Browse Prior Art Database

Formatted Journal Trace Facility

IP.com Disclosure Number: IPCOM000110801D
Original Publication Date: 1994-Jan-01
Included in the Prior Art Database: 2005-Mar-26
Document File: 2 page(s) / 82K

Publishing Venue

IBM

Related People

Hogge, WC: AUTHOR

Abstract

A journal has the capability to record all changes to a database file. It does this by keeping a copy of record images as they are added, changed, or deleted from the file. Other information is also recorded, such as the time, the name of program making the change, the job, the user ID, the record number, and the type of change. The changes are recorded in the order of occurrence from ALL sources of change on the system. Access from the same job, different jobs on the same system, or even from jobs on other systems are recorded as they occur.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Formatted Journal Trace Facility

      A journal has the capability to record all changes to a
database file.  It does this by keeping a copy of record images as
they are added, changed, or deleted from the file.  Other information
is also recorded, such as the time, the name of program making the
change, the job, the user ID, the record number, and the type of
change.  The changes are recorded in the order of occurrence from ALL
sources of change on the system.  Access from the same job, different
jobs on the same system, or even from jobs on other systems are
recorded as they occur.

      A journal can also record changes for several files at the same
time, thus recording very complicated sequences of events arising
from the interaction of several jobs acting on the database.
However, a detailed analysis of the changes of the CONTENT of the
data is difficult because the journaling support provided by
operating systems do not have sufficient information to represent the
data structures contained within the record images.  However, many
database systems are capable of providing the detail necessary to
provide this representation.

      Journaling can provide before and after images of changed
records.  This, if considered in combination with the format of the
data structures, can provide a detailed analysis of all changes down
to the field level.  This information can be used in several tasks of
the development and support of software systems.  In an effort to
understand an existing system, this can be used to help reverse
engineer the data flows through the system.  Also, it can be used in
the testing of new systems, or changes to existing systems.  As an
aid in problem analysis, it provides a quick and effective means of
locating components of a system introducing erroneous data.  This can
be particularly helpful in cases where a problem is intermittent and
the cause is not easily determined.

      A prototype of a Formatted Journal Trace has been developed on
the AS/400.  Many commands on the AS/400 provide data base files as
an output medi...