Online maintenance of very large random samples

  • Authors:

  • Christopher Jermaine;Abhijit Pol;Subramanian Arumugam

  • Affiliations:

  • University of Florida, Gainesville, FL;University of Florida, Gainesville, FL;University of Florida, Gainesville, FL

  • Venue:
  • SIGMOD '04 Proceedings of the 2004 ACM SIGMOD international conference on Management of data
  • Year:
  • 2004

Quantified Score

Hi-index 0.00

Visualization

Abstract

Random sampling is one of the most fundamental data management tools available. However, most current research involving sampling considers the problem of how to use a sample, and not how to compute one. The implicit assumption is that a "sample" is a small data structure that is easily maintained as new data are encountered, even though simple statistical arguments demonstrate that very large samples of gigabytes or terabytes in size can be necessary to provide high accuracy. No existing work tackles the problem of maintaining very large, disk-based samples from a data management perspective, and no techniques now exist for maintaining very large samples in an online manner from streaming data. In this paper, we present online algorithms for maintaining on-disk samples that are gigabytes or terabytes in size. The algorithms are designed for streaming data, or for any environment where a large sample must be maintained online in a single pass through a data set. The algorithms meet the strict requirement that the sample always be a true, statistically random sample (without replacement) of all of the data processed thus far. Our algorithms are also suitable for biased or unequal probability sampling.