Evaluation of Bitmap Index Compression using Data Pump in Oracle Database

Abstract

Bitmap index is most commonly used technique for efficient query processing and mostly in the Data warehouse environment. We review the existing technologies of Compression and introduce the bitmap index compression through data pump. According to conventional wisdom bitmap index is more efficient for minimum unique value. But through data pump it doesn't require either bitmap index is created on high degree of cardinality or low degree of cardinality. In this paper, we propose data pump utility for release the disk space in database after deletion of records. Bitmap index point the old location even after deletion of records from table, This utility doesn't release disk space. We have implemented data pump for compression, to release the space and change the index pointing location. Data pump which is often used for logical backups in oracle database. Finally we review the bitmap index which commonly used for industrial purpose and discuss open issues for future evolution and development.