The Effect of Buffering on the Performance of R-Trees
نویسندگان
چکیده
ÐPast R-tree studies have focused on the number of nodes visited as a metric of query performance. Since database systems usually include a buffering mechanism, we propose that the number of disk accesses is a more realistic measure of performance. We develop a buffer model to analyze the number of disk accesses required for spatial queries using R-trees. The model can be used to evaluate the quality of R-tree update operations, such as various node splitting and tree restructuring policies, as measured by query performance on the resulting tree. We use our model to study the performance of three well-known R-tree loading algorithms. We show that ignoring buffer behavior and using number of nodes accessed as a performance metric can lead to incorrect conclusions, not only quantitatively, but also qualitatively. In addition, we consider the problem of how many levels of the R-tree should be pinned in the buffer. Index TermsÐAnalytical model, buffer model, multidimensional indexing, performance evaluation, R-tree.
منابع مشابه
Acute effect of calcium lactate supplementation intake on the performance and buffering capacity of elite amateur boxing athletes
This study aimed to assess the effects of acute calcium lactate supplementation intake on the performance and buffering capacity of elite amateur boxing athletes. 8 elite amateur boxers (180±4.33 cm, 24.12±3.68 years, Weight categories: -75, -64, -69, +81) were assigned to acutely receive calcium lactate (0.5 g, 80 mg calcium lactate/kg body weight) and placebo in a double-blind crossover desig...
متن کاملApplication of classification trees-J48 to model the presence of roach (Rutilus rutilus) in rivers
In the present study, classification trees (CTs-J48 algorithm) were used to study the occurrence of roach in rivers in Flanders (Belgium). The presence/absence of roach was modelled based on a set of river characteristics. The predictive performance of the CTs models was assessed based on the percentage of Correctly Classified Instances (CCI) and Cohen's kappa statistics. To find the best model...
متن کاملThe Effect of Cigarette Smoking on Human Sperm Creatine Kinase Activity: As An ATP Buffering System in Sperm
متن کامل
The response of blood buffering capacity and H+ regulation to three types of recovery during repeated high-intensity endurance training
Background/aim: Many studies were shown the effect of type's recovery on performance. Active recovery has been reported by some to promote greater exercise capacity, while others have not confirmed these results. The aim of this study was to determine the effect of three types of recovery during repeated high-intensity endurance training on blood buffering capacity and H+ regulation. Desig...
متن کاملAn Improvement in WRP Block Replacement Policy with Reviewing and Solving its Problems
One of the most important items for better file system performance is efficient buffering of disk blocks in main memory. Efficient buffering helps to reduce the widespeed gap between main memory and hard disks. In this buffering system, the block replacement policy is one of the most important design decisions that determines which disk block should be replaced when the buffer is full. To o...
متن کاملUse of classification tree methods to study the habitat requirements of tench (Tinca tinca) (L., 1758)
Classification trees (J48) were induced to predict the habitat requirements of tench (Tinca tinca). 306 datasets were used for the given fish during 8 years in the river basins in Flanders (Belgium). The input variables consisted of the structural-habitat (width, depth, gradient slope and distance from the source) and physic chemical (pH, dissolved oxygen, water temperature and electric conduct...
متن کامل