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On-the-Fly, Incremental, Consistent Reading of Entire Databases

ALGORITHMICA 1986年第1-4期1卷 271-287页

作者： Pu, Calton Univ Washington Dept Comp Sci Seattle WA 98195 USA

We describe an algorithm to read entire databases with locking concurrency control allowing multiple readers or an exclusive writer. The algorithm runs concurrently with the normal transaction processing (on-the-fly), and locks the entities in the database one by one (incremental). We prove that the algorithm produces consistent pictures of the database. We also show that conflicts between the algorithm and some updates, although necessary, can be resolved. Reading entire databases consistently, on-the-fly, incremental algorithms can avoid the database downtime trade-off between frequent checkpoints and crash recovery delay, thus improving system availability and reliability. Our algorithm reads the database once and writes only to sequential output, lowering its implementation and execution costs. A simple extension runs in parallel on several processors and produces consistent pictures of entire distributed databases.

关键词： Checkpoint Locking Non-two-phase query distributed query Available databases

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Quantum associative memory with distributed queries

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INFORMATION SCIENCES 2000年第3-4期128卷 271-293页

作者： Ezhov, AA Nifanova, AV Ventura, D Troitsk Inst Innovat & Fus Res Troitsk 142092 Moscow Region Russia Penn State Univ Grad Fac Comp Sci & Engn University Pk PA 16802 USA

This paper discusses a model of quantum associative memory which generalizes the completing associative memory proposed by Ventura and Martinet. Similar to this model, our system is based on Grover's well-known algorithm for searching an unsorted quantum database. However, the model presented in this paper suggests the use of a distributed query of general form. It is demonstrated that spurious memories form an unavoidable part of the quantum associative memory model;however, the very presence of these spurious states provides the possibility of organizing a controlled process of data retrieval using a specially formed initial state of the quantum database and also of the transformation performed upon it. Concrete examples illustrating the properties of the proposed model are also presented. (C) 2000 Elsevier Science Inc. All rights reserved.

关键词： quantum associative memory distributed query spurious memory

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MSTDB: A Hybrid Storage-Empowered Scalable Semantic Blockchain Database

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IEEE TRANSACTIONS ON KNOWLEDGE AND DATA ENGINEERING 2023年第8期35卷 8228-8244页

作者： Zhou, Enyuan Hong, Zicong Xiao, Yang Zhao, Dongxiao Pei, Qingqi Guo, Song Akerkar, Rajendra Hong Kong Polytech Univ Dept Comp Hung Hom Hong Kong Peoples R China Xidian Univ Sch Cyber Engn State Key Lab ISN Xian 710071 Shaanxi Peoples R China Xidian Univ State Key Lab ISN Shaanxi Key Lab Blockchain & Secure Comp Xian 710071 Shaanxi Peoples R China Western Norway Res Inst Big Data Res Grp N-6856 Sogndal Norway

Blockchain has been regarded as a trusted carrier for distributed data storage. With large volumes of valuable data stored on blockchain, data query has become a major requirement. However, the existing blockchains do not provide efficient query functionality because of their deep-rooted chain structure. Blockchain database is a new direction that constructs index on top of blockchain to provide rich query functionalities. The existing works are either insecure because the query process separates from the blockchain consensus, or inscalable because all the data needs to be stored in the block. In this paper, we propose a novel semantic blockchain database called MSTDB. We design a hybrid on/off chain blockchain storage architecture in which the majority of blockchain storage is offloaded to the off-chain storage and a novel index structure named Merkle Semantic Trie (MST) is designed to be a secure and semantic bridge between on- and off-chain. Based on MST, MSTDB provides a variety of semantic query functions including multi-keyword query, range query, Top-K query, and cross-chain query. To improve the performance further, we design some index compression and query preprocessing techniques for MSTDB. Extensive experiments demonstrate the effectiveness and efficiency of our blockchain database.

