The widening performance gap between CPU and disk is significant for hash join performance. Most current hash join methods try t o reduce the volume of data transferred between memory and disk. In this paper, we try to reduce hash-join times b y reducing random I/O. We study how current algorithms incur random I/O, and propose a new hash join method, Seq+, that converts much of the random 1/0 t...

This paper presents an improved parallel hash-based join algorithm on a hypercube computer in the presence of double skew. We describe a load balancing technique to evenly distribute both join relations across all processors in order to deal with double skew eeectively. Moreover, we propose a permutation join method which reduces main memory requirement for the local join operation in the previ...

Mini-Bucket Elimination (MBE) is a well-known approximation algorithm deriving lower and upper bounds on quantities of interest over graphical models. It relies on a procedure that partitions a set of functions, called bucket, into smaller subsets, called mini-buckets. The method has been used with a single partitioning heuristic throughout, so the impact of the partitioning algorithm on the qu...

Histograms have long been used to capture attribute value distribution statistics for query optimizers. More recently, there has been a growing interest in the use of histograms to produce quick approximate answers to decision support queries. This motivates nding good strategies for specifying histogram buckets. Under the assumption that nding optimal bucket boundaries is computationally ineec...

In this paper, we present a hierarchical clustering algorithm of the large text datasets using Locality-Sensitive Hashing (LSH). The main idea of the LSH is to “hash” items several times, in such a way that similar items are more likely to be hashed to the same bucket than dissimilar are. The main drawback of the conventional hierarchical algorithms is a large time complexity (e.g. Single Linka...

This paper considers a dairy industry problem on integrated planning and scheduling of set yoghurt production. A mixed integer linear programming formulation is introduced to integrate tactical and operational decisions and a heuristic approach is proposed to decompose time buckets of the decisions. The decomposition heuristic improves computational efficiency by solving big bucket planning and...

Data structures, such as hash tables, are often accessed from within critical sections in multi-threaded environments in order to preserve data integrity. The extent of mutual exclusion greatly affects the performance by limiting the level of achievable parallelism. Increasing the resolution of locking allows higher throughput at the cost of increased memory use with all its side effects. Highl...

We consider a model for generating a random graph using the configuration model. In the configuration model, each node draws a degree independently from a marginal degreed distribution and endpoints pair randomly. We establish non-trivial bounds on the expected sizes of “buckets” for large graphs. We define nodes i and j in a graph as neighbors if they share an edge, and we define the “bucket” ...

The widening performance gap between CPU and disk is signiicant for hash join performance. Most current hash join methods try to reduce the volume of data transferred between memory and disk. In this paper , we try to reduce hash-join times by reducing random I/O. We study how current algorithms incur random I/O, and propose a new hash join method, Seq + , that converts much of the random I/O t...