OLAP Query Processing for Partitioned Data Warehouses
نویسندگان
چکیده
On-line analytical processing (OLAP) queries can take hours or even days to execute on very large data warehouses. Therefore, there is a need to employ techniques that can facilitate efficient execution of these queries. Data partitioning concept that has been studied in the context of relational databases aims to reduce query execution time and facilitate the parallel execution of queries. In this paper, we develop a framework for applying the partitioning technique on DW schema (star schema) to reduce the total query execution cost. We develop an analytical cost model for executing a set of OLAP queries on a partitioned star schema. We conduct experiments to evaluate the utility of partitioning in efficiently executing OLAP queries. Finally,we show how partitioning can be used to facilitate parallel execution of OLAP queries.
منابع مشابه
Algorithms for data warehouse design to enhance decision-making
On-line analytical processing (OLAP) queries are strongly affected by the amount data needed to be accessed from the disk. Therefore, there is a need to employ techniques that can facilitate efficient execution of these queries. There has been a lot of work to optimize the performance of relational data warehouses. Among the two fragmentation techniques, vertical fragmentation is often consider...
متن کاملTop-k Queries in Uncertain OLAP Master Scholarly Paper
Top-k is the most important query type in OLAP, a common data warehouses model. Recently, OLAP was extended to represent data ambiguity, specifically imprecision and uncertainty. However, how to deal with top-k queries in uncertain OLAP still remains an unanswered question. This project introduces a solution for top-k query evaluation in uncertain OLAP including query semantic definition, query...
متن کاملTop-k Queries in Uncertain OLAP
Top-k is the most important query type in OLAP, the most common data warehouses model. Recently, OLAP was extended to represent data ambiguity, specifically imprecision and uncertainty. However, how to deal with top-k queries in uncertain OLAP still remain an unanswered question. This project introduces a complete solution for top-k query in uncertain OLAP including query semantic definition, q...
متن کاملRewriting OLAP Queries Using Materialized Views and Dimension Hierarchies in Data Warehouses
OLAP queries involve a lot of aggregations on a large amount of data in data warehouses. To process expensive OLAP queries efficiently, we propose a new method for rewriting a given OLAP query using various kinds of materialized aggregate views which already exist in data warehouses. We first define the normal forms of OLAP queries and materialized views based on the lattice of dimension hierar...
متن کاملAn Authorization Model for Data Warehouses and OLAP
In this paper we discuss a basic authorization model for data warehouses and OLAP offering greater expressiveness and highly increased usability with respect to security. Based on a simple formal notation we will show that access privileges can be expressed more intuitively than using SQL’s grant statements.
متن کامل