Departmental Colloquium

Adaptive Scheduling of Web Transactions

Shenoda Guirguis

Pitt CS

Monday March 23, 2009
12:30 pm - SENSQ 5317

Hosted by Jose' Carlos Brustoloni

Abstract

In highly interactive dynamic web database systems, user satisfaction determines their success. In such systems, user requested web pages are dynamically created by executing a number of database queries or web transactions. In this paper, we model the interrelated transactions generating a web page as workflows and quantify the user satisfaction by associating dynamic web pages with soft-deadlines. Further, we model the importance of transactions in generating a page by associating different weights to transactions. Using this framework, system success is measured in terms of minimizing the deviation from the deadline (i.e., tardiness) and also minimizing the weighted such deviation (i.e., weighted tardiness). In order to efficiently support the materialization of dynamic web pages, we propose ASETS, which is a parameter-free adaptive scheduling algorithm that automatically adapts to, not only system load, but also transactions\' characteristics (i.e., interdependencies, deadlines and weights). ASETS prioritizes the execution of transactions with the objective of minimizing weighted tardiness. It is also capable of balancing the tradeoff between optimizing average- and worst-case performance when needed. The performance advantages of ASETS are experimentally demonstrated.

Biography of Speaker

Shenoda holds a B.Eng. in Computers and Automatic Control, and M.Sc. in Computer Science from the Alexandria University. He joined the ADMT lab (http://db.cs.pitt.edu) in the CS dept. @ Pitt on January 2006, working towards his PhD degree. His research interests are in the areas of Web databases, data streams and data mining.