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Browse Prior Art Database

Side Tables for Performance Enhancement of Distributed Libraries

IP.com Disclosure Number: IPCOM000109889D
Original Publication Date: 1992-Sep-01
Included in the Prior Art Database: 2005-Mar-24
Document File: 1 page(s) / 38K

Publishing Venue

IBM

Related People

Gladney, HM: AUTHOR

Abstract

Disclosed are two methods of improving the performance of distributed libraries of digital images and other objects. The basic method for the kind of libraries to which these methods apply are described in H. M. Gladney, Inter-Machine Protocols for Document/Image Libraries, IBM Research Report RJ-8049, April 1991.

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This is the abbreviated version, containing approximately 89% of the total text.

Side Tables for Performance Enhancement of Distributed Libraries

       Disclosed are two methods of improving the performance of
distributed libraries of digital images and other objects.  The basic
method for the kind of libraries to which these methods apply are
described in H. M. Gladney, Inter-Machine Protocols for
Document/Image Libraries, IBM Research Report RJ-8049, April 1991.

      The libraries in question require that the catalog include a
"most recently referenced" timestamp for each object.  Since
transactions may be long and since changing this timestamp puts an
exclusive lock on the object catalog record, all objects whose
catalog records share the page of recently referenced records are
potentially inaccessible for long periods.  This problem is avoided
by the use of a side table to record temporarily which objects have
been retrieved, with the contents of this table being updated into
the database immediately before the COMMIT operation, so that
retrieval timestamps may be recorded without locking portions of the
database exclusively.

      The kind of library described in the cited Research Report
calls for single copies of objects stored in locations potentially
close to using locations but remote from the central catalog.
Retrieval performance in a widely distributed network can often be
improved by storing replica objects in several object stores.  This
can be managed by an addition to the basic library catalog - a table
which maps e...