EP0286807A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method for regulating access by concurrent transactions to resources
Assignee: International Business Machines Corp
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Filing: 1988-02-24
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Granted: —
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Expires: 2008-02-24
Abstract
Abstract A method for regulating access by concurrent transactions to hierarchically-related resources distributed about a loosely-coupled multiprocessor system is disclosed. Lock requests are first decided by a local lock manager (2a...2n) and then by a central lock manager (1). When a single local lock manager (2a...2n) holds locks on a resource, that local lock manager has sole interest in the resource. While a lock manager has sole interest in a resource, it can acquire locks subsidiary to the resource without consulting with the central lock manager (1). Sole interests of objects are shifted dynamically for optimising local control of objects, thereby minimising communication and transaction wait time.
Inventors
- 👤 Ronald Lester Obermarck
- 👤 Kurt Alan Shoens
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 14:36
CPC Classifications
G; G06; G06F; G06F9/00; G06F9/06; G06F9/46; G06F9/50; G06F9/466
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
197 words
A method for regulating access by concurrent transactions to potentially hierarchically-related resources distributed about a loosely-coupled multiple-processor system wherein each resource has a lock associated therewith, and a plurality of transactions are executing each in a respective processor, and a central processor maintaining a concordance of resource identities, hierarchical relations, if any, among the resources and processor identities (IDs), the method comprising, upon receipt of a request from a transaction for access to a resource, the steps of: (a) ascertaining, at the local processor wherein the requesting transaction is executing whether the local processor has control over the requested resource or its antecedents, the local processor being given control over the resource or its antecedents when the local processor is the only processor accessing the requested resource or its antecedents; (b) if the local processor has control of the requested resource or its antecedents, granting a lock by the local processor on the requested resource to the requesting transaction if the lock is compatible with a then current combined lock state of the resource; and (c) if the local processor does not have control of the requested resource, then submitting the resource request to other non-local processors.
Claim 2
Independent Claim
197 words
A method for regulating access by concurrent transactions to potentially hierarchically-related resources distributed about a loosely-coupled multiple-processor system wherein each resource has a lock associated therewith, and a plurality of transactions are executing each in a respective processor, and a central processor maintaining a concordance of resource identities, hierarchical relations, if any, among the resources and processor identities (IDs), the method comprising, upon receipt of a request from a transaction for access to a resource, the steps of: (a) ascertaining, at the local processor wherein the requesting transaction is executing whether the local processor has control over the requested resource or its antecedents, the local processor being given control over the resource or its antecedents when the local processor is the only processor accessing the requested resource or its antecedents; (b) if the local processor has control of the requested resource or its antecedents, granting a lock by the local processor on the requested resource to the requesting transaction if the lock is compatible with a then current combined lock state of the resource; and (c) if the local processor does not have control of the requested resource, then submitting the resource request to other non-local processors.
Claim 3
Dependent Claim
63 words
A method as claimed in claim 1, wherein each non-local processor is responsive to a received request, to execute the further steps of: (i) granting a lock on the requested resource or its antecedent if the resource or its antecedent is not locked; and (ii) either granting a compatible lock where a lock exists or forcing the requesting transaction into a wait state.
Claim 4
Dependent Claim
34 words
A method as claimed in claim 1 or claim 2, wherein each local processor updates the central processor's concordance as to the set of resources and the hierarchic span with which it is associated.
Claim 5
Dependent Claim
39 words
A method as claimed in claim 1 or claim 2, wherein control of a resource and its descendants is dynamically given to a processor at the highest hierarchical level if the processor is the only processor accessing the resource.
Claim 6
Dependent Claim
77 words
A method as claimed in claim 4, wherein, if a first processor is having control of a resource at a first level and a second processor is requesting to share access to the resource at the first level, the first processor's control in the resource is degraded to a descendant lower than the first level of the resource if such degradation is compatible with the then current combined lock state of the resource in the first processor.
Claim 7
Dependent Claim
39 words
A method as claimed in claim 5, wherein, if all other processors no longer share access to a resource and its descendants at a second level, a remaining processor's control of the resource is upgraded to the second level.
References Cited (Backward Citations)
No citation records indexed.
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