Determining the number of remote sites accessed in distributed transaction processing

The number of remote accesses and the number of distinct remote sites accessed by global transactions in a distributed database environment are characterized. Both measures are important in determining the overhead of distributed transaction processing and are affected by the distribution of transaction size (number of distinct objects accessed by a transaction) and the distribution of remote accesses made by a transaction. Keeping the mean transaction size fixed, it is shown that in the case of some commonly used distributions for the number of remote accesses variable size transactions access fewer distinct remote sites on the average than fixed size transactions. Also, for these and some other distributions the mean number of remote accesses is independent of the distribution of transaction size, but this is not generally true