Hf. Korth et G. Speegle, FORMAL ASPECTS OF CONCURRENCY-CONTROL IN LONG-DURATION TRANSACTION SYSTEMS USING THE NT PV MODEL/, ACM transactions on database systems, 19(3), 1994, pp. 492-535
Citations number
42
Categorie Soggetti
Computer Sciences","Computer Science Information Systems","Computer Science Software Graphycs Programming
In the typical database system, an execution is correct if it is equiv
alent to some serial execution. This criterion, called serializability
, is unacceptable for new database applications which require long-dur
ation transactions. We present a new transaction model which allows co
rrectness criteria more suitable for these applications. This model co
mbines three enhancements to the standard model: nested transactions,
explicit predicates, and multiple versions. These features yield the n
ame of the new model, nested transactions with predicates and versions
, or NT/PV. The modular nature of the NT/PV model allows a straightfor
ward representation of simple systems. It also provides a formal frame
work for describing complex interactions. The most complex interaction
s the model allows can be captured by a protocol which exploits all of
the semantics available to the NT/PV model. An example of these inter
actions is shown in a CASE application. The example shows how a system
based on the NT/PV model is superior to both standard database techni
ques and unrestricted systems in both correctness and performance.