Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

Distributed Method for Optimal Key-Range Query Searches

IP.com Disclosure Number: IPCOM000117469D
Original Publication Date: 1996-Mar-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

Hoffman, RL: AUTHOR [+2]

Abstract

Disclosed is an efficient distributed disk access scheduling for key-range delineated queries with parallel execution in an environment with peripheral disk processors.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 76% of the total text.

Distributed Method for Optimal Key-Range Query Searches

      Disclosed is an efficient distributed disk access scheduling
for key-range delineated queries with parallel execution in an
environment with peripheral disk processors.

      When an Index is present, selection processing for a query can
be satisfied by limiting the search to only those records which
satisfy a limited range of key values.  The order in which these rows
are read from disk can be sequenced so as to provide greater locality
of reference thereby improving overall query performance.  The
resulting order of disk pages read will be different than the order
of key values encountered.

      The method described here navigates selectively through each
designated range of keys in the Index by utilizing key-selection
logic to limit the search to only those ranges of consecutive keys
satisfying the selection criteria.  Each of these searches of the
Index is performed in parallel.

      The associated Record Id (RID) is extracted from the suffix
of each selected key.  The RID is transformed into a matching virtual
address.  The virtual address is employed to identify the matching
disk arm.  The disk arm read requests on behalf of the matching row
from the queried table is routed as a message to an arm-task (one
such arm task per disk arm configured on the machine).  The arm task,
which resides on a peripheral I/O processor managing a set of disk
arms, sequences the disk read requests...