Well some days back i was attending one of finest session ever attended on Business Intelligence. At very moment what i think that, i should document all the basic used in Business Intelligence as per the SharePoint 2010 is concern.
So what i have heard much in that session are these three words, MOLAP, ROLAP and HOLAP. I got the concept from that session. But in order to document it some where for the future, i googled it and found some good material. Below is the tabular information regarding all.
|MOLAP (Multidimensional Online Analytical Processing)||ROLAP (Relational Online Analytical Processing)||HOLAP (Hybrid Online Analytical Processing)|
|The MOLAP storage mode causes the aggregations of the partition and a copy of its source data to be stored in a multidimensional structure in Analysis Services when the partition is processed.||The ROLAP storage mode causes the aggregations of the partition to be stored in indexed views in the relational database that was specified in the partition’s data source.||The HOLAP storage mode combines attributes of both MOLAP and ROLAP. Like MOLAP, HOLAP causes the aggregations of the partition to be stored in a multidimensional structure in an SQL Server Analysis Services instance.|
|This MOLAP structure is highly optimized to maximize query performance. The storage location can be on the computer where the partition is defined or on another computer running Analysis Services. Because a copy of the source data resides in the multidimensional structure, queries can be resolved without accessing the partition’s source data.||Unlike the MOLAP storage mode, ROLAP does not cause a copy of the source data to be stored in the Analysis Services data folders. Instead, when results cannot be derived from the query cache, the indexed views in the data source are accessed to answer queries.||HOLAP does not cause a copy of the source data to be stored. For queries that access only summary data in the aggregations of a partition, HOLAP is the equivalent of MOLAP.|
|Query response times can be decreased substantially by using aggregations. The data in the partition’s MOLAP structure is only as current as the most recent processing of the partition.||Query response is generally slower with ROLAP storage than with the MOLAP or HOLAP storage modes. Processing time is also typically slower with ROLAP. However, ROLAP enables users to view data in real time and can save storage space when you are working with large datasets that are infrequently queried, such as purely historical data.||Queries that access source data—for example, if you want to drill down to an atomic cube cell for which there is no aggregation data—must retrieve data from the relational database and will not be as fast as they would be if the source data were stored in the MOLAP structure. With HOLAP storage mode, users will typically experience substantial differences in query times depending upon whether the query can be resolved from cache or aggregations versus from the source data itself.|