HOME

TheInfoList



Click Here for Items Related To - Delta Consistency
OR:
Delta Consistency on:   [Wikipedia]   [Google]   [Amazon]

Delta 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 consistent and the results of readi ...
s used in the domain of
parallel programming Parallel computing is a type of computation in which many calculations or processes are carried out simultaneously. Large problems can often be divided into smaller ones, which can then be solved at the same time. There are several different for ...
, for example 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 memor ...
,
distributed transactions A distributed transaction is a database transaction in which two or more network hosts are involved. Usually, hosts provide transactional resources, while the transaction manager is responsible for creating and managing a global transaction that enc ...
, and
Optimistic replication Optimistic replication, also known as lazy replication, is a strategy for replication, in which replicas are allowed to diverge. Traditional pessimistic replication systems try to guarantee from the beginning that all of the replicas are identi ...
The delta consistency model states that an update will propagate through the system and all replicas will be
consistent In classical deductive logic, a consistent theory is one that does not lead to a logical contradiction. The lack of contradiction can be defined in either semantic or syntactic terms. The semantic definition states that a theory is consistent i ...
after a fixed time period δ. In other words, the result of any read operation is consistent with a read on the original copy of an object except for a (short) bounded interval after a modification. So basically, if you have an object which is modified, during the short period of time following its modification, the read will not be consistent. Then, after a fixed time period, the modification is propagated and the read will be consistent.


Sources

* Communication Systems: The State of the Art : IFIP 17th World Computer Congress, Lyman Chapin ed. 2002 Consistency models {{Compu-lang-stub