Darcy G. Benoit

Today's DBMSs: how autonomic are they

The increasing complexity of database management systems (DBMSs) and the dearth of their experienced administrators make an urgent call for an autonomic DBMS that is capable of managing and maintaining itself. In this paper, we examine the characteristics that a DBMS should have in order to be considered autonomic and assess the position of todays commercial DBMSs such as DB2, SQL Server, and Oracle.

Automatic Diagnosis of Performance Problems in Database Management Systems

Database performance is directly linked to database management system (DBMS) resource allocation. Complex relationships between resources make problem diagnosis and performance tuning difficult, time-consuming tasks. Database administrators (DBAs) currently tune and re-tune the DBMS as the database grows and workloads change. Increased performance and reduced cost of ownership can be achieved by automating the tuning process, starting with resource allocation problem diagnosis. In this paper we overview an automatic diagnosis framework designed to diagnose resource problems. Our diagnosis model and results demonstrate an ability to correctly identify system bottlenecks for a generic on-line transaction processing workload

Security Analysis and Authentication Improvement for IEEE 802.11i Specification

The IEEE 802.11i amendment has been finalized to address the security issues in wireless local area networks. A prodigious amount of research has demonstrated that the IEEE 802.11i specification is sufficient to prevent unauthorized access and use. In this paper, we analyze the IEEE 802.11i wireless networking amendment with respect to data confidentiality, integrity, mutual authentication and availability. Our analysis indicates that a number of serious threats have still not been addressed by the 802.11i amendment. This includes DoS attacks, insider attacks, offline guessing attacks, etc. Furthermore, configuring security features on a commercial Wi-Fi network is moderately-to-very difficult. Towards this end, this paper proposes an improved authentication mechanism which adopts asymmetric cryptography and thus accomplishes link-layer frame protection. Through our further analysis and discussion, we conclude that the proposed mechanism not only prevents potential security threats but also accomplishes autonomic security configuration without human intervention.

World's first web census

Purpose – To measure the exact size of the world wide web (i.e. a census). The measure used is the number of publicly accessible web servers on port 80.Design/methodology/approach – Every IP address on the internet is queried for the presence of a web server.Findings – The census found 18,560,257 web servers.Research limitations/implications – Any web servers hidden behind a firewall, or that did not respond within a reasonable amount of time (20 seconds) were not counted by the census.Practical implications – Whenever a server is found, we download and store a copy of its homepage. The resulting database of homepages is a historical snapshot of the web which will be mined for information in the future.Originality/value – Past web surveys performed by various research groups were only estimates of the size of the web. This is the first time its size has been exactly measured.

Using reflection to introduce self-tuning technology into DBMSs

The increasing complexity of database management systems (DBMSs) and their workloads means that manually managing their performance has become a difficult and time-consuming task. Autonomic computing systems have emerged as a promising approach to dealing with this complexity. Current DBMSs have begun to move in the direction of autonomic computing with the introduction of parameters that can be dynamically adjusted. A logical next step is the introduction of self-tuning technology to diagnose performance problems and to select the dynamic parameters that must be adjusted. We introduce a method for automatically diagnosing performance problems in DBMSs and then describe how this method can be incorporated into current DBMSs using the concept of reflection. We demonstrate the feasibility of our approach with a proof-of-concept implementation for DB2 universal database.

Negotiation Strategies for Agent-based Meeting Scheduling System

Managing personal meetings and events is a complicated task. It becomes more problematic when a person has numerous meetings or events in their schedule. One of the challenges of managing meetings is to find a proper meeting time when a conflict occurs. This paper presents negotiation strategies for an agent-based meeting scheduling system to automatically solve meeting conflicts. These relieve the user from having to find free meeting times manually. The agent will utilize these negotiation strategies to find an acceptable time slot that best fits the constraints and preferences for its user. A prototype is implemented and demonstrated

World's First Class C Web Census: The First Step in a Complete Census of the Web

Our research goal is to measure the exact size of the World Wide Web (i.e., a census). The measure we are interested in is the number of publicly accessible web servers on port 80. We present the results from an initial survey of 3.5% of all addressable IP addresses. This is the largest survey of the Web performed to date. We then present results from the world’s first census of all Class C IP addresses. We also describe our approach for a full census of the Internet.

A Web census is possible

How big is the World Wide Web? Over the last few years, researchers have used various approaches to estimate the size of the Web. The large size of the Web and the technology available at the time dictated that only estimation experiments were feasible. We hypothesize that an exact measurement (i.e., a census) of the Web is now possible. We present evidence for our hypothesis, and describe a census we performed to test the hypothesis

Automatic performance diagnosis for changing workloads in DBMSs

Database performance is directly linked to database management system (DBMS) resource allocation. Complex relationships between DBMS resources make problem diagnosis and performance tuning difficult, time-consuming tasks. Database administrators are currently required to retune the DBMS as databases grow and workloads change. Performance can be increased and cost of ownership reduced by automating the tuning process, starting specifically with the diagnosis of resource allocation problems. In this paper, we overview our automatic diagnosis framework designed to determine resource problems. We present our results demonstrating the ability to correctly identify system bottlenecks for a generic on-line transaction processing workload when new transactions are added to the workload.

A Visualization of All the IP Addresses That Host a Publicly Accessible Web Server

Every valid IP address was checked for the presence of a publicly accessible web server on port 80. To better understand the distribution of web servers across the available address space, we map the results to a 2-dimentional Cartesian plane. The resulting graph is presented and discussed.