AN OPTIMAL STATIC PESSIMISTIC SCHEME FOR FAULT TOLERANT DISTRIBUTED DATABASE SYSTEMS

Author(s):  
HOANG PHAM ◽  
DAVID POTOSKI

A distributed database system often replicates data across its servers to provide a fault-resistant application, which maximizes server availability. Various replication control protocols have been developed to ensure data consistency. In this paper, we develop optimal design methods for the quorum-consensus replication protocol, which (1) maximizes availability of the distributed database systems and (2) minimizes the total system cost by calculating the optimal read quorum and the optimal number of system servers. Several numerical examples and applications are provided to illustrate the results.

2014 ◽  
Vol 13 (9) ◽  
pp. 4859-4867
Author(s):  
Khaled Saleh Maabreh

Distributed database management systems manage a huge amount of data as well as large and increasingly growing number of users through different types of queries. Therefore, efficient methods for accessing these data volumes will be required to provide a high and an acceptable level of system performance.  Data in these systems are varying in terms of types from texts to images, audios and videos that must be available through an optimized level of replication. Distributed database systems have many parameters like data distribution degree, operation mode and the number of sites and replication. These parameters have played a major role in any performance evaluation study. This paper investigates the main parameters that may affect the system performance, which may help with configuring the distributed database system for enhancing the overall system performance.


Author(s):  
MD. SHAZZAD HOSAIN ◽  
MUHAMMAD ABDUL HAKIM NEWTON

In this paper we present a multi-key index model that enables us to search a record with more than one attribute values in distributed database systems. Indices provide fast and efficient access of data and so become a major aspect in centralized database systems. Most of the centralized database systems use B + tree or other types of index structures such as bit vector, graph structure, grid file etc. But in distributed database systems no index model is found in the literature. Therefore efficient access is a major problem in distributed databases. Our proposed index model avoids the query-flooding problem of existing system and thus optimizes network bandwidth.


Author(s):  
Amita Goyal Chin

In a distributed database system, an increase in workload typically necessitates the installation of additional database servers followed by the implementation of expensive data reorganization strategies. We present the Partial REALLOCATE and Full REALLOCATE heuristics for efficient data reallocation. Complexity is controlled and cost minimized by allowing only incremental introduction of servers into the distributed database system. Using first simple examples and then, a simulator, our framework for incremental growth and data reallocation in distributed database systems is shown to produce near optimal solutions when compared with exhaustive methods.


Author(s):  
Amita Goyal Chin

In a distributed database system, an increase in workload typically necessitates the installation of additional database servers followed by the implementation of expensive data reorganization strategies. We present the Partial REALLOCATE and Full REALLOCATE heuristics for efficient data reallocation. Complexity is controlled and cost minimized by allowing only incremental introduction of servers into the distributed database system. Using first simple examples and then, a simulator, our framework for incremental growth and data reallocation in distributed database systems is shown to produce near optimal solutions when compared with exhaustive methods.


Author(s):  
Anastasya Latubessy ◽  
Ahmad Ashari

AbstrakKemampuan socket yang bekerja pada komunikasi low level dalam melakukan transfer data antar aplikasi, diharapkan dapat diterapkan dalam sistem basis data terdistribusi. Beberapa alasan untuk membangun basis data terdistribusi adalah pemakaian bersama, kehandalan, ketersediaan, dan kecepatan pemrosesan query. Dengan pertimbangan tersebut, instansi-instansi baik pemerintah maupun swasta mulai tertarik untuk menggunakan sistem terdistribusi dalam pengelolaan pekerjaan pada instansinya. Hal ini dijadikan alasan untuk membangun sistem kenaikan gaji berkala otomatis di Dinas Informasi dan Komunikasi (Infokom) Provinsi Maluku. Selain itu, belum adanya sistem terkomputerisasi yang menangani sistem ini. Sistem kenaikan gaji berkala merupakan sistem yang bersifat kritis atau penting karena berhubungan dengan masalah uang, sehingga diperlukan juga sebuah sistem yang fault tolerant.Arsitektur sistem dibangun dengan metode client server yang memanfaatkan socket sebagai middleware dalam proses komunikasi pada jaringan. Menggunakan pendekatan full replica dengan pendekatan file replication using a group untuk menjamin konsistensi data. SQL Statement yang dikirimkan client akan diubah kedalam format XML yang kemudian akan dikirimkan ke kedua basisdata server menggunakan socket. Model redundansi data dan rendundansi proses diatur oleh middleware socket. Hasil yang diperoleh dalam penelitian ini adalah aplikasi socket sebagai middleware yang menangani distribusi data dari aplikasi web client ke basisdata server yang diimplementasikan pada sistem kenaikan gaji berkala otomatis di Dinas Infokom Provinsi Maluku.  Kata kunci— Socket, basisdata terdistribusi, client server AbstractSockets ability to transfer data between application  that work on the low level communication was expected to be implemented in a distributed database system. Some of the reasons for building a distributed database was data sharing, reliability, availability, and query processing speed. With these considerations, both government agencies and private sector became interested to use distributed systems to manage their job at the office. It is used as a reason to build an automated KGB system of Infokom Department in Province of Moluccas. Furthermore, there was no computerized system to handle this system before. Because of it was a critical or important system, then it was requires to build a system that has a fault tolerant capability.The system architecture was built by client server method using sockets as middleware in the process of network communicaton. The system method was used full replica, and used file replication using a group to ensure data consistency. The SQL Statement was sent by the client would be converted into an XML format which then would be sent to the server using a socket. Data redundancy model and process redundancy model managed by socket middleware.The results of this research was a middleware application using socket that handle the distribution of databases from client applications to database server that were implemented on a periodic system of automatic salary increases in the Office of Information and Communication in Province of Moluccas.  Keywords— Socket, distributed database, replication


2021 ◽  
Author(s):  
Mohsen Taki ◽  
Mohammadreza Mollahoseini Ardakani

Abstract One of the most critical aspects of distributed database design and management is fragmentation. If the fragmentation is done properly, we can expect to achieve better throughput from such systems. The primary concern of DBMS design is the fragmentation and allocation of the underlying database. The distribution of data across various sites of computer networks involves making proper fragmentation and placement decisions. The first phase in the process of distributing a database is fragmentation which clusters information into fragments. This process is followed by the allocation phase which distributes, and if necessary, replicates the generated fragments among the nodes of a computer network. The use of data fragmentation to improve performance is not new and commonly appears in file design and optimization literature. An efficient functionality of any distributed database system is highly dependent on its proper design in terms of adopted fragmentation and allocation methods. Fragmentations of large, global databases are performed by dividing the database horizontally, vertically or combination of both. In order to enable the distributed database systems to work efficiently, the fragments have to be allocated across the available sites in such a way that reduces communication cost of data.In this article, we have tried to describe the existing methods of database fragmentation and have an overview of the existing methods. Finally, we conclude with suggestions for using machine learning to solve the overlap problem in fragments.


Sign in / Sign up

Export Citation Format

Share Document