Fast log apply
AssigneeInternational Business Machines Corporation
InventorsDonald J. Haderle, Thomas Majithia
Life of this patent
Estimating the term…
Abstract
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.
Claims18
A method of restoring a database in a computer, the database containing objects and being stored on a data storage device connected to the computer, the method comprising the steps of:
- reading a log file, wherein the log file contains at least one modification to a database object;
- sorting the read modifications by at least one predefined sorting key value, wherein each database object has an identifier, each of the modifications has an associated time stamp and data page, and the predefined sorting key value comprises the identifier, time stamp, and data page;
- grouping the sorted modifications by database object;
- and
- applying the sorted modifications to each database object in parallel.
An apparatus for restoring a database in a computer, the database containing objects and being stored on a data storage device connected to a computer, comprising:
- a computer having a data storage device connected thereto, wherein the data storage device stores a database;
- one or more computer programs, performed by the computer, for reading a log file, wherein the log file contains at least one modification to a database object, for sorting the read modifications by at least one predefined sorting key value, for grouping the sorted modifications by database object, and for applying the sorted modifications to each database object in parallel, wherein each database object has an identifier, each of the modifications has an associated time stamp and data page, and the predefined sorting key value comprises the identifier, time stamp, and data page.
An article of manufacture comprising a computer program carrier readable by a computer and embodying one or more instructions executable by the computer to perform method steps for restoring a database in a computer, the database containing objects and being stored on a data storage device connected to the computer, the method comprising the steps of:
- reading a log file, wherein the log file contains at least one modification to a database object;
- sorting the read modifications by at least one predefined sorting key value, wherein each database object has an identifier, each of the modifications has an associated time stamp and data page, and the predefined sorting key value comprises the identifier, time stamp, and data page;
- grouping the sorted modifications by database object;
- and
- applying the sorted modifications to each database object in parallel.
Dependencies are inferred from the claim text.