IMS Database Cache Utility for ACB Generation Bottlenecks
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Solution Overview
Problem
The generation of access control blocks (ACBs) for an Information Management System (IMS) database is a time-consuming and resource-intensive process involving multiple direct-access storage device (DASD) reads of program specification block (PSB) and database definition (DBD) information from a secondary storage device.
Innovation Solution
A cache management utility intercepts operating system service calls for IMS database requests, checks if the required information is stored in a cache memory, and retrieves it from there if available, or performs a DASD read from secondary storage and stores it in the cache for future use, reducing redundant reads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple DASD reads are performed to generate ACBs, then complete and accurate ACB generation is achieved, but the process becomes time-consuming and resource-intensive
Solution Approach 1:
The patent implements a cache memory that pre-loads and stores copies of PSB and DBD information from secondary storage before ACB generation is requested. This preliminary action allows the system to have data ready in fast memory, eliminating the need for time-consuming DASD reads during actual ACB generation, thus resolving the contradiction between complete ACB generation and generation time.
Solution Approach 2:
The patent introduces a cache memory as an intermediary layer between the secondary storage (DASD) and the ACB generation process. This intermediary stores frequently accessed PSB and DBD information, allowing rapid retrieval without direct DASD access, thereby maintaining data completeness while dramatically reducing access time and resource consumption.
2Reliability
If DASD reads are performed for every ACB generation request, then data accuracy is maintained, but resource usage increases significantly
Solution Approach 1:
The patent creates copies of PSB and DBD information from the secondary storage and stores them in a cache memory. These copies maintain data accuracy for ACB generation purposes, eliminating the need for repeated DASD reads and significantly reducing resource consumption while preserving data integrity.
Solution Approach 2:
The system performs preliminary loading of data into cache memory before it is needed for ACB generation. This advance preparation ensures data accuracy is maintained while avoiding the high resource cost of repeated DASD operations during actual processing.
3Productivity
If ACB generation processes are run in parallel, then productivity increases, but coordination complexity and resource management difficulty increase
Solution Approach 1:
The patent merges multiple ACB generation processes into a single coordinated system that shares a common cache memory. By combining resource access through a unified cache structure with appropriate locking mechanisms, the system enables parallel processing of ACB generation while simplifying coordination complexity through centralized resource management.
Solution Approach 2:
The cache memory is designed as a universal resource that serves multiple ACB generation processes simultaneously. This multi-functional cache structure allows different processes to access the same cached data with proper synchronization, increasing productivity while managing complexity through a standardized access interface.
Data Source
AI summary
A method includes performing, by a processor of a database server: intercepting an operating system supervisor call involving a request for information associated with an information Management System (IMS) database from a secondary storage device, the IMS database being embodied in the secondary storage device; determining whether the information that was requested is stored in a cache memory embodied in a primary storage device; retrieving the information that was requested responsive to determining that the information that was requested is stored in the cache memory; executing the operating system supervisor call to perform a read of the secondary storage device to obtain the information that was requested responsive to determining that the information that was requested is not stored in the cache memory; and storing the information that was requested in the cache memory responsive to executing the operating system supervisor call to obtain the information that was requested.