Database Replication Research Articles

BVAGQ-AR for Fragmented Database Replication Management

Large amounts of data have been produced at a rapid rate since the invention of computers. This condition is the key motivation for up-to-date and forthcoming research frontiers. Replication is one of the mechanisms for managing data, since it improves data accessibility and reliability in the distributed database environment. In recent years, the amount of various data grows rapidly with widely available low-cost technology. Although we have been packed with data, we still have lacked of knowledge. Nevertheless, if the impractical data is used in database replication, this will cause waste of data storage and the time taken for a replication process will be delayed. This paper proposes Binary Vote Assignment on Grid Quorum with Association Rule (BVAGQ-AR) algorithm in order to handle fragmented database synchronous replication. BVAGQ-AR algorithm is capable for partitioning the database into disjoint fragments. Fragmentation in distributed database is very useful in terms of usage, reliability and efficiency. Managing fragmented database replication becomes a concern for the administrator because the distributed database is disseminated into split replica partitions. The result from the experiment shows that handling fragmented database synchronous replication through proposed BVAGQ-AR algorithm able to preserve data consistency in distributed environment.

REPLICATION OF COMPARATIVE METHODS FOR SINGLE DATABASE PERFORMANCE IN CENTOS OPERATION SYSTEM WITH MAXSCALE

Processing data in an institution or organization has become an activity or routine for each meeting. In processing data, of course there are various kinds of problems, ranging from missing data, either because of an error in entering data or the result of a system failure. To overcome these problems, in an agency or company must have data backup, so as to create problems that occur in the data, the institution still has data backup. To call, another method of database replication is used. From the test results obtained data on the value of RTA (Round Trip Average) that is the time required for one time sending and receiving data from the replication database is 5426.22 ms and for compilation service diagrams a query attack occurs with a percentage of 29% in the database applications that produce 1774.45 ms results and for service diagrams at a query attack percentage of 29% a single database estimates the server down .

The Replication of Academic Database System using Linux Ubuntu Server Technology

Replication system is a system that is currently widely used, with the advantage of data security that can be guaranteed security. The replication of the Web-Based Student Academic System Database is implemented using VMWare workstation 9.0. By using Ubuntu Server 12.04 which is a server, there are three servers that are built including the master server, slave 1 and slave 2, with the three servers synchronized and replicated automatically in the system, with a system like this it is hoped that the data inside is guaranteed the security and distribution are faster. The system is implemented using a Local Area Network (LAN) using a client, which is accessed from the browser on the client

An improved vertical fragmentation, allocation and replication for enhancing e‐learning in distributed database environment

AbstractE‐learning is the indispensable technique to educate huge number of people and students in short period of time with optimized usage of different kind of required resources. It is employed as a crucial teaching approach by almost all kind of educational institutions all around the world. Since e‐learning involves significant amount of resource utilization and cost, it requires some essential methodology to enhance the current system of e‐learning more efficient. The mere publication of the educational content in websites is not enough. It is very clear that, without applying suitable strategic models and concepts and establishing appropriate communication channels between contributors of e‐learning system, the educational goals cannot be achieved as we desired. Distributed database involves greater contribution in the field of cloud based e‐learning process. Basically, data replication is crucial decision of companies as database distribution can be achieved effectively by the method of database replication which generates the same copies of information called replicas. In this article, we analyze the supremacy of synergetic learning and concentrates on data replication's significance in cloud based learning system. Here we propose an excellent mechanism for data replication and enhancing the performance in terms optimized access and update of data by the determination of exact location of data through dynamic programming. The efficiency of proposed mechanism is clearly illustrated by experimental results.

A Platform for Electronic Health Record Sharing in Environments with Scarce Resource Using Cloud Computing

One of the main objectives of Electronic Health Record (EHR) is the transferability of patient data from one location to another. Many locations with scarce resources, particularly unreliable internet connectivity, face difficulties in accessing and sharing EHR data. This article presents our proposed design that utilizes Amazon Web Services (AWS) for a sharing mechanism platform among distributed healthcare organizations found in an environment with scarce resources. We proposed the use of database replication mechanism and REST (Representational State Transfer) web service to perform information exchange among health organizations and public health information systems.

Asymmetric-partition replication for highly scalable distributed transaction processing in practice

Database replication is widely known and used for high availability or load balancing in many practical database systems. In this paper, we show how a replication engine can be used for three important practical cases that have not previously been studied very well. The three practical use cases include: 1) scaling out OLTP/OLAP-mixed workloads with partitioned replicas, 2) efficiently maintaining a distributed secondary index for a partitioned table, and 3) efficiently implementing an online re-partitioning operation. All three use cases are crucial for enabling a high-performance shared-nothing distributed database system. To support the three use cases more efficiently, we propose the concept of asymmetric-partition replication , so that replicas of a table can be independently partitioned regardless of whether or how its primary copy is partitioned. In addition, we propose the optimistic synchronous commit protocol which avoids the expensive two-phase commit without sacrificing transactional consistency. The proposed asymmetric-partition replication and its optimized commit protocol are incorporated in the production versions of the SAP HANA in-memory database system. Through extensive experiments, we demonstrate the significant benefits that the proposed replication engine brings to the three use cases.

