International Business Machines Corporation

Haakon Roberts

Ka Chun Ng

Jeffrey Allen Berger

Laura Michiko Kunioka-Weis

Thomas Majithia

William James Franklin

David Arlen Elko

David Harold Surman

Jeffrey William Josten

John Joseph Campbell

Embodiments of the present invention disclose a computer program product for rebalancing partitioned data based, at least in part, on limit key extrapolation in a database and one or more characteristics of the plurality of database partitions. Responsive to a determination that an upper limit key value of the last loaded record is greater than an upper limit key value of an empty partition, the computer redefines the upper limit key value of the empty partition using an extrapolated upper limit key value that is based, at least in part, on a range of limit key values. The computer updates one or more characteristics of the database, wherein the one or more characteristics include one or both of a) an average number of records per partition, and b) an average number of unique limit key values per partition.

Method for rebalancing data partitions

A database recovery and index rebuilding method involves reading data pages for a database to be recovered as recovery bases; retrieving all log records from stored post-backup updates and sorting the retrieved log records; as the data pages to be recovered are read, applying the sorted log records to their respective data pages; as the applying completes for individual data pages, extracting and sorting index keys from the individual data pages for which the applying is complete, until all index keys have been extracted from all individual data pages and sorted; on an individual recovered page basis, writing the recovered individual data pages into the database; and when all index keys have been extracted and sorted from all of the recovered individual data pages, rebuilding indexes of the database using the sorted index keys and writing the rebuilt indexes to the non-transitory storage.

Relational database recovery

Embodiments of the present invention disclose a method, computer program product, and system for rebalancing partitioned data based, at least in part, on one or more characteristics of the plurality of database partitions. The computer updating characteristics, wherein the one or more characteristics include one or both of a) an average number of records per partition, and b) an average number of unique limit key values per partition. Embodiments of the present invention disclose a method, computer program product, and system for limit key extrapolation in a database. Responsive to a determination that the upper limit key value of the last loaded record is greater than the first upper limit key value of the first empty partition, the computer redefines the first upper limit key value of the first empty partition by an extrapolated upper limit key value based, at least in part, on the range of limit key values.

A database recovery and index rebuilding system involves at least one processor coupled to memory, storage, a database, and sets of image copies and post-backup updates. When database reconstruction is required, the processor will i) access the image copies; ii) access post-backup updates to be re-applied; iii) without regard to 'ii)', read data pages to be recovered into objects; iv) concurrently with 'iii)', retrieve and sort log records from the post-backup updates; v) as the data pages to be recovered are read in &#x201c;iii)&#x201d;, apply the sorted log records; vi) as &#x201c;e)&#x201d; completes and concurrently with &#x201c;v)&#x201d;, extract and sort index keys; vii) concurrently with &#x201c;vi)&#x201d; and on an individual recovered page basis, write the recovered data pages into the database; viii) when all index keys have been extracted and sorted, initiate database index rebuilds; and ix) when rebuilt, store the rebuilt indexes without regard to whether &#x201c;vii)&#x201d; has completed.

A database recovery method involves: a) accessing image copies; b) accessing updates to be re-applied to reconstruct the database; c) reading into objects, from the image copies, data pages to be recovered; d) concurrently with 'c)' retrieving and sorting log records from the updates; e) as the data pages are read into the objects in 'c)', applying the sorted log records, in timestamp order; f) as &#x201c;e)&#x201d; completes for individual pages, and concurrently with &#x201c;e)&#x201d; with respect to pages for which applying is not complete, extracting and sorting index keys, from pages for which the applying is complete, until all index keys have been extracted and sorted; g) concurrently with &#x201c;f)&#x201d;, writing recovered pages into the database; h) initiating a rebuild of database indexes using the extracted and sorted index keys; and i) when the database indexes have been rebuilt, writing them to storage without regard to whether &#x201c;g)&#x201d; completed.

Disclosed is a system, method, and program for transferring data. When a transaction commits, multiple data objects that have been changed by the transaction are identified. The multiple data objects are written from local storage to a cache structure using a batch write command. When changed data objects at a first system that are not cached in the shared external storage are written to disk, a batch cross invalidation command is used to invalidate the data objects at a second system. Additionally, multiple data objects are read from the cache structure into a processor storage using a batch castout command.

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San Jose, CA, United States of America

Haakon Roberts