PDSE Member Generation Clustering for Safe Reversion
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Solution Overview
Problem
Current PDSE data sets lack the ability to determine which members were affected by a particular job or task, making it difficult to reverse changes safely due to data dependencies and relationships, limiting the usefulness of the generations feature.
Innovation Solution
A method is introduced to track changes made by a job using a data structure (cluster) that references previous generations of data elements, allowing the data set to be reverted to a prior state, with the cluster stored within the PDSE data set and a log structure maintained in the coupling facility to ensure valid reversibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If PDSE data sets retain multiple generations of members, then the ability to reverse individual member changes is improved, but the ability to determine which members were affected by a particular job and to safely reverse changes is worsened
Solution Approach 1:
The system performs preliminary actions by creating a cluster data structure that records all members to be modified and their previous generations before the job executes. This pre-recording of affected members and their states enables subsequent reversal operations to safely restore the PDSE data set to its state before the job, resolving the contradiction by having the information ready in advance rather than trying to determine it after the fact
2Adaptability or versatility
If PDSE data sets support multiple generations of members, then archival capability is improved, but the complexity of managing data dependencies and relationships increases
Solution Approach 1:
The system segments the complexity of managing data dependencies by creating a separate cluster data structure that independently tracks affected members and their relationships. This segmentation isolates the complexity of dependency management from the actual PDSE data set operations, allowing multiple generations to be retained for archival purposes while the cluster handles the bookkeeping of dependencies and relationships
3Device complexity
If no tracking mechanism is implemented, then the system simplicity is maintained, but the ability to safely reverse changes made by a particular job is worsened
Solution Approach 1:
The system introduces a cluster data structure as an intermediary between the job and the PDSE data set. This intermediary records which members are affected and their previous generations, enabling safe reversal of job changes. The cluster acts as a mediator that provides the necessary tracking information without fundamentally changing the PDSE data set structure, thus maintaining relative simplicity while improving reliability
Data Source
AI summary
A method for enabling data set changes to be reverted to a prior point in time or state is disclosed. In one embodiment, such a method includes providing a data set comprising one or more data elements and a specified number of generations of the data elements. In certain embodiments, the data set is a partitioned data set extended (PDSE) data set, and the data elements are “members” within the PDSE data set. The method further includes tracking changes made by a job to data elements of the data set. The method further references, in a data structure (also referred to herein as a “cluster”) associated with the job, previous generations of the data elements changed by the job. In certain embodiments, the data structure is stored in the data set. A corresponding system and computer program product are also disclosed.