Approximate estimation of transaction response time

This paper describes a study of different approximation techniques used to predict the response times of database transactions represented as patterns of resource consumption and modelled with non-product-form queueing networ ks. The techniques are applied to a range of examples. The experiments show that none of the approximation techniques has a consistent advantage over the others for all cases considered. On the other hand, a simple heuristic rule is formulated which provides an acceptable approximation to the averag e transaction response time for the entire range of examples. The rule spec ifies a procedure for labelling each queue in a queueing network as either an M/M/1 or an M/G/1 resource. The resulting network can then be solved to obtain the mean response time of individual transactions.