Journal of KIISE:Databases (한국정보과학회논문지:데이타베이스)

Korean Institute of Information Scientists and Engineers (한국정보과학회)
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An Efficient ROLAP Cube Generation Scheme

효율적인 ROLAP 큐브 생성 방법

  • 김명 (이화여자대학교 컴퓨터학과) ;
  • 송지숙 (이화여자대학교 컴퓨터학과)
  • Published : 2002.04.01
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Abstract

ROLAP(Relational Online Analytical Processing) is a process and methodology for a multidimensional data analysis that is essential to extract desired data and to derive value-added information from an enterprise data warehouse. In order to speed up query processing, most ROLAP systems pre-compute summary tables. This process is called 'cube generation' and it mostly involves intensive table sorting stages. (1) showed that it is much faster to generate ROLAP summary tables indirectly using a MOLAP(multidimensional OLAP) cube generation algorithm. In this paper, we present such an indirect ROLAP cube generation algorithm that is fast and scalable. High memory utilization is achieved by slicing the input fact table along one or more dimensions before generating summary tables. High speed is achieved by producing summary tables from their smallest parents. We showed the efficiency of our algorithm through experiments.

ROLAP(Relational Online Analytical Processing)은 다차원적 데이타 분석을 위한 제반 기술로써, 전사적 데이타 웨어하우스로부터 고부가가치를 창출하는데 필수적인 기술이다. 질의처리 성능을 높이기 위해서 대부분의 ROLAP 시스템들은 집계 테이블들을 미리 계산해 둔다. 이를 큐브 생성이라고 하며, 이 과정에서 기존의 방법들은 데이타를 여러 차례 정렬해야 하고 이는 큐브 생성의 성능을 저하시키는 큰 요인이다. (1)은 MOLAP 큐브 생성 알고리즘을 통해 간접적으로 ROLAP 큐브를 생성하는 것이 훨씬 빠르다는 것을 보였다. 본 연구에서도 MOLAP 큐브 생성 알고리즘을 사용한 신속하고 확장적인 ROLAP 큐브 생성 알고리즘을 제시하였다. 분석할 입력 사실 테이블을 적절하게 조각내어 메모리 효율을 높였고, 집계 테이블들을 최소 부모 집계 테이블로부터 생성하도록 하여 큐브 생성 시간을 단축하였다. 제안한 방법의 효율성은 실험을 통해 검증하였다.

Keywords

References

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