Earticle

초록

영어

At the moment many of modern relational databases support set valued attributes. Despite such attributes don’t fit in classical relational theory, they expands the possibilities of data storage and manipulation. Search query on set valued attribute can be represented in specific search predicates which can be easily expressed in set-theoretic operations. Accurate enough selectivity estimation for search predicates on set valued attributes is essential for query optimizer in the same way as selectivity estimation for regular search predicates. This paper introduces a probabilistic model for estimating selectivity of search predicates on set valued attributes. This model uses frequencies of set elements occurrences as well as histogram of set values cardinality. Parameters of the model are estimated during preliminary analysis of database contents. The model was implemented for array types of DBMS PostgreSQL, which are implementation of ordered set valued attributes. Experimental verification of this implementation showed that highly accurate selectivity estimation is provided on the basis of the proposed model.

목차

Abstract
 1. Introduction
 2. Proposed Model
 3. Selectivity Estimation
 4. Experimental Evaluation
 5. Conclusion
 References

키워드

저자

• Alexander Korotkov [ Postgres Professional 7A Dmitriya Ulyanova, Russia ]
• Konstantin Kudryavtsev [ National Research Nuclear University MEPhI 31, Russia ]

참고문헌

발행기관

간행물

표지보기 관심저널 등록

• 간행물명

  International Journal of Database Theory and Application

• 간기

  격월간

• pISSN

  2005-4270

• 수록기간

  2008~2016

• 십진분류

  KDC 505 DDC 605