关键词： Blockchain database data sharing distributed query index

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Join queries optimization in the distributed databases using a hybrid multi-objective algorithm

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CLUSTER COMPUTING-THE JOURNAL OF NETWORKS SOFTWARE TOOLS AND APPLICATIONS 2022年第3期25卷 2021-2036页

作者： Azhir, Elham Navimipour, Nima Jafari Hosseinzadeh, Mehdi Sharifi, Arash Unal, Mehmet Darwesh, Aso Islamic Azad Univ Dept Comp Engn Sci & Res Branch Tehran Iran Natl Yunlin Univ Sci & Technol Future Technol Res Ctr 123 Univ RdSect 3 Touliu 64002 Yunlin Taiwan Gachon Univ Pattern Recognit & Machine Learning Lab 1342 Seongnamdaero Seongnam 13120 South Korea Islamic Azad Univ Dept Comp Engn Sci & Res Branch Tehran Iran Nisantasi Univ Dept Comp Engn TR-34485 Istanbul Turkey Univ Human Dev Dept Informat Technol Sulaymaniyah Iraq

In the distributed database systems, the relations needed by a query can be kept in several locations. This process significantly increases potential corresponding query Execution Plans (QEP's) for a user query. Henceforth, in addition to the expense of local computing, the charge of transferring data between different cloud sites should also be considered. It does not sound logical to investigate all potential query plans in a high setting like this. The best query plan (regarding cost) must be generated for processing a given query. A new hybrid multi-objective genetic and bat algorithm, a Multi-Objective Genetic Algorithm with BAT (MOGABAT), is used in the present article to produce the best query plans. The functionality comparison is made on different join graph structures, among MOGABAT, Multi-Objective BAT (MOBAT), and Non-dominated Sorting Genetic Algorithm II (NSGA-II). The obtained results have shown that the quality of generated query plans is enhanced for the join graph structures. Nevertheless, more execution time is needed.

关键词： distributed query Multi-Objective Optimization MOBAT Genetic Algorithm

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Implementing a MIRC query interface for a database driven teaching file

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JOURNAL OF DIGITAL IMAGING 2003年第2期16卷 180-184页

作者： Tellis, WM Andriole, KP Univ Calif San Francisco Lab Radiol Informat San Francisco CA 94143 USA

This paper describes the authors' experience with integrating an existing database-driven teaching file with the RSNA (Radiological Society of North America) Medical Imaging Resource Center [MIRC). MIRC is the product of an RSNA-sponsored initiative to enable medical institutions to share their electronic medical content (images, text, and multimedia) by creating a distributed repository accessible from the Internet. An existing database-driven teaching file, developed by the authors and used extensively by the University of California San Francisco (UCSF) Department of Radiology since 1998, was retrofitted to include an interface for handling broadcast queries initiated by a MIRC query service. These queries take place through the exchange of XML documents via HTTP. After all the storage services have responded, the results are collated by the query service and presented to the user. The teaching file and MIRC interface were developed using the 4th Dimension Relational Database Management System (RDBMS). The integration process primarily involved mapping the "MIRCdocument" schema to the teaching file's schema, translating the actual MIRC query into the internal query language of the database and extending the access control mechanisms of the teaching file to allow public access. A working implementation of the interface required only 3 days of development time, with refinements taking place over several months. Interface development was greatly aided by MIRC's use of well-established Internet standards. This project has demonstrated the feasibility of implementing a MIRC interface on an existing teaching file server.

关键词： MIRC teaching files XML distributed query 4th dimension RDBMS Web-based

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GDPS: An Efficient Approach for Skyline Queries over distributed Uncertain Data

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BIG DATA RESEARCH 2014年 1卷 23-36页

作者： Li, Xiaoyong Wang, Yijie Li, Xiaoling Wang, Xiaowei yu, Jie Natl Univ Def Technol Coll Comp Sci Natl Key Lab Parallel & Distributed Proc Changsha 410073 Hunan Peoples R China

The skyline query as an important aspect of big data management, has received considerable attention from the database community, due to its importance in many applications including multi-criteria decision making, preference answering, and so forth. Moreover, the uncertain data from many applications have become increasing distributed, which makes the central assembly of data at one location for storage and query infeasible and inefficient. The lack of global knowledge and the computational complexity derived from the introduction of the data uncertainty make the skyline query over distributed uncertain data extremely challenging. Although many efforts have addressed the skyline query problem over various distributed scenarios, existing studies still lack the approaches to efficiently process the query. In this paper, we extensively study the distributed probabilistic skyline query problem and propose an efficient approach GDPS to address the problem with an optimized iterative feedback mechanism based on the grid summary. Furthermore, many strategies for further optimizing the query are also proposed, including the optimization strategies for the local pruning, tuple selecting and the server pruning. Extensive experiments on real and synthetic data sets have been conducted to verify the effectiveness and efficiency of our approach by comparing with the state-of-the-art approaches. (C) 2014 Elsevier Inc. All rights reserved.

关键词： Uncertain data Probabilistic skyline distributed query Grid summary

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A peer-to-peer architecture for secure data storage with query

A peer-to-peer architecture for secure data storage with que...

