Highly Available Database Management Systems

2009 ◽  
pp. 28-34
Author(s):  
Wenbing Zhao
Keyword(s):  
Database Management ◽  
Database Systems ◽  
Database Management Systems ◽  
High Availability ◽  
Management Systems ◽  
Database Replication ◽  
The Subject ◽  
Database Clustering ◽  
Alternative Solutions

The subject of highly available database systems has been studied for more than two decades, and there exist many alternative solutions (Agrawal, El Abbadi, & Steinke, 1997; Kemme, & Alonso, 2000; Patino-Martinez, Jimenez-Peris, Kemme, & Alonso, 2005). In this article, we provide an overview of two of the most popular database high availability strategies, namely database replication and database clustering. The emphasis is given to those that have been adopted and implemented by major database management systems (Davies & Fisk, 2006; Ault & Tumma, 2003).

A Framework for Cost-Based Query Optimization in Native XML Database Management Systems

2010 ◽  
pp. 160-183 ◽  
Author(s):  
Andreas M. Weiner ◽  
Theo Härder
Keyword(s):  
Query Optimization ◽  
Database Management ◽  
Cost Model ◽  
Database Systems ◽  
Database Management Systems ◽  
Management Systems ◽  
Xml Database ◽  
Xml Documents ◽  
Native Xml Database ◽  
Query Optimizers

Since the very beginning of query processing in database systems, cost-based query optimization has been the essential strategy for effectively answering complex queries on large documents. XML documents can be efficiently stored and processed using native XML database management systems. Even though such systems can choose from a huge repertoire of join operators (e. g., Structural Joins and Holistic Twig Joins) and various index access operators to efficiently evaluate queries on XML documents, the development of full-fledged XML query optimizers is still in its infancy. Especially the evaluation of complex XQuery expressions using these operators is not well understood and needs further research. The extensible, rule-based, and cost-based XML query optimization framework proposed in this chapter, serves as a testbed for exploring how and whether well-known concepts from relational query optimization (e. g., join reordering) can be reused and which new techniques can make a significant contribution to speed-up query execution. Using the best practices and an appropriate cost model that will be developed using this framework, it can be turned into a robust cost-based XML query optimizer in the future.

Algorithms, that implement set-theoretic operations on tables and multitables

2019 ◽  
Vol 33 ◽  
pp. 100-111
Author(s):  
Iryna Kanarskaya
Keyword(s):  
Database Management ◽  
Relational Databases ◽  
Database Management Systems ◽  
Management Systems ◽  
Actual Number ◽  
Average Case ◽  
Distribution Of Values ◽  
Processing Information ◽  
The Subject ◽  
Optimal Implementation

The paper is devoted to the research of algorithms implementing intersection, union and difference in tables and multitables. The subject of the work is relevant, since despite the importance and applicability of set-theoretical operations in relational databases, for some reason, the attention of researchers was focused on optimizing other table operations, first of all, the join. Meanwhile, the optimal implementation of set-theoretical operations will lead to a faster execution of the query, which containing at least one of set-theoretical operations, and will significantly reduce the time of processing information in the database management systems. For each set-theoretical operation algorithms that implement them on tables, in which strings are not repeat, and on multi-tables, in which the strings can be repeated, are considered. After that the modifications of the basic algorithms, that we found, which allow to significantly reduce the number of computations are considered. As an average case, we understand the most general case in which the domain of each attribute of the table schema is fixed and known above, and the distribution of values for each attribute in each table is uniform. For each of the six cases (three table operations and three multi-table operations), the fastest algorithms by this criterion were found. For all 6 algorithms considered on the tables (basic and fastest modifications of the basic ones) we found exact complexity on average. The found formulas defining the complexity of the proposed algorithms do not contain O-asymptotics. For the experimental confirmation of the results we developed the software system, which, for tables with given parameters, finds the actual number of computations performed for each of the proposed algorithms. The experiments carried out confirmed the theoretical estimates found for the tables and identified the fastest algorithms for the multitables. The results of the work can be used both in relational databases theory and in practice in queries optimization and to reduce the processing time in database management systems.

scholarly journals Experimenting with recursive queries in database and logic programming systems

2008 ◽  
Vol 8 (2) ◽  
pp. 129-165 ◽  
Author(s):  
G. TERRACINA ◽  
N. LEONE ◽  
V. LIO ◽  
C. PANETTA
Keyword(s):  
Database Management ◽  
State Of The Art ◽  
Database Systems ◽  
Database Management Systems ◽  
Main Memory ◽  
Management Systems ◽  
Distributed Data ◽  
Complex Reasoning ◽  
Programming Systems ◽  
New System

