Lock Manager Research Articles

GaussDB: A Cloud-Native Multi-Primary Database with Compute-Memory-Storage Disaggregation

Cloud-native databases have been widely deployed due to high elasticity, high availability and low cost. However, most existing cloud-native databases do not support multiple writers and thus have limitations on write throughput and scalability. To alleviate this limitation, there is a need for multi-primary databases which provide high write throughput and high scalability. In this paper, we present a cloud-native multi-primary database, GaussDB, which adopts a three layer (compute-memory-storage) disaggregation framework, where the compute layer is in charge of transaction processing, the memory layer is responsible for global buffer management and global lock management, and the storage layer is used for page and log persistence. To provide multi-primary capabilities, GaussDB logically partitions the pages to different compute nodes and then assigns the ownership of each page to a compute node. For each transaction posed to a compute node, if the compute node owns all relevant pages of this query, the compute node can process the query locally; otherwise, GaussDB transfers the ownership of relevant pages to this node. To capture data affinity and reduce page transmission costs, GaussDB designs a novel page placement and query routing method. To improve recovery performance, GaussDB employs a two-tier (memory-storage) checkpoint recovery method which uses memory checkpoints combined with on-demand page recovery to significantly improve recovery performance. We have implemented and deployed GaussDB internally at Huawei and with customers, and the results show that GaussDB achieves higher throughput, lower latency, and faster recovery than state-of-the-art baselines.

CLMD: Making Lock Manager Predictable and Concurrent for Deterministic Concurrency Control

CLMD: Making Lock Manager Predictable and Concurrent for Deterministic Concurrency Control

Distributed File System to Leverage Data Locality for Large-File Processing

Over the past decade, significant technological advancements have led to a substantial increase in data proliferation. Both scientific computation and Big Data workloads play a central role, manipulating massive data and challenging conventional high-performance computing architectures. Efficiently processing voluminous files using cost-effective hardware remains a persistent challenge, limiting access to new technologies for individuals and organizations capable of higher investments. In response to this challenge, AwareFS, a novel distributed file system, addresses the efficient reading and updating of large files by consistently exploiting data locality on every copy. Its distributed metadata and lock management facilitate sequential and random I/O patterns with minimal data movement over the network. The evaluation of the AwareFS local-write protocol demonstrated efficiency across various update patterns, resulting in a performance improvement of approximately 13%, while benchmark assessments conducted across diverse cluster sizes and configurations underscored the flexibility and scalability of AwareFS. The innovative distributed mechanisms outlined herein are positioned to contribute to the evolution of emerging technologies related to the computation of data stored in large files.

Smart Lock Technology: Developing and Enhancing Home Security using Android-Based Controlled Door Locking App’s

This study presents an overview of the study on the implementation and potential of a novel Android-based controlled door locking app to advance home security in the context of smart homes. The app leverages the capabilities of android devices to offer remote access and management of door locks, empowering homeowners with seamless control over their access points. The study evaluates the app's performance in usability, accuracy, efficiency, portability, security, and maintainability, revealing its commendable capabilities with an average score of 4.17 out of 5. With minor enhancements, the app shows promising potential as a reliable and user-friendly access control solution, driving the evolution of smart lock technology and home security in the modern era.

Research on smart-locks cybersecurity and vulnerabilities

Smart-locks have become increasingly popular for access to homes and businesses in many countries, because of their ease of use and adaptability. These locks offer a simple and secure alternative to traditional key-based entry, making them an attractive choice for both residential and commercial properties. Nevertheless, it is essential to acknowledge the potential security threats that come with any new technology. The security of smart-locks is particularly critical, as a breach could result in unauthorized entry. Since the smart-locks can connect, there are different ways to check if vulnerabilities can be found easily or on the contrary, if the security level is high. Two of the main ways of checking the security level of this kind of IoT device are the information that can be obtained from the Android application and the security level of the Bluetooth connection. Many vulnerabilities can be found in the Android smart lock management application. This application is very useful to perform all the configurations with such a lock, but if it is not properly implemented and secured, it can provide clues for malicious users to perform unauthorized access to the system. Another security factor is the Bluetooth connection. This ensures that only authorized users have access to the property. In this work, we have analyzed the security level of different parts of smart-locks. In particular, we have analyzed the security of the applications for the most important smart-locks on the market. This study reveals relevant information such as whether the application is obfuscated or not, the encryption algorithm for the Bluetooth connection, or relevant URLs that applications use to connect to the cloud. The security of the Bluetooth connection between the smartphone application and two selected smart-locks was also analyzed. It was demonstrated that if no encryption is used for the Bluetooth connection, the smart-lock is not secure, but if AES encryption is used, the security level is high.

