[Sys-research] October 17, Yogesh Simmhan

[Beth A Plale]

                        Systems Research Seminar
                     Thursday October 17 1-2:00, LH101


              XMessages: Building Reliable, Persistent Messaging
                         Middleware for the Grid
                             Yogesh L. Simmhan

paper co-authored with Aleksander Slominski, Dennis Gannon, Mathew
Farrellee, Albert Rossi, Octav Chipara

XMessages is a messaging middleware system designed for Grid applications
that reliably delivers XML messages from publishers to subscribers even
when a subscriber moves to a new location or a publisher has to be
restarted.  Reliability is achieved by using a unique combination of
message "push" and "pull" coupled with a "persistent event channel" based
on very resilient database technology.  Additional reliability is provided
by moving as much of the subscriber's state out of the server and to the
subscriber.

The system is intended to be used for logging and debugging Grid
applications and for monitoring Grid services. For example, XMessages is
being used for control signals in managing distributed application
workflow and logging application output metadata.  An XMessages message
can be an arbitrary XML fragment and SOAP is used as the package protocol
on the wire. Messages are published to persistent event channels, which
save the message for future message subscribers. In addition, a client,
using either simple RDBMS queries or XPath expressions, can search the
channel content.

Direct inquiries to Beth Plale at plale_at_cs.indiana.edu.