AbstractThis article considers the problem of reasoning on massive amounts of (possibly distributed) data. Presently, existing proposals show some limitations: (i) the quantity of data that can be handled contemporarily is limited, because reasoning is generally carried out in main-memory; (ii) the interaction with external (and independent) Database Management Systems is not trivial and, in several cases, not allowed at all; and (iii) the efficiency of present implementations is still not sufficient for their utilization in complex reasoning tasks involving massive amounts of data. This article provides a contribution in this setting; it presents a new system, called DLVDB, which aims to solve these problems. Moreover, it reports the results of a thorough experimental analysis we have carried out for comparing our system with several state-of-the-art systems (both logic and databases) on some classical deductive problems; the other tested systems are LDL++, XSB, Smodels, and three top-level commercial Database Management Systems. DLVDB significantly outperforms even the commercial database systems on recursive queries.

A Newly Proposed Cloud Computing Based Strengthen Distributed Database System Model and Its Applications in Database Modelling

2021 ◽  
Vol 9 (10) ◽  
pp. 442-449
Author(s):  
Shivankur Thapliyal
Keyword(s):  
Data Storage ◽  
Database Management ◽  
Large Data ◽  
Database Systems ◽  
Distributed Database ◽  
Database Management Systems ◽  
Management Systems ◽  
Data Sets ◽  
Distributed Database System ◽  
Distributed Database Management

Abstract: In the modern era of today’s exceptional Information age, the day to day transactions of huge sensitive data sets, which is in the form of PBs (Peta-Bytes) 250 bytes and YBs (Yotta – Bytes) 280 bytes are drastically increases with enormous speed on CLOUD data storage environment. CLOUDs data storage environment are one of the most superior and reliable platform for storing a large sets of data both at enterprise level or local level. Because CLOUD provides online data fetching capability to restore or fetching data at any geographical locations through login their correspondent credentials. But to enhancement or spread of these large data sets are becomes also very complex with respect to maintenance of these data with take concern of consistency and data security, because to maintain these large data sets with full of consistency and integrity are really a very typical and rational tasks, so here In this paper we proposed a distributed database management systems for CLOUD interface also preserves or to take concern data security features with full restoration of CIA (Confidentiality, Integrity, Availability or Authenticity) trade of Information Security. Here we also improvised the mechanisms of traditional distributed database management systems because the tendency to preserves information and recover ability after any misconceptions happens that we restore data which belongs to similar person may have to be stored at different locations, but this newly proposed distributed database systems architecture contains all information or record which belong to similar person are stored in one database rather restore it different databases but the location of these data have to be changes mean while that the content or data which resides in one databases have to be moved to some other database and also preserves the security features, and this model also have capability to run older traditional methodology based distributed database management systems using this model. So the detailed description about these models and communication infrastructure among different CLOUDs are append in the upcoming sections of this paper. Keywords: Cloud based Distributed Database system model, Distributed system, Distributed Database model of CLOUD, Cloud Distributed Database, CLOUD based database systems

scholarly journals Seasonality and Software Vulnerabilities in Major Database Management Systems

2020 ◽  
Vol 5 (12) ◽  
pp. 76-81
Author(s):  
HyunChul Joh
Keyword(s):  
Database Management ◽  
Database Systems ◽  
Database Management Systems ◽  
Sql Server ◽  
Management Systems ◽  
Security Risks ◽  
Oracle Database ◽  
Software Vulnerabilities ◽  
Security Effectiveness ◽  
Relational Database Management

Popularity and marketshare are very important index for software users and vendors since more popular systems tend to engage better user experience and environments. periodical fluctuations in the popularity and marketshare could be vital factors when we estimate the potential risk analysis in target systems. Meanwhile, software vulnerabilities, in major relational database management systems, are detected every now and then. Today, all most every organizations depend on those database systems for store and retrieve their any kinds of informations for the reasons of security, effectiveness, etc. They have to manage and evaluate the level of risks created by the software vulnerabilities so that they could avoid potential losses before the security defects damage their reputations. Here, we examine the seasonal fluctuations with respect to the view of software security risks in the four major database systems, namely MySQL, MariaDB, Oracle Database and Microsoft SQL Server.

scholarly journals Deriving Triggers from Integrity Constraint Specifications in the Database Management Systems

10.14311/286 ◽  
2001 ◽  
Vol 41 (6) ◽  
Author(s):  
M. Badawy ◽  
K. Richta
Keyword(s):  
Database Management ◽  
Database Systems ◽  
Database System ◽  
Database Management Systems ◽  
Integrity Constraints ◽  
Management Systems ◽  
Integrity Constraint ◽  
Simple Rules

Supporting integrity constraints is essential for database systems. Integrity constraints are used to ensure that the data in a database complies with rules that have been set to establish accurate and acceptable information for a database. Triggers provide a very powerful and flexible means to realize effective constraint enforcing mechanisms. Implementing triggers based on constraint specifications follows some simple rules that are basically independent of a particular commercial database system. This paper gives these rules, which can be used to derive triggers from constraint specifications. A comparison of advantages of constraints and triggers is also given in this paper.

