Cassandra
MentionedDatabase
Also known as: Apache Cassandra
Distributed NoSQL database built for high availability and massive write volumes.
Cassandra, explained
Written by EduVerseWhat it is
Apache Cassandra is an open-source, distributed NoSQL database. It spreads data across many servers (nodes) and copies each piece to several of them, without a single main server in charge. You query it with CQL, which resembles SQL, but you design tables around the exact queries you plan to run.
Why teams use it
Some systems face a constant flood of writes, such as sensor readings or activity events, and can’t afford downtime. Cassandra scales by adding nodes and keeps running when some of them fail. You give up joins and flexible queries, so for a typical web app PostgreSQL is usually the simpler choice.
An example from work
You join a team that stores sensor readings in Cassandra and write a query that filters on a column outside the primary key. cqlsh rejects it with an error that mentions ALLOW FILTERING. That’s when you learn each table is shaped for specific queries, and a new question often needs a new table.
Our own explanation, not a quote from the book.
In the book
Sentences from The Software Realm, Decoded that mention Cassandra, exactly as printed.
1 more passages about Cassandra in the full book
Read every conversation where Cassandra comes up, with the interactive slides and demos.
Where it fits
Time-series data, IoT, very large distributed datasets
Coverage in the book
Mentioned as part of the wider landscape, without in-depth coverage.
