In version 4, Essbase would precalculate and store all four values. In Essbase 5, the Variance and Percent Variance values can be dynamically calculated on request, cutting the size of the hypercube in half and reducing hypercube calculation times proportionally while adding imperceptibly to query response times. Member values can also be dynamically calculated and stored so only the first requester suffers any response time penalty. The partitions are linked along their common, conformed dimensions to let end users drill across from one related dataset to another and create views that span multiple physical databases. The physical partitioning of Essbase cubes also lets you bring parallel processing technology to bear against the loading and aggregation of Essbase databases.
End users see the finished database as a single hypercube.
The real constraint has always been the amount of time required to aggregate the hypercube and write it out to disk versus the amount of time available to complete the job. In a typical single-processor Essbase 4 setup, the Essbase calculation engine writes out roughly 1GB per hour. Thus, a 50GB Essbase 4 hypercube took about two days to build. However, if you use dynamic calculations to cut the size of the hypercube in half and divide the remaining task among eight processors, Essbase 5 can comfortably build the same database within an overnight processing window. When the OLAP Council s APB-1 benchmark for OLAP server performance was first run with Essbase 4.1, the incremental data load and aggregate calculation portions of the benchmark took more than five hours.