Client-based Logging: A New Paradigm of Distributed Transaction Management

The proliferation of inexpensive workstations and networks has created a new era in distributed computing. At the same time, non-traditional applications such as computer-aided design (CAD), computer-aided software engineering (CASE), geographic-information systems (GIS), and office-information systems (OIS) have placed increased demands for high-performance transaction processing on database systems. The combination of these factors gives rise to significant challenges in the design of modern database systems. In this thesis, we propose novel techniques whose aim is to improve the performance and scalability of these new database systems. These techniques exploit client resources through client-based transaction management. Client-based transaction management is realized by providing logging facilities locally even when data is shared in a global environment. This thesis presents several recovery algorithms which utilize client disks for storing recovery related information (i.e., log records). Our algorithms work with both coarse and fine-granularity locking and they do not require the merging of client logs at any time. Moreover, our algorithms support fine-granularity locking with multiple clients permitted to concurrently update different portions of the same database page. The database state is recovered correctly when there is a complex crash as well as when the updates performed by different clients on a page are not present on the disk version of the page, even though some of the updating transactions have committed. This thesis also presents the implementation of the proposed algorithms in a memory-mapped storage manager as well as a detailed performance study of these algorithms using the OO1 database benchmark. The performance results show that client-based logging is superior to traditional server-based logging. This is because client-based logging is an effective way to reduce dependencies on server CPU and disk resources and, thus, prevents the server from becoming a performance bottleneck as quickly when the number of clients accessing the database increases

Models of higher-order, type-safe, distributed computation over autonomous persistent object stores

A remote procedure call (RPC) mechanism permits the calling of procedures in another address space. RPC is a simple but highly effective mechanism for interprocess communication and enjoys nowadays a great popularity as a tool for building distributed applications. This popularity is partly a result of their overall simplicity but also partly a consequence of more than 20 years of research in transpaxent distribution that have failed to deliver systems that meet the expectations of real-world application programmers. During the same 20 years, persistent systems have proved their suitability for building complex database applications by seamlessly integrating features traditionally found in database management systems into the programming language itself. Some research. effort has been invested on distributed persistent systems, but the outcomes commonly suffer from the same problems found with transparent distribution. In this thesis I claim that a higher-order persistent RPC is useful for building distributed persistent applications. The proposed mechanism is: realistic in the sense that it uses current technology and tolerates partial failures; understandable by application programmers; and general to support the development of many classes of distributed persistent applications. In order to demonstrate the validity of these claims, I propose and have implemented three models for distributed higher-order computation over autonomous persistent stores. Each model has successively exposed new problems which have then been overcome by the next model. Together, the three models provide a general yet simple higher-order persistent RPC that is able to operate in realistic environments with partial failures. The real strength of this thesis is the demonstration of realism and simplicity. A higherorder persistent RPC was not only implemented but also used by programmers without experience of programming distributed applications. Furthermore, a distributed persistent application has been built using these models which would not have been feasible with a traditional (non-persistent) programming language

Thesaurus-Based Methodologies and Tools for Maintaining Persistent Application Systems

The research presented in this thesis establishes thesauri as a viable foundation for models, methodologies and tools for change management. Most of the research has been undertaken in a persistent programming environment. Persistent language technology has enabled the construction of sophisticated and well-integrated change management tools; tools and applications reside in the same store. At the same time, the research has enhanced persistent programming environments with models, methodologies and tools that are crucial to the exploitation of persistent programming in construction and maintenance of long-lived, data-intensive application systems

Abstracts of manuscripts submitted in 1993 for publication

This volume contains the abstracts of manuscripts submitted for publication during calendar year 1993 by the staff and students of the Woods Hole Oceanographic Institution. We identify the journal of those manuscripts which are in press or have been published. The volume is intended to be informative, but not a bibliography. The abstracts are listed by title in the Table of Contents and ar grouped into one of our five departents, Marine Policy Center, Coastal Research Center, or the student category. An author index is presented in the back to facilitate locating specific papers

Sea Mines and Countermeasures: A Bibliography

This compilation was prepared for the Dudley Knox Library, Naval Postgraduate School, Monterey, CA

Abstracts of manuscripts submitted in 1991 for publication

This volume contains the abstracts of manuscripts submitted for publication during calendar year 1991 by the staff and students of the Woods Hole Oceanographic Institution. We identify the journal of those manuscripts which are in press or have been published. The volume is intended to be informative, but not a bibliography. The abstracts are listed by title in the Table of Contents and are grouped into one of our five departents, Marine Policy Center, Coastal Research Center, or the student category. An author index is presented in the back to facilitate locating specific papers

Reports to the President

A compilation of annual reports for the 1999-2000 academic year, including a report from the President of the Massachusetts Institute of Technology, as well as reports from the academic and administrative units of the Institute. The reports outline the year's goals, accomplishments, honors and awards, and future plans

Annual Report of the University, 1994-1995, Volumes 1-4

DEMONSTRATING THE STRENGTH OF DIVERSITY A walk around the UNM campus as students change classes demonstrates UNM\\u27s commitment to diversity. Students and professors from a variety of ethnic backgrounds crowd the sidewalks and fill classrooms. Over the past year UNM moved forward with existing and new programs to interest more minority students, faculty and staff in the University and to aid in their success while here. Hispanic Outlook in Higher Education recently recognized the University\\u27s endeavors, ranking UNM as one of the best colleges in the nation at graduating Hispanic students. Provost Mary Sue Coleman says diversity contributes to a stimulating environment where faculty and students have different points of view and experiences. The campus becomes a more intellectually alive place, she says. The efforts to build a diverse campus go hand in hand with the University\\u27s goals of achieving academic excellence and attracting the best and brightest. MINORITY ENROLLMENT In the fall of 1994 a total of 32 percent of the student body came from underrepresented groups. The UNM School of Law had the largest number of Native Americans enrolled in any law school in the country