- HOLAP
HOLAP (Hybrid Online Analytical Processing) is a combination of
ROLAP andMOLAP which are other possible implementation ofOLAP . HOLAP allows to store part of the data in theMOLAP store and another part of the data inROLAP store. The degree of control that cube designer has over this partitioning varies from product to product.Vertical partitioning
In this mode HOLAP stores "aggregations" in
MOLAP for fast query performance, and detailed data inROLAP to optimize time of cube "processing".Horizontal partitioning
In this mode HOLAP stores some slice of data, usually the more recent one (i.e. sliced by Time dimension) in
MOLAP for fast query performance, and older data inROLAP . Moreover, we can store some dices inMOLAP and others inROLAP , leveraging the fact that in a large cuboid, there will be dense and sparse subregions [Owen Kaser and Daniel Lemire, [http://arxiv.org/abs/cs.DB/0702143 Attribute Value Reordering for Efficient Hybrid OLAP] , Information Sciences, Volume 176, Issue 16, pages 2279-2438, 2006. ] .Products
Examples of commercial products which support HOLAP storage mode are
Microsoft Analysis Services ,MicroStrategy andSAP AG BI Accelerator.Footnotes
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