Abstract
What-if analysis can provide more meaningful information than classical OLAP. Multi-scenario hypothesis based on historical data needs efficient what-if data view support. In general, delta table for what-if analysis is more general than other solutions such as query re-writing prototype of Sesame. Delta table is independent of base table and is more suitable to represent complex hypothetical updates and multi-version hypothetical updates. Due to low efficiency of traditional delta table merging algorithm which is based on set operation, there are few researches focus on delta table merging algorithm but on query re-writing algorithm. By analyzing the difference between what-if query and what-if analysis and improving the delta table merging algorithm, we propose novel algorithms without set operation of difference. Considering the feature of aggregate operations in OLAP analysis, pre-merge algorithm is presented without the generation of what-if data view before group-bys in the scenario of SUM, AVERAGE and COUNT function OLAP queries. In our experiments, the pre-merge algorithm greatly improved the efficiency of delta table merging procedure which is close to base group-by statement and superior to the re-writing algorithm. A complete comparison between all candidate delta table merging algorithms and re-writing algorithm with different what-if update conditions of update, deletion, insertion and mixed what-if updates is exhibited in our experiments, the policy of what-if analysis among different types is also discussed.
Supported by the National Natural Science Foundation of China under Grant No. 60473069,60496325; the joint research of HP Lab China and Information School of Renmin University(Large Scale Data Management);the joint research of Beijing Municipal Commission of education and Information School of Renmin University(Main Memory OLAP Server).
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References
Hurtado, C.A., Mendelzon, A.O., Vaisman, A.A.: Maintaining Data Cubes under Dimension Updates. In: Proc. workshop on DOLAP, pp. 60–66 (1999)
Balmin, A., et al.: Hypothetical Queries in an OLAP Environment. In: Proc. VLDB 2000, pp. 220–231 (2000)
Lee, K.Y., Kim, M.: Efficient Incremental Maintenance Of Data Cubes. In: Proc. VLDB 2006, pp. 823–833 (2006)
Witkowski, A., Bellamkonda, S., Bozkayz, T., Folkert, N., Gupta, A., Sheng, L., Subramanian, S.: Business Modeling Using SQL Spreadsheets. In: Proc. VLDB 2003, pp. 1117–1120 (2003)
Witkowski, A., Bellamkonda, S., Bozkayz, T., Naimat, A., Sheng, L., Subramanian, S., Waingold, A.: Query By Excel. In: Proc. VLDB 2005, pp. 1204–1215 (2005)
Lehner, W., Sidle, R., Pirahesh, H., Cochrane, R.: Maintenance Of Cube Automatic Summary Tables. In: Proc. SIGMOD, pp. 512–513 (2000)
Lakshmanan, L.V.S., Russakovsky, A., Sashikanth, V.: What-if OLAP Queries with Changing Dimensions. In: Proc. ICDE 2008 (2008)
Bebel, B., Eder, J., Koncilia, C., Morzy, T., Wrembel, R.: Creation And Management Of Versions In Multiversion Data Warehouse. In: Proceedings of the 2004 ACM symposium on Applied computing, Nicosia, Cyprus, pp. 717–723. ACM, NY (2004)
Morzy, T., Wrembel, R.: On Querying Versions Of Multiversion Data Warehouse. In: Proceedings of the 7th ACM international workshop on Data warehousing and OLAP, Washington, DC, USA, pp. 92–101. ACM, NY (2004)
Wang, S., Xiao, Y.-Q., Zhang, Y.-S., Chen, H.: Research on OLAP System Supporting What-if Analysis. Chinese Journal of Computers 31(9), 1573–1587 (2008)
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Zhang, Y., Zhang, Y., Xiao, Y., Wang, S., Chen, H. (2009). The Tradeoff of Delta Table Merging and Re-writing Algorithms in What-If Analysis Application. In: Li, Q., Feng, L., Pei, J., Wang, S.X., Zhou, X., Zhu, QM. (eds) Advances in Data and Web Management. APWeb WAIM 2009 2009. Lecture Notes in Computer Science, vol 5446. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-00672-2_24
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DOI: https://doi.org/10.1007/978-3-642-00672-2_24
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