Browse Prior Art Database

Method to display Legacy Access events with an associated Legacy server

IP.com Disclosure Number: IPCOM000123048D
Original Publication Date: 1998-Apr-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 3 page(s) / 119K

Publishing Venue

IBM

Related People

Labadie, E: AUTHOR [+3]

Abstract

A method for displaying interactions between an instrumented client and an uninstrumented server is disclosed. This allows interactions with legacy servers to be represented graphically.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 49% of the total text.

Method to display Legacy Access events with an associated Legacy
server

      A method for displaying interactions between an instrumented
client and an uninstrumented server is disclosed.  This allows
interactions with legacy servers to be represented graphically.

      Previously described techniques provide a mechanism for
displaying the interactions between processes in a parallel or
distributed system (1,2) Those techniques assume that instrumentation
is present in all processes, so that event data may be obtained from
all processes during execution.

      The display produced by these techniques consists of horizontal
lines, called event traces, representing processes or threads.
Symbols on those lines represent events of interest.  Interactions
between processes or threads are represented by drawing a connecting
line between  event symbols on the two event traces.

      If a client that has been instrumented interacts with a server
that has not been instrumented (subsequently referred to as a
"legacy" server), only half of each event pair will be received.  A
simple solution can be devised in which short arrows perpendicular to
the "trace line" represent interaction with a process not shown, but
this does not indicate whether different instances represent
interactions with one or several legacy servers and does not indicate
in what order  those interactions occurred at the legacy server(s).

      This invention provides a mechanism for constructing an event
trace corresponding to a legacy server that represents the behavior
of the server as accurately as possible, given the available
information.  It assumes that the client-server interactions are
synchronous, as is usually the case.  Once the "missing" event traces
have been constructed, a display may be produced using the previously
described techniques, without any further special handling.

      For this solution to be feasible, client instrumentation must
be able to determine (a) whether an event involves interaction with a
legacy server and (b) the identity of a legacy server.  Events
reported by client instrumentation must contain these two pieces of
data.

      When an instrumented client reports an event representing an
interaction with a legacy server, it attaches a flag to indicate
this.  It also includes the identity of the legacy server involved.

      If these events are not modified, they will cause the
display-drawing code to produce short arrows perpendicular to the
trace line.  Normally, a  process will be executed that uses
information in these events to build an event trace for the legacy
server.

      To build event traces for legacy servers, the timestamp
algorithm is executed, to assign vector timestamps representing the
partial order of events.  It will not be able to assign a timestamp
to an event representing an interaction with a legacy server, since
the two events of a synchronous pair must be timestam...