Applying OLAP Pre-Aggregation Techniques to ... - Jacobs University
Applying OLAP Pre-Aggregation Techniques to ... - Jacobs University
Applying OLAP Pre-Aggregation Techniques to ... - Jacobs University
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4 Answering Basic Aggregate Queries Using <strong>Pre</strong>-Aggregated Data 63<br />
4.1 Framework . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63<br />
4.1.1 <strong>Aggregation</strong> . . . . . . . . . . . . . . . . . . . . . . . . . . . 64<br />
4.1.2 <strong>Pre</strong>-<strong>Aggregation</strong> . . . . . . . . . . . . . . . . . . . . . . . . 64<br />
4.1.3 Aggregate Query and <strong>Pre</strong>-Aggregate Equivalence . . . . . . . 64<br />
4.2 Cost Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67<br />
4.2.1 Computing Queries from Raw Data . . . . . . . . . . . . . . 68<br />
4.2.2 Computing Queries from Independent and Overlapped <strong>Pre</strong>-<br />
Aggregates . . . . . . . . . . . . . . . . . . . . . . . . . . . 68<br />
4.2.3 Computing Queries from Dominant <strong>Pre</strong>-Aggregates . . . . . 69<br />
4.3 Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70<br />
4.4 Experimental Results . . . . . . . . . . . . . . . . . . . . . . . . . . 73<br />
4.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74<br />
5 <strong>Pre</strong>-<strong>Aggregation</strong> Support Beyond Basic Aggregate Operations 77<br />
5.1 Non-Standard Aggregate Operations . . . . . . . . . . . . . . . . . . 77<br />
5.2 Conceptual Framework . . . . . . . . . . . . . . . . . . . . . . . . . 78<br />
5.2.1 Lattice Representation . . . . . . . . . . . . . . . . . . . . . 79<br />
5.2.2 <strong>Pre</strong>-<strong>Aggregation</strong> Selection Problem . . . . . . . . . . . . . . 80<br />
5.3 <strong>Pre</strong>-Aggregates Selection . . . . . . . . . . . . . . . . . . . . . . . . 82<br />
5.3.1 Complexity Analysis . . . . . . . . . . . . . . . . . . . . . . 83<br />
5.4 Answering Scaling Operations Using <strong>Pre</strong>-Aggregated Data . . . . . . 83<br />
5.5 Experimental Results . . . . . . . . . . . . . . . . . . . . . . . . . . 85<br />
5.5.1 2D Datasets . . . . . . . . . . . . . . . . . . . . . . . . . . . 86<br />
5.5.2 3D Datasets . . . . . . . . . . . . . . . . . . . . . . . . . . . 91<br />
5.5.3 4D Datasets . . . . . . . . . . . . . . . . . . . . . . . . . . . 98<br />
5.6 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100<br />
6 Conclusion 103<br />
6.1 Future Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104