Ship lock management and dynamic congestion toll for ships

Water transportation occupies the most proportion in transportation industry, as it is superior to other transportation modes in terms of economic scale. This paper focuses on a management problem of ship lock, which is quite common when ships pass a channel or a canal with a lock. Poor ship lock management will cause ship congestion and increase the cost of ships. Therefore, this paper formulates the problem as an activity-based bottleneck model, discusses the selection and decision of ship's departure time by taking container ships as examples with the constraints of ship lock service time window. And this paper also proposes a dynamic toll scheme for ships, with the aim at eliminating the waiting and stopping of container ships at lock, which can effectively reduce the social and economic losses. In addition, with the toll scheme, the waiting cost of ships at lock is converted into the congestion fee charged by the government, which is used to serve for locks and ships. Finally, a numerical experiment is used to illustrate the applicability of our proposed model.

Research on the Realization of Travel Recommendations for Different Users Through Deep Learning Under Global Information Management

This article is mainly to study the realization of travel recommendations for different users through deep learning under global information management. The personalized travel route recommendation is realized by establishing personalized travel dynamic interest (PTDR) algorithm and distributed lock manager (DLM) model. It is hoped that this model can provide more complete data information of tourist destinations on the basis of the past, and can also meet the needs of users. The innovation of this article is to compare and analyze with a large number of baseline algorithms, highlighting the superiority of this model in personalized travel recommendation. In addition, the model incorporates the topic factor features, geographic factor features, and user preference features to make the data more in line with user needs and improve the efficiency and applicability of the model. It is hoped that the plan proposed in this article can help users make choices of tourist destinations more conveniently.

A NOVEL MULTI GRANULARITY LOCKING SCHEME BASED ON CONCURRENT MULTI -VERSION HIERARCHICAL STRUCTURE

We present an efficient locking scheme in a hierarchical data structure. The existing multi-granularity locking mechanism works on two extremes: fine-grained locking through which concurrency is being maximized, and coarse grained locking that is being applied to minimize the locking cost. Between the two extremes, there lies several pare to-optimal options that provide a trade-off between the concurrency that can be attained. In this work, we present a locking technique, Collaborative Granular Version Locking (CGVL) which selects an optimal locking combination to serve locking requests in a hierarchical structure. In CGVL a series of version is being maintained at each granular level which allows the simultaneous execution of read and write operation on the data item. Our study reveals that in order to achieve optimal performance the lock manager explore various locking options by converting certain non-supporting locking modes into supporting locking modes thereby improving the existing compatibility matrix of multiple granularity locking protocol. Our claim is being quantitatively validated by using a Java Sun JDK environment, which shows that our CGVL perform better compared to the state-of-the-art existing MGL methods. In particular, CGVL attains 20% reduction in execution time for the locking operation that are being carried out by considering, the following parameters: i) The number of threads ii) The number of locked object iii) The duration of critical section (CPU Cycles) which significantly supports the achievement of enhanced concurrency in terms of the number of concurrent read accesses.

Development and application of an internet of things door lock Network Bridge for classroom access control management

School classroom doors are usually managed using conventional machine locks. This can cause inconvenience for the borrowing and returning of keys. In addition, issues on the copying and embezzlement of keys are persistent. To avoid these problems, schools have replaced conventional locks with card readers and magnetic locks to manage classroom access; users need only a RFID card to enter and exit classrooms. However, the hardware and software equipment required for such control schemes is expensive and entails cumbersome installation processes. This study developed an innovative Internet of Things (IoT) door lock network bridge, which can be installed on conventional electronic locks to transform it into IoT locks. The developed bridge can be integrated with a customized web-based classroom access information system and QR code scanning to establish a low-cost classroom access control system. The system can be provided to schools to perform user management, lock management, and lock matching. Each door in the school is assigned with a unique QR code for unlocking. Users only need to use the QR code scanner on their smart phone to send relevant information required for unlocking a door to the web-based classroom access information system, which then performs user and lock matching verification. Verified users can then unlock the door and enter the venue. The proposed classroom access control system does not require card readers or RFID cards. The cable installation of the system is simplified through by using wireless connections, thereby greatly reducing the time, cost, and human resource required for installation. In addition, users and locks can be matched directly using the proposed system. This greatly improves the convenience of classroom management in schools.

