HOLAP stands for Hybrid Online Analytical Processing. As the name suggests, it is a hybrid model consisting of two different types of OLAP, such as Relational Online Analytical Processing (ROLAP) and Multidimensional Online Analytical Processing (MOLAP). OLAP is nothing but a method applied form business intelligence activities, like Managing and Analyzing the data in the Data Warehouse systems. In a HOLAP-based Model, the system consists of tables and databases which are constructed using Relational and Multidimensional Database Management Systems. In other words, HOLAP permits to store data in both the relational type of databases and the multidimensional type of databases, with the use of its caching feature for a repeatedly used set of data and complex queries for multidimensional tables.
In a HOLAP system, the user can access the data from the relational database system and the multidimensional database system using simple queries for relational databases and complex aggregate queries for a multidimensional database. As the querying process is complex and the same queries can be reused on a multidimensional system, it is efficient to build a cached data server just for the aggregates and repeatedly fetch data from the relational database.
Technologies that use a combination of ROLAP and MOLAP are examples of HOLAP.