International Business Machines Corporation

Thomas Majithia

Laura Michiko Kunioka-Weis

Jeffrey Allen Berger

Haakon Roberts

William James Franklin

James Zu-Chia Teng

Jeffrey William Josten

Namik Hrle

James Alan Ruddy

Donald J Haderle

Yufen Wang

Deborah A Matamoros

Daniel Keith Courter

Haakon Philip Roberts

Ming-Hung Hu

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

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.

A system, method a computer usable storage medium tangibly embodying a program of instructions executable by the computer to perform a computer-based method for restoration of a database from a failed data recovery. For each failed data recovery the method generates a log error data set having log records of a faulty transaction unapplied to data due to inconsistency. Log error data set is directly useable by a log analysis tool to regenerate and redo the unapplied faulty transaction to recover the data and by a print log tool to diagnose the faulty transaction. Log records mimic format of records of an archive log data set and identify data objects, faulty transactions on the data objects and a range of the unapplied data objects' updates.

System and method for minimizing data outage time and data loss while handling errors detected during recovery

A method for performing a system level backup of a log-ahead database management system (DBMS) without suspending updates by application programs is described. The DBMS comprises a database mainline system, a backup utility and a restore utility. The data and log records are stored on separate storage volumes. Log records are written to identify objects that require special handling during the point-in-time recovery. The database engine operates normally during a backup except for suspending actions that would alter the file system catalog or write updates across a storage volume boundary; and by freezing the REDO log point in its checkpoint information. The backup utility copies the data volumes first and optionally the log volumes second while updates are allowed. The resulting inconsistencies are resolved either during a DBMS restart or during a point-in-time (PIT) recovery performed by the restore utility.

DBMS backup without suspending updates and corresponding recovery using separately stored log and data files

The present invention discloses a technique for restoring a database in a computer. In accordance with the present invention, the database contains objects and is stored on a data storage device connected to the computer. After a system failure, a log file is read. The log file contains one or more modifications to the database objects. Each modification has an associated data page and time stamp or sequence number. The modifications are sorted by at least one predefined sorting key value. The sorted modifications are then grouped by database object. The sorted modifications are applied to each database object in parallel.

Fast log apply

A method, apparatus, and article of manufacture for a computer implemented recovery system for restoring a database in a computer. The database contains objects and is stored on a primary data storage device connected to the computer. Objects of different types in the database are copied from the primary data storage device to a secondary data storage device. Modifications to the objects are logged in a log file. A recovery indicator is received that indicates that recovery of the objects in the database is required. The objects are copied from the secondary data storage device to the database on the primary data storage device. Modifications in the log file are applied to the copied objects during one pass through the log file.

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San Jose, CA, United States of America

Thomas Majithia