Distributed concurrency control relates to the concurrency control of a system distributed over a computer network. In Computer science, especially in the fields of Computer programming (see also Concurrent programming, Parallel programming) Operating systems A computer network is a group of interconnected Computers. Networks may be classified according to a wide variety of characteristics
In database systems and transaction processing distributed concurrency control relates primarily to the concurrency control of a distributed database. A database management system ( DBMS) is Computer software designed for the purpose of managing Databases DBMSes may use any of a variety of Data models For other meanings see the disambiguation page at Transaction. A distributed database is a Database that is under the control of a central Database management system (DBMS in which storage devices are not all attached It also relates to the concurrency control in a multidatabase environment (federated database; see global concurrency control). A federated database system is a type of Meta-[[database management system]] (DBMS which transparently integrates multiple autonomous database systems into a single Global concurrency control typically pertains to the Concurrency control of a system comprising several components each with its own concurrency control A major goal for distributed concurrency control is serializability (or global serializability for multidatabase systems). In Databases and Transaction processing, a schedule (transaction history is Serializable, has the Serializability property if its In Databases ' and Transaction processing, global serializability is a property of a global schedule of Transactions. Distributed concurrency control poses special challenges beyond centralized one, primarily due to communication and computer latency. Latency is a time delay between the moment something is initiated and the moment one of its effects begins or becomes detectable It often requires special techniques, like distributed lock manager over fast computer networks with low latency, like switched fabric (e. A distributed lock manager (DLM provides distributed applications with a means to synchronize their accesses to shared resources A computer network is a group of interconnected Computers. Networks may be classified according to a wide variety of characteristics Switched fabric, switching fabric, or just fabric, is a Network topology where network nodes connect with each other via one or more Network switches g. , InfiniBand). InfiniBand is a Switched fabric communications link primarily used in High-performance computing.
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. In Databases and Transaction processing, two phase locking, ( 2PL) is a Concurrency control locking protocol mechanism that guarantees SS2PL provides both the serializability, strictness, and commitment ordering properties. In Databases and Transaction processing, a schedule (transaction history is Serializable, has the Serializability property if its In the field of Databases a schedule is a list of actions (ie In Databases ' and Transaction processing, Commitment ordering (or Commit ordering; CO is a Serializability technique Strictness, a special case of recoverability, is utilized for effective recovery from failure, and commitment ordering allows participating in a general solution for global serializability. In Databases and Transaction processing, a schedule (transaction history is Serializable, has the Serializability property if its In Databases ' and Transaction processing, global serializability is a property of a global schedule of Transactions. For large-scale distribution and complex transactions, distributed locking's typical heavy performance penalty (due to delays, latency) can be saved by using atomic commitment protocol (e. g. , 2PC, or a simpler one in a reliable system) together with local commitment ordering (e. In Computer networking and Databases the two-phase commit protocol (2PC is a Distributed algorithm that lets all nodes in a Distributed system In Databases ' and Transaction processing, Commitment ordering (or Commit ordering; CO is a Serializability technique g. , local SS2PL) instead of distributed locking, to achieve global serializability in the entire system. In Databases and Transaction processing, two phase locking, ( 2PL) is a Concurrency control locking protocol mechanism that guarantees In Databases ' and Transaction processing, global serializability is a property of a global schedule of Transactions. Such technique can be utilized for a large-scale parallel database, where a single large database, residing on many nodes and using a distributed lock manager, is replaced with a (homogeneous) multidatabase, comprising many relatively small databases, fitting each into a single node, together with some simple atomic commitment protocol (without using the distributed lock manager). A parallel Database system seeks to improve performance through Parallelization of various operations such as loading data building indexes and evaluating queries A distributed lock manager (DLM provides distributed applications with a means to synchronize their accesses to shared resources
See also
- Concurrency control
- Serializability
- SS2PL
- Distributed lock manager
- Distributed database
- Global concurrency control