Database index journaling for enhanced recovery
First Claim
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1. A method of journaling indexes relating to data spaces comprising the steps of:
- a. journaling to a journal unchanged pages of indexes which have changes as a result of the changes to be made to a data space so that the indexes are synchronized with the data space at a desired point in the journal; and
b. journaling changes to the data space prior to changing the data space.
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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.
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Citations
14 Claims
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1. A method of journaling indexes relating to data spaces comprising the steps of:
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a. journaling to a journal unchanged pages of indexes which have changes as a result of the changes to be made to a data space so that the indexes are synchronized with the data space at a desired point in the journal; and b. journaling changes to the data space prior to changing the data space.
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2. 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 comprising the steps of:
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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 to a journal 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.
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3. 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 comprising:
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storage means for storing journaling information; data space journaling means coupled to the storage means for journaling information relating to changes to be made to data spaces to the storage means; and index journaling means coupled to the storage 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. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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Specification