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Algorithm for Redistributing SQL Table Files for Better Disk Workload Balancing

IP.com Disclosure Number: IPCOM000109536D
Original Publication Date: 1992-Sep-01
Included in the Prior Art Database: 2005-Mar-24
Document File: 3 page(s) / 122K

Publishing Venue

IBM

Related People

Schwendemann, W: AUTHOR [+2]

Abstract

This article assumes: o a table consists of a set of table files, o a table file can reside on only one disk, and o disks contain only database related information (i.e., disks are dedicated to database activity). GIVEN INPUT TO THE ALGORITHM (Image Omitted) ALGORITHM FOR REDISTRIBUTING TABLE FILES TO IMPROVE DISK WORKLOAD INITIALIZATION: 1. Initially, the number of files processed for redistribution is zero. files_processed = 0 2. There is a flag for each table file and it will be set when the file is processed for redistribution. for i = 1 to m { table_file_flag[i] = 0 } STEPS: 1. For those disks which still have table files that have not been processed for redistribution, find the disk that has the most number of accesses.

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Algorithm for Redistributing SQL Table Files for Better Disk Workload Balancing

       This article assumes:
  o   a table consists of a set of table files,
  o   a table file can reside on only one disk, and
  o   disks contain only database related information (i.e., disks
are dedicated to database activity).
GIVEN INPUT TO THE ALGORITHM

                            (Image Omitted)

ALGORITHM FOR REDISTRIBUTING TABLE FILES TO IMPROVE DISK WORKLOAD
INITIALIZATION:
1.  Initially, the number of files processed for redistribution is
zero.
       files_processed = 0
2.  There is a flag for each table file and it will be set when
the file is processed for redistribution.
       for i = 1 to m {
          table_file_flag[i] = 0
       }
STEPS:
1.  For those disks which still have table files that have not been
processed for redistribution, find the disk that has the most number
of accesses.
     Most_active_disk = MAX(disk_access[i]), where 1 <=i<= N and
disk[i] still has table files not processed.
2.  Find the most active table file which has not been processed on
that disk.

                            (Image Omitted)

     Set the table_file_flag(most_active_table_file) to one, and
increment the value of file_processed.
3.  Find the most inactive disk unto which the table file of the
prior step will be moved to
     least_active_disk = MIN(disk_access[i]) , 1<= i <= N
4.  If available free space in the least_active_disk is greater than
the size of most_active_table_file, move the most_active_table_file
from the...