<p>We study the problem of scheduling applications composed of a large number of tasks on heterogeneous clusters. Tasks are identical, independent from each other, and can hence be computed in any order. The goal is to execute all the tasks as quickly as possible. We use the Master-Worker paradigm, where tasks are maintained by the master which will hand out batches of a variable amount of tasks to requesting workers. We introduce a new scheduling strategy, the Monitor strategy, and compare it to other strategies suggested in the literature. An image filtering application, known as matched filtering, has been used to compare the different strategies. Our implementation involves datastaging techniques in order to circumvent the possible bottleneck incurred by the master, and multi-threading to prevent possible processor idleness.</p>

CONTENTS vi Title: Implementation of parallel query processing in PostgreSQL Author: Bc. Daniel Vojtek Department: Department of Software Engineering Supervisor: Mgr. Július Štroffek Supervisor's e-mail address: julo@stroffek.cz Abstract: Parallel query processing can help with processing of huge amounts of data stored in database systems. The aim of this diploma the- sis was to explore the possibilities, analyze, design and finally implement parallel query processing in open source database system PostgreSQL. I used a Master/Worker design pattern, in which standard PostgreSQL backend process is a master. As workers I used processes created from postmaster. In the thesis I focused on preparing an infrastructure nec- essary for parallel processing. I defined a new top level memory context over shared memory, which allows efficient and convenient memory al- locations. Then I implemented creation of new worker processes, based on master process requirements. To be able to control these workers I defined controlling structures using state machines. Then I implemented parallel sort operation and SQL operator UNION ALL using this infras- tructure. The result of this diploma thesis is not only implementation of infrastructure and some parallel operations, but also description of the problems encountered during the...