The present disclosure in general relates to technologies for processing data in a distributed data storage system, and more particularly, to a method, a system, and a computer program product for analytical processing of data by using the processing power of the distributed data storage system. In one embodiment, a system for analytical processing of data in a distributed data storage system is disclosed. The system comprises: a data extraction module configured to perform analytical operations to extract data from source databases in one or more data formats; and a processing module configured to perform data refinement operations to categorize the data while the data is being extracted. The processing module comprises: a mapping module configured to perform mapping operations of the categorized data; and a transformation module configured to perform an analytical transforming operation of the mapped categorized data to obtain a transformed categorized data.