Strong consistency is one of the
consistency model
In computer science, a consistency model specifies a contract between the programmer and a system, wherein the system guarantees that if the programmer follows the rules for operations on memory, memory will be data consistency, consistent and th ...
s used in the domain of
concurrent programming
Concurrent means happening at the same time. Concurrency, concurrent, or concurrence may refer to:
Law
* Concurrence, in jurisprudence, the need to prove both ''actus reus'' and ''mens rea''
* Concurring opinion (also called a "concurrence"), a ...
(e.g., in
distributed shared memory
In computer science, distributed shared memory (DSM) is a form of memory architecture where physically separated memories can be addressed as a single shared address space. The term "shared" does not mean that there is a single centralized memo ...
,
distributed transactions
A distributed transaction operates within a Distributed computing, distributed environment, typically involving multiple nodes across a network depending on the location of the data. A key aspect of distributed transactions is Atomicity (programmin ...
).
The protocol is said to support strong consistency if:
# All accesses are seen by all parallel processes (or nodes, processors, etc.) in the same order (sequentially)
Therefore, only one consistent state can be observed, as opposed to
weak consistency
The name weak consistency can be used in two senses. In the first sense, strict and more popular, weak consistency is one of the consistency models used in the domain of concurrent programming (e.g. in distributed shared memory, distributed transac ...
, where different parallel processes (or nodes, etc.) can perceive variables in different states.
See also
*
CAP theorem
In database theory, the CAP theorem, also named Brewer's theorem after computer scientist Eric Brewer (scientist), Eric Brewer, states that any distributed data store can provide at most Inconsistent triad, two of the following three guarantees:
; ...
References
Consistency models
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