PMC: Select Materialized Cells in Data Cubes

QC-Trees is one of the most storage-efficient structures for data cubes in a MOLAP system. Although QC-Trees can achieve a high compression ratio, it is still a fully materialized data cube. In this paper, we present an improved structure PMC, which allow us to partially materialize cells in a QC-Trees. There is a sharp contrast between our partially materialization algorithm and other extensively studied materialized view selection algorithms. If a view is selected in a traditional algorithm, then all cells in this selected view are to be materialized. Our algorithm, however, selects and materializes data by cells. Experiments results show that PMC can further reduce storage space occupied by the data cube, and can shorten the time for update the cube. Along with further reduced space and update cost, our algorithm can ensure a stable query performance.

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