International Business Machines Corporation

Yufen Wang

Christina Marie Lee

Robert William Lyle

James Alan Ruddy

Laura Michiko Kunioka-Weis

David L Levish

Thomas Majithia

Michael R Shadduck

Robert J Hollines, Iii

Hsiao Ming Wang

Deborah A Matamoros

Daniel Keith Courter

Stephen J Schmandt

Ming-Hung Hu

Provided is a system, method, and program for performing a reverse scan of an index implemented as a tree of pages. Each leaf page includes one or more ordered index keys and previous and next pointers to the previous and next pages, respectively. The scan is searching for keys in the leaf pages that satisfy the search criteria. If a current index key is a first key on a current page, then a request is made for a conditional shared latch on a previous page prior to the current page. If the requested conditional shared latch is not granted, then the latch on the current page is released and a request is made for unconditional latches on the previous page and the current page. After receiving the latches on the previous and current pages, a determination is made of whether the current index key is on the current page if the current page was modified since the unconditional latch was requested. The current index key is located on the current page if the current index key is on the current page. A determination is then made of whether the located current index key satisfies the search criteria.

Method, system, and program for reverse index scanning

Database index key versioning

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.

Recovering different types of objects with one pass of the log

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Saratoga, CA, United States of America

Yufen Wang