Dependence-Cognizant Locking Improvement for the Main Memory Database Systems

The traditional lock manager (LM) seriously limits the transaction throughput of the main memory database systems (MMDB). In this paper, we introduce dependence-cognizant locking (DCLP), an efficient improvement to the traditional LM, which dramatically reduces the locking space while offering efficiency. With DCLP, one transaction and its direct successors are collocated in its context. Whenever a transaction is committed, it wakes up its direct successors immediately avoiding the expensive operations, such as lock detection and latch contention. We also propose virtual transaction which has better time and space complexity by compressing continuous read-only transactions/operations. We implement DCLP in Calvin and carry out experiments in both multicore and shared-nothing distributed databases. Experiments demonstrate that, in contrast with existing algorithms, DCLP can achieve better performance in many workloads, especially high-contention workloads.

Subaxial Cervical Spine Injuries: WFNS Spine Committee Recommendations.

To formulate specific guidelines for the recommendation of subaxial cervical spine injuries concerning classification, management, posttraumatic locked facets and vertebral artery injury. Computerized literature was searched on PubMed and google scholar database from 2009 to 2020. For classification, keywords “Sub Axial Cervical Spine Classification,” resulting in 22 articles related to subaxial cervical spine injury classification system (SLICS) system and 11 articles related to AO (Arbeitsgemeinschaft für Osteosynthesefragen, German for “Association for the Study of Internal Fixation”) Spine system. The literature search yielded 210 and 78 articles on “management of subaxial cervical spine injuries” and the role of “SLICS” and “AO Spine” respectively. Keywords “management of traumatic facet locks” were searched and closed reduction, traction, approaches and techniques were studied. “Vertebral artery injury and cervical fracture” exhibited 2,328 references from the last 15 years. The objective was to identify the appropriate diagnostic tests and optimal treatment. Up-to-date information was reviewed, and statements were produced to reach a consensus in 2 separate consensus meetings of World Federation of Neurosurgical Societies (WFNS) Spine Committee. The statements were voted and reached a positive or negative consensus using Delphi method. Based on the most relevant literature, panelists in Moscow consensus meeting conducted in May 2019 drafted the statements, and after a preliminary voting session, the consensus was identified on various statements. Another meeting was conducted at Peshawar in November 2019, where in addition to previous statements, few other statements were discussed and voted. Specific recommendations were then formulated guiding classification, management, locked facets and vertebral artery injuries. This review summarizes the WFNS Spine Committee recommendations on subaxial cervical spine injuries.

Ensuring Consistent Transactions in a Web Service Environment With Prediction-Based Performance Metrics

In this paper, we propose transaction scheduling for web service database transactions. Our solution ensures consistency while preserving efficiency. We propose a prediction-based metric that promotes transactions with reliable reputations based on the transactions performance metrics. Performance metrics are based on the transactions likelihood to commit and their execution time. We propose a customized lock management solution to guarantee execution consistency in concurrent web service environments. We formally prove that our solution guarantees consistent execution history of concurrent web transactions and increases concurrency and performance over traditional locking methods. We developed a simulation using a multi-threaded approach. We generated sample workloads of simulated concurrent transactions over seven tests. Our results show that the solution works comparatively with traditional locking and no-locking solutions with the added benefit of ensured consistency in some cases and deadlock avoidance in others.

Effectiveness of Stretching Exercises in TMJ Closed Lock Management - Case Reports

Internal derangement in temporomandibular joint (TMJ), including disc displacement without reduction with limited mouth opening, is a common TMJ disorder. The main symptoms of closed lock are limited mouth opening and pain in the affected TMJ. In such clinical cases, therapeutic management might be administered by physical therapy.

Using RFID technology to develop an intelligent equipment lock management system

The equipment lock has acted as an important tool for power companies to protect the electricity metering equipment. However, the conventional equipment lock has two potential problems: vandalism and counterfeiting. To fulfil the control and track the potential illegal behaviour, the human labour and paper are required to proceed with related operations, resulting in the consumption of a large amount of human resources and maintenance costs. This research focused on the design of RFID technology applied to the traditional equipment lock, with the mobile and electronic technology, we are able to strengthen the management/operating convenience of the lock and provide the solutions for anti-counterfeiting and spoilage detection, so that the national energy can be properly protected and fairly distributed. The integration of RFID data interface and mobile sensing devices will enhance the control of electricity meters and other metering devices for the power company, it will also provide accurate and mobile support with interactive mode, real-time display by the system, and real-time information services. It will serve as the 'last-mile' management tool for the electrical equipment and improve development of the intelligent electric grids.

