EP0249090A2
Expired / Lapsed
EP
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Database index journaling for enhanced recovery
Assignee: International Business Machines Corp
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Filing: 1987-05-26
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Granted: —
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Expires: 2007-05-26
Abstract
Abstract A quick recovery of logical files which provide alternate views of databases is provided. Unchanged logical file pages are journaled before being changed. Transactions affecting databases covered by the logical files are also journaled. To recover a logical file, the journaled unchanged pages of the logical file that correspond to the changed pages are inserted back into the logical file, and the transactions that were journaled are processed to provide the changes to the logical file and to the database. This brings the logical file and the underlying database up to date, and in synchronization with each other.
Inventors
- 👤 Dennis Steven Delorme
- 👤 Peter Bernard Passe
- 👤 Mark Larry Holm
- 👤 Gary Ross Ricard
- 👤 Wilson Douglas Lee
- 👤 George David Timms, Jr.
- 👤 Larry William Youngren
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 17:09
CPC Classifications
G; G06; G06F; G06F11/00; G06F11/07; G06F11/14; G06F11/1471
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
148 words
A method of journaling indexes relating to a data space in a computer system which pages data to and from a main storage and auxiliary storage, the method being characterized in that it comprises the steps of: a. determining which index pages require changing as a function of requested data space changes; b. pinning such index pages to prevent them from being written to auxiliary storage; c. journaling unchanged pages of indexes which have changes as a result of the changes to be made to the data space so that the indexes are synchronized with the data space at a desired point in the journal; d. changing said indexes; e. journaling changes to the data space prior to changing the data space; f. writing the journal to auxiliary storage; g. unpinning the index pages so that they may float to auxiliary storage; and h. changing the data space.
Claim 2
Independent Claim
148 words
A method of journaling indexes relating to a data space in a computer system which pages data to and from a main storage and auxiliary storage, the method being characterized in that it comprises the steps of: a. determining which index pages require changing as a function of requested data space changes; b. pinning such index pages to prevent them from being written to auxiliary storage; c. journaling unchanged pages of indexes which have changes as a result of the changes to be made to the data space so that the indexes are synchronized with the data space at a desired point in the journal; d. changing said indexes; e. journaling changes to the data space prior to changing the data space; f. writing the journal to auxiliary storage; g. unpinning the index pages so that they may float to auxiliary storage; and h. changing the data space.
Claim 3
Dependent Claim
111 words
A journaling device for a computer system utilizing paging between a main storage and auxiliary storage, the computer system having data spaces and indexes relating to said data spaces, the journaling device being characterized in that it comprises: storage means for storing journaling information; data space journaling means for journaling information relating to changes to be made to data spaces to the storage means; and index journaling means for journaling unchanged pages of indexes affected by the changes to be made to a data space to the storage means such that the storage means contains information from which the data space and indexes are recoverable to a same point in time.
Claim 4
Dependent Claim
111 words
A journaling device for a computer system utilizing paging between a main storage and auxiliary storage, the computer system having data spaces and indexes relating to said data spaces, the journaling device being characterized in that it comprises: storage means for storing journaling information; data space journaling means for journaling information relating to changes to be made to data spaces to the storage means; and index journaling means for journaling unchanged pages of indexes affected by the changes to be made to a data space to the storage means such that the storage means contains information from which the data space and indexes are recoverable to a same point in time.
Claim 5
Dependent Claim
17 words
The journaling device of claim 2 characterized in that the storage means comprises a nonvolatile storage device.
Claim 6
Dependent Claim
35 words
The journaling device of claim 3 characterized in that the journaling information for both the data space and the unchanged index pages relating thereto are written to the nonvolatile storage device in the same operation.
Claim 7
Dependent Claim
39 words
The journaling device of claim 3 or 4 characterized in that the journaling information is written to the nonvolatile storage device prior to permanent changes being made to the auxiliary storage image of both the data space and index.
Claim 8
Dependent Claim
53 words
The journaling device of anyone of claims 3-5 characterized in that the storage means further comprises an area in main storage, and wherein index pages which have been journaled in main storage but have not been written to nonvolatile storage are pinned to prevent changes to them from being written to auxiliary storage.
Claim 9
Dependent Claim
57 words
The journaling device of anyone of claims 2-6 characterized in that it further comprises recovery means coupled to the storage means for rolling back the indexes relating to a data space following a system failure and using the data space journaled information to effect changes to the rolled back indexes to synchronize them with the data space.
Claim 10
Dependent Claim
38 words
The journaling device of anyone of claims 2-7 characterized in that it further comprises: detecting means coupled to the index journaling means for detecting the index pages affected by the changes to be made to a data space.
Claim 11
Dependent Claim
51 words
The journaling device of anyone of claims 2-8 characterized in that it further comprises: cloning means coupled to the index journaling means for copying all the unchanged pages in the index to auxiliary storage when the detecting means determines that a predetermined ratio of pages in the index will be changed.
Claim 12
Dependent Claim
32 words
The journaling device of claim 9 characterized in that the journaling means journals an indication that a copy of an index has been made, said indication identifying the location of said copy.
References Cited (Backward Citations)
No citation records indexed.
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