Cassandra Design Patterns - Second Edition

Aggregation pattern

Design separate Cassandra column families to store the aggregated and summarized operational data. Aggregated data is used for various reporting and analytical purposes. Cassandra does not inherently support any joins between column families. Cassandra does not support the commonly seen SQL aggregation constructs such as GROUP BY, HAVING, and so on. Because of these constraints, it is better to preprocess the operational data to do the aggregation, summarization, and storage of the processed data in Cassandra column families. The lack of ability to do real-time aggregation using CQL can be converted to an advantage of using Cassandra, which is serving fast reads of already aggregated data and exploiting its highly scalable ...