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Conference on Defense Transformation and Network-Centric Systems

作者： Marceau, C Hanna, J McCullough, D Popli, A Stillerman, M Architecture Technol Corp Ithaca NY 14850 USA

ISBN: (纸本)0819458058

Net-centric information systems such as the Air Force's Joint Battlespace Infosphere (JBI) require a secure, scalable, object repository to support the vision of a globally accessible, secure, distributed information "space." Peer-to-peer (P2P) technology holds significant promise for these large-scale information repositories because of its demonstrated scalability and robustness. The development of a P2P object repository poses significant challenges: distributed query processing and security. This paper presents and discusses ORIS, a peer-to-peer object repository that not only stores objects but also supports database-type queries. The ORIS P2P technology ensures resilience and scalability and also employs secret sharing techniques and access control to ensure the confidentiality, integrity, and availability of objects even if a number of peers are physically or clandestinely compromised by an enemy attack. The Air Force Research Laboratory has developed the distributed Information Enterprise Modeling and Simulation (DIEMS) framework that efficiently supports the modeling and simulation of large globally distributed computer networks. DIEMS has been used to model prototypes of the JBI and is currently being used to assess the system performance, scalability, and survivability of ORIS. Preliminary results indicate query performance to be acceptable given an adequate network 14 configuration. We also present the results of this modeling and simulation assessment.

关键词： JBI P2P modeling & simulation network security distributed database distributed query

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Research on Mobile-Agent Based Data Access Model in Pervasive Computing Environment

Research on Mobile-Agent Based Data Access Model in Pervasiv...

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3rd IEEE Asia-Pacific Service Computing Conference (APSCC 2008)

作者： Li Fan Jiang WeiJian Wuhan Univ Sci & Engn Wuhan 430073 Hubei Peoples R China Jiangxi Blue Sky Univ Nanchang 330029 Jiangxi Peoples R China

ISBN: (纸本)9781424440993

This paper discusses the deficiency of data access technology based on C/S in pervasive computing environment. A data access model of distributed information system based on Mobile Agent is introduced, which has the features of heterogeneity data source integration,extensibility,loose coupling and high availability. To solve agent migration expiration, an agent dock system is designed. The performance evaluation shows that the system can reduce network overhead and network transmission time delay.

关键词： distributed query Mobile Agent Pervasive Computing

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The Design of Distribution query Processor Based on Specified Model

The Design of Distribution Query Processor Based on Specifie...

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3rd IEEE International Conference on Computer Science and Information Technology (ICCSIT)

作者： Zhang, Jun Capital Univ Econ & Business Sch Informat Beijing Peoples R China

ISBN: (纸本)9781424455379

In this paper, we discuss a general integrated query problem for the heterogeneous data. We first assume that there exist a global and loosely coupled distribution data model, and then based on this assumption a general integrated query processor is designed, which can integrate query processing for the heterogeneous data sources in large-scale distributed environment.

关键词： distributed query p2p network data grid

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querying distributed Sensor Streams in the Edge-to-Cloud Continuum 6

Querying Distributed Sensor Streams in the Edge-to-Cloud Con...

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6th IEEE International Conference on Edge Computing and Communications (IEEE EDGE)

作者： Karlstetter, Roman Widhopf-Fenk, Robert Schulz, Martin IfTA GmbH Puchheim Germany Tech Univ Munich Garching Germany

ISBN: (数字)9781665481403

ISBN: (纸本)9781665481403

Sensor data is of crucial importance in many IoT scenarios. It is used for online monitoring as well as long term data analytics, enabling countless use cases from damage prevention to predictive maintenance. Multivariate sensor time series data is acquired and initially stored close to the sensor, at the edge. It is also beneficial to summarize this data in windowed aggregations at different resolutions. A subset of the resulting aggregation hierarchy is typically sent to a cloud infrastructure, often via intermittent or low bandwidth connections. Consequently, different views on the data exist on different nodes in the edge-to-cloud continuum. However, when querying this data, users are interested in a fast response and a complete, unified view on the data, regardless of which part in the infrastructure continuum they send the query to and where the data is physically stored. In this paper, we present a loosely coupled approach that enables fast range queries on a distributed and hierarchical sensor database. Our system only assumes the possibility of fast local range queries on a hierarchical sensor database. It does not require any shared state between nodes and thus degrades gracefully in case certain parts of the hierarchy are unreachable. We show that our system is suitable for driving interactive data exploration sessions on terabytes of data while unifying the different views on the data. Thus, our system can improve the data analysis experience in many geo-distributed scenarios.

关键词： edge cloud multivariate sensor data stream distributed query

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