Wyniki wyszukiwania - BazTech

1

Thespis: Causally-consistent OLTP

Camilleri Carl, Vella Joseph G., Nezval Vitezslav

Annals of Computer Science and Information Systems

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2021

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Vol. 25

261--269

EN

Data Consistency defines the validity of a data set according to some set of rules, and different levels of data consistency have been proposed. Causal consistency is the strongest type of consistency possible when data is stored in multiple locations, and fault tolerance is desired. Thespis is a middleware that leverages the Actor model to implement causal consistency over a DBMS, whilst abstracting complexities for application developers behind a REST interface. ThespisTRX is an extension that provides read-only transaction capabilities, whilst ThespisDIIP is another extension that handles distributed integrity invariant preservation. Here, we analyse standard transactional workloads on the relational data model, which is richer than the key-value data model supported by the Thespis interface. We show the applicability of the Thespis approach for this data model by designing new operations for the Thespis interface, which ensure correct execution of such workloads in a convergent, causally consistent distributed environment.

2

Fed-agent – a Transparent ACID-Enabled Transactional Layer for Multidatabase Microservice Architectures

Nikolić Lazar, Dimitrieski Vladimir

Annals of Computer Science and Information Systems

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2021

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Vol. 25

489--492

EN

With the recent expansion of specialized databases and departure from the "one size fits all" paradigm, engineers might decide to use multiple databases. Each database holds a representation of a data object but offers transactions and consistency guarantees only locally. Existing solutions either require additional coding or do not provide global ACID transactions. In this paper, we present fed-agent, a transactional layer that provides global consistency and ACID transactions for single data objects within multidatabase systems. It requires no additional coding besides configuration files. We show that fed-agent scales linearly and introduces an overhead small enough for most microservice solutions.

3

Elimination of task starvation in conflictless scheduling concept

Smoliński M.

Information Systems in Management

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2016

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Vol. 5, No. 2

237--247

EN

New concept of conflictless task scheduling is an alternative approach to existing solutions in concurrency. Conflictless task scheduling includes data structures and algorithm that prevents occurrence of resource conflict between tasks executed in parallel. The range of applications the conflictless task scheduling includes different environments like transactions processing in database management systems, scheduling of processes or threads in operating systems or business processes management. Task scheduling without any resource conflicts is dedicated to high contention of limited resources environments and its algorithm can be implemented in modern GPU. This paper presents concept of local task scheduling without resources conflicts occurrence, discusses features of new approach and focuses on problem of task starvation. Elimination of task starvation is included in conflictless task scheduling concept, detailed explanation are contained in this paper.

4

Zachowanie spójności danych w wybranych systemach NoSQL

Augustyn D., Bajerski P., Brzeski R..

Studia Informatica

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2012

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Vol. 33, nr 2A

27-48

PL

Zachowanie spójności przetwarzanych danych jest problemem ogólnym, w szczególności dotyczącym systemów NoSQL, w których efektywność przetwarzania jest czynnikiem najistotniejszym. Wysoką efektywność przetwarzania w bazach NoSQL osiąga się przez uproszczenie mechanizmów wewnętrznych, w tym, częściowo, kosztem utrudnienia programowania – aplikacje korzystające z baz NoSQL muszą zawierać kod odpowiedzialny za utrzymanie spójności danych. Programowe metody zachowania spójności przetwarzanych danych rozważono w kontekście wybranych systemów NoSQL: MongoDB, Mircosoft Windows Azure, Apache Cassandra, Oracle NoSQL.

EN

Consistency preservation is a general problem in data processing, especially in NoSQL systems. NoSQL databases introduce a new approach, in which the efficiency is a major feature. It is partially achieved at the expense of some difficulties of programming. The application should handle situations which may introduce inconsistency in data. The paper presents the methods of data consistency preservation in selected NoSQL: MongoDB, Mircosoft Windows Azure, Apache Cassandra, Oracle NoSQL.

5

Systolic computation for conflict elimination between parallel executed distributed transactions

Smoliński M.

Metody Informatyki Stosowanej

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2011

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nr 4

223-229

EN

Serializable history defines execution order for every distributed transaction requested by enterprise information systems, that share many data source i.e. databases. However parallel execution of distributed transactions could cause a conflict. Many conflicts could have a negative effect as a deadlock between executed transactions and stop further processing in associated enterprise informational systems. Prepared rigorous history eliminates conflicts between distributed transactions. All required computations are processed ahead by dedicated hardware unit, a systolic array. Designed systolic algorithm base on simple condition enabling transaction conflict detection. Main features of systolic array are parallel and streaming processing. Designed systolic algorithm that supports transaction conflict detection is also flexible in usage for various distributed environment.