Strict Serializable Multidatabase Certification with Out-of-Order Updates

Multi-phase atomic commitment protocols require long-lived resource locks on the participants and introduce blocking behaviour at the coordinator. They are also pessimistic in nature, preventing reads from executing concurrently with writes. Despite their known shortfalls, multi-phase protocols are the mainstay of transactional integration between autonomous, federated systems. This paper presents a novel atomic commitment protocol, STRIDE (Speculative Transactions in Decentralised Environments), that offers strict serializable certification of distributed transactions across autonomous, replicated sites. The protocol follows the principles of optimistic concurrency control, operating on the premise that conflicting transactions are infrequent. When they do occur, conflicting transactions are identified through antidependency testing on the certifier, which may be replicated for performance and availability. The majority of transactions can be certified entirely in memory. Unlike its multi-phase counterparts, STRIDE is nonblocking, decentralised and does not mandate the use of long-lived resource locks on the participants. It also offers a flexible isolation model for read-only transactions, which can be served directly from the participant sites without undergoing certification. Also, update transactions are Φ-serializable, making the certifier immune to the recently disclosed logical timestamp skew anomaly.

Strict Serializable Multidatabase Certification with Out-of-Order Updates

Multi-phase atomic commitment protocols require long-lived resource locks on the participants and introduce blocking behaviour at the coordinator. They are also pessimistic in nature, preventing reads from executing concurrently with writes. Despite their known shortfalls, multi-phase protocols are the mainstay of transactional integration between autonomous, federated systems. This paper presents a novel atomic commitment protocol, STRIDE (Speculative Transactions in Decentralised Environments), that offers strict serializable certification of distributed transactions across autonomous, replicated sites. The protocol follows the principles of optimistic concurrency control, operating on the premise that conflicting transactions are infrequent. When they do occur, conflicting transactions are identified through antidependency testing on the certifier, which may be replicated for performance and availability. The majority of transactions can be certified entirely in memory. Unlike its multi-phase counterparts, STRIDE is nonblocking, decentralised and does not mandate the use of long-lived resource locks on the participants. It also offers a flexible isolation model for read-only transactions, which can be served directly from the participant sites without undergoing certification. Also, update transactions are Φ-serializable, making the certifier immune to the recently disclosed logical timestamp skew anomaly.

Strict Serializable Multidatabase Certification with Out-of-Order Updates

Multi-phase atomic commitment protocols require long-lived resource locks on the participants and introduce blocking behaviour at the coordinator. They are also pessimistic in nature, preventing reads from executing concurrently with writes. Despite their known shortfalls, multi-phase protocols are the mainstay of transactional integration between autonomous, federated systems. This paper presents a novel atomic commitment protocol, STRIDE (Serializable Transactions in Decentralised Environments), that offers strict serializable certification of distributed transactions across autonomous, replicated sites. The protocol follows the principles of optimistic concurrency control, operating on the premise that conflicting transactions are infrequent. When they do occur, conflicting transactions are identified through antidependency testing on the certifier, which may be replicated for performance and availability. The majority of transactions can be certified entirely in memory. Unlike its multi-phase counterparts, STRIDE is nonblocking, decentralised and does not mandate the use of long-lived resource locks on the participants. It also offers a flexible isolation model for read-only transactions, which can be served directly from the participant sites without undergoing certification. Also, update transactions are Φ-serializable, making the certifier immune to the recently disclosed logical timestamp skew anomaly.

Strict Serializable Multidatabase Certification with Out-of-Order Updates

Multi-phase atomic commitment protocols require long-lived resource locks on the participants and introduce blocking behaviour at the coordinator. They are also pessimistic in nature, preventing reads from executing concurrently with writes. Despite their known shortfalls, multi-phase protocols are the mainstay of transactional integration between autonomous, federated systems. This paper presents a novel atomic commitment protocol, STRIDE (Serializable Transactions in Decentralised Environments), that offers strict serializable certification of distributed transactions across autonomous, replicated sites. The protocol follows the principles of optimistic concurrency control, operating on the premise that conflicting transactions are infrequent. When they do occur, conflicting transactions are identified through antidependency testing on the certifier, which may be replicated for performance and availability. The majority of transactions can be certified entirely in memory. Unlike its multi-phase counterparts, STRIDE is nonblocking, decentralised and does not mandate the use of long-lived resource locks on the participants. It also offers a flexible isolation model for read-only transactions, which can be served directly from the participant sites without undergoing certification. Also, update transactions are Φ-serializable, making the certifier immune to the recently disclosed logical timestamp skew anomaly.

RESEARCH OF ACID TRANSACTION IMPLEMENTATION METHODS FOR DISTRIBUTED DATABASES USING REPLICATION TECHNOLOGY

Today, databases are an integral part of most modern applications designed to store large amounts of data and to request from many users. To solve business problems in such conditions, databases are scaled, often horizontally on several physical servers using replication technology. At the same time, many business operations require the implementation of transactional compliance with ACID properties. For relational databases that traditionally support ACID transactions, horizontal scaling is not always effective due to the limitations of the relational model itself. Therefore, there is an applied problem of efficient implementation of ACID transactions for horizontally distributed databases. The subject matter of the study is the methods of implementing ACID transactions in distributed databases, created by replication technology. The goal of the work is to increase the efficiency of ACID transaction implementation for horizontally distributed databases. The work is devoted to solving the following tasks: analysis and selection of the most relevant methods of implementation of distributed ACID transactions; planning and experimental research of methods for implementing ACID transactions by using of NoSQL DBMS MongoDB and NewSQL DBMS VoltDB as an example; measurements of metrics of productivity of use of these methods and formation of the recommendation concerning their effective use. The following methods are used: system analysis; relational databases design; methods for evaluating database performance. The following results were obtained: experimental measurements of the execution time of typical distributed transactions for the subject area of e-commerce, as well as measurements of the number of resources required for their execution; revealed trends in the performance of such transactions, formed recommendations for the methods studied. The obtained results allowed to make functions of dependence of the considered metrics on loading parameters. Conclusions: the strengths and weaknesses of the implementation of distributed ACID transactions using MongoDB and VoltDB were identified. Practical recommendations for the effective use of these systems for different types of applications, taking into account the resources consumed and the types of requests.

Chiller

Distributed transactions on high-overhead TCP/IP-based networks were conventionally considered to be prohibitively expensive. In fact, the primary goal of existing partitioning schemes is to minimize the number of cross-partition transactions. However, with the new generation of fast RDMAenabled networks, this assumption is no longer valid. In this paper, we first make the case that the new bottleneck which hinders truly scalable transaction processing in modern RDMA-enabled databases is data contention, and that optimizing for data contention leads to different partitioning layouts than optimizing for the number of distributed transactions. We then present Chiller, a new approach to data partitioning and transaction execution, which aims to minimize data contention for both local and distributed transactions.

Block-Chain-Based Security and Privacy in Smart City IoT

The current technology has given arms, hands, and wings to the smart objects-internet of things, which create the centralized data collection and analysis nightmare. Even with the distributed big data-enabled computing, the relevant data filtering for the localized decisions take a long time. To make the IOT data communication smoother and make the devices talk to each other in a coherent way the device data transactions are made to communicate through the block chain, and the applications on the localized destination can take the decisions or complete transaction without the centralized hub communication. This chapter focuses on adding vendor-specific IOT devices to the public or private block chain and the emerging challenges and the possible solutions to make the devices talk to each other and have the decision enablement through the distributed transactions through the block chain technology.