Distributed concurrency control is the

concurrency control In information technology and computer science, especially in the fields of computer programming, operating systems, multiprocessors, and databases, concurrency control ensures that correct results for concurrent operations are generated, whil ...

of a system

distributed Distribution may refer to: Mathematics *Distribution (mathematics), generalized functions used to formulate solutions of partial differential equations *Probability distribution, the probability of a particular value or value range of a varia ...

over a

computer network A computer network is a collection of communicating computers and other devices, such as printers and smart phones. In order to communicate, the computers and devices must be connected by wired media like copper cables, optical fibers, or b ...

( Bernstein et al. 1987, Weikum and Vossen 2001). In ''

database systems In computing, a database is an organized collection of Data (computing), data or a type of data store based on the use of a database management system (DBMS), the software that interacts with end users, Application software, applications, and ...

'' and ''

transaction processing In computer science, transaction processing is information processing that is divided into individual, indivisible operations called ''transactions''. Each transaction must succeed or fail as a complete unit; it can never be only partially c ...

'' (''transaction management'') distributed concurrency control refers primarily to the concurrency control of a

distributed database A distributed database is a database in which data is stored across different physical locations. It may be stored in multiple computers located in the same physical location (e.g. a data centre); or maybe dispersed over a computer network, netwo ...

. It also refers to the concurrency control in a multidatabase (and other multi-transactional object) environment (e.g.,

federated database A federated database system (FDBS) is a type of meta-database management system (DBMS), which transparently maps multiple autonomous database systems into a single federated database. The constituent databases are interconnected via a computer ne ...

grid computing Grid computing is the use of widely distributed computer resources to reach a common goal. A computing grid can be thought of as a distributed system with non-interactive workloads that involve many files. Grid computing is distinguished fro ...

, and

cloud computing Cloud computing is "a paradigm for enabling network access to a scalable and elastic pool of shareable physical or virtual resources with self-service provisioning and administration on-demand," according to International Organization for ...

environments. A major goal for distributed concurrency control is distributed

serializability In the fields of databases and transaction processing (transaction management), a schedule (or history) of a system is an abstract model to describe the order of executions in a set of transactions running in the system. Often it is a ''list'' o ...

(or global serializability for multidatabase systems). Distributed concurrency control poses special challenges beyond centralized one, primarily due to communication and computer latency. It often requires special techniques, like

distributed lock manager A distributed lock manager (DLM) runs in every machine in a cluster, with an identical copy of a cluster-wide lock database. Operating systems use lock managers to organise and serialise the access to resources. In this way a DLM provides software ...

over fast

s with low latency, like switched fabric (e.g.,

InfiniBand InfiniBand (IB) is a computer networking communications standard used in high-performance computing that features very high throughput and very low latency. It is used for data interconnect both among and within computers. InfiniBand is also used ...

). The most common distributed concurrency control technique is ''strong strict two-phase locking'' ( SS2PL, also named ''rigorousness''), which is also a common centralized concurrency control technique. SS2PL provides both the ''serializability'' and '' strictness''. Strictness, a special case of recoverability, is utilized for effective recovery from failure. For large-scale distribution and complex transactions, distributed locking's typical heavy performance penalty (due to delays, latency) can be saved by using the atomic commitment protocol, which is needed in a distributed database for (distributed) transactions' atomicity.

References

* Philip A. Bernstein, Vassos Hadzilacos, Nathan Goodman (1987)
''Concurrency Control and Recovery in Database Systems''
Addison Wesley Publishing Company, 1987, * Gerhard Weikum, Gottfried Vossen (2001)
''Transactional Information Systems''
Elsevier, {{ISBN, 1-55860-508-8 Data management Distributed computing problems Databases Concurrency control Transaction processing

See also

References