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Solution Overview
Problem
Conventional methods for resynchronizing primary and mirror copies in large databases are costly and inefficient, requiring extensive data transfer and often necessitating prolonged downtime, which can result in significant revenue loss.
Innovation Solution
Implementing a change tracking mode that intercepts write-related changes, stores them in a log, and compacts the log to eliminate duplicates, allowing for efficient resynchronization by only transferring necessary data blocks, thus reducing the time and resources required for synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all data is copied from mirror to primary during resynchronization, then data consistency is achieved, but transfer time and resource usage increase significantly
Solution Approach 1:
The patent extracts only the necessary data blocks that contain actual changes from the mirror copy, rather than copying all data. The system identifies and transfers only those specific blocks that differ between primary and mirror, significantly reducing transfer time while maintaining data consistency.
Solution Approach 2:
Instead of performing a complete data copy, the patent applies partial action by transferring only the subset of data blocks that are necessary for resynchronization. This partial transfer approach achieves the required data consistency without the excessive time cost of full data replication.
2Reliability
If mirror copy is kept non-active during data transfer, then data integrity is maintained, but database availability and revenue are reduced
Solution Approach 1:
The patent performs preliminary actions by tracking and logging all data changes in real-time during normal database operation. This change tracking infrastructure is established beforehand, enabling the system to identify exactly which data blocks need synchronization later, allowing the mirror to remain active while ensuring data integrity during resynchronization.
Solution Approach 2:
The patent introduces a change tracking log as an intermediary mechanism that records all modifications to data blocks. This intermediary structure allows the system to maintain the mirror copy in an active state while using the log to guide precise, targeted synchronization operations that preserve data integrity without requiring prolonged downtime.
3Reliability
If complete data transfer is performed, then full synchronization is achieved, but resource usage and cost increase
Solution Approach 1:
The patent segments the data transfer process into individual data block operations. Instead of treating the entire database as a single transfer unit, the system divides data into discrete blocks and transfers only those segments that contain changes. This segmentation approach achieves complete synchronization for affected areas while minimizing overall resource consumption.
Solution Approach 2:
The patent applies partial action by performing only the necessary portion of data transfer required for synchronization. By identifying and transferring only the changed data blocks rather than all data, the system achieves complete synchronization where needed while avoiding excessive resource usage on unchanged portions.
Data Source
AI summary
A method, article of manufacture, and apparatus for recovering databases. In some embodiments, this includes switching an active segment to a resynchronization mode, receiving a change tracking log, determining a data block based on the change tracking log, and resynchronizing the determined data block with a non-active segment. In some embodiments, writes performed on the active segment are synchronized with the non-active segment.