Sampling Methods in Approximate Query Answering Systems

Sampling Methods in Approximate Query Answering Systems

Author: 
Das, Gautam
Place: 
Hershey
Publisher: 
IGI Global
Date published: 
2008
Editor: 
Wang, John
Journal Title: 
Encyclopedia of Data Warehousing and Mining, Second Edition
Source: 
Encyclopedia of Data Warehousing and Mining, Second Edition
Abstract: 

In recent years, advances in data collection and management technologies have led to a proliferation of very large databases. These large data repositories typically are created in the hope that, through analysis such as data mining and decision support, they will yield new insights into the data and the real-world processes that created them. In practice, however, while the collection and storage of massive datasets has become relatively straightforward, effective data analysis has proven more difficult to achieve. One reason that data analysis successes have proven elusive is that most analysis queries, by their nature, require aggregation or summarization of large portions of the data being analyzed. For multi-gigabyte data repositories, this means that processing even a single analysis query involves accessing enormous amounts of data, leading to prohibitively expensive running times. This severely limits the feasibility of many types of analysis applications, especially those that depend on timeliness or interactivity. While keeping query response times short is very important in many data mining and decision support applications, exactness in query results is frequently less important. In many cases, ballpark estimates are adequate to provide the desired insights about the data, at least in preliminary phases of analysis. For example, knowing the marginal data distributions for each attribute up to 10% error often will be enough to identify top-selling products in a sales database or to determine the best attribute to use at the root of a decision tree.

CITATION: Das, Gautam. Sampling Methods in Approximate Query Answering Systems edited by Wang, John . Hershey : IGI Global , 2008. Encyclopedia of Data Warehousing and Mining, Second Edition - Available at: https://library.au.int/sampling-methods-approximate-query-answering-systems