Evaluation of Replication Mechanisms on Selected Database Systems

This paper is focused on comparing database replication over spatial data in PostgreSQL and MySQL. Database replication means solving various problems with overloading a single database server with writing and reading queries. There are many replication mechanisms that are able to handle data differently. Criteria for objective comparisons were set for testing and determining the bottleneck of the replication process. The tests were done over the real national vector spatial datasets, namely, ArcCR500, Data200, Natural Earth and Estimated Pedologic-Ecological Unit. HWMonitor Pro was used to monitor the PostgreSQL database, network and system load. Monyog was used to monitor the MySQL activity (data and SQL queries) in real-time. Both database servers were run on computers with the Microsoft Windows operating system. The results from the provided tests of both replication mechanisms led to a better understanding of these mechanisms and allowed informed decisions for future deployment. Graphs and tables include the statistical data and describe the replication mechanisms in specific situations. PostgreSQL with the Slony extension with asynchronous replication synchronized a batch of changes with a high transfer speed and high server load. MySQL with synchronous replication synchronized every change record with low impact on server performance and network bandwidth.

Database replication method for real-time measurement pH parameter of fishery using a wireless sensor system

The problem of mass fish mortality in Indonesia is already common, Environmental conditions determine the survival of fish. Determination of water environmental conditions has water parameters including water (depth, brightness, water temperature, acidity (pH), dissolved oxygen (DO) and ORP (Oxidation Reduction Potential)). Acidity (pH) is one of the important things in determining the water quality of water. The pH generally increases due to polluted waters. Environmental conditions that are always changing will affect the life processes of organisms in it, especially fish need to be monitored in realtime, especially to avoid massive fish mortality. This paper purpose the real-time acquisition builds with combine the wireless sensor system and database replication concept. From the result of implementation database replication method for real-time measurement pH parameter of fishery agriculture using wireless sensor system, that’s the system can perform continuously to real-time acquisition data online

Cost Saving Replication Technique in Data Grid

Replication is a useful technique for distributed database systems. An existing popular technique that has been used before are Read One-write-All Monitoring Synchronization Transactions System (ROWA-MSTS) and Hierarchical Replication Scheme (HRS). Nevertheless, these techniques have their flaws in terms of replication time taken. Subsequently, ROWA and HRS take more executing time in order to complete a transaction. It is because they have to copy their data to all sites. This research, Binary Voting Fragmented Database Replication (BVFDR) model, the some-data-to-some-sites technique is proposed. In order to handle transactions in the systems, BVFDR considers the neighbouring servers binary vote assignment to its logical grid structure on fragmented data copies. Therefore, it reduces storage capacity. An experiment has been carried out in three replicated servers. The results have been compared with existing techniques such ROWA and HRS. The result shows that BVFDR is able to preserve data consistency and outperformed in terms of time taken for a complete transaction compare to existing techniques. Overall, BVFDR able to handle fragmented data replication as well as capable to manage transaction management in distributed database environment by maintaining consistency of the data through the synchronization approach.

Reliable Loan Information System Using Eager Replication

Replication is the process of sharing information so to ensure consistency between redundant resources, such as software or hardware components. One of the challenges in database replication is to introduce replication without severely affecting performance. Because of this difficulty, current database products use lazy replication, which is very efficient but can compromise consistency. As an alternative, eager replication guarantees consistency but most existing protocols have a prohibitive cost. In the distributed systems community, software-based replication is seen as a cost-effective way to increase availability. Depending on the application, data to be replicated may be stored in a file or a file collection, a database or a database table, or an object stored in a file or in a database. This system is applied eager replication method for loan databases in loan organizations. This system can support reliable replicated data for the loan system between replicated databases.

OLAP parallel query processing in clouds with C‐ParGRES

SummaryThe advent of big data technologies has changed the way many companies manage their data. Several companies moved their data to the cloud using the concept of database‐as‐a‐service (DBaaS). Moving databases to the cloud presents several challenges related to flexible and scalable management of data. Although some of these companies migrated to NoSQL databases, most still rely on relational databases in the cloud to manage data, especially data that is critical to the decision making process. Online analytical processing (OLAP) queries take a long time to be processed, thus demanding high‐performance capabilities from their associated database systems to get results in a feasible time. In this article, we propose a middleware solution that can be deployed in any cloud provider, named C‐ParGRES, which explores database replication and interquery and intraquery parallelism to efficiently support OLAP queries in the cloud. C‐ParGRES is an extension of ParGRES, an open‐source database cluster middleware for high‐performance OLAP query processing in clusters. C‐ParGRES exploits cloud capabilities such as on‐demand resource provisioning and elasticity. In addition, C‐ParGRES can create multiple and independent virtual clusters for different database and users. We evaluate C‐ParGRES with two real‐world OLAP applications, both from the Brazilian Institute of Geography and Statistics. Results show that C‐ParGRES is a cost‐effective solution for OLAP query processing in the cloud.