Highly Available Database Management Systems

2011 ◽  
pp. 1733-1737
Author(s):  
Wenbing Zhao
Keyword(s):  
Management System ◽  
Database Management ◽  
Database Management Systems ◽  
High Availability ◽  
Database Management System ◽  
Management Systems ◽  
Web Servers ◽  
Web Based ◽  
Application Servers ◽  
The Web

In the Internet age, real-time Web-based services are becoming more pervasive every day. They span virtually all business and government sectors, and typically have a large number of users. Many such services require continuous operation, 24 hours a day, seven days a week. Any extended disruption in services, including both planned and unplanned downtime, can result in significant financial loss and negative social effects. Consequently, the systems providing these services must be made highly available. A Web-based service is typically powered by a multi-tier system, consisting of Web servers, application servers, and database management systems, running in a server farm environment. The Web servers handle direct Web traffic and pass requests that need further processing to the application servers. The application servers process the requests according to the predefined business logic. The database management systems store and manage all mission-critical data and application states so that the Web servers and application servers can be programmed as stateless servers. (Some application servers may cache information, or keep session state. However, the loss of such state may reduce performance temporarily or may be slightly annoying to the affected user, but not critical.) This design is driven by the demand for high scalability (to support a large number of users) and high availability (to provide services all the time). If the number of users has increased, more Web servers and application servers can be added dynamically. If a Web server or an application server fails, the next request can be routed to another server for processing. Inevitably, this design increases the burden and importance of the database management systems. However, this is not done without good reason. Web applications often need to access and generate a huge amount of data on requests from a large number of users. A database management system can store and manage the data in a well-organized and structured way (often using the relational model). It also provides highly efficient concurrency control on accesses to shared data. While it is relatively straightforward to ensure high availability for Web servers and application servers by simply running multiple copies in the stateless design, it is not so for a database management system, which in general has abundant state. The subject of highly available database systems has been studied for more than two decades, and there exist many alternative solutions (Agrawal, El Abbadi, & Steinke, 1997; Kemme, & Alonso, 2000; Patino-Martinez, Jimenez- Peris, Kemme, & Alonso, 2005). In this article, we provide an overview of two of the most popular database high availability strategies, namely database replication and database clustering. The emphasis is given to those that have been adopted and implemented by major database management systems (Davies & Fisk, 2006; Ault & Tumma, 2003).

Active Federated Database Systems

2005 ◽  
pp. 5-10
Author(s):  
Genoveva Vargas-Solar
Keyword(s):  
Database Management ◽  
Database Systems ◽  
Database Management Systems ◽  
Management Systems ◽  
Two Phase ◽  
Global Database ◽  
Loosely Coupled ◽  
Data Definition ◽  
Federated Database ◽  
Database Operations

Database management systems (DBMS) are becoming part of environments composed of large-scale distributed heterogeneous and networks of autonomous, loosely coupled components. In particular, federated database management systems (FDBMS) can be seen as networks that integrate a number of pre-existing autonomous DBMS which can be homogeneous or heterogeneous. They can use different underlying data models, data definition and manipulation facilities, transaction management, and concurrency control mechanisms. DBMS in the federation can be integrated by a mediator providing a unified view of data: a global schema, a global query language, a global catalogue, and a global transaction manager. The underlying transaction model considers, in general, a set of transactions synchronized by a global transaction. Synchronization is achieved using protocols such as the Two-Phase Commit protocol. FDBMS applications are built upon this global environment, and they interact with the mediator to execute global database operations (i.e., operations that can concern various DBMS in the federation).

Joy Arulraj Speaks Out on Non- Volatile Memory Database Systems

2021 ◽  
Vol 50 (3) ◽  
pp. 29-31
Author(s):  
Marianne Winslett ◽  
Vanessa Braganholo
Keyword(s):  
Database Management ◽  
Database Systems ◽  
Assistant Professor ◽  
Database Management Systems ◽  
Management Systems ◽  
Georgia Tech ◽  
Design And Implementation ◽  
Non Volatile Memory ◽  
Volatile Memory

Welcome to this installment of the ACM SIGMOD Record's series of interviews with distinguished members of the database community. I'm Marianne Winslett, and today I have here with me Joy Arulraj, who won the 2019 ACM SIGMOD Jim Gray Dissertation Award for his thesis entitled The Design and Implementation of Non-volatile Memory Database Management Systems. Joy is now an Assistant Professor at Georgia Tech, and his PhD is from the Carnegie Mellon University, where he worked with Andy Pavlo, who won this same award in his time. So, Joy, welcome!

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