EP0280773A2
Expired / Lapsed
EP
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Method for recovery enhancement in a transaction-oriented data processing system
Assignee: International Business Machines Corp
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Filing: 1987-11-24
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Granted: —
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Expires: 2007-11-24
Abstract
Abstract The number of log records required to be written and read in supporting the reconstruction of a volatile queue of objects is minimised and conveniently relocated by selectively relogging on attaining an activity threshold post start or the most recent checkpoint. Only those objects which remain in the queue for a long period of time will be rewritten. If high activity reflects high queue usage, then the objects will qualify for relogging in a shorter period of clock time.
Inventors
- 👤 Richard Dievendorff
- 👤 Earle Henderson Jenner
- 👤 John Davis Palmer
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 10:50
CPC Classifications
G; G06; G06F; G06F11/00; G06F11/07; G06F11/14; G06F11/1471
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
95 words
A method for enhancing recovery in a transaction-oriented data processing system in which a sequentially recorded message log is maintained and to which log, periodic checkpointing is made, the method comprising selectively reprocessing message activity sequentially recorded in the log by: (a) counting message activity recorded in the log and invoking system checkpoint processing each time the count matches a predetermined threshold; and (b) rerecording a subset of message activity recorded in said log to a checkpoint after an interval has elapsed since the initial log recording or most recent checkpoint rerecording of the subset;
Claim 2
Independent Claim
95 words
A method for enhancing recovery in a transaction-oriented data processing system in which a sequentially recorded message log is maintained and to which log, periodic checkpointing is made, the method comprising selectively reprocessing message activity sequentially recorded in the log by: (a) counting message activity recorded in the log and invoking system checkpoint processing each time the count matches a predetermined threshold; and (b) rerecording a subset of message activity recorded in said log to a checkpoint after an interval has elapsed since the initial log recording or most recent checkpoint rerecording of the subset;
Claim 3
Dependent Claim
25 words
whereby, in the event of system restart and recovery processing, all messages subject to recovery are clustered within a relatively small span along the log.
Claim 4
Dependent Claim
25 words
whereby, in the event of system restart and recovery processing, all messages subject to recovery are clustered within a relatively small span along the log.
Claim 5
Dependent Claim
33 words
A method as claimed in claim 1, wherein messages inbound to the system are enqueued by transaction type for processing, and messages outbound from said system are enqueued by destination identity for transmission.
Claim 6
Independent Claim
39 words
A method as claimed in either preceding claim wherein only those messages not otherwise deleted are rewritten whereby rewriting of messages is a function of threshold message activity and delay and the number of data objects rewritten is reduced.
Claim 7
Independent Claim
76 words
A method as claimed in any preceding claim, said system including a log resource manager for operatively controlling log access responsive to system message activity, said message activity including messages to be added to the system and messages for deleting previously added messages from the system, wherein a table is maintained of only those messages not deleted since the last checkpoint and only those messages identified in the table and recorded on said log are rerecorded.
Claim 8
Dependent Claim
56 words
A method as claimed in claim 4, said system including a recovery manager, wherein said recovery manager in cooperation with the log resource manager, in the event of system failure and subsequent restart, recreates the table by reading the log starting with a begin checkpoint record and adding and deleting from the table entries so identified.
References Cited (Backward Citations)
No citation records indexed.
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