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This item represents a case in PACER, the U.S. Government's website for federal case data. This information is uploaded quarterly. To see our most recent version please use the source url parameter, linked below. To see the canonical source for this data, please consult PACER directly.

This item represents a case in PACER, the U.S. Government's website for federal case data. This information is uploaded quarterly. To see our most recent version please use the source url parameter, linked below. To see the canonical source for this data, please consult PACER directly.

This item represents a case in PACER, the U.S. Government's website for federal case data. This information is uploaded quarterly. To see our most recent version please use the source url parameter, linked below. To see the canonical source for this data, please consult PACER directly.

From the bitsavers.org collection, a scanned-in computer-related document. xerox :: parc :: techReports :: CSL-90-2 Rebuilding Database Caches During Fast Crash Recovery

From the bitsavers.org collection, a scanned-in computer-related document. xerox :: parc :: techReports :: CSL-90-2 Rebuilding Database Caches During Fast Crash Recovery

The purpose of this thesis is to analyze the operations of a distributed database management system under network partitions, review a number of existing methods proposed to deal with this problem and to present an alternate approach that will allow multiple operating partitions upon network partitioning. When a network that supports a distributed database with redundant data becomes partitioned, each partition may function separately. Due to this, independent updates at each partition may cause inconsistencies to arise. At network reconnection time such divergent data, in particular copies of the same data in different partitions have to be reconciled. There is no known general method for doing so. Existing solutions are often unacceptable because system availability is reduced. Two recently proposed methods that allow continuous operation of multiple partitions may work for certain applications but are not general enough.

This is the first of the three volumes of the final technical report for the project Distributed Database Control and Allocation. This volume describes frameworks for understanding concurrency control and recovery algorithms for centralized and distributed database systems.

A modern database transaction may involve a long series of updates, deletions, and insertions of data and a complex mix of these primary database operations. Due to its length and complexity, the transaction requires back-up and recovery procedures. The back-up procedure allows the user to either commit or abort a lengthy and complex transaction without comprising the integrity of the data. The recovery procedure allows the system to maintain the data integrity during the execution of a transaction, should the transaction be interrupted by the system. With both the back-up and recovery procedures, the modern database system will be able to provide consistent data throughout the life-span of a database without ever corrupting either its data values or its data types. However, the implementation of back-up and recovery procedures in a database system is a difficult and involved effort since it effects the base as well as meta data of the database. Further, it effects the state of the database system. This thesis is mainly focused on the design trade-offs and issues of implementing an effective and efficient mechanism for back-up and recovery in the multimodel, multilingual, and multi backend database system. Keywords: Data base management systems.

This paper presents considerations about several topics that have a direct influence on data reliability and performance in object oriented database management systems. These topics are: physical storage management (clustering), concurrency control, crash recovery, garbage collection, and database security. Each topic is illustrated by its application to the Tactical Database as designed for the Low Cost Combat Direction System.

Redundant disk arrays provide a way for achieving rapid recovery from media failures with a relatively low storage cost for large scale database systems requiring high availability. In this paper we propose a method for using redundant disk arrays to support rapid recovery from system crashes and transaction aborts in addition to their role in providing media failure recovery. A twin page scheme is used to store the parity information in the array so that the time for transaction commit processing is not degraded. Using an analytical model, we show that the proposed method achieves a significant increase in the throughput of database systems using redundant disk arrays by reducing the number of recovery operations needed to maintain the consistency of the database.

Redundant disk arrays provide a way for achieving rapid recovery from media failures with a relatively low storage cost for large scale database systems requiring high availability. In this paper we propose a method for using redundant disk arrays to support rapid recovery from system crashes and transaction aborts in addition to their role in providing media failure recovery. A twin page scheme is used to store the parity information in the array so that the time for transaction commit processing is not degraded. Using an analytical model, we show that the proposed method achieves a significant increase in the throughput of database systems using redundant disk arrays by reducing the number of recovery operations needed to maintain the consistency of the database.

Redundant disk arrays provide a way for achieving rapid recovery from media failures with a relatively low storage cost for large scale database systems requiring high availability. In this paper we propose a method for using redundant disk arrays to support rapid recovery from system crashes and transaction aborts in addition to their role in providing media failure recovery. A twin page scheme is used to store the parity information in the array so that the time for transaction commit processing is not degraded. Using an analytical model, we show that the proposed method achieves a significant increase in the throughput of database systems using redundant disk arrays by reducing the number of recovery operations needed to maintain the consistency of the database.

The three traditional failure classes are system, media, and transaction failures. Sometimes, however, modern storage exhibits failures that differ from all of those. In order to capture and describe such cases, single-page failures are introduced as a fourth failure class. This class encompasses all failures to read a data page correctly and with plausible contents despite all correction attempts in lower system levels. Efficient recovery seems to require a new data structure called the page recovery index. Its transactional maintenance can be accomplished writing the same number of log records as today's efficient implementations of logging and recovery. Detection and recovery of a single-page failure can be sufficiently fast that the affected data access is merely delayed, without the need to abort the transaction.

