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Long-lived Transaction
A long-lived transaction is a transaction that spans multiple database transactions. The transaction is considered "long-lived" because its boundaries must, by necessity of business logic, extend past a single database transaction. A long-lived transaction can be thought of as a sequence of database transactions grouped to achieve a single atomic result. A common example is a multi-step sequence of requests and responses of an interaction with a user through a web client. A long-lived transaction creates challenges of concurrency control and scalability. A chief strategy in designing long-lived transactions is optimistic concurrency control with versioning. See also *Long-running transaction Long-running transactions (also known as the saga interaction pattern) are computer database transactions that avoid lock (computer science), locks on non-local resources, use compensation to handle failures, potentially aggregate smaller ACID tran ... Data management Transaction proces ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Database Transaction
A database transaction symbolizes a unit of work, performed within a database management system (or similar system) against a database, that is treated in a coherent and reliable way independent of other transactions. A transaction generally represents any change in a database. Transactions in a database environment have two main purposes: # To provide reliable units of work that allow correct recovery from failures and keep a database consistent even in cases of system failure. For example: when execution prematurely and unexpectedly stops (completely or partially) in which case many operations upon a database remain uncompleted, with unclear status. # To provide isolation between programs accessing a database concurrently. If this isolation is not provided, the programs' outcomes are possibly erroneous. In a database management system, a transaction is a single unit of logic or work, sometimes made up of multiple operations. Any logical calculation done in a consistent mode in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 computing, concurrent operations are generated, while getting those results as quickly as possible. Computer systems, both software and computer hardware, hardware, consist of modules, or components. Each component is designed to operate correctly, i.e., to obey or to meet certain consistency rules. When components that operate concurrently interact by messaging or by sharing accessed data (in Computer memory, memory or Computer data storage, storage), a certain component's consistency may be violated by another component. The general area of concurrency control provides rules, methods, design methodologies, and Scientific theory, theories to maintain the consistency of components operating concurrently while interacting, and thus the consistency and correctness of the who ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scalability
Scalability is the property of a system to handle a growing amount of work by adding resources to the system. In an economic context, a scalable business model implies that a company can increase sales given increased resources. For example, a package delivery system is scalable because more packages can be delivered by adding more delivery vehicles. However, if all packages had to first pass through a single warehouse for sorting, the system would not be as scalable, because one warehouse can handle only a limited number of packages. In computing, scalability is a characteristic of computers, networks, algorithms, networking protocols, programs and applications. An example is a search engine, which must support increasing numbers of users, and the number of topics it indexes. Webscale is a computer architectural approach that brings the capabilities of large-scale cloud computing companies into enterprise data centers. In mathematics, scalability mostly refers to closure u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optimistic Concurrency Control
Optimistic concurrency control (OCC), also known as optimistic locking, is a concurrency control method applied to transactional systems such as relational database management systems and software transactional memory. OCC assumes that multiple transactions can frequently complete without interfering with each other. While running, transactions use data resources without acquiring locks on those resources. Before committing, each transaction verifies that no other transaction has modified the data it has read. If the check reveals conflicting modifications, the committing transaction rolls back and can be restarted. Optimistic concurrency control was first proposed by H. T. Kung and John T. Robinson. OCC is generally used in environments with low data contention. When conflicts are rare, transactions can complete without the expense of managing locks and without having transactions wait for other transactions' locks to clear, leading to higher throughput than other concurrency cont ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Version Control
In software engineering, version control (also known as revision control, source control, or source code management) is a class of systems responsible for managing changes to computer programs, documents, large web sites, or other collections of information. Version control is a component of software configuration management. Changes are usually identified by a number or letter code, termed the "revision number", "revision level", or simply "revision". For example, an initial set of files is "revision 1". When the first change is made, the resulting set is "revision 2", and so on. Each revision is associated with a timestamp and the person making the change. Revisions can be compared, restored, and, with some types of files, merged. The need for a logical way to organize and control revisions has existed for almost as long as writing has existed, but revision control became much more important, and complicated, when the era of computing began. The numbering of book editions ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Long-running Transaction
Long-running transactions (also known as the saga interaction pattern) are computer database transactions that avoid lock (computer science), locks on non-local resources, use compensation to handle failures, potentially aggregate smaller ACID transactions (also referred to as atomic transactions), and typically use a coordinator to complete or abort the transaction. In contrast to rollback (data management), rollback in ACID transactions, compensation restores the original state, or an equivalent, and is business-specific. For example, the compensating action for making a hotel reservation is canceling that reservation. A number of protocols have been specified for long-running transactions using Web services within business processes. OASIS Business Transaction Processing and WS-CAF are examples. These protocols use a coordinator to mediate the successful completion or use of compensation in a long-running transaction. See also *Optimistic concurrency control *Long-lived transact ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Data Management
Data management comprises all disciplines related to handling data as a valuable resource. Concept The concept of data management arose in the 1980s as technology moved from sequential processing (first punched cards, then magnetic tape) to random access storage. Since it was now possible to store a discrete fact and quickly access it using random access disk technology, those suggesting that data management was more important than business process management used arguments such as "a customer's home address is stored in 75 (or some other large number) places in our computer systems." However, during this period, random access processing was not competitively fast, so those suggesting "process management" was more important than "data management" used batch processing time as their primary argument. As application software evolved into real-time, interactive usage, it became obvious that both management processes were important. If the data was not well defined, the data wo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