Identifying potential targets for prevention and treatment of amyotrophic lateral sclerosis based on a screen of medicare prescription drugs

Background: Few well-established factors are associated with risk of amyotrophic lateral sclerosis (ALS). We comprehensively evaluate prescription drugs use in administrative health claims from U.S. Medicare beneficiaries in relation to ALS risk to generate hypotheses for further research. Methods: This is a population-based case–control study of 10,450 U.S. Medicare participants (ages 66–89 years) diagnosed with ALS, based on Medicare Parts A and B fee-for-service claims, between 1 January 2008, and 31 December 2014, and 104,500 controls (1:10 ratio) frequency-matched on age, sex, and selection year. Odds ratios (ORs) for the ALS association with 685 prescription drugs were estimated using logistic regression models for both a one- and three-year lag period. Covariates included demographic characteristics and key comorbidities, among other factors. Prescription drug use was based on Medicare Part D claims. We adjusted for multiple comparisons using a Bonferroni correction. Additional a priori analyses of sex hormone drugs were also undertaken. Results: In the large drug screen, we found 10 drugs significantly associated with lower ALS risk after the multiple-testing correction in a one-year and three-year lag analysis. These included several drugs for hypertension, diabetes, and cardiovascular disease. In a separate a priori inquiry of sex hormone drugs, tamoxifen was related to lower ALS risk, and testosterone to a higher risk in women. Conclusions: These associations warrant replication in databases that include information on the severity and duration of medical conditions underlying drug use, and drug use over a longer portion of individuals’ lifespans, to further help evaluate confounding by indication.

Consistency in Cloud-based database systems

Cloud computing covers the large spectrum of services available on the internet. Cloud services use replication to ensure high availability. Within database replication; various copies of the same data item are stored in different sites, this situation requires managing the consistency of the multiple copies. In fact, the requirement for consistency level can be different following to application natures and other metrics; a delay of some minutes in visualizing latest posts in social networks can be tolerated, while some seconds can make a loss of a bid in an auction system. Wide variety of database management systems are used actually by cloud services. They support different level of consistency to meet the diverse needs of consistency levels. This paper draws a presentation of the main characteristics of cloud computing and data management systems and describes different consistency models. Then it discusses the most famous cloud-based database management systems from the point of view of their data and consistency models.

Advanced Pre-fetching Based Dynamic Data Replication under Small World Network Model

The database replication keeps up contents of database such as tables, in various geographical locations that fabricate an arrangement of distributed database. The necessities of database replication are expanding with the time as the use of internet is also increasing. With the purpose of meeting these prerequisites, priorities among requests can be included. In this work two types of priorities i.e., low and high priority is considered in this research article. It is noticeable that the high priority requests are more vital in comparison to low priority requests and therefore low priority requests can be delayed or dropped. The rate of request loss can be lessened utilizing the conditions of load balancing where a portion of the contending requests are transferred to other nodes. In this paper, internet is modelled as small world network, and performance assessment of A-PDDRA (Advanced Pre-bringing Based Dynamic Data Replication Algorithm) is carried out on small world network while considering both priorities and load balancing using computer simulation.

A Case Study of Snapshot Replication and Transfer of Data in Distributed Databases

The database replication refers to distributing a database among multiple locations. There are three kinds of database replication system: snapshot, transactional and merge. The snapshot replication refers to the fragment of database items and distributing them to multi databases at once. An important goal in this paper is to experiment with a distributed database study the snapshot replication and examine the issues associated with it. In this work, the data from another database is used to increase availability and flexibility as well as provide the information exchange between databases. In this process, the data is infrequently updated at specified periods by copying and changing the data from the original database towards the subscriber database. The work of agents in this technology will do the most of the work to achieve the stated goal. The experimental results show that at both vertical and horizontal fragmentation, the proposed approach of replicating distributed database is efficient and the performance is significantly improved in terms of data transfer time, load sharing and update of database fragmentation. Hence the snapshot replication system is much schedulable and protective replication in business markets.

