Identifying New Directions in Database Performance Tuning

Database performance tuning is a complex and varied active research topic. With enterprise relational database management systems still reliant on the same set-based relational concepts that defined early data management products, the disparity between the object-oriented application development model and the object-relational database model, called the object-relational impedance mismatch problem, is addressed by techniques such as object-relational mapping (ORM). However, this has resulted in generally poor query performance for SQL developed by object applications and an irregular fit with cost-based optimisation algorithms, and leads to questions about the need for the relational model to better adapt to ORM-generated queries. This paper discusses database performance optimisation developments and seeks to demonstrate that current database performance tuning approaches need re-examination. Proposals for further work include exploring concepts such as dynamic schema redefinition; query analysis and optimisation modelling driven by machine learning; and augmentation or replacement of the cost-based optimiser model

The relational model is dead, SQL is dead, and I don't feel so good myself

We report the opinions expressed by well-known database researchers on the future of the relational model and SQL during a panel at the International Workshop on Non-Conventional Data Access (NoCoDa 2012), held in Florence, Italy in October 2012 in conjunction with the 31st International Conference on Conceptual Modeling. The panelists include: Paolo Atzeni (Università Roma Tre, Italy), Umeshwar Dayal (HP Labs, USA), Christian S. Jensen (Aarhus University, Denmark), and Sudha Ram (University of Arizona, USA). Quotations from movies are used as a playful though effective way to convey the dramatic changes that database technology and research are currently undergoing

Development of a methodological approach for hybrid SQL/NOSQL database design and usage

Ова дисертација је настала из потребе теоретског, развојног и практичног решавања проблема пројектовања и коришћења хибридне SQL/NoSQL базе података. Различити типови база података, како је описано у наставку, садрже специфичности које је потребно узети у обзир приликом развоја методолошког приступа за реализацију процеса пројектовања и коришћења. Дисертација је написана као резултат спровођења процеса научног истраживања, прегледа области истраживања, анализе постојећих решења и приступа, развоја нових приступа пројектовања и коришћења (са свим њиховим саставним деловима), примене новоразвијених приступа на примере из праксе, тестирања изабраних аспеката перформанси (по одређеним критеријумима) и компаративне анализе постигнутих резултата хибридне базе података пројектоване применом новог приступа и „традиционално“ пројектоване базе података. Циљ ове докторске дисертације је био развој новог приступа за пројектовање хибридне SQL/NoSQL базе података и интеграцију и униформно коришћење њених компоненти (SQL и NoSQL база података). У докторској дисертацији су анализирани погодни критеријуми за доношење одлуке о оправданости преласка са постојеће SQL базе података на хибридну базу података. Укључивање аспеката пројектовања нових и редизајна постојећих база података у новоразвијени приступ, проширио је опсег његове могуће примене. За потребе приступа развијена је и нова архитектура, која је омогућила да се над целокупном хибридном базом података (и свим базама података које чине њене саставне компоненте) управља мета подацима, правилима интегритета, правилима мапирања и извршавањем наредби као над јединственом логичком базом податка.This dissertation has originated out of the need for theoretical, developmental and practical solving of the issue of the design and integral and uniform usage of hybrid SQL/NoSQL databases. As described in the course of this dissertation, various types of databases contain specificities that have to be taken into account when developing a methodological approach for the realization of aforementioned processes of database design and usage. The dissertation is written based on many activities. It was driven by conducting scientific research, review of research areas, analysis of existing solutions and approaches. Besides that, dissertation included development of new approach for design and usage (with all their integral parts), application of newly developed approach to examples from practice, testing of chosen aspects of performances (based on certain criteria) and comparative analysis of achieved results of hybrid database developed by applying a new approach and ‘traditionally’ designed database. The aim of this doctoral dissertation was the development of a new approach for the design of hybrid SQL/NoSQL database and integration and uniform usage of its components (SQL and NoSQL databases). A criterion for making a decision on the justification of transition from existing SQL database to hybrid database has been defined in this dissertation. Including aspect of new database design, as well as including aspect of existing database redesign expanded the scope of newly developed approach. For the approach needs, a new architecture has also been developed, which enabled managing metadata, integrity rules, mapping rules and statement execution over the entire hybrid database (including all its component databases) as over a unique logical database

