Datafile Reorganization to Shrink Files
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Solution Overview
Problem
Information handling systems face challenges in efficiently consolidating used datafile areas to the beginning of a datafile, especially when relocating extents without affecting ongoing applications, and in recovering unused space from datafiles with mixed used and unused areas.
Innovation Solution
A datafile reorganization method that identifies and relocates segments with extents to lower addresses by creating copies, synchronizing changes, and swapping segments, allowing for consolidation of all used areas to the beginning of the datafile, thereby reducing its size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If a datafile resize operation is performed to reduce the size of a datafile, then the datafile size is reduced and disk space is recovered, but the operation cannot remove areas that are currently used and thus cannot recover unused space effectively
Solution Approach 1:
The patent performs a preliminary datafile reorganization operation before resizing. This reorganization consolidates all used areas to the beginning of the datafile and removes unused areas in between, creating a compact structure. Only after this preliminary consolidation is the resize operation performed, enabling maximum space recovery while preserving all used data.
2Loss of substance
If extents are relocated to consolidate used areas to the beginning of the datafile, then more unused space is recovered, but the relocation must not affect ongoing applications using these objects
Solution Approach 1:
The patent creates a copy of the datafile during the reorganization process. The original datafile continues to serve ongoing applications without interruption, while the copy is modified to consolidate extents and remove unused areas. Once the copy is prepared, it replaces the original, ensuring application continuity while achieving the consolidation goal.
Solution Approach 2:
The patent uses an intermediary approach by maintaining the original datafile structure during reorganization. Applications continue to access the original datafile while the system performs extent consolidation in the background. The intermediary state ensures no disruption to applications while enabling the restructuring needed for space recovery.
3Loss of substance
If the datafile structure is reorganized to consolidate used areas, then the datafile can be shrunk more effectively, but the reorganization process is more complex than a simple resize operation
Solution Approach 1:
The patent segments the datafile reorganization process into distinct phases: identifying used areas, consolidating extents, removing unused areas, and performing the resize operation. This segmentation of the complex process into manageable steps makes the overall operation more controllable and implementable, despite the inherent complexity of consolidating extents while maintaining data integrity.
Data Source
AI summary
A system, method, and computer-readable medium for consolidating all the currently used areas to the beginning of the datafile by performing a datafile reorganization operation. With this consolidation, more space can be recovered from the datafile. More specifically, with the consolidation, because each used area can contain extents related to several different segments, locating all the segments that have extents in a used area and relocate these segments to lower addresses in the datafile can be challenging.