Optimistic concurrency control relies on end-of-transaction validation rather than lock acquisition prior to data accesses. Optimistic concurrency control is popular and various systems employ it based on a conviction that it increases concurrency, performance, and scalability. In contrast, we have concluded that optimistic concurrency control permits more concurrency than pessimistic concurren...

A CRDT is a data type whose operations commute when they are concurrent. Replicas of a CRDT eventually converge without any complex concurrency control. As an existence proof, we exhibit a non-trivial CRDT: a shared edit buffer called Treedoc. We outline the design, implementation and performance of Treedoc. We discuss how the CRDT concept can be generalised, and its limitations. Key-words: Dat...

Observing that it is impractical to use traditional methods to control concurrency in broadcast-based asymmetric communication environment, we introduce a concurrency control protocol designed for broadcast-based transaction processing called STUBcast (Server Timestamp and Update Broadcast Supported Concurrency). STUBcast supports two new correctness criteria proposed in this paper Single Seria...

A version control mechanism is proposed that enhances the modularity and extensibility of multiversion concurrency control algorithms. We decouple the multiversion algorithms into two components: version control and concurrency control. This permits modular development of multiversion protocols, and simplifies the task of proving the correctness of these protocols. A set of procedures for versi...

Adaptive indexing initializes and optimizes indexes incrementally, as a side effect of query processing. The goal is to achieve the benefits of indexes while hiding or minimizing the costs of index creation. However, index-optimizing side effects seem to turn readonly queries into update transactions that might, for example, create lock contention. This paper studies concurrency control in the ...

Ideas that are used in the design, development, and performance of concurrency control mechanisms have been summarized. The locking, time-stamp, optimistic-based mechanisms are included. The ideas of validation in optimistic approach are presented in some detail. The degree of concurrency and classes of serializability for various algorithms have been presented. Questions that relate arrival ra...

When independently executing processes share data, some form of concurrency control is needed to enforce the atomicity and sequencing constraints imposed by the program. We believe that concurrency control is hard largely because existing architectural support is inadequate. We define a new class of interconnection networks called isotach networks and explore isotach-based concurrency control b...

As the demand for ever larger knowledge bases grows knowledge base management techniques assume paramount importance In this paper we show that large multi user knowledge bases need concurrency control We discuss known techniques from database concurrency control and explain their inad equacies in the context of knowledge bases We o er a concurrency control algorithm called the Dynamic Directed...

The proliferation of shared mutable state in object-oriented programming complicates software development as two seemingly unrelated operations may interact via an alias and produce unexpected results. In concurrent programming this manifests itself as data-races. Concurrent objectoriented programming further suffers from the fact that code that warrants synchronisation cannot easily be disting...