We propose a multiversion concurrency control algorithm for real-time databases. Based on a priority cognitive algorithm commonly used in real-time processing, the proposed algorithm resolves data connicts among transactions in favor of the urgent transactions, i.e., those with higher priority. Our algorithm increases the degree of transaction concurrency while minimizing the transactions that ...

This work presents a model of a distributed database system which provides the framework to study the performance of timestamp ordering concurrency control. We exhibit an analytical solution, which has been tested with extensive simulation. The accuracy seems to be very high. We assume perfect and also imperfect clocks for synchronization and quantify the way in which local clock inaccuracies a...

Fast Path supports a variety of methods of concurrency control for a vanety 0/ different uses of data. This arose naturally out of efforts to meet the typical ner~ds of large on-line transaction processing businesses. The elements of "optimistic loeking" apply to one type of data, and "group commit" appLies to all types of data. Fast Path development ex.perience supports the idea that the use o...

Using the [LM] model for database concurrency control and recovery, we describe a general method for proving serial correctness of concurrency control algorithms which use timestamp ordering. This method is then used to prove serial correctness of Reed's [R] object history mechanism. Thesis Supervisor: Title: Nancy Lynch Professor of Computer Science, Massachusetts Institute of Technology

We present an eecient protocol for multi-version concurrency control in distributed databases. The protocol creates no more than three versions of any data item, while guaranteeing that (1) update transactions never interfere with read-only transactions, (2) the version advancement mechanism is completely asynchronous with (both update and read-only) user transactions, and (3) read-only transac...

Many researches in managing global transactions in multidatabase systems(MDBS) have been proposed to solve problems of ensuring the global serializability. In these method, a few opportunities are provided to the global transaction to execute concurrently. We concentrate our attention on 1) maintaining consistent database state that is defined by global integrity constraints and 2) investigatio...

Composition of software components via Web technologies, scalability demands, and Mobile Computing has led to a questioning of the classical transaction concept. Some researchers have moved away from a synchronous model with strict atomicity, consistency, isolation and durability (ACID) to an asynchronous, disconnected one with possibly weaker ACID properties. Ensuring consistency in disconnect...