An evaluation of the performance of a NoSQL document database in a simulation of a large scale Electronic Health Record (EHR) system

Electronic Healthcare Record (EHR) systems can provide significant benefits by improving the effectiveness of healthcare systems. Research and industry projects focusing on storing healthcare information in NoSQL databases has been triggered by practical experience demonstrating that a relational database approach to managing healthcare records has become a bottleneck. Previous studies show that NoSQL databases based on consistency, availability and partition tolerance (CAP) theorem have significant advantages over relational databases such as easy and automatic scaling, better performance and high availability. However, there is limited empirical research that has evaluated the suitability of NoSQL databases for managing EHRs. This research addressed this identified research problem and gap in the literature by investigating the following general research: How can a simulation of a large EHR system be developed so that the performance of NoSQL document databases comparative to relational databases can be evaluated? Using a Design Science approach informed by a pragmatic worldview, a number of IT artefacts were developed to enable an evaluation of performance of a NoSQL document oriented database comparative to a relational database in a simulation of a large scale EHR system. These were healthcare data models (NoSQL document database, relational database) for the Australian Healthcare context, a random healthcare data generator and a prototype EHR system. The performance of a NoSQL document database (Couchbase) was evaluated comparative to a relational database (MySQL) in terms database operations (insert, update, delete of EHRs), scalability, EHR sharing and data analysis (complex querying) capabilities in a simulation of a large scale EHR system, constructed in the cloud environment of Amazon Web Services (AWS). Test scenarios consisted of a number of different configurations ranging from 1, 2, 4, 8 and 16 nodes for 1Million, 10 Million, 100 Million and 500 Million records to simulate database operations in a large scale and distributed EHR system environment. The Couchbase NoSQL document database was found to perform significantly better than the MySQL relational database in most of the test cases in terms of database operations -insert, update, delete of EHRs, scalability and EHR sharing. However, the MySQL relational database was found to perform significantly better than the Couchbase NoSQL document database for the complex query test that demonstrates basic analysis capabilities. Furthermore, the Couchbase NoSQL document database used significantly more disk space than the MySQL relational database to store the same number of EHRs. This research made a number of important contributions to knowledge, theory and practice. The main theoretical contribution to design theory was the design and evaluation of a prototype EHR system for simulating database management operations in a large scale EHR system environment. The prototype EHR system was underpinned by the development of two data models with data structures designed for a NoSQL document database and a relational database and a random healthcare data generator which were based on Australian Healthcare data characteristics and statistics. The design of a data model for EHRs for a NoSQL document database using an aggregated document modelling approach provided an important contribution to data modelling theory for NoSQL document databases using de-normalisation and document aggregation. The design of a random healthcare data generator was another important contribution to design theory and was based on a data distribution algorithm (multinomial distribution and probability theory) informed by National Health Data Dictionary and published Australian Healthcare statistics. The prototype EHR system allowed this study to demonstrate through a simulated performance evaluation that a NoSQL document database has significant and proven performance advantages over relational databases in most of the database management test cases. Hence this study demonstrated the utility and efficacy of a NoSQL document database in the simulation of a large scale EHR system. This research has made a number of important contributions to practice. Foremost is that the IT artefacts (namely, a data model for storing EHRs in a NoSQL document database, a random healthcare data generator and a prototype EHR system) developed and evaluated in this research can be readily adopted by practitioners. Another important practical contribution of this research is that it is based on the open source availability of NoSQL database and relational database alternatives. Hence, this research can provide a sound basis for lower-income countries as well higher-income countries to establish their own cost-effective national EHR systems without the restrictions, limitations, complexity or complications of similar proprietary relational database systems