Using RFID technology to develop an intelligent equipment lock management system

The equipment lock has acted as an important tool for power companies to protect the electricity metering equipment. However, the conventional equipment lock has two potential problems: vandalism and counterfeiting. To fulfil the control and track the potential illegal behaviour, the human labour and paper are required to proceed with related operations, resulting in the consumption of a large amount of human resources and maintenance costs. This research focused on the design of RFID technology applied to the traditional equipment lock, with the mobile and electronic technology, we are able to strengthen the management/operating convenience of the lock and provide the solutions for anti-counterfeiting and spoilage detection, so that the national energy can be properly protected and fairly distributed. The integration of RFID data interface and mobile sensing devices will enhance the control of electricity meters and other metering devices for the power company, it will also provide accurate and mobile support with interactive mode, real-time display by the system, and real-time information services. It will serve as the 'last-mile' management tool for the electrical equipment and improve development of the intelligent electric grids.

Performance Evaluation of the Asymmetric Distributed Lock Management in Cloud Computing

Performance Evaluation of the Asymmetric Distributed Lock Management in Cloud Computing

The Construction of Heterogeneous Platform of Unified Service System Based on Cloud Computing

The primary function of intelligent grid information platform is to realize the integration and the optimization of large-scale heterogeneous information and resources, and to provide the data center of resource intensive configuration for smart grid. The platform can set all the business systems together, assign tasks reasonably, and have high concurrent access, fault transfer, fault-tolerant mechanism, buffering mechanism and other functions with distributed lock Manager. It is a unified information platform to meet the modern smart grid.

Contention-aware lock scheduling for transactional databases

Lock managers are among the most studied components in concurrency control and transactional systems. However, one question seems to have been generally overlooked: "When there are multiple lock requests on the same object, which one(s) should be granted first?"Nearly all existing systems rely on a FIFO (first in, first out) strategy to decide which transaction(s) to grant the lock to. In this paper, however, we show that the lock scheduling choices have significant ramifications on the overall performance of a transactional system. Despite the large body of research on job scheduling outside the database context, lock scheduling presents subtle but challenging requirements that render existing results on scheduling inapt for a transactional database. By carefully studying this problem, we present the concept of contention-aware scheduling, show the hardness of the problem, and propose novel lock scheduling algorithms (LDSF and bLDSF), which guarantee a constant factor approximation of the best scheduling. We conduct extensive experiments using a popular database on both TPC-C and a microbenchmark. Compared to FIFO---the default scheduler in most database systems---our bLDSF algorithm yields up to 300x speedup in overall transaction latency. Alternatively, our LDSF algorithm, which is simpler and achieves comparable performance to bLDSF, has already been adopted by open-source community, and was chosen as the default scheduling strategy in MySQL 8.0.3+

The Resource Manager the ATLAS Trigger and Data Acquisition System

The Resource Manager is one of the core components of the Data Acquisition system of the ATLAS experiment at the LHC. The Resource Manager marshals the right for applications to access resources which may exist in multiple but limited copies, in order to avoid conflicts due to program faults or operator errors. The access to resources is managed in a manner similar to what a lock manager would do in other software systems. All the available resources and their association to software processes are described in the Data Acquisition configuration database. The Resource Manager is queried about the availability of resources every time an application needs to be started. The Resource Manager’s design is based on a client-server model, hence it consists of two components: the Resource Manager “server” application and the “client” shared library. The Resource Manager server implements all the needed functionalities, while the Resource Manager client library provides remote access to the “server” (i.e., to allocate and free resources, to query about the status of resources). During the LHC’s Long Shutdown period, the Resource Manager’s requirements have been reviewed at the light of the experience gained during the LHC’s Run 1. As a consequence, the Resource Manager has undergone a full re-design and re-implementation cycle with the result of a reduction of the code base by 40% with respect to the previous implementation. This contribution will focus on the way the design and the implementation of the Resource Manager could leverage the new features available in the C++11 standard, and how the introduction of external libraries (like Boost multi-container) led to a more maintainable system. Additionally, particular attention will be given to the technical solutions adopted to ensure the Resource Manager could effort the typical requests rates of the Data Acquisition system, which is about 30000 requests in a time window of few seconds coming from more than 1000 clients.

Automated Data Partitioning for Highly Scalable and Strongly Consistent Transactions

Modern transactional processing systems need to be fast and scalable, but this means many such systems settled for weak consistency models. It is however possible to achieve all of strong consistency, high scalability and high performance, by using fine-grained partitions and light-weight concurrency control that avoids superfluous synchronization and other overheads such as lock management. Independent transactions are one such mechanism, that rely on good partitions and appropriately defined transactions. On the downside, it is not usually straightforward to determine optimal partitioning schemes, especially when dealing with non-trivial amounts of data. Our work attempts to solve this problem by automating the partitioning process, choosing the correct transactional primitive, and routing transactions appropriately.