PERANCANGAN DAN IMPLEMENTASI SISTEM REPLIKASI DATABASE TERDISTRIBUSI PADA FAKULTAS TEKNIK UNIVERSITAS HALU OLEO

Current technological developments are very influential on the process of data distribution that is demanded fast because every second of information can change. One of the methods used in data exchange is to use data replication in a distributed database. The speed of the process and the number of rows that can be replicated in units of time are some of the things that can be taken into consideration when trying to determine how to replicate data in a distributed database. In replication, a software is used to find or more precisely track changes that occur in a database. After changes in one database are identified and known, then changes are made so that all databases are the same as other databases. This study implements two computers consisting of master and slave, each of which is a database server that is connected to each other in the network. The test results obtained in this study are that with the database replication, every data that is stored periodically always backups the slave computer. Keywords — Replication, Database, Distributed Database DOI : 10.5281/zenodo.1493829

Managing Database Replication Using Binary Vote Assignment on Grid Quorum with Association Rule

Nowadays, many organizations deploy the database application systems in order to manage their business operation. Administrations is required to deliver up to date data to users who live distantly, thus replicated databases can be one solution to increase the business operations performance in the distributed environment. Even though data availability is increased, common existing replication strategies neglect the correlation among the different data files in a Distributed Database Systems. In this paper, Binary Vote Assignment on Grid Quorum with Association Rules (BVAGQ-AR) has been proposed to manage the database replication. This technique combines data replication and data mining approaches in order to decrease the job processing time. The result shows that BVAGQ-AR has the lowest job processing time compared to other techniques. BVAGQ-AR performs 66.548 ms to complete a transaction compared to BRS with 137.157 ms, HRS with 257.928 ms, and ROWA with 262.243 ms. From the results, it is proved that managing replication and transaction through the proposed BVAGQ-AR able to preserve data consistency with low job processing time.

Performance Evaluation of Novel Dynamic Data Replication Algorithm under Optical Burst Switching

Abstract The database replication mechanism ensures the duplication of data from one geographical location to another. In recent past, PDDRA (pre-fetching-based dynamic data replication algorithm) is investigated heavily under various classes of request arrivals. The request arriving at a particular server for replication depends on many factors such as bandwidth supported by link, its geographical location and routing algorithms. The number of served requests depends on the processing speed and buffering capacity of a particular server. If a request cannot be served at the server, it is dropped. If a bunch of requests arrive at a server, then traffic modelled as bursty traffic. The objective of this paper is to investigate the performance of dynamic replication algorithm under bursty request arrival. In a similar context, a mathematical model is detailed for the estimation of request burst length, such that both buffering capacity and transmission delay can be kept minimal. Finally, simulation results are present to evaluate the fraction of successful request under diverse conditions.

Analisis Kesiapan Kebutuhan Infrastruktur Replikasi Basis Data pada Sekolah Musik Indonesia Solo

Sekolah Musik Indonesia (SMI) Solo is the center of SMI which has internal data using web-based application at appssmi.com site with SQL Server database and has not been backed up regularly. Database replication is a technique for copying and distributing data and database objects from one database to another and implementing synchronization so data consistency can be guaranteed. Replication can be implemented to the cloud by requiring Internet access. The main concern in SMI Solo was the quality access of the Internet connection and also infrastructure used in SMI Solo. The purpose of this research is to analyze the readiness of data replication infrastructure needs at SMI Solo. The results of the analysis are then used as the basis for making recommendations and design of information technology architecture in the implementation of SMI database replication. We concluded that the infrastructure owned by SMI Solo is sufficient to be used for database replication. This is demonstrated by the very satisfactory performance of the SMI Solo server network with 3.85 Mbps download throughput, 3.49 Mbps upload throughput, 0% packet loss, 25.88 ms delay, and 0.09 ms jitter. On database replication performance thorough test scenarios, average performance on snapshot replication is using for CPU 4.78%, DTU 5.94%, I/O 0.06% and log data I/O 5.25%. The average performance on transactional replication is CPU 0.09%, DTU 0.09%, data I/O 0%, and log I/O 0.04%. Some of the challenges in developing database replication infrastructure to be implemented in all SMI’s can run efficiently if each SMI has a local server and Internet network albeit with unstable throughput.
 Index Terms—Network Performance, Replication, Snapshot, Transactional

LABAREDA: A Predictive and Elastic Load Balancing Service for Cloud-Replicated Databases

Cloud computing emerges as an alternative to promote quality of service for data-driven applications. Database management systems must be available to support the deployment of cloud applications resorting to databases.Many solutions use database replication as a strategy to increase availability and decentralize the workload of database transactions among replicas. Due to the distribution of database transactions among replicas, load balancing techniques improve the computational resources utilization. However, several solutions use the current state of the database service to make decisions for the distribution of transactions. This article proposes a predictive and elastic load balancing service for replicated cloud databases. Experiments carried out showed that the use of prediction models can help to predict possible SLA violations in time series that represent workloads of cloud-replicated databases.