The three traditional failure classes are system, media, and transaction failures. Sometimes, however, modern storage exhibits failures that differ from all of those. In order to capture and describe such cases, single-page failures are introduced as a fourth failure class. This class encompasses all failures to read a data page correctly and with plausible contents despite all correction attempts in lower system levels. Efficient recovery seems to require a new data structure called the page recovery index. Its transactional maintenance can be accomplished writing the same number of log records as today's efficient implementations of logging and recovery. Detection and recovery of a single-page failure can be sufficiently fast that the affected data access is merely delayed, without the need to abort the transaction.

Title from cover

Title from cover

The purpose of this thesis is to analyze the operation of a distributed database management system under network partitions, review a number of existing methods proposed to deal with this problem and to present an alternate approach that will allow multiple operating partitions upon network partitioning. When a network that supports a distributed database with redundant data becomes partitioned, each partition may function separately. Due to this, independent updates at each partition may cause inconsistencies to arise. At network reconnection time such divergent data, in particular copies of the same data in different partitions have to be reconciled. There is no known general method for doing so. Existing solutions are often unacceptable because system availability is reduced. Two recently proposed methods that allow continuous operation of multiple partitions may work for certain applications but are not general enough.

A computer Security/Recovery System (CS/RS) model was designed with the goal of implementing it into a Relational Database Management System. In addition, the relational database was to serve as a pedagogical tool for teaching database management and manipulation techniques as well as security measures and issues. Toward these goals, an extensive literature search and analysis of the current state of the art Computer Security models was required in order to identify current unresolved issues and areas of research. The advantages and disadvantages associated with six computer security models were explored and addressed in this thesis. Then the requirements for a CS/RS model were indentified and defined, and based on certain favorable criteria, one of the computer security models analyzed was selected. Further, only one of the six models had ever been implemented using a relational database and none had ever been implemented using a microcomputer. Consequently, the ability to take one of the existing computer security models and to apply the security concepts used within this model was not an easy task and in some instances was not possible. Finally, the CS/RS model designed did not include the hierarchically ordered military security sensitivity levels. (Author)

Periodically, researchers have been sharing their constant attempts to improve the existing methods for data replication in distributed database system. The main goal is to work for an efficient distributed environment. An efficient environment may handle huge amount of data and preserve data availability. The occasionally failures in distributed systems will affect the end results, such as data loss, income loss etc. Thus, to prevent the data loss and guarantee the continuity of the business, many organizations have applied disaster recovery solutions in their system. One of the widely used is database replication, because it guarantees data safety and availability. However, disaster still can occur in database replication. Hence, an automatic failure recovery technique called distributed database replication with fault tolerance (DDR-FT) has been proposed in this research. DDR-FT uses heartbeat message for node monitoring. Subsequently, a foundation of binary vote assignment for fragmented database (BVAFD) replication technique has been used. In DDR-FT, the data nodes are continuously monitored while auto reconfiguring for automatic failure recovery. From the conducted experiments, it is proved that DDR-FT can preserve system availability. It shows that DDR-FT technique provides a convenient approach to system availability for distributed database replication in real time environment. 

Periodically, researchers have been sharing their constant attempts to improve the existing methods for data replication in distributed database system. The main goal is to work for an efficient distributed environment. An efficient environment may handle huge amount of data and preserve data availability. The occasionally failures in distributed systems will affect the end results, such as data loss, income loss etc. Thus, to prevent the data loss and guarantee the continuity of the business, many organizations have applied disaster recovery solutions in their system. One of the widely used is database replication, because it guarantees data safety and availability. However, disaster still can occur in database replication. Hence, an automatic failure recovery technique called distributed database replication with fault tolerance (DDR-FT) has been proposed in this research. DDR-FT uses heartbeat message for node monitoring. Subsequently, a foundation of binary vote assignment for fragmented database (BVAFD) replication technique has been used. In DDR-FT, the data nodes are continuously monitored while auto reconfiguring for automatic failure recovery. From the conducted experiments, it is proved that DDR-FT can preserve system availability. It shows that DDR-FT technique provides a convenient approach to system availability for distributed database replication in real time environment. 

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This annotated bibliography of material from the ERIC database presents 48 annotations on the topic of research on Reading Recovery. The bibliography begins with: (1) a 2-page Education Research Consumer Guide entitled "Reading Recovery" (which defines the topic and answers some pertinent questions about it; and (2) a sample ERIC abstract. Entries in the annotated bibliography are grouped under the topics of Reading Recovery project descriptions; evaluative, feasibility and technical reports; and miscellania. The journal articles, books, reports, practica, conference papers, and theses in the annotated bibliography were published between 1986 and 1992. (RS)

A modern database transaction may involve a long series of updates, deletions, and insertions of data and a complex mix of these primary database operations. Due to its length and complexity, the transaction requires back-up and recovery procedures. The back-up procedure allows the user to either commit or abort a lengthy and complex transaction without comprising the integrity of the data. The recovery procedure allows the system to maintain the data integrity during the execution of a transaction, should the transaction be interrupted by the system. With both the back-up and recovery procedures, the modern database system will be able to provide consistent data throughout the life-span of a database without ever corrupting either its data values or its data types. However, the implementation of back-up and recovery procedures in a database system is a difficult and involved effort since it effects the base as well as meta data of the database. Further, it effects the state of the database system. This thesis is mainly focused on the design trade-offs and issues of implementing an effective and efficient mechanism for back-up and recovery in the multimodel, multilingual, and multi backend database system. Keywords: Data base management systems. (KR)

Thesis advisor, David K. Hsiao

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