Rephrasing rules for off-the-shelf SQL database servers

We have reported previously (Gashi et al., 2004) results of a study with a sample of bug reports from four off-the-shelf SQL servers. We checked whether these bugs caused failures in more than one server. We found that very few bugs caused failures in two servers and none caused failures in more than two. This would suggest a fault-tolerant server built with diverse off-the-shelf servers would be a prudent choice for improving failure detection. To study other aspects of fault tolerance, namely failure diagnosis and state recovery, we have studied the "data diversity" mechanism and we defined a number of SQL rephrasing rules. These rules transform a client sent statement to an additional logically equivalent statement, leading to more results being returned to an adjudicator. These rules therefore help to increase the probability of a correct response being returned to a client and maintain a correct state in the database

ПОРІВНЯЛЬНИЙ АНАЛІЗ МЕТОДІВ ВІДНОВЛЕННЯ ПРОПУЩЕНИХ ДАНИХ ЧАСУ ДОСТУПНОСТІ СЕРВЕРА В ІНФОРМАЦІЙНО- EКОНОМІЧНИХ ПРОСТОРАХ

In the article presents results of research of primary statistical characteristics of time of processing and data transmission are given in systems of information economic area. On the basis of the received results the analysis of methods of recovery of the passed data is made. In work methods of data processing with admissions are analyzed and the most rational are chosen. Change of the law of distribution of selection depending on a way of elimination of the passed data is investigated. Forecasting of time of availability of the server of information economic area is executed. The goal of this paper is primary statistical characteristics research of data processing and transmission time in IES. Particularly, the server availability time (SAT) was studied within this work. This time consists of Client-to-Server connection time, Server data processing time, and Server answer transfer time. The values of service time were taken for research, that were received while studying of cloud computing performance. It was established that if data loss is not over 6% distribution law of initial model selection saves. If data loss is between 9% and 15% methods primary statistical characteristics of studied selection were determined without consideration of data missing. Missed data was filled with data distributed by the same law as for initial selection with admissions.В статье приведены результаты исследования первичных статистических характеристик времени обработки и передачи данных в информационно-экономических пространствах. На основании полученных результатов выполнен  анализ методов восстановления пропущенных данных. В работе проанализированы приемы обработки данных с пропускам и выбраны наиболее рациональные. Исследовано изменение  закона распределения выборки в зависимости от способа устранения пропущенных данных. Выполнено прогнозирование времени доступности сервера в информационно-экономических пространствах. Цель работы состояла в исследование первичных статистических характеристик времени обработки и передачи данных в информационно-экономических пространствах.  В частности, в рамках данной работы изучалось время доступности сервера.У статті наведено  результати дослідження первинних статистичних характеристик часу обробки і передачі даних в інформаційно-економічних просторах. На підставі отриманих результатів виконано  аналіз методів відновлення пропущених даних. Проаналізовано прийоми обробки даних з пропускам та  обрано найбільш раціональні. Досліджена зміна  закону розподілу вибірки залежно від способу усунення пропущених  даних.  Виконано прогнозування часу доступності сервера економічних просторів. Мета роботи полягала у дослідження первинних статистичних характеристик часу обробки і передачі даних в інформаційно-економічних просторах. Зокрема, в рамках даної роботи вивчалося час доступності сервера

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