Learning Apache Cassandra - Second Edition

Precomputation versus read-time aggregation

Now we have a table that's optimized to aggregate our analytics data in a specific way. The advantage of this approach is that we can now answer questions about daily views very efficiently; the downside is that we need to create and maintain a table just to aggregate the data in this one way. Each time we record a view, we need to update both the status_update_views and daily_status_update_views tables. We can easily imagine dozens of different ways in which we might want to aggregate analytics data, each requiring its own purpose-built table, each needing to be updated when an observation is made.

Cassandra is well-suited to this sort of precomputed aggregation because of properties that we explored ...