[[Cassandra - The Definitive Guide, (Revised) Third Edition]] p.93より引用。 >One design trap that many new users fall into is attempting to use Cassandra as a queue. Each item in the queue is stored with a timestamp in a wide partition. Items are appended to the end of the queue and read from the front, being deleted after they are read. This is a design that seems attractive, especially given its apparent similarity to the time series pattern. The problem with this approach is that the deleted items are now tombstones that Cassandra must scan past in order to read from the front of the queue. Over time, a growing number of tombstones begins to degrade read per‐ formance. We’ll discuss tombstones in Chapter 6. > >The queue anti-pattern serves as a reminder that any design that relies on the deletion of data is potentially a poorly performing design.